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  • ASP.NET Performance tip- Combine multiple script file into one request with script manager

    - by Jalpesh P. Vadgama
    We all need java script for our web application and we storing our JavaScript code in .js files. Now If we have more then .js file then our browser will create a new request for each .js file. Which is a little overhead in terms of performance. If you have very big enterprise application you will have so much over head for this. Asp.net Script Manager provides a feature to combine multiple JavaScript into one request but you must remember that this feature will be available only with .NET Framework 3.5 sp1 or higher versions.  Let’s take a simple example. I am having two javascript files Jscrip1.js and Jscript2.js both are having separate functions. //Jscript1.js function Task1() { alert('task1'); } Here is another one for another file. ////Jscript1.js function Task2() { alert('task2'); } Now I am adding script reference with script manager and using this function in my code like this. <form id="form1" runat="server"> <asp:ScriptManager ID="myScriptManager" runat="server" > <Scripts> <asp:ScriptReference Path="~/JScript1.js" /> <asp:ScriptReference Path="~/JScript2.js" /> </Scripts> </asp:ScriptManager> <script language="javascript" type="text/javascript"> Task1(); Task2(); </script> </form> Now Let’s test in Firefox with Lori plug-in which will show you how many request are made for this. Here is output of that. You can see 5 Requests are there. Now let’s do same thing in with ASP.NET Script Manager combined script feature. Like following <form id="form1" runat="server"> <asp:ScriptManager ID="myScriptManager" runat="server" > <CompositeScript> <Scripts> <asp:ScriptReference Path="~/JScript1.js" /> <asp:ScriptReference Path="~/JScript2.js" /> </Scripts> </CompositeScript> </asp:ScriptManager> <script language="javascript" type="text/javascript"> Task1(); Task2(); </script> </form> Now let’s run it and let’s see how many request are there like following. As you can see now we have only 4 request compare to 5 request earlier. So script manager combined multiple script into one request. So if you have lots of javascript files you can save your loading time with this with combining multiple script files into one request. Hope you liked it. Stay tuned for more!!!.. Happy programming.. Technorati Tags: ASP.NET,ScriptManager,Microsoft Ajax

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  • My Mother Bought a Droid

    - by Ben Griswold
    I converted to iPhone two years ago when I left my former employer and my Blackberry behind. The truth is I half-heartedly purchased my iPhone. It was a great looking device, but as far as I was concerned, it was a mere toy compared to my Blackberry.  I remember hiding the toy in my briefcase when attending business meetings because I didn’t consider it to be professional enough.  I’ve since owned all three generations of the iPhone and, well, iPhone seems to have caught on. I still miss the click of the Blackberry keyboard and the blinking red light letting me know that someone/something requires my attention, but I’m officially an iPhone fanboy now.  My mom called last weekend and asked if she should buy an iPhone. I talked her ear off about everything I love about iPhone. I went on for about twenty minutes. I couldn’t help myself. I mentioned everything from my podcast subscriptions to the application which manages my workouts.  I went as far as to say that someday all smart phones will be referred to as iPhones just like all tissues are referred to as Kleenex and all sodas are referred to as Cokes.  I was really on a roll and then I stopped. I had to…the call dropped.  There I was, strategically standing in the far corner of my backyard where I get the most reliable AT&T reception and the call drops in middle of my iPhone pitch.  Folks, I don’t care how good a salesperson you are, it’s tough to recover from a situation like this.   I dialed my mom back and jokingly asked if she was planning to make calls with her new phone. I explained that AT&T is bound to provide better service eventually but I’m not sure she should wait. After all, I have troubles with the network in San Diego and I can only image how bad it would be for her in Western Massachusetts. Mom called back a few days later exclaiming, “I bought a Droid! I love this phone! I haven’t done anything with it but make phone calls, but I love it.”  I had to laugh.  My mom made the right call (pun intended.)  The iPhone is an amazing device, but owners are constantly reminded that its core function (it’s a phone, remember?) is subpar.  If you love gadgets, you’re probably enthralled by iPhone’s many bells and whistles and, relatively speaking, the terrible phone service might not amount to much.  (Maybe it amounts to a rant on your blog.) The overall iPhone offering is so attractive that consumers are willing to wait for AT&T to straighten up their act or wait until Apple grants a choice of carriers.  But I don’t see either of these remedies coming soon. In the interim, I’m willing to take my iPhone for what it is and just continue to enjoy my favorite features while pretending that poor coverage isn’t a big deal. With any luck, more and more reasonable folks will recognize that Android Phones are legitimate players in the smart phone space, they will buy loads of them and there will become plenty of functional phones to borrow when my “phone” is showing zero bars.  Heck, I’m already covered when I visit my mom.

