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• Is there a Post-Build Extensible Installer System

  - by Will Hughes

  We have a product that we need to create an installer for. It has a number of components which can be installed or not as the situation demands. When we ship our installation package, we want to be able to have that include any number of additional components to be installed. For example, Foo Manager Pro contains: Foo Manager Console Foo Manager Database Foo Manager Services That might be shipped as something like: FooManagerInstaller.exe FMPConsole.pkg FMPDatabase.pkg FMPServices.pkg A package might consist of something like: Manifest Files to be deployed Additional scripts to be executed (eg find file foo.config, do some XML Manipulation) If a client wants to add custom skins and a series of plugins as part of the install, they create their own packages: FMPConsoleSkins.pkg ClientWebservices.pkg If that client then ships it to someone else who wants to add more customisation - they can do so in the same way. We can build this from scratch - but wanted to check if this sort of install system already exists. We already have a set of NAnt scripts which do something not too far from this. But they're difficult to maintain, and quite complex. They don't offer any of the 'niceties' that we'd expect from an installer (like tracking deployed files and removing them if the install fails). We've been looking a little bit at NSIS and building MSIs using WiX, but it's not clear that these can offer us the capability for downstream to provide additional packages, without inventing our own installer language.

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• How do You Center a TextView in Layout?

  - by Ken

  I have a complex layout, part of which features a value centered over a label, with + and - buttons on either side of the value. I want the value to center between the buttons, whether it is "1" or "99". It looks fine when it's a 2-digit number like "99", but when it's a single digit the number is left-justified. How do I properly center that value? Here's the portion of my layout that does this: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@id/runway_label" android:layout_centerHorizontal="true" android:orientation="horizontal"> <ImageView android:id="@+id/dec_runway_button" android:src="@drawable/minus_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical"/> <TextView android:id="@+id/runway_value" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#FFFFFF" android:textStyle="bold" android:textSize="40.0sp" android:minWidth="50sp" android:layout_centerInParent="true" android:layout_gravity="center" android:shadowColor="#333333" android:shadowDx="2.0" android:shadowDy="2.0" android:shadowRadius="3.0" /> <ImageView android:id="@+id/inc_runway_button" android:src="@drawable/plus_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical"/> </LinearLayout>

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• Oracle why does creating trigger fail when there is a field called timestamp?

  - by Omar Kooheji

  I've just wasted the past two hours of my life trying to create a table with an auto incrementing primary key bases on this tutorial, The tutorial is great the issue I've been encountering is that the Create Target fails if I have a column which is a timestamp and a table that is called timestamp in the same table... Why doesn't oracle flag this as being an issue when I create the table? Here is the Sequence of commands I enter: Creating the Table: CREATE TABLE myTable (id NUMBER PRIMARY KEY, field1 TIMESTAMP(6), timeStamp NUMBER, ); Creating the Sequence: CREATE SEQUENCE test_sequence START WITH 1 INCREMENT BY 1; Creating the trigger: CREATE OR REPLACE TRIGGER test_trigger BEFORE INSERT ON myTable REFERENCING NEW AS NEW FOR EACH ROW BEGIN SELECT test_sequence.nextval INTO :NEW.ID FROM dual; END; / Here is the error message I get: ORA-06552: PL/SQL: Compilation unit analysis terminated ORA-06553: PLS-320: the declaration of the type of this expression is incomplete or malformed Any combination that does not have the two lines with a the word "timestamp" in them works fine. I would have thought the syntax would be enough to differentiate between the keyword and a column name. As I've said I don't understand why the table is created fine but oracle falls over when I try to create the trigger... CLARIFICATION I know that the issue is that there is a column called timestamp which may or may not be a keyword. MY issue is why it barfed when I tried to create a trigger and not when I created the table, I would have at least expected a warning. That said having used Oracle for a few hours, it seems a lot less verbose in it's error reporting, Maybe just because I'm using the express version though. If this is a bug in Oracle how would one who doesn't have a support contract go about reporting it? I'm just playing around with the express version because I have to migrate some code from MySQL to Oracle.

