record count - Page 163

Why won't Webmaster Tools let me set a preferred domain? (says to verify, but it should already be)

- by Su'

I've got a domain that I apparently forgot to set a preferred domain for, so I just tried to do it. Webmaster Tools instead popped up a little box: Part of the process of setting a preferred domain is to verify that you own http://www.example.com/. Please verify http://www.example.com/. I'm running into some problems following these instructions: As far as I can tell I already did verify sometime in the past. There's a TXT DNS record with the gibberish Google tells you to set for it that I couldn't have come up with myself. …and nothing is telling me this information is bad. So let's assume the site is somehow not actually verified. All the various methods' instructions start with "click the Manage Site button next to the site you want, and then click Verify this site." That button doesn't even exist on my screens. (It presumably goes away when you successfully verify?) Those instructions were all updated pretty recently, and the DNS one in particular just a couple weeks ago so it seems a bit unlikely they're inaccurate. I am not using Apps, and won't be, so can't try out the verification through there. Note that I also have another domain that I have not done any verification for which is showing the same behavior(no such button, being told to verify when it seems impossible etc.) so something appears to just be broken. I already have a no-www process in place server-side, so we can skip that. I'm just trying to get the box checked off in GWT. If I don't get any resolution, I'll eventually scrap the TXT record and see if the site gets un-verified(or whatever since it thinks it isn't), and see if I can just restart the process. It's not urgent so I'm just trying to figure out if I've gone blind to something or what. Did the button move?

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Problem in domain name of site in google search [on hold]

- by Jayadratha Mondal

My domain provider dont supports advanced DNS at this moment. So I have used iframe to forward to my webserver. Suppose my domain abc.com have a simple html which is opening xyz.com via Iframe. Google was showing abc.com on the search. But from last two days it is showing xyz.com, other things like description, name of the site are ok only the domain changed to xyz.com, but I want to show abc.com. When I'm typing the full domain then google showing the domain as I want. But If I type a part or any keyword then it showing that xyz.com. Anyone have any idea how to show abc.com again? EDIT: I dont know the domain name provider because its not mine. When I'm trying to set new A record its showing that "you need advanced dns to do this currently you are using simple DNS". I'm doing this from cpanel. Normally as per I know there are 3 sections. 1 domain name 2 A record 3Cname. But I dont have any domain name section.

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After installing Ubuntu my computer boots into GRUB rescue mode after displaying 'no such partition' error message.

- by VictorVictor5

I wanted Ubuntu on my Gateway Solo Laptop. It had Win98 on the C:\ and WinXP on the D:\. Before the install, I could not boot from CD, but I could boot from floppy. I installed Ubuntu to run alongside Windows XP as that was one of the options. It didn't detect Win98, but I swear it's on there. Install seemed fine and then it asked me to reboot. When I rebooted, I got the message error: no such partition and the grub rescue> command prompt. I've looked around, but some commands, like sudo, don't work. One command I did get to work was set root=(hd0,0) if that helps. I'm a noob, and it was a pain installing Win98 and XP since this system is so old. I don't want to wipe my drive and start all over! Additional details copied from comments Addendum, I restored my master boot record via my Win98 boot floppy and typing in frisk /mbr. But, I'd still like to get ubuntu - any help? If I restored my master boot record - did I delete Ubuntu?

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One email user keeps disconnecting from our exchange server

- by Funky Si

I have one user who keeps reporting that Outlook keeps disconnecting from our email server. All other users are fine. Our email server is running Exchange 2010 and the client is running Outlook 2003. The disconnection only lasts a moment. I have checked for logs on the client and Exchange server and can not see any reason for the disconnect, On the Client I get EventId 26 telling me Outlook has disconnected and reconnected but no reason why. Can anyone give me some suggestions of things to try and track down where the problem could be? --Update-- I have found the following log file C:\Program Files\Microsoft\Exchange Server\V14\Logging\RPC Client Access which suggests that it is a problem with RPC sessions. Excerpt is below 2013-01-31T15:21:24.015Z,6413,15,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,0,00:00:00,"BS=Conn:24,HangingConn:0,AD:$null/$null/0%,CAS:$null/$null/2%,AB:$null/$null/0%,RPC:$null/$null/1%,FC:$null/0,Policy:ClientThrottlingPolicy2,Norm[Resources:(Mdb)Mailbox Database 0765959540(Health:-1%,HistLoad:0),(Mdb)Public Folder Database 1945427388(Health:-1%,HistLoad:0),];GC:6/1/0;", 2013-01-31T15:21:24.015Z,6413,16,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,PublicLogoff,0,00:00:00,LogonId: 1, 2013-01-31T15:21:24.015Z,6413,16,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,,00:00:00,"BS=Conn:24,HangingConn:0,AD:$null/$null/0%,CAS:$null/$null/2%,AB:$null/$null/0%,RPC:$null/$null/1%,FC:$null/0,Policy:ClientThrottlingPolicy2,Norm[Resources:(Mdb)Mailbox Database 0765959540(Health:-1%,HistLoad:0),(Mdb)Public Folder Database 1945427388(Health:-1%,HistLoad:0),];GC:6/1/0;", 2013-01-31T15:21:24.015Z,6417,5,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,OwnerLogoff,0,00:00:00,LogonId: 0, 2013-01-31T15:21:24.015Z,6417,5,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,0x6BA (rpc::Exception),00:02:54.7668000,Budget Highs [AD = 0][CAS = 3][RPC = 1] Session Throttled Count = 0; SessionDropped,"RpcEndPoint: [ServerUnavailableException] Connection must be re-established - [SessionDeadException] Connection doesn't have any open logons, but has client activity. This may be masking synchronization stalls. Dropping a connection." 2013-01-31T15:21:24.015Z,6420,7,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,DelegateLogoff,0,00:00:00,LogonId: 0, 2013-01-31T15:21:24.031Z,6420,7,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,,00:00:00.0156000,Budget Highs [AD = 0][CAS = 3][RPC = 1] Session Throttled Count = 0, 2013-01-31T15:21:24.031Z,6420,7,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,Disconnect,0,00:02:54.2364000,, 2013-01-31T15:21:24.031Z,6419,5,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,OwnerLogoff,0,00:00:00,LogonId: 0, 2013-01-31T15:21:24.031Z,6419,5,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,,00:00:00,Budget Highs [AD = 0][CAS = 3][RPC = 1] Session Throttled Count = 0, 2013-01-31T15:21:24.031Z,6419,5,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,Disconnect,0,00:02:54.4392000,, 2013-01-31T15:21:24.031Z,6416,7,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,DelegateLogoff,0,00:00:00,LogonId: 0, 2013-01-31T15:21:24.031Z,6416,7,/o=EUROSAFEUK/ou=first administrative group/cn=Recipients/cn=andy,,OUTLOOK.EXE,11.0.8303.0,Classic,,,ncacn_ip_tcp,,,,00:00:00,Budget Highs [AD = 0][CAS = 3][RPC = 1] Session Throttled Count = 0, Can anyone help point me in the right direction for a solution?

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Bonding: works only for download

- by Crazy_Bash

I would like to install bonding with 4 links with mode 4. but only "download/receiving" works with bondig. for transmitting the system chooses one link. ifconfig bond0 Link encap:Ethernet HWaddr 90:E2:BA:0F:76:B4 inet addr:ip Bcast:ip Mask:255.255.255.248 inet6 addr: fe80::92e2:baff:fe0f:76b4/64 Scope:Link UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 RX packets:239187413 errors:0 dropped:10944 overruns:0 frame:0 TX packets:536902370 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:14688536197 (13.6 GiB) TX bytes:799521192901 (744.6 GiB) eth2 Link encap:Ethernet HWaddr 90:E2:BA:0F:76:B4 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:54969488 errors:0 dropped:0 overruns:0 frame:0 TX packets:2537 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3374778591 (3.1 GiB) TX bytes:314290 (306.9 KiB) eth3 Link encap:Ethernet HWaddr 90:E2:BA:0F:76:B4 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:64935805 errors:0 dropped:1 overruns:0 frame:0 TX packets:2532 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3993499746 (3.7 GiB) TX bytes:313968 (306.6 KiB) eth4 Link encap:Ethernet HWaddr 90:E2:BA:0F:76:B4 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:57352105 errors:0 dropped:2 overruns:0 frame:0 TX packets:536894778 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3524236530 (3.2 GiB) TX bytes:799520265627 (744.6 GiB) eth5 Link encap:Ethernet HWaddr 90:E2:BA:0F:76:B4 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:61930025 errors:0 dropped:3 overruns:0 frame:0 TX packets:2540 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3796021948 (3.5 GiB) TX bytes:314274 (306.9 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:62 errors:0 dropped:0 overruns:0 frame:0 TX packets:62 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:5320 (5.1 KiB) TX bytes:5320 (5.1 KiB) those are my configs: DEVICE="eth2" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth3" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth4" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth5" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE=bond0 IPADDR=<ip> BROADCAST=<ip> NETWORK=<ip> GATEWAY=<ip> NETMASK=<ip> USERCTL=no BOOTPROTO=none ONBOOT=yes NM_CONTROLLED=no cat /proc/net/bonding/bond0 Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011) Bonding Mode: IEEE 802.3ad Dynamic link aggregation Transmit Hash Policy: layer2 (0) MII Status: up MII Polling Interval (ms): 100 Up Delay (ms): 0 Down Delay (ms): 0 802.3ad info LACP rate: slow Aggregator selection policy (ad_select): stable Active Aggregator Info: Aggregator ID: 1 Number of ports: 4 Actor Key: 17 Partner Key: 11 Partner Mac Address: 00:24:51:12:63:00 Slave Interface: eth2 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: 90:e2:ba:0f:76:b4 Aggregator ID: 1 Slave queue ID: 0 Slave Interface: eth3 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: 90:e2:ba:0f:76:b5 Aggregator ID: 1 Slave queue ID: 0 Slave Interface: eth4 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: 90:e2:ba:0f:76:b6 Aggregator ID: 1 Slave queue ID: 0 Slave Interface: eth5 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: 90:e2:ba:0f:76:b7 Aggregator ID: 1 Slave queue ID: 0 /etc/modprobe.d/bonding.conf alias bond0 bonding options bond0 mode=4 miimon=100 updelay=200 #downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1 Linux: Linux 3.0.0+ #1 SMP Fri Oct 26 07:55:47 EEST 2012 x86_64 x86_64 x86_64 GNU/Linux what i've tried: downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1 mode 6

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Cisco 678 Will Not Work using PPPoE - Possibly Because I Configured it Incorrectly..?