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  • Amazon Product Advertising API SOAP Namespace Changes

    - by Rick Strahl
    About two months ago (twowards the end of February 2012 I think) Amazon decided to change the namespace of the Product Advertising API. The error that would come up was: <ItemSearchResponse > was not expected. If you've used the Amazon Product Advertising API you probably know that Amazon has made it a habit to break the services every few years or so and I guess last month was about the time for another one. Basically the service namespace of the document has been changed and responses from the service just failed outright even though the rest of the schema looks fine. Now I looked around for a while trying to find a recent update to the Product Advertising API - something semi-official looking but everything is dated around 2009. Really??? And it's not just .NET - the newest thing on the sample/APIs is dated early 2011 and a handful of 2010 samples. There are newer full APIs for the 'cloud' offerings, but the Product Advertising API apparently isn't part of that. After searching for quite a bit trying to trace this down myself and trying some of the newer samples (which also failed) I found an obscure forum post that describes the solution of getting past the namespace issue. FWIW, I've been using an old version of the Product Advertising API using the old Microsoft WSE3 services (pre-WCF), which provides some of the WS* security features required by the Amazon service. The fix for this code is to explicitly override the namespace declaration on each of the imported service method signatures. The old service namespace (at least on my build) was: http://webservices.amazon.com/AWSECommerceService/2009-03-31 and it should be changed to: http://webservices.amazon.com/AWSECommerceService/2011-08-01 Change it on the class header:[Microsoft.Web.Services3.Messaging.SoapService("http://webservices.amazon.com/AWSECommerceService/2011-08-01")] [System.Xml.Serialization.XmlIncludeAttribute(typeof(Property[]))] [System.Xml.Serialization.XmlIncludeAttribute(typeof(BrowseNode[]))] [System.Xml.Serialization.XmlIncludeAttribute(typeof(TransactionItem[]))] public partial class AWSECommerceService : Microsoft.Web.Services3.Messaging.SoapClient { and on all method signatures:[Microsoft.Web.Services3.Messaging.SoapMethodAttribute("http://soap.amazon.com/ItemSearch")] [return: System.Xml.Serialization.XmlElementAttribute("ItemSearchResponse", Namespace="http://webservices.amazon.com/AWSECommerceService/2011-08-01")] public ItemSearchResponse ItemSearch(ItemSearch ItemSearch1) { Microsoft.Web.Services3.SoapEnvelope results = base.SendRequestResponse("ItemSearch", ItemSearch1); return ((ItemSearchResponse)(results.GetBodyObject(typeof(ItemSearchResponse), this.SoapServiceAttribute.TargetNamespace))); } It's easy to do with a Search and Replace on the above strings. Amazon Services <rant> FWIW, I've not been impressed by Amazon's service offerings. While the services work well, their documentation and tool support is absolutely horrendous. I was recently working with a customer on an old AWS application and their old API had been completely removed with a new API that wasn't even a close match. One old API call resulted in requiring three different APIs to perform the same functionality. We had to re-write the entire piece from scratch essentially. The documentation was downright wrong, and incomplete and so scattered it was next to impossible to follow. The examples weren't examples at all - they're mockups of real service calls with fake data that didn't even provide everything that was required to make same service calls work. Additionally there appears to be just about no public support from Amazon, only peer support which is sparse at best - and getting a hold of somebody at Amazon, even for pay seems to be mythical task. It's a terrible business model they have going. I can't see why anybody would put themselves through this sort of customer and development experience. Sad really, but an experience we see more and more these days. Nobody puts in the time to document anything anymore, leaving it to devs to figure this stuff out over and over again… </rant>© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  Web Services   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • OBIEE 11.1.1 - User Interface (UI) Performance Is Slow With Internet Explorer 8