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• AS3 URLRequest in for Loop problem

  - by Adrian

  Hi guys, I read some data from a xml file, everything works great besides urls. I can't figure what's the problem with the "navigateURL" function or with the eventListener... on which square I click it opens the last url from the xml file for(var i:Number = 0; i <= gamesInput.game.length() -1; i++) { var square:square_mc = new square_mc(); //xml values var tGame_name:String = gamesInput.game.name.text()[i];//game name var tGame_id:Number = gamesInput.children()[i].attributes()[2].toXMLString();//game id var tGame_thumbnail:String = thumbPath + gamesInput.game.thumbnail.text()[i];//thumb path var tGame_url:String = gamesInput.game.url.text()[i];//game url addChild(square); square.tgname_txt.text = tGame_name; square.tgurl_txt.text = tGame_url; //load & attach game thumb var getThumb:URLRequest = new URLRequest(tGame_thumbnail); var loadThumb:Loader = new Loader(); loadThumb.load(getThumb); square.addChild(loadThumb); // square.y = squareY; square.x = squareX; squareX += square.width + 10; square.buttonMode = true; this.addEventListener(MouseEvent.CLICK, navigateURL); } function navigateURL(event:MouseEvent):void { var url:URLRequest = new URLRequest(tGame_url); navigateToURL(url, "_blank"); trace(tGame_url); } Many thanks!

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• What is optimal hardware configuration for heavy load LAMP application

  - by Piotr Kochanski

  I need to run Linux-Apache-PHP-MySQL application (Moodle e-learning platform) for a large number of concurrent users - I am aiming 5000 users. By concurrent I mean that 5000 people should be able to work with the application at the same time. "Work" means not only do database reads but writes as well. The application is not very typical, since it is doing a lot of inserts/updates on the database, so caching techniques are not helping to much. We are using InnoDB storage engine. In addition application is not written with performance in mind. For instance one Apache thread usually occupies about 30-50 MB of RAM. I would be greatful for information what hardware is needed to build scalable configuration that is able to handle this kind of load. We are using right now two HP DLG 380 with two 4 core processors which are able to handle much lower load (typically 300-500 concurrent users). Is it reasonable to invest in this kind of boxes and build cluster using them or is it better to go with some more high-end hardware? I am particularly curious how many and how powerful servers are needed (number of processors/cores, size of RAM) what network equipment should be used (what kind of switches, network cards) any other hardware, like particular disc storage solutions, etc, that are needed Another thing is how to put together everything, that is what is the most optimal architecture. Clustering with MySQL is rather hard (people are complaining about MySQL Cluster, even here on Stackoverflow).

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• HATEOAS - Discovery and URI Templating

  - by Paul Kirby

  I'm designing a HATEOAS API for internal data at my company, but have been having troubles with the discovery of links. Consider the following set of steps for someone to retrieve information about a specific employee in this system: User sends GET to http://coredata/ to get all available resources, returns a number of links including one tagged as rel = "http://coredata/rels/employees" User follows HREF on the rel from the first request, performing a GET at (for example) http://coredata/employees The data returned from this last call is my conundrum and a situation where I've heard mixed suggestions. Here are some of them: That GET will return all employees (with perhaps truncated data), and the client would be responsible for picking the one it wants from that list. That GET would return a number of URI templated links describing how to query / get one employee / get all employees. Something like: "_links": { "http://coredata/rels/employees#RetrieveOne": { "href": "http://coredata/employees/{id}" }, "http://coredata/rels/employees#Query": { "href": "http://coredata/employees{?login,firstName,lastName}" }, "http://coredata/rels/employees#All": { "href": "http://coredata/employees/all" } } I'm a little stuck here with what remains closest to HATEOAS. For option 1, I really do not want to make my clients retrieve all employees every time for the sake of navigation, but I can see how using URI templating in example two introduces some out-of-band knowledge. My other thought was to use the RetrieveOne, Query, and All operations as my cool URLs, but that seems to violate the concept that you should be able to navigate to the resources you want from one base URI. Has anyone else managed to come up with a good way to handle this? Navigation is dead simple once you've retrieved one resource or a set of resources, but it seems very difficult to use for discovery.

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• CentOS 6.3 Virtual under OpenVZ cannot ping, host lookups, outbound connections while postfix running