- by Brian Stinar

I am attempting to configure a Cisco 678 because I am totally sick on my Actiontec. However, I am running into some problems. It seems as though the Cisco is able to train the line, but I am unable to ping out. I am all right at programming, but still learning a lot when it comes to being a system administrator. I apologize in advance if I did something ridiculous, or am attempting to configure this device to do something it was not designed to do. It is almost like I am not correctly configuring the device to grab it's IP using PPPoA (like my Actiontec.) The output from "show running" (below) makes me think this too. Below are the commands I ran in order to configure this: # en # set nvram erase # write # reboot # en # set nat enable # set dhcp server enable # set PPP wan0-0 ipcp 0.0.0.0 # set ppp wan0-0 dns 0.0.0.0 # set PPP wan0-0 login xxxxx // My actual login # set PPP wan0-0 password yyyyy // My actual password # set PPP restart enabled # set int wan0-0 close # set int wan0-0 vpi 0 # set int wan0-0 vci 32 # set int wan0-0 open # write # reboot Here is the output from a few commands I thought could provide some useful information: cbos#ping 74.125.224.113 Sending 1 8 byte ping(s) to 74.125.224.113 every 2 second(s) Request timed out cbos#show version Cisco Broadband Operating System CBOS (tm) 678 Software (C678-I-M), Version v2.4.9 - Release Software Copyright (c) 1986-2001 by cisco Systems, Inc. Compiled Nov 17 2004 15:26:29 DMT FULL firmware version G96 NVRAM image at 0x1030f000 cbos#show errors - Current Error Messages - ## Ticks Module Level Message 0 000:00:00:00 PPP Info IPCP Open Event on wan0-0 1 000:00:00:14 ATM Info Wan0 Up 2 000:00:00:14 PPP Info PPP Up Event on wan0-0 3 000:00:01:54 PPP Info PPP Down Event on wan0-0 Total Number of Error Messages: 4 cbos#show interface wan0 wan0 ADSL Physical Port Line Trained Actual Configuration: Overhead Framing: 3 Trellis Coding: Enabled Standard Compliance: T1.413 Downstream Data Rate: 1184 Kbps Upstream Data Rate: 928 Kbps Interleave S Downstream: 4 Interleave D Downstream: 16 Interleave R Downstream: 16 Interleave S Upstream: 4 Interleave D Upstream: 8 Interleave R Upstream: 16 Modem Microcode: G96 DSP version: 0 Operating State: Showtime/Data Mode Configured: Echo Cancellation: Disabled Overhead Framing: 3 Coding Gain: Auto TX Power Attenuation: 0dB Trellis Coding: Enabled Bit Swapping: Disabled Standard Compliance: T1.413 Remote Standard Compliance: T1.413 Tx Start Bin: 0x6 Tx End Bin: 0x1f Data Interface: Utopia L1 Status: Local SNR Margin: 19.0dB Local Coding Gain: 7.5dB Local Transmit Power: 12.5dB Local Attenuation: 46.0dB Remote Attenuation: 31.0dB Local Counters: Interleaved RS Corrected Bytes: 0 Interleaved Symbols with CRC Errors: 2 No Cell Delineation Interleaved: 0 Out of Cell Delineation Interleaved: 0 Header Error Check Counter Interleaved: 0 Count of Severely Errored Frames: 0 Count of Loss of Signal Frames: 0 Remote Counters: Interleaved RS Corrected Bytes: 0 Interleaved Symbols with CRC Errors: 1 No Cell Delineation Interleaved: 0 Header Error Check Counter Interleaved: 0 Count of Severely Errored Frames: 0 Count of Loss of Signal Frames: 0 cbos#show int wan0-0 WAN0-0 ATM Logical Port PVC (VPI 0, VCI 32) is configured. ScalaRate set to Auto AAL 5 UBR Traffic IP Port Enabled cbos#show running Warning: traffic may pause while NVRAM is being accessed [[ CBOS = Section Start ]] NSOS MD5 Enable Password = XXXX NSOS MD5 Root Password = XXXX NSOS MD5 Commander Password = XXXX [[ PPP Device Driver = Section Start ]] PPP Port User Name = 00, "XXXX" PPP Port User Password = 00, XXXX PPP Port Option = 00, IPCP,IP Address,3,Auto,Negotiation Not Required,Negotiable ,IP,0.0.0.0 PPP Port Option = 00, IPCP,Primary DNS Server,129,Auto,Negotiation Not Required, Negotiable,IP,0.0.0.0 PPP Port Option = 00, IPCP,Secondary DNS Server,131,Auto,Negotiation Not Require d,Negotiable,IP,0.0.0.0 [[ ATM WAN Device Driver = Section Start ]] ATM WAN Virtual Connection Parms = 00, 0, 32, 0 [[ DHCP = Section Start ]] DHCP Server = enabled [[ IP Routing = Section Start ]] IP NAT = enabled [[ WEB = Section Start ]] WEB = enabled cbos# wtf...? Thank you all very much for taking the time to read this, and the help.

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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XNA 3D model collision is inaccurate

- by Daniel Lopez

I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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Using CSS3 media queries in HTML 5 pages

- by nikolaosk

This is going to be the seventh post in a series of posts regarding HTML 5. You can find the other posts here , here , here, here , here and here. In this post I will provide a hands-on example on how to use CSS 3 Media Queries in HTML 5 pages. This is a very important feature since nowadays lots of users view websites through their mobile devices. Web designers were able to define media-specific style sheets for quite a while, but have been limited to the type of output. The output could only be Screen, Print .The way we used to do things before CSS 3 was to have separate CSS files and the browser decided which style sheet to use. Please have a look at the snippet below - HTML 4 media queries <link rel="stylesheet" type="text/css" media="screen" href="styles.css"> <link rel="stylesheet" type="text/css" media="print" href="print-styles.css"> ?he browser determines which style to use. With CSS 3 we can have all media queries in one stylesheet. Media queries can determine the resolution of the device, the orientation of the device, the width and height of the device and the width and height of the browser window.We can also include CSS 3 media queries in separate stylesheets. In order to be absolutely clear this is not (and could not be) a detailed tutorial on HTML 5. There are other great resources for that.Navigate to the excellent interactive tutorials of W3School. Another excellent resource is HTML 5 Doctor. Two very nice sites that show you what features and specifications are implemented by various browsers and their versions are http://caniuse.com/ and http://html5test.com/. At this times Chrome seems to support most of HTML 5 specifications.Another excellent way to find out if the browser supports HTML 5 and CSS 3 features is to use the Javascript lightweight library Modernizr. In this hands-on example I will be using Expression Web 4.0.This application is not a free application. You can use any HTML editor you like.You can use Visual Studio 2012 Express edition. You can download it here. Before I go on with the actual demo I will use the (http://www.caniuse.com) to see the support for CSS 3 Media Queries from the latest versions of modern browsers. Please have a look at the picture below. We see that all the latest versions of modern browsers support this feature. We can see that even IE 9 supports this feature. Let's move on with the actual demo. This is going to be a rather simple demo.I create a simple HTML 5 page. The markup follows and it is very easy to use and understand.This is a page with a 2 column layout. <!DOCTYPE html><html lang="en"> <head> <title>HTML 5, CSS3 and JQuery</title> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" > <link rel="stylesheet" type="text/css" href="style.css"> </head> <body> <div id="header"> <h1>Learn cutting edge technologies</h1> <p>HTML 5, JQuery, CSS3</p> </div> <div id="main"> <div id="mainnews"> <div> <h2>HTML 5</h2> </div> <div> <p> HTML5 is the latest version of HTML and XHTML. The HTML standard defines a single language that can be written in HTML and XML. It attempts to solve issues found in previous iterations of HTML and addresses the needs of Web Applications, an area previously not adequately covered by HTML. </p> <div class="quote"> <h4>Do More with Less</h4> <p> jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development. </p> </div> <p> The HTML5 test(html5test.com) score is an indication of how well your browser supports the upcoming HTML5 standard and related specifications. Even though the specification isn't finalized yet, all major browser manufacturers are making sure their browser is ready for the future. Find out which parts of HTML5 are already supported by your browser today and compare the results with other browsers. The HTML5 test does not try to test all of the new features offered by HTML5, nor does it try to test the functionality of each feature it does detect. Despite these shortcomings we hope that by quantifying the level of support users and web developers will get an idea of how hard the browser manufacturers work on improving their browsers and the web as a development platform.</p> </div> </div> <div id="CSS"> <div> <h2>CSS 3 Intro</h2> </div> <div> <p> Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation semantics (the look and formatting) of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML, but the language can also be applied to any kind of XML document, including plain XML, SVG and XUL. </p> </div> </div> <div id="CSSmore"> <div> <h2>CSS 3 Purpose</h2> </div> <div> <p> CSS is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation, including elements such as the layout, colors, and fonts.[1] This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple pages to share formatting, and reduce complexity and repetition in the structural content (such as by allowing for tableless web design). </p> </div> </div> </div> <div id="footer"> <p>Feel free to google more about the subject</p> </div> </body> </html> The CSS code (style.css) follows body{ line-height: 30px; width: 1024px; background-color:#eee; } p{ font-size:17px; font-family:"Comic Sans MS" } p,h2,h3,h4{ margin: 0 0 20px 0; } #main, #header, #footer{ width: 100%; margin: 0px auto; display:block; } #header{ text-align: center; border-bottom: 1px solid #000; margin-bottom: 30px; } #footer{ text-align: center; border-top: 1px solid #000; margin-bottom: 30px; } .quote{ width: 200px; margin-left: 10px; padding: 5px; float: right; border: 2px solid #000; background-color:#F9ACAE; } .quote :last-child{ margin-bottom: 0; } #main{ column-count:2; column-gap:20px; column-rule: 1px solid #000; -moz-column-count: 2; -webkit-column-count: 2; -moz-column-gap: 20px; -webkit-column-gap: 20px; -moz-column-rule: 1px solid #000; -webkit-column-rule: 1px solid #000; } Now I view the page in the browser.Now I am going to write a media query and add some more rules in the .css file in order to change the layout of the page when the page is viewed by mobile devices. @media only screen and (max-width: 480px) { body{ width: 480px; } #main{ -moz-column-count: 1; -webkit-column-count: 1; } } I am specifying that this media query applies only to screen and a max width of 480 px. If this condition is true, then I add new rules for the body element. I change the number of columns to one. This rule will not be applied unless the maximum width is 480px or less. As I decrease the size-width of the browser window I see no change in the column's layout. Have a look at the picture below. When I resize the window and the width of the browser so the width is less than 480px, the media query and its respective rules take effect.We can scroll vertically to view the content which is a more optimised viewing experience for mobile devices. Have a look at the picture below Hope it helps!!!!