    - by Ahmed A
    The OBIEE 11g UI is performance is slow in IE 8 and faster in Firefox.  For VPN or WAN users, it takes long time to display links on Dashboards via IE 8. Cause is IE 8 generates many HTTP 304 return calls and this caused the 11g UI slower when compared to the Mozilla FireFox browser. To resolve this issue, you can implement HTTP compression and caching. This is a best practice.Why use Web Server Compression / Caching for OBIEE? Bandwidth Savings: Enabling HTTP compression can have a dramatic improvement on the latency of responses. By compressing static files and dynamic application responses, it will significantly reduce the remote (high latency) user response time. Improves request/response latency: Caching makes it possible to suppress the payload of the HTTP reply using the 304 status code.  Minimizing round trips over the Web to re-validate cached items can make a huge difference in browser page load times. This screen shot depicts the flow and where the compression and decompression occurs: Solution: a. How to Enable HTTP Caching / Compression in Oracle HTTP Server (OHS) 11.1.1.x 1. To implement HTTP compression / caching, install and configure Oracle HTTP Server (OHS) 11.1.1.x for the bi_serverN Managed Servers (refer to "OBIEE Enterprise Deployment Guide for Oracle Business Intelligence" document for details). 2. On the OHS machine, open the file HTTP Server configuration file (httpd.conf) for editing. This file is located in the OHS installation directory.For example: ORACLE_HOME/Oracle_WT1/instances/instance1/config/OHS/ohs13. In httpd.conf file, verify that the following directives are included and not commented out: LoadModule expires_module "${ORACLE_HOME}/ohs/modules/mod_expires.soLoadModule deflate_module "${ORACLE_HOME}/ohs/modules/mod_deflate.so 4. Add the following lines in httpd.conf file below the directive LoadModule section and restart the OHS: Note: For the Windows platform, you will need to enclose any paths in double quotes ("), for example:Alias "/analytics ORACLE_HOME/bifoundation/web/app"<Directory "ORACLE_HOME/bifoundation/web/app"> Alias /analytics ORACLE_HOME/bifoundation/web/app#Pls replace the ORACLE_HOME with your actual BI ORACLE_HOME path<Directory ORACLE_HOME/bifoundation/web/app>#We don't generate proper cross server ETags so disable themFileETag noneSetOutputFilter DEFLATE# Don't compress imagesSetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary<FilesMatch "\.(gif|jpeg|png|js|x-javascript|javascript|css)$">#Enable future expiry of static filesExpiresActive onExpiresDefault "access plus 1 week"     #1 week, this will stops the HTTP304 calls i.e. generated by IE 8Header set Cache-Control "max-age=604800"</FilesMatch>DirectoryIndex default.jsp</Directory>#Restrict access to WEB-INF<Location /analytics/WEB-INF>Order Allow,DenyDeny from all</Location> Note: Make sure you replace above placeholder "ORACLE_HOME" to your correct path for BI ORACLE_HOME.For example: my BI Oracle Home path is /Oracle/BIEE11g/Oracle_BI1/bifoundation/web/app Important Notes: Above caching rules restricted to static files found inside the /analytics directory(/web/app). This approach is safer instead of setting static file caching globally. In some customer environments you may not get 100% performance gains in IE 8.0 browser. So in that case you need to extend caching rules to other directories with static files content. If OHS is installed on separate dedicated machine, make sure static files in your BI ORACLE_HOME (../Oracle_BI1/bifoundation/web/app) is accessible to the OHS instance. The following screen shot summarizes the before and after results and improvements after enabling compression and caching:

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  • Error while installing emacs23 from Software Center

    - by vrcmr
    Trying to install emacs in Software Center Ubuntu 12.04 got this error. installArchives() failed: Selecting previously unselected package emacs23. (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 182385 files and directories currently installed.) Unpacking emacs23 (from .../emacs23_23.3+1-1ubuntu9_i386.deb) ... Processing triggers for desktop-file-utils ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for gnome-menus ... Processing triggers for man-db ... Setting up emacs23 (23.3+1-1ubuntu9) ... update-alternatives: using /usr/bin/emacs23-x to provide /usr/bin/emacs (emacs) in auto mode. emacs-install emacs23 install/dictionaries-common: Byte-compiling for emacsen flavour emacs23 Warning: Lisp directory `/usr/share/emacs/23.3/site-lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/site-lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/leim' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/leim' does not exist. Error: charsets directory (/usr/share/emacs/23.3/etc/charsets) does not exist. Emacs will not function correctly without the character map files. Please check your installation! Warning: Could not find simple.el nor simple.elc Cannot open load file: bytecomp emacs-install: /usr/lib/emacsen-common/packages/install/dictionaries-common emacs23 failed at /usr/lib/emacsen-common/emacs-install line 28, <TSORT> line 3. dpkg: error processing emacs23 (--configure): subprocess installed post-installation script returned error exit status 255 No apport report written because MaxReports is reached already Errors were encountered while processing: emacs23 Error in function: Setting up emacs23 (23.3+1-1ubuntu9) ... emacs-install emacs23 install/dictionaries-common: Byte-compiling for emacsen flavour emacs23 Warning: Lisp directory `/usr/share/emacs/23.3/site-lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/site-lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/leim' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/lisp' does not exist. Warning: Lisp directory `/usr/share/emacs/23.3/leim' does not exist. Error: charsets directory (/usr/share/emacs/23.3/etc/charsets) does not exist. Emacs will not function correctly without the character map files. Please check your installation! Warning: Could not find simple.el nor simple.elc Cannot open load file: bytecomp emacs-install: /usr/lib/emacsen-common/packages/install/dictionaries-common emacs23 failed at /usr/lib/emacsen-common/emacs-install line 28, <TSORT> line 3. dpkg: error processing emacs23 (--configure): subprocess installed post-installation script returned error exit status 255

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  • simple collision detection with box2dweb