  - by Paul Cravey

  My best theory is that some kernel limit is being hit preventing outbound connections. We have tried basically everything from tcpdumps to provisioning an entirely new virtual server (we do not have this problem on any other virtuals), however the problem somehow carried over, even with new postfix build (working). Emails work, and outbound connections work, so long as postfix does not have too much going on. /proc/user_beancounters shows no limits being hit (show below). Nevertheless, pings fail even to IP addresses. TCP stack appears healthy. Load is low. No iowait. Flushed iptables already. Has anyone experienced anything like this? uid resource held maxheld barrier limit failcnt 3: kmemsize 166216365 170262528 9223372036854775807 9223372036854775807 0 lockedpages 0 0 9223372036854775807 9223372036854775807 0 privvmpages 285727 351885 9223372036854775807 9223372036854775807 0 shmpages 16933 17605 9223372036854775807 9223372036854775807 0 dummy 0 0 0 0 0 numproc 150 303 9223372036854775807 9223372036854775807 0 physpages 314156 326191 0 1280000 0 vmguarpages 0 0 9223372036854775807 9223372036854775807 0 oomguarpages 165355 165355 9223372036854775807 9223372036854775807 0 numtcpsock 89 172 9223372036854775807 9223372036854775807 0 numflock 22 76 9223372036854775807 9223372036854775807 0 numpty 1 2 9223372036854775807 9223372036854775807 0 numsiginfo 0 75 9223372036854775807 9223372036854775807 0 tcpsndbuf 2733472 4371752 9223372036854775807 9223372036854775807 0 tcprcvbuf 1798336 5427296 9223372036854775807 9223372036854775807 0 othersockbuf 491120 1000760 9223372036854775807 9223372036854775807 0 dgramrcvbuf 0 238728 9223372036854775807 9223372036854775807 0 numothersock 361 505 9223372036854775807 9223372036854775807 0 dcachesize 135941831 136114679 9223372036854775807 9223372036854775807 0 numfile 2905 4990 9223372036854775807 9223372036854775807 0 dummy 0 0 0 0 0 dummy 0 0 0 0 0 dummy 0 0 0 0 0 numiptent 8 9 9223372036854775807 9223372036854775807 0 [root@bni /]# ping 4.2.2.1 PING 4.2.2.1 (4.2.2.1) 56(84) bytes of data. --- 4.2.2.1 ping statistics --- 9 packets transmitted, 0 received, 100% packet loss, time 8493ms [root@bni /]# service postfix stop [root@bni /]# ping 4.2.2.1 PING 4.2.2.1 (4.2.2.1) 56(84) bytes of data. 64 bytes from 4.2.2.1: icmp_seq=1 ttl=53 time=8.63 ms 64 bytes from 4.2.2.1: icmp_seq=2 ttl=53 time=8.62 ms 64 bytes from 4.2.2.1: icmp_seq=3 ttl=53 time=8.63 ms 64 bytes from 4.2.2.1: icmp_seq=4 ttl=53 time=8.66 ms Outbound connections of all sorts fail when postfix is running.

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• Assigning figure size to a figure with a given handle (MATLAB)

  - by James

  Hi, is there a way to assign the outerposition property of a figure to a figure with a given handle? For example, if I wanted to define a figure as say figure 1, I would use: figure(1) imagesc(Arrayname) % I.e. any array I can also change the properties of a figure using the code: figure('Name', 'Name of figure','NumberTitle','off','OuterPosition',[scrsz(1) scrsz(2) 700 700]); Is there a propertyname I can use to assign the outerposition property to the figure assigned as figure 1? The reason I am asking this is because I am using a command called save2word (from the MATLAB file exchange) to save some plots from a function I have made to a word file, and I want to limit the number of figures I have open as it does this. The rest of the code I have is: plottedloops = [1, 5:5:100]; % Specifies which loops I want to save GetGeometry = getappdata(0, 'GeometryAtEachLoop') % Obtains a 4D array containing geometry information at each loop NumSections = size(GetGeometry,4); %Defined by the fourth dimension of the 4D array for j = 1:NumSections for i = 1:plottedloops P = GetGeometry(:,:,i,j); TitleSize = 14; Fsize = 8; % Save Geometry scrsz = get(0,'ScreenSize'); %left, bottom, width height figure('Name', 'Geometry at each loop','NumberTitle','off','OuterPosition',[scrsz(1) scrsz(2) 700 700]); This specifies the figure name, dims etc., but also means multiple figures are opened as the command runs. % I have tried this, but it doesn't work: % figure(0, 'OuterPosition',[scrsz(1) scrsz(2) 700 700]); imagesc(P), title('Geometry','FontSize', TitleSize), axis([0 100 0 100]); text(20,110,['Loop:',num2str(i)], 'FontSize', TitleSize); % Show loop in figure text(70,110,['Section:',num2str(j)], 'FontSize', TitleSize);% Show Section number in figure save2word('Geometry at each loop'); % Saves figure to a word file end end Thanks

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• php POST response

  - by amit

  I am making a POST to another php file that I want to render in the browser. so clearly, using jquery POST wont work, since it works through AJAX. echo '<div class="showcase_URL"><a class="purl" name="'.$row->num.'" href="#">PROJECT URL</a></div>'; what I have till now in javascript is: $(".showcase_URL a").click(function() { //alert($(this).attr("name")); var number = $(this).attr("name"); $.post( "app-display.php", {app: number}, function(data){ top.location.href = 'app-display.php'; }); }); what I have in app-display.php: $query = 'SELECT num, title, thumb_url, url, type, cat, dated, details FROM app WHERE `num` = "$_POST[app]"'; but it is currently giving me a page without the contents of app-display.php. all the other fragments of the page are loading: header, footer etc. the PHP Response (in Firebug) I am getting is the normal html of the page. how should i do it?