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Nullpointerexcption & abrupt IOStream closure with inheritence and subclasses

- by user1401652

A brief background before so we can communicate on the same wave length. I've had about 8-10 university courses on programming from data structure, to one on all languages, to specific ones such as java & c++. I'm a bit rusty because i usually take 2-3 month breaks from coding. This is a personal project that I started thinking of two years back. Okay down to the details, and a specific question, I'm having problems with my mutator functions. It seems to be that I am trying to access a private variable incorrectly. The question is, am I nesting my classes too much and trying to mutate a base class variable the incorrect way. If so point me in the way of the correct literature, or confirm this is my problem so I can restudy this information. Thanks package GroceryReceiptProgram; import java.io.*; import java.util.Vector; public class Date { private int hour, minute, day, month, year; Date() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What's the hour? (Use 1-24 military notation"); hour = Integer.parseInt(keyboard.readLine()); System.out.println("what's the minute? "); minute = Integer.parseInt(keyboard.readLine()); System.out.println("What's the day of the month?"); day = Integer.parseInt(keyboard.readLine()); System.out.println("Which month of the year is it, use an integer"); month = Integer.parseInt(keyboard.readLine()); System.out.println("What year is it?"); year = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (IOException e) { System.out.println("Yo houston we have a problem"); } } public void setHour(int hour) { this.hour = hour; } public void setHour() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What hour, use military notation?"); this.hour = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getHour() { return hour; } public void setMinute(int minute) { this.minute = minute; } public void setMinute() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What minute?"); this.minute = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ": doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": minute shall not cooperate"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in the setMinute function of the Date class"); } } public int getMinute() { return minute; } public void setDay(int day) { this.day = day; } public void setDay() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What day 0-6?"); this.day = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getDay() { return day; } public void setMonth(int month) { this.month = month; } public void setMonth() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What month 0-11?"); this.month = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getMonth() { return month; } public void setYear(int year) { this.year = year; } public void setYear() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What year?"); this.year = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getYear() { return year; } public void set() { setMinute(); setHour(); setDay(); setMonth(); setYear(); } public Vector<Integer> get() { Vector<Integer> holder = new Vector<Integer>(5); holder.add(hour); holder.add(minute); holder.add(month); holder.add(day); holder.add(year); return holder; } }; That is the Date class obviously, next is the other base class Location. package GroceryReceiptProgram; import java.io.*; import java.util.Vector; public class Location { String streetName, state, city, country; int zipCode, address; Location() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What is the street name"); streetName = keyboard.readLine(); System.out.println("Which state?"); state = keyboard.readLine(); System.out.println("Which city?"); city = keyboard.readLine(); System.out.println("Which country?"); country = keyboard.readLine(); System.out.println("Which zipcode?");//if not u.s. continue around this step zipCode = Integer.parseInt(keyboard.readLine()); System.out.println("What address?"); address = Integer.parseInt(keyboard.readLine()); } catch (IOException e) { System.out.println(e.toString()); } } public void setZipCode(int zipCode) { this.zipCode = zipCode; } public void setZipCode() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What zipCode?"); this.zipCode = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public void set() { setAddress(); setCity(); setCountry(); setState(); setStreetName(); setZipCode(); } public int getZipCode() { return zipCode; } public void setAddress(int address) { this.address = address; } public void setAddress() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.address = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getAddress() { return address; } public void setStreetName(String streetName) { this.streetName = streetName; } public void setStreetName() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.streetName = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getStreetName() { return streetName; } public void setState(String state) { this.state = state; } public void setState() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.state = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getState() { return state; } public void setCity(String city) { this.city = city; } public void setCity() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.city = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getCity() { return city; } public void setCountry(String country) { this.country = country; } public void setCountry() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.country = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getCountry() { return country; } }; their parent(What is the proper name?) class package GroceryReceiptProgram; import java.io.*; public class FoodGroup { private int price, count; private Date purchaseDate, expirationDate; private Location location; private String name; public FoodGroup() { try { setPrice(); setCount(); expirationDate.set(); purchaseDate.set(); location.set(); } catch (NullPointerException e) { System.out.println(e.toString() + ": in the constructor of the FoodGroup class"); } } public void setPrice(int price) { this.price = price; } public void setPrice() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What Price?"); price = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": in the FoodGroup class, setPrice function"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in FoodGroup class. SetPrice()"); } } public int getPrice() { return price; } public void setCount(int count) { this.count = count; } public void setCount() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What count?"); count = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": in the FoodGroup class, setCount()"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in FoodGroup class, setCount"); } } public int getCount() { return count; } public void setName(String name) { this.name = name; } public void setName() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.name = keyboard.readLine(); } catch (IOException e) { System.out.println(e.toString()); } } public String getName() { return name; } public void setLocation(Location location) { this.location = location; } public Location getLocation() { return location; } public void setPurchaseDate(Date purchaseDate) { this.purchaseDate = purchaseDate; } public void setPurchaseDate() { this.purchaseDate.set(); } public Date getPurchaseDate() { return purchaseDate; } public void setExpirationDate(Date expirationDate) { this.expirationDate = expirationDate; } public void setExpirationDate() { this.expirationDate.set(); } public Date getExpirationDate() { return expirationDate; } } and finally the main class, so I can get access to all of this work. package GroceryReceiptProgram; public class NewMain { public static void main(String[] args) { FoodGroup test = new FoodGroup(); } } If anyone is further interested, here is a link the UML for this. https://www.dropbox.com/s/1weigjnxih70tbv/GRP.dia

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mdadm: Win7-install created a boot partition on one of my RAID6 drives. How to rebuild?

- by EXIT_FAILURE

My problem happened when I attempted to install Windows 7 on it's own SSD. The Linux OS I used which has knowledge of the software RAID system is on a SSD that I disconnected prior to the install. This was so that windows (or I) wouldn't inadvertently mess it up. However, and in retrospect, foolishly, I left the RAID disks connected, thinking that windows wouldn't be so ridiculous as to mess with a HDD that it sees as just unallocated space. Boy was I wrong! After copying over the installation files to the SSD (as expected and desired), it also created an ntfs partition on one of the RAID disks. Both unexpected and totally undesired! . I changed out the SSDs again, and booted up in linux. mdadm didn't seem to have any problem assembling the array as before, but if I tried to mount the array, I got the error message: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so dmesg: EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! EXT4-fs (md0): group descriptors corrupted! I then used qparted to delete the newly created ntfs partition on /dev/sdd so that it matched the other three /dev/sd{b,c,e}, and requested a resync of my array with echo repair > /sys/block/md0/md/sync_action This took around 4 hours, and upon completion, dmesg reports: md: md0: requested-resync done. A bit brief after a 4-hour task, though I'm unsure as to where other log files exist (I also seem to have messed up my sendmail configuration). In any case: No change reported according to mdadm, everything checks out. mdadm -D /dev/md0 still reports: Version : 1.2 Creation Time : Wed May 23 22:18:45 2012 Raid Level : raid6 Array Size : 3907026848 (3726.03 GiB 4000.80 GB) Used Dev Size : 1953513424 (1863.02 GiB 2000.40 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Mon May 26 12:41:58 2014 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 4K Name : okamilinkun:0 UUID : 0c97ebf3:098864d8:126f44e3:e4337102 Events : 423 Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 1 8 32 1 active sync /dev/sdc 2 8 48 2 active sync /dev/sdd 3 8 64 3 active sync /dev/sde Trying to mount it still reports: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so and dmesg: EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! EXT4-fs (md0): group descriptors corrupted! I'm a bit unsure where to proceed from here, and trying stuff "to see if it works" is a bit too risky for me. This is what I suggest I should attempt to do: Tell mdadm that /dev/sdd (the one that windows wrote into) isn't reliable anymore, pretend it is newly re-introduced to the array, and reconstruct its content based on the other three drives. I also could be totally wrong in my assumptions, that the creation of the ntfs partition on /dev/sdd and subsequent deletion has changed something that cannot be fixed this way. My question: Help, what should I do? If I should do what I suggested , how do I do that? From reading documentation, etc, I would think maybe: mdadm --manage /dev/md0 --set-faulty /dev/sdd mdadm --manage /dev/md0 --remove /dev/sdd mdadm --manage /dev/md0 --re-add /dev/sdd However, the documentation examples suggest /dev/sdd1, which seems strange to me, as there is no partition there as far as linux is concerned, just unallocated space. Maybe these commands won't work without. Maybe it makes sense to mirror the partition table of one of the other raid devices that weren't touched, before --re-add. Something like: sfdisk -d /dev/sdb | sfdisk /dev/sdd Bonus question: Why would the Windows 7 installation do something so st...potentially dangerous? Update I went ahead and marked /dev/sdd as faulty, and removed it (not physically) from the array: # mdadm --manage /dev/md0 --set-faulty /dev/sdd # mdadm --manage /dev/md0 --remove /dev/sdd However, attempting to --re-add was disallowed: # mdadm --manage /dev/md0 --re-add /dev/sdd mdadm: --re-add for /dev/sdd to /dev/md0 is not possible --add, was fine. # mdadm --manage /dev/md0 --add /dev/sdd mdadm -D /dev/md0 now reports the state as clean, degraded, recovering, and /dev/sdd as spare rebuilding. /proc/mdstat shows the recovery progress: md0 : active raid6 sdd[4] sdc[1] sde[3] sdb[0] 3907026848 blocks super 1.2 level 6, 4k chunk, algorithm 2 [4/3] [UU_U] [>....................] recovery = 2.1% (42887780/1953513424) finish=348.7min speed=91297K/sec nmon also shows expected output: ¦sdb 0% 87.3 0.0| > |¦ ¦sdc 71% 109.1 0.0|RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR > |¦ ¦sdd 40% 0.0 87.3|WWWWWWWWWWWWWWWWWWWW > |¦ ¦sde 0% 87.3 0.0|> || It looks good so far. Crossing my fingers for another five+ hours :) Update 2 The recovery of /dev/sdd finished, with dmesg output: [44972.599552] md: md0: recovery done. [44972.682811] RAID conf printout: [44972.682815] --- level:6 rd:4 wd:4 [44972.682817] disk 0, o:1, dev:sdb [44972.682819] disk 1, o:1, dev:sdc [44972.682820] disk 2, o:1, dev:sdd [44972.682821] disk 3, o:1, dev:sde Attempting mount /dev/md0 reports: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so And on dmesg: [44984.159908] EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! [44984.159912] EXT4-fs (md0): group descriptors corrupted! I'm not sure what do do now. Suggestions? Output of dumpe2fs /dev/md0: dumpe2fs 1.42.8 (20-Jun-2013) Filesystem volume name: Atlas Last mounted on: /mnt/atlas Filesystem UUID: e7bfb6a4-c907-4aa0-9b55-9528817bfd70 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 244195328 Block count: 976756712 Reserved block count: 48837835 Free blocks: 92000180 Free inodes: 243414877 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 791 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 RAID stripe width: 2 Flex block group size: 16 Filesystem created: Thu May 24 07:22:41 2012 Last mount time: Sun May 25 23:44:38 2014 Last write time: Sun May 25 23:46:42 2014 Mount count: 341 Maximum mount count: -1 Last checked: Thu May 24 07:22:41 2012 Check interval: 0 (<none>) Lifetime writes: 4357 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 Default directory hash: half_md4 Directory Hash Seed: e177a374-0b90-4eaa-b78f-d734aae13051 Journal backup: inode blocks dumpe2fs: Corrupt extent header while reading journal super block