    - by skywalker
    im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground execute simple function like function sucs(){alert("the box on the floor !")}; this is my code var CANVAS_WIDTH = 1024, CANVAS_HEIGHT = 700, SCALE = 30; var b2Vec2 = Box2D.Common.Math.b2Vec2 , b2BodyDef = Box2D.Dynamics.b2BodyDef , b2Body = Box2D.Dynamics.b2Body , b2FixtureDef = Box2D.Dynamics.b2FixtureDef , b2Fixture = Box2D.Dynamics.b2Fixture , b2World = Box2D.Dynamics.b2World , b2MassData = Box2D.Collision.Shapes.b2MassData , b2PolygonShape = Box2D.Collision.Shapes.b2PolygonShape , b2CircleShape = Box2D.Collision.Shapes.b2CircleShape , b2DebugDraw = Box2D.Dynamics.b2DebugDraw; var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); var world = new b2World(new b2Vec2(0, 8), true); var fixDef = new b2FixtureDef(); var bodyDef = new b2BodyDef(); fixDef.density = 1.0; fixDef.friction = 0.5; bodyDef.type = b2Body.b2_staticBody; fixDef.shape = new b2PolygonShape; fixDef.shape.SetAsBox(20, 2); bodyDef.position.Set(10, 400 / 30 + 1.8); world.CreateBody(bodyDef).CreateFixture(fixDef); fixDef.density = 1.0; fixDef.friction = 0.5; fixDef.restitution = 0.3; bodyDef.type = b2Body.b2_dynamicBody; bodyDef.position.Set(50 / SCALE, 0 / SCALE); //bodyDef.linearVelocity.Set((Math.random() * 12) + 2, (Math.random() * 12) + 2); fixDef.shape = new b2PolygonShape(); fixDef.shape.SetAsBox(25 / SCALE, 25 / SCALE); world.CreateBody(bodyDef).CreateFixture(fixDef); var debugDraw = new b2DebugDraw(); debugDraw.SetSprite(document.getElementById("canvas").getContext("2d")); debugDraw.SetDrawScale(30.0); debugDraw.SetFillAlpha(0.5); debugDraw.SetLineThickness(1.0); debugDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit); world.SetDebugDraw(debugDraw); var image = new Image(); image.src = "image.png"; window.setInterval(gameLoop, 1000 / 60); function gameLoop() { world.Step(1 / 60, 8, 3); world.ClearForces(); context.clearRect(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT); b = world.GetBodyList() var pos = b.GetPosition(); context.save(); context.translate(pos.x * SCALE, pos.y * SCALE); context.rotate(b.GetAngle()); context.drawImage(image, -25, -25); context.restore(); b = b.GetNext(); pos = b.GetPosition(); context.save(); context.translate(pos.x * SCALE, pos.y * SCALE); //b.GetAngle()++; context.rotate(b.GetAngle()); context.drawImage(image, -25, -25); context.restore(); world.DrawDebugData(); };

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  • Unable to build my c++ code with g++ 4.6.3