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• bind event handler on keydown listen function JavaScript jQuery

  - by user1644123

  I am trying to bind a handler to an event. The event is a keydown function. The handler will listen for hit variables to produce one of two conditions. The 1st condition (odd number of hits) will perform 1 function, the 2nd (even number of hits) will perform another function. To elaborate, the 1st function will scroll to one element, the 2nd will scroll to another element. My syntax may be the wrong approach, but it works for the 1st condition, but not the 2nd. I think I have the conditional statement in the wrong place. How can I rewrite this to work as intended? Thank you kindly, in advance! $(document).keydown(function(e) { switch (e.which) { case 37: break; case 38: break; case 39: break; case 40: //bottom arrow key var hits = 0; if (hits % 2 !== 0) { $('#wrap').animate({ scrollTop: $("#scrollToHere").offset().top }, 2800); } else { $('#wrap').animate({ scrollTop: $("#scroll2ToHere").offset().top }, 2800); } hits++; return false; break; } })? *I moved "var hits = 0;" to the top, but it only works! But is there a way I can reset the whole thing after every two hits? I want to reset because when there is a bug and if I press a 3rd time it scrolls to the very top of the page, where there is no element to make it scroll to the top. Why would it scroll to the top of the page if I never scripted it to do so?? *

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• Java: Implement own message queue (threadsafe)

  - by derMax

  The task is to implement my own messagequeue that is thread safe. My approach: public class MessageQueue { /** * Number of strings (messages) that can be stored in the queue. */ private int capacity; /** * The queue itself, all incoming messages are stored in here. */ private Vector<String> queue = new Vector<String>(capacity); /** * Constructor, initializes the queue. * * @param capacity The number of messages allowed in the queue. */ public MessageQueue(int capacity) { this.capacity = capacity; } /** * Adds a new message to the queue. If the queue is full, it waits until a message is released. * * @param message */ public synchronized void send(String message) { //TODO check } /** * Receives a new message and removes it from the queue. * * @return */ public synchronized String receive() { //TODO check return "0"; } } If the queue is empty and I call remove(), I want to call wait() so that another thread can use the send() method. Respectively, I have to call notifyAll() after every iteration. Question: Is that possible? I mean does it work that when I say wait() in one method of an object, that I can then execute another method of the same object? And another question: Does that seem to be clever?

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• Access cost of dynamically created objects with dynamically allocated members

  - by user343547

  I'm building an application which will have dynamic allocated objects of type A each with a dynamically allocated member (v) similar to the below class class A { int a; int b; int* v; }; where: The memory for v will be allocated in the constructor. v will be allocated once when an object of type A is created and will never need to be resized. The size of v will vary across all instances of A. The application will potentially have a huge number of such objects and mostly need to stream a large number of these objects through the CPU but only need to perform very simple computations on the members variables. Could having v dynamically allocated could mean that an instance of A and its member v are not located together in memory? What tools and techniques can be used to test if this fragmentation is a performance bottleneck? If such fragmentation is a performance issue, are there any techniques that could allow A and v to allocated in a continuous region of memory? Or are there any techniques to aid memory access such as pre-fetching scheme? for example get an object of type A operate on the other member variables whilst pre-fetching v. If the size of v or an acceptable maximum size could be known at compile time would replacing v with a fixed sized array like int v[max_length] lead to better performance? The target platforms are standard desktop machines with x86/AMD64 processors, Windows or Linux OSes and compiled using either GCC or MSVC compilers.

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• Codeigniter Pagination: Run the Query Twice?

  - by Frank

  I'm using codeigniter and the pagination class. This is such a basic question, but I need to make sure I'm not missing something. In order to get the config items necessary to paginate results getting them from a MySQL database it's basically necessary to run the query twice is that right? In other words, you have to run the query to determine the total number of records before you can paginate. So I'm doing it like: Do this query to get number of results $this->db->where('something', $something); $query = $this->db->get('the_table_name'); $num_rows = $query->num_rows(); Then I'll have to do it again to get the results with the limit and offset. Something like: $this->db->where('something', $something); $this->db->limit($limit, $offset); $query = $this->db->get('the_table_name'); if($query->num_rows()){ foreach($query->result_array() as $row){ ## get the results here } } I just wonder if I'm actually doing this right in that the query always needs to be run twice? The queries I'm using are much more complex than what is shown above.