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Hibernate unable to instantiate default tuplizer - cannot find getter

- by ZeldaPinwheel

I'm trying to use Hibernate to persist a class that looks like this: public class Item implements Serializable, Comparable<Item> { // Item id private Integer id; // Description of item in inventory private String description; // Number of items described by this inventory item private int count; //Category item belongs to private String category; // Date item was purchased private GregorianCalendar purchaseDate; public Item() { } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public int getCount() { return count; } public void setCount(int count) { this.count = count; } public String getCategory() { return category; } public void setCategory(String category) { this.category = category; } public GregorianCalendar getPurchaseDate() { return purchaseDate; } public void setPurchasedate(GregorianCalendar purchaseDate) { this.purchaseDate = purchaseDate; } My Hibernate mapping file contains the following: <property name="puchaseDate" type="java.util.GregorianCalendar"> <column name="purchase_date"></column> </property> When I try to run, I get error messages indicating there is no getter function for the purchaseDate attribute: 577 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - Using Hibernate built-in connection pool (not for production use!) 577 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - Hibernate connection pool size: 20 577 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - autocommit mode: false 592 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - using driver: com.mysql.jdbc.Driver at URL: jdbc:mysql://localhost:3306/home_inventory 592 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - connection properties: {user=root, password=****} 1078 [main] INFO org.hibernate.cfg.SettingsFactory - RDBMS: MySQL, version: 5.1.45 1078 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC driver: MySQL-AB JDBC Driver, version: mysql-connector-java-5.1.12 ( Revision: ${bzr.revision-id} ) 1103 [main] INFO org.hibernate.dialect.Dialect - Using dialect: org.hibernate.dialect.MySQLDialect 1107 [main] INFO org.hibernate.engine.jdbc.JdbcSupportLoader - Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4 1109 [main] INFO org.hibernate.transaction.TransactionFactoryFactory - Using default transaction strategy (direct JDBC transactions) 1110 [main] INFO org.hibernate.transaction.TransactionManagerLookupFactory - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) 1110 [main] INFO org.hibernate.cfg.SettingsFactory - Automatic flush during beforeCompletion(): disabled 1110 [main] INFO org.hibernate.cfg.SettingsFactory - Automatic session close at end of transaction: disabled 1110 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC batch size: 15 1110 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC batch updates for versioned data: disabled 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Scrollable result sets: enabled 1111 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC3 getGeneratedKeys(): enabled 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Connection release mode: auto 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Maximum outer join fetch depth: 2 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Default batch fetch size: 1 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Generate SQL with comments: disabled 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Order SQL updates by primary key: disabled 1111 [main] INFO org.hibernate.cfg.SettingsFactory - Order SQL inserts for batching: disabled 1112 [main] INFO org.hibernate.cfg.SettingsFactory - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 1113 [main] INFO org.hibernate.hql.ast.ASTQueryTranslatorFactory - Using ASTQueryTranslatorFactory 1113 [main] INFO org.hibernate.cfg.SettingsFactory - Query language substitutions: {} 1113 [main] INFO org.hibernate.cfg.SettingsFactory - JPA-QL strict compliance: disabled 1113 [main] INFO org.hibernate.cfg.SettingsFactory - Second-level cache: enabled 1113 [main] INFO org.hibernate.cfg.SettingsFactory - Query cache: disabled 1113 [main] INFO org.hibernate.cfg.SettingsFactory - Cache region factory : org.hibernate.cache.impl.NoCachingRegionFactory 1113 [main] INFO org.hibernate.cfg.SettingsFactory - Optimize cache for minimal puts: disabled 1114 [main] INFO org.hibernate.cfg.SettingsFactory - Structured second-level cache entries: disabled 1117 [main] INFO org.hibernate.cfg.SettingsFactory - Echoing all SQL to stdout 1118 [main] INFO org.hibernate.cfg.SettingsFactory - Statistics: disabled 1118 [main] INFO org.hibernate.cfg.SettingsFactory - Deleted entity synthetic identifier rollback: disabled 1118 [main] INFO org.hibernate.cfg.SettingsFactory - Default entity-mode: pojo 1118 [main] INFO org.hibernate.cfg.SettingsFactory - Named query checking : enabled 1118 [main] INFO org.hibernate.cfg.SettingsFactory - Check Nullability in Core (should be disabled when Bean Validation is on): enabled 1151 [main] INFO org.hibernate.impl.SessionFactoryImpl - building session factory org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer] at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:110) at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:135) at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:80) at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:323) at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:475) at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:133) at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84) at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:295) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1385) at service.HibernateSessionFactory.currentSession(HibernateSessionFactory.java:53) at service.ItemSvcHibImpl.generateReport(ItemSvcHibImpl.java:78) at service.test.ItemSvcTest.testGenerateReport(ItemSvcTest.java:226) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at junit.framework.TestCase.runTest(TestCase.java:164) at junit.framework.TestCase.runBare(TestCase.java:130) at junit.framework.TestResult$1.protect(TestResult.java:106) at junit.framework.TestResult.runProtected(TestResult.java:124) at junit.framework.TestResult.run(TestResult.java:109) at junit.framework.TestCase.run(TestCase.java:120) at junit.framework.TestSuite.runTest(TestSuite.java:230) at junit.framework.TestSuite.run(TestSuite.java:225) at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:107) ... 29 more Caused by: org.hibernate.PropertyNotFoundException: Could not find a getter for puchaseDate in class domain.Item at org.hibernate.property.BasicPropertyAccessor.createGetter(BasicPropertyAccessor.java:328) at org.hibernate.property.BasicPropertyAccessor.getGetter(BasicPropertyAccessor.java:321) at org.hibernate.mapping.Property.getGetter(Property.java:304) at org.hibernate.tuple.entity.PojoEntityTuplizer.buildPropertyGetter(PojoEntityTuplizer.java:299) at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:158) at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:77) ... 34 more I'm new to Hibernate, so I don't know all the ins and outs, but I do have the getter and setter for the purchaseDate attribute. I don't know what I'm missing here - does anyone else? Thanks!

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SQL SERVER – Advanced Data Quality Services with Melissa Data – Azure Data Market

- by pinaldave

There has been much fanfare over the new SQL Server 2012, and especially around its new companion product Data Quality Services (DQS). Among the many new features is the addition of this integrated knowledge-driven product that enables data stewards everywhere to profile, match, and cleanse data. In addition to the homegrown rules that data stewards can design and implement, there are also connectors to third party providers that are hosted in the Azure Datamarket marketplace. In this review, I leverage SQL Server 2012 Data Quality Services, and proceed to subscribe to a third party data cleansing product through the Datamarket to showcase this unique capability. Crucial Questions For the purposes of the review, I used a database I had in an Excel spreadsheet with name and address information. Upon a cursory inspection, there are miscellaneous problems with these records; some addresses are missing ZIP codes, others missing a city, and some records are slightly misspelled or have unparsed suites. With DQS, I can easily add a knowledge base to help standardize my values, such as for state abbreviations. But how do I know that my address is correct? And if my address is not correct, what should it be corrected to? The answer lies in a third party knowledge base by the acknowledged USPS certified address accuracy experts at Melissa Data. Reference Data Services Within DQS there is a handy feature to actually add reference data from many different third-party Reference Data Services (RDS) vendors. DQS simplifies the processes of cleansing, standardizing, and enriching data through custom rules and through service providers from the Azure Datamarket. A quick jump over to the Datamarket site shows me that there are a handful of providers that offer data directly through Data Quality Services. Upon subscribing to these services, one can attach a DQS domain or composite domain (fields in a record) to a reference data service provider, and begin using it to cleanse, standardize, and enrich that data. Besides what I am looking for (address correction and enrichment), it is possible to subscribe to a host of other services including geocoding, IP address reference, phone checking and enrichment, as well as name parsing, standardization, and genderization. These capabilities extend the data quality that DQS has natively by quite a bit. For my current address correction review, I needed to first sign up to a reference data provider on the Azure Data Market site. For this example, I used Melissa Data’s Address Check Service. They offer free one-month trials, so if you wish to follow along, or need to add address quality to your own data, I encourage you to sign up with them. Once I subscribed to the desired Reference Data Provider, I navigated my browser to the Account Keys within My Account to view the generated account key, which I then inserted into the DQS Client – Configuration under the Administration area. Step by Step to Guide That was all it took to hook in the subscribed provider -Melissa Data- directly to my DQS Client. The next step was for me to attach and map in my Reference Data from the newly acquired reference data provider, to a domain in my knowledge base. On the DQS Client home screen, I selected “New Knowledge Base” under Knowledge Base Management on the left-hand side of the home screen. Under New Knowledge Base, I typed a Name and description of my new knowledge base, then proceeded to the Domain Management screen. Here I established a series of domains (fields) and then linked them all together as a composite domain (record set). Using the Create Domain button, I created the following domains according to the fields in my incoming data: Name Address Suite City State Zip I added a Suite column in my domain because Melissa Data has the ability to return missing Suites based on last name or company. And that’s a great benefit of using these third party providers, as they have data that the data steward would not normally have access to. The bottom line is, with these third party data providers, I can actually improve my data. Next, I created a composite domain (fulladdress) and added the (field) domains into the composite domain. This essentially groups our address fields together in a record to facilitate the full address cleansing they perform. I then selected my newly created composite domain and under the Reference Data tab, added my third party reference data provider –Melissa Data’s Address Check- and mapped in each domain that I had to the provider’s Schema. Now that my composite domain has been married to the Reference Data service, I can take the newly published knowledge base and create a project to cleanse and enrich my data. My next task was to create a new Data Quality project, mapping in my data source and matching it to the appropriate domain column, and then kick off the verification process. It took just a few minutes with some progress indicators indicating that it was working. When the process concluded, there was a helpful set of tabs that place the response records into categories: suggested; new; invalid; corrected (automatically); and correct. Accepting the suggestions provided by Melissa Data allowed me to clean up all the records and flag the invalid ones. It is very apparent that DQS makes address data quality simplistic for any IT professional. Final Note As I have shown, DQS makes data quality very easy. Within minutes I was able to set up a data cleansing and enrichment routine within my data quality project, and ensure that my address data was clean, verified, and standardized against real reference data. As reviewed here, it’s easy to see how both SQL Server 2012 and DQS work to take what used to require a highly skilled developer, and empower an average business or database person to consume external services and clean data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology Tagged: DQS