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• How can I change some specific carps into croaks in Perl?

  - by sid_com

  I tried to catch a carp-warning: carp "$start is > $end" if (warnings::enabled()); ) with eval {} but it didn't work, so I looked in the eval documentation and I discovered, that eval catches only syntax-errors, run-time-errors or executed die-statements. How could I catch a carp warning? #!/usr/bin/env perl use warnings; use strict; use 5.012; use List::Util qw(max min); use Number::Range; my @array; my $max = 20; print "Input (max $max): "; my $in = <>; $in =~ s/\s+//g; $in =~ s/(?<=\d)-/../g; eval { my $range = new Number::Range( $in ); @array = sort { $a <=> $b } $range->range; }; if ( $@ =~ /\d+ is > \d+/ ) { die $@ }; # catch the carp-warning doesn't work die "Input greater than $max not allowed $!" if defined $max and max( @array ) > $max; die "Input '0' or less not allowed $!" if min( @array ) < 1; say "@array";

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• Client-Side Dynamic Removal of <script> Tags in <head>

  - by merv

  Is it possible to remove script tags in the <head> of an HTML document client-side and prior to execution of those tags? On the server-side I am able to insert a <script> above all other <script> tags in the <head>, except one, and I would like to be able to remove all subsequent scripts. I do not have the ability to remove <script> tags from the server side. What I've tried: (function (c,h) { var i, s = h.getElementsByTagName('script'); c.log("Num scripts: " + s.length); i = s.length - 1; while(i > 1) { h.removeChild(s[i]); i -= 1; } })(console, document.head); However, the logged number of scripts comes out to only 1, since (as @ryan pointed out) the code is being executed prior to the DOM being ready. Although wrapping the code above in a document.ready event callback does enable proper calculation of the number of <script> tags in the <head>, waiting until the DOM is ready fails to prevent the scripts from loading. Is there a reliable means of manipulating the HTML prior to the DOM being ready? Background If you want more context, this is part of an attempt to consolidate scripts where no option for server-side aggregation is available. Many of the JS libraries being loaded are from a CMS with limited configuration options. The content is mostly static, so there is very little concern about manually aggregating the JavaScript and serving it from a different location. Any suggestions for alternative applicable aggregation techniques would also be welcome.

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• linux new/delete, malloc/free large memory blocks

  - by brian_mk

  Hi folks, We have a linux system (kubuntu 7.10) that runs a number of CORBA Server processes. The server software uses glibc libraries for memory allocation. The linux PC has 4G physical memory. Swap is disabled for speed reasons. Upon receiving a request to process data, one of the server processes allocates a large data buffer (using the standard C++ operator 'new'). The buffer size varies depening upon a number of parameters but is typically around 1.2G Bytes. It can be up to about 1.9G Bytes. When the request has completed, the buffer is released using 'delete'. This works fine for several consecutive requests that allocate buffers of the same size or if the request allocates a smaller size than the previous. The memory appears to be free'd ok - otherwise buffer allocation attempts would eventually fail after just a couple of requests. In any case, we can see the buffer memory being allocated and freed for each request using tools such as KSysGuard etc. The problem arises when a request requires a buffer larger than the previous. In this case, operator 'new' throws an exception. It's as if the memory that has been free'd from the first allocation cannot be re-allocated even though there is sufficient free physical memory available. If I kill and restart the server process after the first operation, then the second request for a larger buffer size succeeds. i.e. killing the process appears to fully release the freed memory back to the system. Can anyone offer an explanation as to what might be going on here? Could it be some kind of fragmentation or mapping table size issue? I am thinking of replacing new/delete with malloc/free and use mallopt to tune the way the memory is being released to the system. BTW - I'm not sure if it's relevant to our problem, but the server uses Pthreads that get created and destroyed on each processing request. Cheers, Brian.

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• Stop Excel from changing cell contents, ever

  - by Enable Manual-Correct

  I work with card numbers, like credit card and ID numbers. We do not do any calculations with card numbers, obviously. They are "text." I format them as text, I type them like text. I know how that works. Excel doesn't care. 16 digit card numbers get their last digit turned into a zero, changed into scientific notation, stupid stuff that I did not tell Excel to do. I need to do things like Find/Remove spaces from cells in files downloaded from our currently imperfect web-system. The system sends me files with 16 digit numbers, cells formatted as text, but due to bugs there are spaces at the end. I do Find/Remove all spaces and all my card numbers are transformed into scientific notation and the last digit turned into a 0. THEY ARE TEXT, they are formatted as text, I yelled into the screen that they are text, why does Excel refuse to acknowledge that they are text? (I would rather find a way to stop Excel's action than find a way to tell our programmers to put an apostrophe in every cell) How do I make it so that Excel just STOPS doing anything that I didn't tell it to do? Or at least stop it from doing anything to numbers it doesn't like. Maybe I can write a macro for whenever it discovers "Uhoh I should change that number to something different!" I'll make it format that cell to text a thousand times instead. Give me an error when I try calculating with a number larger than 15 digits, make my computer explode violently, that's fine. Just stop changing the numbers. Is it possible? I have many thousands of numbers that need changing in many different scenarios. I just want to stop it from trying to help. I can't understand why that would be difficult. I have 2007, but answers for other versions would be great as well. Thank you!

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• Java: Infinite loop using Scanner in.hasNextInt()

  - by Tomek

  Hi everyone, I am using the following code: while (invalidInput) { // ask the user to specify a number to update the times by System.out.print("Specify an integer between 0 and 5: "); if (in.hasNextInt()) { // get the update value updateValue = in.nextInt(); // check to see if it was within range if (updateValue >= 0 && updateValue <= 5) { invalidInput = false; } else { System.out.println("You have not entered a number between 0 and 5. Try again."); } } else { System.out.println("You have entered an invalid input. Try again."); } } However, if I enter a 'w' it will tell me "You have entered invalid input. Try Again." and then it will go into an infinite loop showing the text "Specify an integer between 0 and 5: You have entered an invalid input. Try again." Why is this happening? Isn't the program supposed to wait for the user to input and press enter each time it reaches the statement: if (in.hasNextInt()) Thanks in advance, Tomek

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• Reversible pseudo-random sequence generator

  - by user350651

  I would like some sort of method to create a fairly long sequence of random numbers that I can flip through backwards and forwards. Like a machine with "next" and "previous" buttons, that will give you random numbers. Something like 10-bit resolution (i.e. positive integers in a range from 0 to 1023) is enough, and a sequence of 100k numbers. It's for a simple game-type app, I don't need encryption-strength randomness or anything, but I want it to feel fairly random. I have a limited amount of memory available though, so I can't just generate a chunk of random data and go through it. I need to get the numbers in "interactive time" - I can easily spend a few ms thinking about the next number, but not comfortably much more than that. Eventually it will run on some sort of microcontroller, probably just an Arduino. I could do it with a simple linear congruential generator (LCG). Going forwards is simple, to go backwards I'd have to cache the most recent numbers and store some points at intervals so I can recreate the sequence from there. But maybe there IS some pseudo-random generator that allows you to go both forwards and forwards? It should be possible to hook up two linear feedback shift registers (LFSRs) to roll in different directions, no? Or maybe I can just get by with garbling the index number using a hash function of some sort? I'm going to try that first. Any other ideas?

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• Is VGA port hot-pluggable?

  - by Martin Bøgelund

  In meetings, I often see people detaching the VGA connector from one running laptop and connecting it to another, while the projector is still on. Is this 100% risk free, and OK by design of the VGA standard? If there's a risk involved in hot-plugging VGA, can it be removed by turning off or suspending either laptop, display, or both? I see this being done all the time without causing disaster, so clearly I'm not interested in answers stating "we do it all the time, so it should be OK!". I want to know if there's a risk - real or in theory - that something breaks when doing this. EDIT: I did an internet search on the topic, and I never found a clear statement as to why it is safe or unsafe to hot swap VGA devices. The typical form is a forum question asking basically the same question as I did, and the following types of statements Yes it's hot swappable! I do it all the time! It involves some kind of risk, so don't do it! You're some kind of moron if you think there's a risk, so just do it! But no explanation as to why it safe or not... Joe Taylors answer below contains a link to a forum post and answers that basically give me the same statements as mentioned above. But again, no good explanation why. So I looked for an actual manual for a projector, and found "Lenovo C500 Projector User’s Guide". It states on page 3-1: Connecting devices Computers and video devices can be connected to the projector at the same time. Check the user’s manual of the connecting device to confirm that it has the appropriate output connector. [image] Attention: As a safety precaution, disconnect all power to the projector and devices before making connections. But again, no good explanation.