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Microsoft TechEd 2010 - Day 3 @ Bangalore

- by sathya

Microsoft TechEd 2010 - Day 3 @ Bangalore Sorry for my delayed post on day 3 because I had to travel from Blore to Chennai So I couldnt write for the past two days. On day 3 as usual we had lot of simultaneous tracks on various sessions. This day I choose the Your Data, Our Platform Track. It had sessions on the following 5 topics : Developing Data-tier Applications in Visual Studio 2010 - by Sanjay Nagamangalam SQL Server Query Optimization, Execution and Debugging Query Performance - by Vinod Kumar M SQL Server Utility - Its about more than 1 SQL Server - by Vinod Kumar Jagannathan Data Recovery / Consistency with CheckDB - by Vinod Kumar M Developing with SQL Server Spatial and Deep dive into Spatial Indexing - by Pinal Dave Developing Data-tier Applications in Visual Studio 2010 - by Sanjay Nagamangalam This was one of the superb sessions i have attended. He explained all the concepts in detail with a demo. The important thing in this is there is something called Data-Tier application project which is newly introduced in this VS2010 with which we can manage all our data along with our application inside our VS itself. We can create DB,Tables,Procs,Views etc. here itself and once we deploy it creates a compressed file called .dacpac which stores all the changes in Table Schema,Created procs, etc. on to that single file which reduces our (developer's) effort in preparing the deployment scripts and giving it to the DBA. It also has some policy configurations which can be managed easily by checking some rules like in outlook. For Ex : IF the SQL Server Version > 10 then deploy else dont. This rule specifies that even if we try to deploy on SQL Server DB with version less than 10 It will not do it. And if we deploy some .dacpac to SQL server production db with the option upgrade DB with this dacpac once everything completes successfully it will say success else it rollsback to the prior version. Even if it gets deployed successfully and later @ a point of time you wish to revert it back to the prior version, you can go ahead and delete the existing dacpac version so that it reverts to the older version of the db changes. And for the good questions that were asked in the session T-Shirts were given. SQL Server Query Optimization, Execution and Debugging Query Performance - by Vinod Kumar M This one too was the best session. The speaker Vinod explained everything very much clearly. This was really useful session and you dont believe, as per my knowledge, in the total 3 days in the TechEd except the Keynote, for this session seats were full (House FULL) People were even standing out to attend this session. Such a great one it was. The speaker did a deep dive in to the Query Plan section and showed which actually causes the problem. Its all about the thing that we need to understand about the execution of SQL server Queries. We think in a way and SQL Server never executes in that way. We need to understand that first. He also told about there might be two plans generated for a single query at a point of time because of parallel processors in the system. The Key is here in every query. There is something called Estimated Row Count and Actual Row Count in the query plan. If the estimated row count by SQL server tallies with the actual row count your performance will be awesome. He said some tweaks to achieve the same. After this as usual we had lunch SQL Server Utility - Its about more than 1 SQL Server - by Vinod Kumar Jagannathan This was more of a DBA's session. Am really sorry I was totally blank and I was not interested to attend this session and walked out to attend Migrating to the cloud by Harish Ranganathan (My favorite Speaker) but unfortunately that was some other persons session. There the speaker was telling about how to configure the connection strings in such a way that we can connect to the SQL Azure platform from our VS and also showed us how to deploy the same in to Windows Azure. In between there were lot of technical problems like laptop hang, user locked and he was switching between systems, also i came in the half so i wasnt able to listen that fully. In between, Since I got an MCTS certification they gave me T-Shirt with the lines 'Iam Certified. Are you?' and they asked me to wear that. If we wear that we might get spotted and they would give us some goodies So on the 3rd day I was wearing that T-Shirt. I got spotted by the person Tarun who was coordinating things about the certification, and he was accompanied with a cameraman and they interviewed me about the certification and I was shown live in the Teched and was seen by 60000 live viewers of the TechEd. I was really happy on that. Data Recovery / Consistency with CheckDB - by Vinod Kumar M This was one of the best sessions too in the TechEd. This guy is really amazing. In front of us he crashed a DB and showed how to recover the same in 6 different ways for different no of failures. Showed about Different types of error msgs like : 823,824,825 msdb..suspect_pages DBCC CheckDB (different parameters to it) I am really waiting for his session to get uploaded live in the Teched Website. Here is his contact info If you wish to connect to him : Twitter : @vinodk_sql Website : www.ExtremeExperts.com Blog : http://blogs.sqlxml.org/vinodkumar Developing with SQL Server Spatial and Deep dive into Spatial Indexing - by Pinal Dave Pinal Dave is a King in SQL and he is a SQL MVP and he is the owner of SQLAuthority.com He took the session on Spatial Databases from the start. Showed about the different types of Spatial : Geometric and Geographic Geometric : x and y axis its a planar surface Geographic : Spherical surface with 3600 as the maximum which is used to represent the geographic points on the earth and easy to draw maps of different kinds. He had a lot of obstacles during his session like rain coming inside the hall, mic wires got bursted due to rain, Videos off on the display screens. In spite of that he asked the audience to come in the front rows and managed to take a good session without ppts and finally we got the displays on and he was showing demos on the same what he explained orally. That was really a fun filled informative session. He gave some books for the persons who asked good questions and answered well for his questions and I got one too (It was a book on Data Mining - Wrox Publishers) And finally after all these things there was Keynote session for close of the TechEd. and we all assembled in a big hall where Mr.Ashok Soota, a man of age around 70 co-founder of Mindtree was called to give some lecture on his successes. He was explaining about his past and what all companies he switched and for what reasons and what are all his successes and what are all his failures and the learnings of him from his past failures. and his success and failures on his partnerships with the other concern. And there were some questions for him like What is your suggestion on young entrepreneur? How did you learn from past failures? What is reiterating your success? What is your suggestion on partnerships? How to choose partnerships? etc. And they said @ 7.30 Pm there would be a party night, but unfortunately i was not able to attend that because I had to catch my train and before that i had to pack things, so I started @ 7 itself. Thats it about the TechED!!! Stay tuned for further Technology updates.

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Why won't my UISearchDisplayController fire the didSelectRowAtIndexPath moethod?

- by John Wells

I am having an odd problem when searching a UITableView using a UISearchDisplayController. The UITableViewController is a subclass of another UITableViewController with a working didSelectRowAtIndexPath method. Without searching the controller handles selections fine, sending the superclass a didSelectRowAtIndexPath call, but if I select a cell when searching the superclass receives nothing but the cell is highlighted. Below is the code from my subclass. @implementation AdvancedViewController @synthesize searchDisplayController, dict, filteredList; - (void)viewDidLoad { [super viewDidLoad]; // Programmatically set up search bar UISearchBar *mySearchBar = [[UISearchBar alloc] init]; mySearchBar.delegate = self; [mySearchBar setAutocapitalizationType:UITextAutocapitalizationTypeNone]; [mySearchBar sizeToFit]; self.tableView.tableHeaderView = mySearchBar; // Programmatically set up search display controller searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:mySearchBar contentsController:self]; [self setSearchDisplayController:searchDisplayController]; [searchDisplayController setDelegate:self]; [searchDisplayController setSearchResultsDataSource:self]; // Parse data from server NSData * jsonData = [NSData dataWithContentsOfURL:[NSURL URLWithString:url]]; NSArray * items = [[NSArray alloc] initWithArray:[[CJSONDeserializer deserializer] deserializeAsArray:jsonData error:nil]]; // Init variables dict = [[NSMutableDictionary alloc] init]; listIndex = [[NSMutableArray alloc] init]; fullList = [[NSMutableArray alloc] init]; filteredList = [[NSMutableArray alloc] init]; // Get each item and format it for the UI for(NSMutableArray * item in items) { // Get the first letter NSString * firstKey = [[[item objectAtIndex:0] substringWithRange:NSMakeRange(0,1)] uppercaseString]; // Put symbols and numbers in the same section if ([[firstKey stringByTrimmingCharactersInSet:[[NSCharacterSet letterCharacterSet] invertedSet]] isEqualToString:@""]) firstKey = @"#"; // If there isn't a section with this key if (![listIndex containsObject:firstKey]) { // Add the key to the index for faster access (because it's already sorted) [listIndex addObject:firstKey]; // Add the key to the unordered dictionary [dict setObject:[NSMutableArray array] forKey:firstKey]; } // Add the object to the dictionary [[dict objectForKey:firstKey] addObject:[[NSMutableDictionary alloc] initWithObjects:item forKeys:[NSArray arrayWithObjects:@"name", @"url", nil]]]; // Add the object to the list for simple searching [fullList addObject:[[NSMutableDictionary alloc] initWithObjects:item forKeys:[NSArray arrayWithObjects:@"name", @"url", nil]]]; } filteredList = [NSMutableArray arrayWithCapacity:[fullList count]]; } #pragma mark - #pragma mark Table view data source // Custom method for object oriented data access - (NSString *)tableView:(UITableView *)tableView dataForRowAtIndexPath:(NSIndexPath *)indexPath withKey:(NSString *)key { return (NSString *)((tableView == self.searchDisplayController.searchResultsTableView) ? [[filteredList objectAtIndex:indexPath.row] objectForKey:key] : [[[dict objectForKey:[listIndex objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row] valueForKey:key]); } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return (tableView == self.searchDisplayController.searchResultsTableView) ? 1 : (([listIndex count] > 0) ? [[dict allKeys] count] : 1); } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return (tableView == self.searchDisplayController.searchResultsTableView) ? [filteredList count] : [[dict objectForKey:[listIndex objectAtIndex:section]] count]; } - (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView { return (tableView == self.searchDisplayController.searchResultsTableView) ? [[NSArray alloc] initWithObjects:nil] : listIndex; } - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { return (tableView == self.searchDisplayController.searchResultsTableView) ? @"" : [listIndex objectAtIndex:section]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *kCellID = @"cellID"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kCellID]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:kCellID] autorelease]; cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; } NSString * name = nil; // TODO: Make dataForRowAtIndexPath work here if (tableView == self.searchDisplayController.searchResultsTableView) { // NOTE: dataForRowAtIndexPath causes this to crash for some unknown reason. Maybe it is called before viewDidLoad and has no data? name = [[filteredList objectAtIndex:indexPath.row] objectForKey:@"name"]; } else { // This always works name = [self tableView:[self tableView] dataForRowAtIndexPath:indexPath withKey:@"name"]; } cell.textLabel.text = name; return cell; } #pragma mark Search Methods - (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope { // Clear the filtered array [self.filteredList removeAllObjects]; // Filter the array for (NSDictionary *item in fullList) { // Compare the item's name to the search text NSComparisonResult result = [[item objectForKey:@"name"] compare:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch) range:NSMakeRange(0, [searchText length])]; if (result == NSOrderedSame) { // Add to the filtered array if it matches [self.filteredList addObject:item]; } } } - (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString { [self filterContentForSearchText:searchString scope: [[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:[self.searchDisplayController.searchBar selectedScopeButtonIndex]]]; // Return YES to cause the search result table view to be reloaded. return YES; } - (void)viewDidUnload { filteredList = nil; } @end