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• Retrieve Records from paypal csv file

  - by Pankaj Khurana

  Hi, I want to retrieve all the records from paypal csv file where type='Payment Processed' and store it in a database table.It should be available in the following format: 'Heading':'Value' The format of the csv is: "Transaction ID","Reference Transaction ID","Date","Type","Subject","Item Number","Item Name","Invoice ID","Name","Email","Shipping Name","Shipping Address Line 1","Shipping Address Line 2","Shipping Address City","Shipping State/Province","Shipping Zip/Postal Code","Shipping Address Country","Shipping Method","Address Status","Contact Phone Number","Gross Amount","Receipt ID","Custom Field","Option 1 Name","Option 1 Value","Option 2 Name","Option 2 Value","Note","Auction Site","Auction User ID","Item URL","Auction Closing Date","Insurance Amount","Currency","Fees","Net Amount","Shipping & Handling Amount","Sales Tax Amount","To Email","Time","Time Zone" "1T","",5/5/2010 2:10:44 PM,"Payment Processed","CFP Self Study Kit","1","CFP Self Study Kit","","User1","[email protected]","","","","","","","","","N","","68.18","R1","","","","","","","","","",,"","USD","-2.62","65.56","0","0","[email protected]","01:40","Asia/Calcutta" "2T","",5/19/2010 4:04:08 PM,"Payment Processed","CFP Self Study Kit","1","CFP Self Study Kit","","User2","[email protected]","","","","","","","","","N","","68.18","R2","","","","","","","","","",,"","USD","-2.62","65.56","0","0","[email protected]","03:34","Asia/Calcutta" "3T","1RT",5/19/2010 5:28:45 PM,"Currency Conversion Completed","","","",""," ","","","","","","","","","","N","","17492.6","","","","","","","","","","",,"","INR","0","17492.6","0","0","","04:58","Asia/Calcutta" "4T","2RT",5/19/2010 5:28:45 PM,"Currency Conversion Completed","","","",""," ","","","","","","","","","","N","","-393.36","","","","","","","","","","",,"","USD","0","-393.36","0","0","","04:58","Asia/Calcutta" "5T","",5/19/2010 5:28:45 PM,"Transfer to Bank Initiated","P1006","","P1006",""," ","","","","","","","","","","N","","-17492.6","","","","","","","","","","",,"","INR","0","-17492.6","0","0","","04:58","Asia/Calcutta" "6T","",5/20/2010 5:38:02 PM,"Transfer to Bank Completed","P1006","","P1006",""," ","","","","","","","","","","N","","-17492.6","","","","","","","","","","",,"","INR","0","-17492.6","0","0","","05:08","Asia/Calcutta" "7T","",5/21/2010 12:32:37 PM,"Payment Processed","FP - LVC Plus","","FP - LVC Plus","","User3","[email protected]","User3","NEW DELHI","BEHIND KARNATAKA BANK LD","SOUTH","NEW DELHI","110023","IN","","N","","283.96","","","","","","","","","","",,"","USD","-9.95","274.01","0","0","[email protected]","00:02","Asia/Calcutta" "8T","",5/25/2010 4:40:48 PM,"Transfer to Bank Initiated","P1006","","P1006",""," ","","","","","","","","","","N","","-12569.85","","","","","","","","","","",,"","INR","0","-12569.85","0","0","","04:10","Asia/Calcutta" "9T","3RT",5/25/2010 4:40:48 PM,"Currency Conversion Completed","","","",""," ","","","","","","","","","","N","","-274.01","","","","","","","","","","",,"","USD","0","-274.01","0","0","","04:10","Asia/Calcutta" "10T","4RT",5/25/2010 4:40:48 PM,"Currency Conversion Completed","","","",""," ","","","","","","","","","","N","","12569.85","","","","","","","","","","",,"","INR","0","12569.85","0","0","","04:10","Asia/Calcutta" "11T","",5/26/2010 4:57:39 PM,"Transfer to Bank Completed","P1006","","P1006",""," ","","","","","","","","","","N","","-12569.85","","","","","","","","","","",,"","INR","0","-12569.85","0","0","","04:27","Asia/Calcutta" "Total","-247.05 USD","-15.19","-262.24" "Total","0.00 INR","0.00","0.00" Please help me on this Thanks

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• DataGrid: dynamic DataTemplate for dynamic DataGridTemplateColumn

  - by Lukas Cenovsky

  I want to show data in a datagrid where the data is a collection of public class Thing { public string Foo { get; set; } public string Bar { get; set; } public List<Candidate> Candidates { get; set; } } public class Candidate { public string FirstName { get; set; } public string LastName { get; set; } ... } where the number of candidates in Candidates list varies at runtime. Desired grid layout looks like this Foo | Bar | Candidate 1 | Candidate 2 | ... | Candidate N I'd like to have a DataTemplate for each Candidate as I plan changing it during runtime - user can choose what info about candidate is displayed in different columns (candidate is just an example, I have different object). That means I also want to change the column templates in runtime although this can be achieved by one big template and collapsing its parts. I know about two ways how to achieve my goals (both quite similar): Use AutoGeneratingColumn event and create Candidates columns Add Columns manually In both cases I need to load the DataTemplate from string with XamlReader. Before that I have to edit the string to change the binding to wanted Candidate. Is there a better way how to create a DataGrid with unknown number of DataGridTemplateColumn? Note: This question is based on dynamic datatemplate with valueconverter

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• R: Why does read.table stop reading a file?