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Of C# Iterators and Performance

- by James Michael Hare

Some of you reading this will be wondering, "what is an iterator" and think I'm locked in the world of C++. Nope, I'm talking C# iterators. No, not enumerators, iterators. So, for those of you who do not know what iterators are in C#, I will explain it in summary, and for those of you who know what iterators are but are curious of the performance impacts, I will explore that as well. Iterators have been around for a bit now, and there are still a bunch of people who don't know what they are or what they do. I don't know how many times at work I've had a code review on my code and have someone ask me, "what's that yield word do?" Basically, this post came to me as I was writing some extension methods to extend IEnumerable<T> -- I'll post some of the fun ones in a later post. Since I was filtering the resulting list down, I was using the standard C# iterator concept; but that got me wondering: what are the performance implications of using an iterator versus returning a new enumeration? So, to begin, let's look at a couple of methods. This is a new (albeit contrived) method called Every(...). The goal of this method is to access and enumeration and return every nth item in the enumeration (including the first). So Every(2) would return items 0, 2, 4, 6, etc. Now, if you wanted to write this in the traditional way, you may come up with something like this: public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval) { List<T> newList = new List<T>(); int count = 0; foreach (var i in list) { if ((count++ % interval) == 0) { newList.Add(i); } } return newList; } So basically this method takes any IEnumerable<T> and returns a new IEnumerable<T> that contains every nth item. Pretty straight forward. The problem? Well, Every<T>(...) will construct a list containing every nth item whether or not you care. What happens if you were searching this result for a certain item and find that item after five tries? You would have generated the rest of the list for nothing. Enter iterators. This C# construct uses the yield keyword to effectively defer evaluation of the next item until it is asked for. This can be very handy if the evaluation itself is expensive or if there's a fair chance you'll never want to fully evaluate a list. We see this all the time in Linq, where many expressions are chained together to do complex processing on a list. This would be very expensive if each of these expressions evaluated their entire possible result set on call. Let's look at the same example function, this time using an iterator: public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval) { int count = 0; foreach (var i in list) { if ((count++ % interval) == 0) { yield return i; } } } Notice it does not create a new return value explicitly, the only evidence of a return is the "yield return" statement. What this means is that when an item is requested from the enumeration, it will enter this method and evaluate until it either hits a yield return (in which case that item is returned) or until it exits the method or hits a yield break (in which case the iteration ends. Behind the scenes, this is all done with a class that the CLR creates behind the scenes that keeps track of the state of the iteration, so that every time the next item is asked for, it finds that item and then updates the current position so it knows where to start at next time. It doesn't seem like a big deal, does it? But keep in mind the key point here: it only returns items as they are requested. Thus if there's a good chance you will only process a portion of the return list and/or if the evaluation of each item is expensive, an iterator may be of benefit. This is especially true if you intend your methods to be chainable similar to the way Linq methods can be chained. For example, perhaps you have a List<int> and you want to take every tenth one until you find one greater than 10. We could write that as: List<int> someList = new List<int>(); // fill list here someList.Every(10).TakeWhile(i => i <= 10); Now is the difference more apparent? If we use the first form of Every that makes a copy of the list. It's going to copy the entire list whether we will need those items or not, that can be costly! With the iterator version, however, it will only take items from the list until it finds one that is > 10, at which point no further items in the list are evaluated. So, sounds neat eh? But what's the cost is what you're probably wondering. So I ran some tests using the two forms of Every above on lists varying from 5 to 500,000 integers and tried various things. Now, iteration isn't free. If you are more likely than not to iterate the entire collection every time, iterator has some very slight overhead: Copy vs Iterator on 100% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 5 Copy 5 5 5 Iterator 5 50 50 Copy 28 50 50 Iterator 27 500 500 Copy 227 500 500 Iterator 247 5000 5000 Copy 2266 5000 5000 Iterator 2444 50,000 50,000 Copy 24,443 50,000 50,000 Iterator 24,719 500,000 500,000 Copy 250,024 500,000 500,000 Iterator 251,521 Notice that when iterating over the entire produced list, the times for the iterator are a little better for smaller lists, then getting just a slight bit worse for larger lists. In reality, given the number of items and iterations, the result is near negligible, but just to show that iterators come at a price. However, it should also be noted that the form of Every that returns a copy will have a left-over collection to garbage collect. However, if we only partially evaluate less and less through the list, the savings start to show and make it well worth the overhead. Let's look at what happens if you stop looking after 80% of the list: Copy vs Iterator on 80% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 4 Copy 5 5 4 Iterator 5 50 40 Copy 27 50 40 Iterator 23 500 400 Copy 215 500 400 Iterator 200 5000 4000 Copy 2099 5000 4000 Iterator 1962 50,000 40,000 Copy 22,385 50,000 40,000 Iterator 19,599 500,000 400,000 Copy 236,427 500,000 400,000 Iterator 196,010 Notice that the iterator form is now operating quite a bit faster. But the savings really add up if you stop on average at 50% (which most searches would typically do): Copy vs Iterator on 50% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 2 Copy 5 5 2 Iterator 4 50 25 Copy 25 50 25 Iterator 16 500 250 Copy 188 500 250 Iterator 126 5000 2500 Copy 1854 5000 2500 Iterator 1226 50,000 25,000 Copy 19,839 50,000 25,000 Iterator 12,233 500,000 250,000 Copy 208,667 500,000 250,000 Iterator 122,336 Now we see that if we only expect to go on average 50% into the results, we tend to shave off around 40% of the time. And this is only for one level deep. If we are using this in a chain of query expressions it only adds to the savings. So my recommendation? If you have a resonable expectation that someone may only want to partially consume your enumerable result, I would always tend to favor an iterator. The cost if they iterate the whole thing does not add much at all -- and if they consume only partially, you reap some really good performance gains. Next time I'll discuss some of my favorite extensions I've created to make development life a little easier and maintainability a little better.

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The blocking nature of aggregates

- by Rob Farley

I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here. In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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The blocking nature of aggregates

- by Rob Farley

I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here. In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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Oracle apresenta resultados do ano

- by pfolgado

A Oracle acabou de apresentar os resultados do 4º trimestre e do ano fiscal FY11. Os resultados mais relevantes são: Receitas de Vendas cresceram 33%, atingindo um total de 35,6 mil milhões de dólares Vendas de Novas licenças cresceram 23% Receitas de Hardware de 4,4 mil milhões de dólares Resultados operacionais cresceram 39% Resultados por acção de cresceram 38% para 1,67 dólares “In Q4, we achieved a 19% new software license growth rate with almost no help from acquisitions,” said Oracle President and CFO, Safra Catz. “This strong organic growth combined with continuously improving operational efficiencies enabled us to deliver a 48% operating margin in the quarter. As our results reflect, we clearly exceeded even our own high expectations for Sun’s business.” “In addition to record setting software sales, our Exadata and Exalogic systems also made a strong contribution to our growth in Q4,” said Oracle President, Mark Hurd. “Today there are more than 1,000 Exadata machines installed worldwide. Our goal is to triple that number in FY12.” “In FY11 Oracle’s database business experienced its fastest growth in a decade,” said Oracle CEO, Larry Ellison. “Over the past few years we added features to the Oracle database for both cloud computing and in-memory databases that led to increased database sales this past year. Lately we’ve been focused on the big business opportunity presented by Big Data.” Oracle Reports Q4 GAAP EPS Up 34% To 62 Cents; Q4 NON-GAAP EPS Up 25% To 75 Cents Q4 Software New License Sales Up 19%, Q4 Total Revenue Up 13% Oracle today announced fiscal 2011 Q4 GAAP total revenues were up 13% to $10.8 billion, while non-GAAP total revenues were up 12% to $10.8 billion. Both GAAP and non-GAAP new software license revenues were up 19% to $3.7 billion. Both GAAP and non-GAAP software license updates and product support revenues were up 15% to $4.0 billion. Both GAAP and non-GAAP hardware systems products revenues were down 6% to $1.2 billion. GAAP operating income was up 32% to $4.4 billion, and GAAP operating margin was 40%. Non-GAAP operating income was up 19% to $5.2 billion, and non-GAAP operating margin was 48%. GAAP net income was up 36% to $3.2 billion, while non-GAAP net income was up 27% to $3.9 billion. GAAP earnings per share were $0.62, up 34% compared to last year while non-GAAP earnings per share were up 25% to $0.75. GAAP operating cash flow on a trailing twelve-month basis was $11.2 billion. For fiscal year 2011, GAAP total revenues were up 33% to $35.6 billion, while non-GAAP total revenues were up 33% to $35.9 billion. Both GAAP and non-GAAP new software license revenues were up 23% to $9.2 billion. GAAP software license updates and product support revenues were up 13% to $14.8 billion, while non-GAAP software license updates and product support revenues were up 13% to $14.9 billion. Both GAAP and non-GAAP hardware systems products revenues were $4.4 billion. GAAP operating income was up 33% to $12.0 billion, and GAAP operating margin was 34%. Non-GAAP operating income was up 27% to $15.9 billion, and non-GAAP operating margin was 44%. GAAP net income was up 39% to $8.5 billion, while non-GAAP net income was up 34% to $11.4 billion. GAAP earnings per share were $1.67, up 38% compared to last year while non-GAAP earnings per share were up 33% to $2.22. “In Q4, we achieved a 19% new software license growth rate with almost no help from acquisitions,” said Oracle President and CFO, Safra Catz. “This strong organic growth combined with continuously improving operational efficiencies enabled us to deliver a 48% operating margin in the quarter. As our results reflect, we clearly exceeded even our own high expectations for Sun’s business.” “In addition to record setting software sales, our Exadata and Exalogic systems also made a strong contribution to our growth in Q4,” said Oracle President, Mark Hurd. “Today there are more than 1,000 Exadata machines installed worldwide. Our goal is to triple that number in FY12.” “In FY11 Oracle’s database business experienced its fastest growth in a decade,” said Oracle CEO, Larry Ellison. “Over the past few years we added features to the Oracle database for both cloud computing and in-memory databases that led to increased database sales this past year. Lately we’ve been focused on the big business opportunity presented by Big Data.” In addition, Oracle also announced that its Board of Directors declared a quarterly cash dividend of $0.06 per share of outstanding common stock. This dividend will be paid to stockholders of record as of the close of business on July 13, 2011, with a payment date of August 3, 2011.

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More Fun with C# Iterators and Generators

- by James Michael Hare

In my last post, I talked quite a bit about iterators and how they can be really powerful tools for filtering a list of items down to a subset of items. This had both pros and cons over returning a full collection, which, in summary, were: Pros: If traversal is only partial, does not have to visit rest of collection. If evaluation method is costly, only incurs that cost on elements visited. Adds little to no garbage collection pressure. Cons: Very slight performance impact if you know caller will always consume all items in collection. And as we saw in the last post, that con for the cost was very, very small and only really became evident on very tight loops consuming very large lists completely. One of the key items to note, though, is the garbage! In the traditional (return a new collection) method, if you have a 1,000,000 element collection, and wish to transform or filter it in some way, you have to allocate space for that copy of the collection. That is, say you have a collection of 1,000,000 items and you want to double every item in the collection. Well, that means you have to allocate a collection to hold those 1,000,000 items to return, which is a lot especially if you are just going to use it once and toss it. Iterators, though, don't have this problem. Each time you visit the node, it would return the doubled value of the node (in this example) and not allocate a second collection of 1,000,000 doubled items. Do you see the distinction? In both cases, we're consuming 1,000,000 items. But in one case we pass back each doubled item which is just an int (for example's sake) on the stack and in the other case, we allocate a list containing 1,000,000 items which then must be garbage collected. So iterators in C# are pretty cool, eh? Well, here's one more thing a C# iterator can do that a traditional "return a new collection" transformation can't! It can return **unbounded** collections! I know, I know, that smells a lot like an infinite loop, eh? Yes and no. Basically, you're relying on the caller to put the bounds on the list, and as long as the caller doesn't you keep going. Consider this example: public static class Fibonacci { // returns the infinite fibonacci sequence public static IEnumerable<int> Sequence() { int iteration = 0; int first = 1; int second = 1; int current = 0; while (true) { if (iteration++ < 2) { current = 1; } else { current = first + second; second = first; first = current; } yield return current; } } } Whoa, you say! Yes, that's an infinite loop! What the heck is going on there? Yes, that was intentional. Would it be better to have a fibonacci sequence that returns only a specific number of items? Perhaps, but that wouldn't give you the power to defer the execution to the caller. The beauty of this function is it is as infinite as the sequence itself! The fibonacci sequence is unbounded, and so is this method. It will continue to return fibonacci numbers for as long as you ask for them. Now that's not something you can do with a traditional method that would return a collection of ints representing each number. In that case you would eventually run out of memory as you got to higher and higher numbers. This method, though, never runs out of memory. Now, that said, you do have to know when you use it that it is an infinite collection and bound it appropriately. Fortunately, Linq provides a lot of these extension methods for you! Let's say you only want the first 10 fibonacci numbers: foreach(var fib in Fibonacci.Sequence().Take(10)) { Console.WriteLine(fib); } Or let's say you only want the fibonacci numbers that are less than 100: foreach(var fib in Fibonacci.Sequence().TakeWhile(f => f < 100)) { Console.WriteLine(fib); } So, you see, one of the nice things about iterators is their power to work with virtually any size (even infinite) collections without adding the garbage collection overhead of making new collections. You can also do fun things like this to make a more "fluent" interface for for loops: // A set of integer generator extension methods public static class IntExtensions { // Begins counting to inifity, use To() to range this. public static IEnumerable<int> Every(this int start) { // deliberately avoiding condition because keeps going // to infinity for as long as values are pulled. for (var i = start; ; ++i) { yield return i; } } // Begins counting to infinity by the given step value, use To() to public static IEnumerable<int> Every(this int start, int byEvery) { // deliberately avoiding condition because keeps going // to infinity for as long as values are pulled. for (var i = start; ; i += byEvery) { yield return i; } } // Begins counting to inifity, use To() to range this. public static IEnumerable<int> To(this int start, int end) { for (var i = start; i <= end; ++i) { yield return i; } } // Ranges the count by specifying the upper range of the count. public static IEnumerable<int> To(this IEnumerable<int> collection, int end) { return collection.TakeWhile(item => item <= end); } } Note that there are two versions of each method. One that starts with an int and one that starts with an IEnumerable<int>. This is to allow more power in chaining from either an existing collection or from an int. This lets you do things like: // count from 1 to 30 foreach(var i in 1.To(30)) { Console.WriteLine(i); } // count from 1 to 10 by 2s foreach(var i in 0.Every(2).To(10)) { Console.WriteLine(i); } // or, if you want an infinite sequence counting by 5s until something inside breaks you out... foreach(var i in 0.Every(5)) { if (someCondition) { break; } ... } Yes, those are kinda play functions and not particularly useful, but they show some of the power of generators and extension methods to form a fluid interface. So what do you think? What are some of your favorite generators and iterators?

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Call methods in main method

- by Niloo

this is my main method that gets 3 integers from command line and I parse then in my validating method. However I have one operation method that calls 3 other methods, but i don't know what type of data and howmany I have to put in my operatinMethod() " cuase switch only gets one); AND also in my mainMethod() for calling the operationMehod(); itself? please let me know if i'm not clear? Thanx! main method: public class test { // Global Constants final static int MIN_NUMBER = 1; final static int MAX_PRIME = 10000; final static int MAX_FACTORIAL = 12; final static int MAX_LEAPYEAR = 4000; //Global Variables static int a,b,c; public static void main (String[] args) { for(int i =0; i< args.length; i++){} if(validateInput(args[0],args[1],args[2])){ performOperations(); } } //Validate User Input public static boolean validateInput(String num1,String num2,String num3){ boolean isValid = false; try{ try{ try{ a = Integer.parseInt(num1); if(!withinRange(a,MIN_NUMBER, MAX_PRIME)) { System.out.println("The entered value " + num1 +" is out of range [1 TO 10000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num1 + " is not a valid integer. Please try again."); } b = Integer.parseInt(num2); if(!withinRange(b,MIN_NUMBER, MAX_FACTORIAL)) { System.out.println("The entered value " + num2 +" is out of range [1 TO 12]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num2 + " is not a valid integer. Please try again."); } c = Integer.parseInt(num3); if(!withinRange(c,MIN_NUMBER, MAX_LEAPYEAR)) { System.out.println("The entered value " + num3 +" is out of range [1 TO 4000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num3 + " is not a valid integer. Please try again."); } return isValid; } //Check the value within the specified range private static boolean withinRange(int userInput ,int min, int max){ boolean isInRange = true; if(userInput < min || userInput > max){ isInRange = false; } return isInRange; } //Perform operations private static void performOperations(int userInput) { switch(userInput) { case 1: // count Prime numbers countPrimes(a); break; case 2: // Calculate factorial getFactorial(b); break; case 3: // find Leap year isLeapYear(c); break; } } // Verify Prime Number private static boolean isPrime(int prime) { for(int i = 2; i <= Math.sqrt(prime) ; i++) { if ((prime % i) == 0) { return false; } } return true; } // Calculate Prime private static int countPrimes(int userInput){ int count =0; for(int i=userInput; i<=MAX_PRIME; i++) { if(isPrime(i)){ count++; } } System.out.println("Exactly "+ count + " prime numbers exist between "+ a + " and 10,000."); return count; } // Calculate the factorial value private static int getFactorial(int userInput){ int ans = userInput; if(userInput >1 ){ ans*= (getFactorial(userInput-1)); //System.out.println("The value of "+ b +"! is "+ getFactorial(userInput)); } return ans; } // Determine whether the integer represents a leap year private static boolean isLeapYear(int userInput){ if (userInput % 4 == 0 && userInput % 400 == 0 && userInput % 100 ==0){ System.out.println("The year "+ c +" is a leap year"); } else { System.out.println("The year "+ c +" is a not leap year"); } return false; } }

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C# UDP decoding datagrams fails randomly