  - by Mike Dewar

  I have a file, called genes.txt, which I'd like to become a data.frame. It's got a lot of lines, each line has three, tab delimited fields: mike$ wc -l genes.txt 42476 genes.txt I'd like to read this file into a data.frame in R. I use the command read.table, like this: genes = read.table( genes_file, sep="\t", na.strings="-", fill=TRUE, col.names=c("GeneSymbol","synonyms","description") ) Which seems to work fine, where genes_file points at genes.txt. However, the number of lines in my data.frame is significantly less than the number of lines in my text file: > nrow(genes) [1] 27896 and things I can find in the text file: mike$ grep "SELL" genes.txt SELL CD62L|LAM1|LECAM1|LEU8|LNHR|LSEL|LYAM1|PLNHR|TQ1 selectin L don't seem to be in the data.frame > grep("SELL",genes$GeneSymbol) integer(0) it turns out that genes = read.delim( genes_file, header=FALSE, na.strings="-", fill=TRUE, col.names=c("GeneSymbol","synonyms","description"), ) works just fine. Why does read.delim work when read.table not? If it's of use, you can recreate genes.txt using the following commands which you should run from a command line curl -O ftp://ftp.ncbi.nlm.nih.gov/gene/DATA/gene_info.gz gzip -cd gene_info.gz | awk -Ft '$1==9606{print $3 "\t" $5 "\t" $9}' > genes.txt be warned, though, that gene_info.gz is 101MBish.

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• Parse numbers in singe textbox for query

  - by Joshua Slocum

  I’ve built a webform in Visual Web Developer Express 2008 to help me with my work. I use a webform to run query requests that are emailed to me. The inputs are in this format 12312 12312 12312 12312 12312 12312 12312 12312 I enter the first number in a textbox and the second number in another textbox and click a button that runs a query and returns the results in a gridview(single row). string strConn, strSQL; strConn = AppConfig.Connection strSQL = 'select fields from table where FirstNum=:FirstNum and SecondNum=:SecondNum'; using (OracleConnection cn = new OracleConnection(strConn)) { OracleCommand cmd = new OracleCommand(strSQL, cn); cmd.Parameters.AddWithValue(":FirstNum", txtFirstNum.Text); cmd.Parameters.AddWithValue(":SeconNum", txtSecondNum.Text); cn.Open(); using (OracleDataReader rdr = cmd.ExecuteReader()) { dgResults.DataSource = rdr; dgResults.DataBind(); } cn.Close(); } I had an idea to help me speed up my work. I’d like to be able to past both numbers in a single textbox ( like this 12312 12312 ) and have the code parse out the nubmers for the query. Or even better would be to past all of them in a multiline textbox like this 12312 12312 12312 12312 12312 12312 12312 12312 And have them all parsed and the query run for each line and the results all output to one gridview. I’m just not sure how to approach this. Any suggestions would be appreciated. Thank you.

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• Is it possible to do A/B testing by page rather than by individual?

  - by mojones

  Lets say I have a simple ecommerce site that sells 100 different t-shirt designs. I want to do some a/b testing to optimise my sales. Let's say I want to test two different "buy" buttons. Normally, I would use AB testing to randomly assign each visitor to see button A or button B (and try to ensure that that the user experience is consistent by storing that assignment in session, cookies etc). Would it be possible to take a different approach and instead, randomly assign each of my 100 designs to use button A or B, and measure the conversion rate as (number of sales of design n) / (pageviews of design n) This approach would seem to have some advantages; I would not have to worry about keeping the user experience consistent - a given page (e.g. www.example.com/viewdesign?id=6) would always return the same html. If I were to test different prices, it would be far less distressing to the user to see different prices for different designs than different prices for the same design on different computers. I also wonder whether it might be better for SEO - my suspicion is that Google would "prefer" that it always sees the same html when crawling a page. Obviously this approach would only be suitable for a limited number of sites; I was just wondering if anyone has tried it?

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