- by Tom Frey

Hi, I'm experiencing an issue in a multi threaded application and have been debugging it for the last 3 days but for the life of it can not figure it out. I'm writing this, hoping that I either have a DUH moment when typing this or somebody sees something obvious in the code snippets I provide. Here's what's going on: I've been working on a new UDP networking library and have a data producer that multicasts UDP datagrams to several receiver applications. The sender sends on two different sockets that are bound to separate UDP multicast addresses and separate ports. The receiver application also creates two sockets and binds each one to one of the sender's multicast address/port. When the receiver receives the datagram, it copies it from the the buffer in a MemoryStream which is then put onto a thread safe queue, where another thread reads from it and decodes the data out of the MemoryStream. Both sockets have their own queues. What happens now is really weird, it happens randomly, non-reproducible and when I run multiple receiver applications, it only happens randomly on one of them every now and then. Basically, the thread that reads the MemoryStream out of the queue, reads it via a BinaryReader like ReadInt32(), etc. and thereby decodes the data. Every now and then however when it reads the data, the data it reads from it is incorrect, e.g. a negative integer number which the sender never would encode. However, as mentioned before, the decoding only fails in one of the receiver applications, in the other ones the datagram decodes fine. Now you might be saying, well, probably the UDP datagram has a byte corruption or something but I've logged every single datagram that's coming in and compared them on all receivers and the datagrams every application receives are absolutely identical. Now it gets even weirder, when I dump the datagram that failed to decode to disk and write a unit test that reads it and runs it through the decoder, it decodes just fine. Also when I wrap a try/catch around the decoder, reset the MemoryStream position in the catch and run it through the decoder again, it decodes just fine. To make it even weirder, this also only happens when I bind both sockets to read data from the sender, if I only bind one, it doesn't happen or at least I wasn't able to reproduce it. Here are is some corresponding code to what's going on: This is the receive callback for the socket: private void ReceiveCompleted(object sender, SocketAsyncEventArgs args) { if (args.SocketError != SocketError.Success) { InternalShutdown(args.SocketError); return; } if (args.BytesTransferred > SequencedUnitHeader.UNIT_HEADER_SIZE) { DataChunk chunk = new DataChunk(args.BytesTransferred); Buffer.BlockCopy(args.Buffer, 0, chunk.Buffer, 0, args.BytesTransferred); chunk.MemoryStream = new MemoryStream(chunk.Buffer); chunk.BinaryReader = new BinaryReader(chunk.MemoryStream); chunk.SequencedUnitHeader.SequenceID = chunk.BinaryReader.ReadUInt32(); chunk.SequencedUnitHeader.Count = chunk.BinaryReader.ReadByte(); if (prevSequenceID + 1 != chunk.SequencedUnitHeader.SequenceID) { log.Error("UdpDatagramGap\tName:{0}\tExpected:{1}\tReceived:{2}", unitName, prevSequenceID + 1, chunk.SequencedUnitHeader.SequenceID); } else if (chunk.SequencedUnitHeader.SequenceID < prevSequenceID) { log.Error("UdpOutOfSequence\tName:{0}\tExpected:{1}\tReceived:{2}", unitName, prevSequenceID + 1, chunk.SequencedUnitHeader.SequenceID); } prevSequenceID = chunk.SequencedUnitHeader.SequenceID; messagePump.Produce(chunk); } else UdpStatistics.FramesRxDiscarded++; Socket.InvokeAsyncMethod(Socket.ReceiveAsync, ReceiveCompleted, asyncReceiveArgs); } Here's some stub code that decodes the data: public static void OnDataChunk(DataChunk dataChunk) { try { for (int i = 0; i < dataChunk.SequencedUnitHeader.Count; i++) { int val = dataChunk.BinaryReader.ReadInt32(); if(val < 0) throw new Exception("EncodingException"); // do something with that value } } catch (Exception ex) { writer.WriteLine("ID:" + dataChunk.SequencedUnitHeader.SequenceID + " Count:" + dataChunk.SequencedUnitHeader.Count + " " + BitConverter.ToString(dataChunk.Buffer, 0, dataChunk.Size)); writer.Flush(); log.ErrorException("OnDataChunk", ex); log.Info("RETRY FRAME:{0} Data:{1}", dataChunk.SequencedUnitHeader.SequenceID, BitConverter.ToString(dataChunk.Buffer, 0, dataChunk.Size)); dataChunk.MemoryStream.Position = 0; dataChunk.SequencedUnitHeader.SequenceID = dataChunk.BinaryReader.ReadUInt32(); dataChunk.SequencedUnitHeader.Count = dataChunk.BinaryReader.ReadByte(); OnDataChunk(dataChunk); } } You see in the catch{} part I simply reset the MemoryStream.Position to 0 and call the same method again and it works just fine that next time? I'm really out of ideas at this point and unfortunately had no DUH moment writing this. Anybody have any kind of idea what might be going on or what else I could do to troubleshoot this? Thanks, Tom

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When is a Seek not a Seek?

- by Paul White

The following script creates a single-column clustered table containing the integers from 1 to 1,000 inclusive. IF OBJECT_ID(N'tempdb..#Test', N'U') IS NOT NULL DROP TABLE #Test ; GO CREATE TABLE #Test ( id INTEGER PRIMARY KEY CLUSTERED ); ; INSERT #Test (id) SELECT V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 1000 ; Let’s say we need to find the rows with values from 100 to 170, excluding any values that divide exactly by 10. One way to write that query would be: SELECT T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; That query produces a pretty efficient-looking query plan: Knowing that the source column is defined as an INTEGER, we could also express the query this way: SELECT T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; We get a similar-looking plan: If you look closely, you might notice that the line connecting the two icons is a little thinner than before. The first query is estimated to produce 61.9167 rows – very close to the 63 rows we know the query will return. The second query presents a tougher challenge for SQL Server because it doesn’t know how to predict the selectivity of the modulo expression (T.id % 10 > 0). Without that last line, the second query is estimated to produce 68.1667 rows – a slight overestimate. Adding the opaque modulo expression results in SQL Server guessing at the selectivity. As you may know, the selectivity guess for a greater-than operation is 30%, so the final estimate is 30% of 68.1667, which comes to 20.45 rows. The second difference is that the Clustered Index Seek is costed at 99% of the estimated total for the statement. For some reason, the final SELECT operator is assigned a small cost of 0.0000484 units; I have absolutely no idea why this is so, or what it models. Nevertheless, we can compare the total cost for both queries: the first one comes in at 0.0033501 units, and the second at 0.0034054. The important point is that the second query is costed very slightly higher than the first, even though it is expected to produce many fewer rows (20.45 versus 61.9167). If you run the two queries, they produce exactly the same results, and both complete so quickly that it is impossible to measure CPU usage for a single execution. We can, however, compare the I/O statistics for a single run by running the queries with STATISTICS IO ON: Table '#Test'. Scan count 63, logical reads 126, physical reads 0. Table '#Test'. Scan count 01, logical reads 002, physical reads 0. The query with the IN list uses 126 logical reads (and has a ‘scan count’ of 63), while the second query form completes with just 2 logical reads (and a ‘scan count’ of 1). It is no coincidence that 126 = 63 * 2, by the way. It is almost as if the first query is doing 63 seeks, compared to one for the second query. In fact, that is exactly what it is doing. There is no indication of this in the graphical plan, or the tool-tip that appears when you hover your mouse over the Clustered Index Seek icon. To see the 63 seek operations, you have click on the Seek icon and look in the Properties window (press F4, or right-click and choose from the menu): The Seek Predicates list shows a total of 63 seek operations – one for each of the values from the IN list contained in the first query. I have expanded the first seek node to show the details; it is seeking down the clustered index to find the entry with the value 101. Each of the other 62 nodes expands similarly, and the same information is contained (even more verbosely) in the XML form of the plan. Each of the 63 seek operations starts at the root of the clustered index B-tree and navigates down to the leaf page that contains the sought key value. Our table is just large enough to need a separate root page, so each seek incurs 2 logical reads (one for the root, and one for the leaf). We can see the index depth using the INDEXPROPERTY function, or by using the a DMV: SELECT S.index_type_desc, S.index_depth FROM sys.dm_db_index_physical_stats ( DB_ID(N'tempdb'), OBJECT_ID(N'tempdb..#Test', N'U'), 1, 1, DEFAULT ) AS S ; Let’s look now at the Properties window when the Clustered Index Seek from the second query is selected: There is just one seek operation, which starts at the root of the index and navigates the B-tree looking for the first key that matches the Start range condition (id >= 101). It then continues to read records at the leaf level of the index (following links between leaf-level pages if necessary) until it finds a row that does not meet the End range condition (id <= 169). Every row that meets the seek range condition is also tested against the Residual Predicate highlighted above (id % 10 > 0), and is only returned if it matches that as well. You will not be surprised that the single seek (with a range scan and residual predicate) is much more efficient than 63 singleton seeks. It is not 63 times more efficient (as the logical reads comparison would suggest), but it is around three times faster. Let’s run both query forms 10,000 times and measure the elapsed time: DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON; SET STATISTICS XML OFF; ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; GO DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; On my laptop, running SQL Server 2008 build 4272 (SP2 CU2), the IN form of the query takes around 830ms and the range query about 300ms. The main point of this post is not performance, however – it is meant as an introduction to the next few parts in this mini-series that will continue to explore scans and seeks in detail. When is a seek not a seek? When it is 63 seeks © Paul White 2011 email: [email protected] twitter: @SQL_kiwi

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Reworking my singly linked list

- by Stradigos

Hello everyone, thanks for taking the time to stop by my question. Below you will find my working SLL, but I want to make more use of C# and, instead of having two classes, SLL and Node, I want to use Node's constructors to do all the work (To where if you pass a string through the node, the constructor will chop it up into char nodes). The problem is, after an a few hours of tinkering, I'm not really getting anywhere... using System; using System.Collections.Generic; using System.Text; using System.IO; namespace PalindromeTester { class Program { static void Main(string[] args) { SLL mySLL = new SLL(); mySLL.add('a'); mySLL.add('b'); mySLL.add('c'); mySLL.add('d'); mySLL.add('e'); mySLL.add('f'); Console.Out.WriteLine("Node count = " + mySLL.count); mySLL.reverse(); mySLL.traverse(); Console.Out.WriteLine("\n The header is: " + mySLL.gethead); Console.In.ReadLine(); } class Node { private char letter; private Node next; public Node() { next = null; } public Node(char c) { this.data = c; } public Node(string s) { } public char data { get { return letter; } set { letter = value; } } public Node nextNode { get { return next; } set { next = value; } } } class SLL { private Node head; private int totalNode; public SLL() { head = null; totalNode = 0; } public void add(char s) { if (head == null) { head = new Node(); head.data = s; } else { Node temp; temp = new Node(); temp.data = s; temp.nextNode = head; head = temp; } totalNode++; } public int count { get { return totalNode; } } public char gethead { get { return head.data; } } public void traverse() { Node temp = head; while(temp != null) { Console.Write(temp.data + " "); temp = temp.nextNode; } } public void reverse() { Node q = null; Node p = this.head; while(p!=null) { Node r=p; p=p.nextNode; r.nextNode=q; q=r; } this.head = q; } } } } Here's what I have so far in trying to work it into Node's constructors: using System; using System.Collections.Generic; using System.Text; using System.IO; namespace PalindromeTester { class Program { static void Main(string[] args) { //Node myList = new Node(); //TextReader tr = new StreamReader("data.txt"); //string line; //while ((line = tr.ReadLine()) != null) //{ // Console.WriteLine(line); //} //tr.Close(); Node myNode = new Node("hello"); Console.Out.WriteLine(myNode.count); myNode.reverse(); myNode.traverse(); // Console.Out.WriteLine(myNode.gethead); Console.In.ReadLine(); } class Node { private char letter; private Node next; private Node head; private int totalNode; public Node() { head = null; totalNode = 0; } public Node(char c) { if (head == null) { head = new Node(); head.data = c; } else { Node temp; temp = new Node(); temp.data = c; temp.nextNode = head; head = temp; } totalNode++; } public Node(string s) { foreach (char x in s) { new Node(x); } } public char data { get { return letter; } set { letter = value; } } public Node nextNode { get { return next; } set { next = value; } } public void reverse() { Node q = null; Node p = this.head; while (p != null) { Node r = p; p = p.nextNode; r.nextNode = q; q = r; } this.head = q; } public void traverse() { Node temp = head; while (temp != null) { Console.Write(temp.data + " "); temp = temp.nextNode; } } public int count { get { return totalNode; } } } } } Ideally, the only constructors and methods I would be left with are Node(), Node(char c), Node(string s), Node reserve() and I'll be reworking traverse into a ToString overload. Any suggestions?

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