    - by Mriganka
    I am facing multiple issues with building my c++ code on Ubuntu 12.04. This code was building and running fine on RH Enterprise. I am using g++ 4.6.3. Here's the output of g++ -v. g++ -v Using built-in specs. COLLECT_GCC=g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.6/lto-wrapper Target: i686-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable-objc-gc --enable-targets=all --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu Thread model: posix gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) Here's a sample of my code: #include "Word.h" #include < string> using namespace std; pthread_mutex_t Word::_lock = PTHREAD_MUTEX_INITIALIZER; Word::Word(): _occurrences(1) { memset(_buf, 0, 25); } Word::Word(char *str): _occurrences(1) { memset(_buf, 0, 25); if (str != NULL) { strncpy(_buf, str, strlen(str)); } } g++ -c -ansi or g++ -c -std=c++98 or g++ -c -std=c++03, none of these options are able to build the code correctly. I get the following compilation errors: mriganka@ubuntu:~/WordCount$ make g++ -c -g -ansi Word.cpp -o Word.o Word.cpp: In constructor ‘Word::Word()’: Word.cpp:10:21: error: ‘memset’ was not declared in this scope Word.cpp: In constructor ‘Word::Word(char*)’: Word.cpp:16:21: error: ‘memset’ was not declared in this scope Word.cpp:19:34: error: ‘strlen’ was not declared in this scope Word.cpp:19:35: error: ‘strncpy’ was not declared in this scope Word.cpp: In member function ‘void Word::operator=(const Word&)’: Word.cpp:37:42: error: ‘strlen’ was not declared in this scope Word.cpp:37:43: error: ‘strncpy’ was not declared in this scope Word.cpp: In copy constructor ‘Word::Word(const Word&)’: Word.cpp:44:21: error: ‘memset’ was not declared in this scope Word.cpp:45:52: error: ‘strlen’ was not declared in this scope Word.cpp:45:53: error: ‘strncpy’ was not declared in this scope So basically g++ 4.6.3 on Ubuntu 12.04 is not able to recognize the standard c++ headers. And I am not finding a way out of this situation. Second problem: In order to make progress, I included < string.h instead of < string. But now I am facing linking errors with my message queue and pthread library functions. Here's the error that I am getting: mriganka@ubuntu:~/WordCount$ make g++ -c -g -ansi Word.cpp -o Word.o g++ -lrt -I/usr/lib/i386-linux-gnu Word.o HashMap.o main.o -o word_count main.o: In function `main': /home/mriganka/WordCount/main.cpp:75: undefined reference to `pthread_create' /home/mriganka/WordCount/main.cpp:90: undefined reference to `mq_open' /home/mriganka/WordCount/main.cpp:93: undefined reference to `mq_getattr' /home/mriganka/WordCount/main.cpp:113: undefined reference to `mq_send' /home/mriganka/WordCount/main.cpp:123: undefined reference to `pthread_join' /home/mriganka/WordCount/main.cpp:129: undefined reference to `mq_close' /home/mriganka/WordCount/main.cpp:130: undefined reference to `mq_unlink' main.o: In function `count_words(void*)': /home/mriganka/WordCount/main.cpp:151: undefined reference to `mq_open' /home/mriganka/WordCount/main.cpp:154: undefined reference to `mq_getattr' /home/mriganka/WordCount/main.cpp:162: undefined reference to `mq_timedreceive' collect2: ld returned 1 exit status Here's my makefile: CC=g++ CFLAGS=-c -g -ansi LDFLAGS=-lrt INC=-I/usr/lib/i386-linux-gnu SOURCES=Word.cpp HashMap.cpp main.cpp OBJECTS=$(SOURCES:.cpp=.o) EXECUTABLE=word_count all: $(SOURCES) $(EXECUTABLE) $(EXECUTABLE): $(OBJECTS) $(CC) $(LDFLAGS) $(INC) -pthread $(OBJECTS) -o $@ .cpp.o: $(CC) $(CFLAGS) $< -o $@ clean: rm -f *.o word_count Please help me to resolve both the issues. I searched online relentlessly for any solution of these problems, but no one seems to have encountered these issues.

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  • Rendering Linear Gradients using the HTML5 Canvas

    - by dwahlin
    Related HTML5 Canvas Posts: Getting Started with the HTML5 Canvas Rendering Text with the HTML5 Canvas Creating a Line Chart using the HTML5 Canvas New Pluralsight Course: HTML5 Canvas Fundamentals Gradients are everywhere. They’re used to enhance toolbars or buttons and help add additional flare to a web page when used appropriately. In the past we’ve always had to rely on images to render gradients which works well, but isn’t necessarily the most efficient (although 1 pixel wide images do work well). CSS3 provides a great way to render gradients in modern browsers (see http://www.colorzilla.com/gradient-editor for a nice online gradient generator tool) but it’s not the only option. If you’re working with charts, games, multimedia or other HTML5 Canvas applications you can also use gradients and render them on the client-side without relying on images. In this post I’ll introduce how to use linear gradients and discuss the different functions that can be used to create them.   Creating Linear Gradients Linear gradients can be created using the 2D context’s createLinearGradient function. The function takes the starting x,y coordinates and ending x,y coordinates of the gradient:   createLinearGradient(x1, y1, x2, y2);   By changing the start and end coordinates you can control the direction that the gradient renders. For example, adding the following coordinates causes the gradient to render from left to right since the y value stays at 0 for both points while the x value changes from 0 to 200. var lgrad = ctx.createLinearGradient(0, 0, 200, 0); Here’s an example of how changing the coordinates affects the gradient direction:   Once a linear gradient object has been created you can set color stops using the addColorStop() function. It takes the location where the color should appear in the gradient with 0 being the beginning and 1 being at the end (0.5 would be in the middle) as well as the color to display in the gradient. lgrad.addColorStop(0, 'white'); lgrad.addColorStop(1, 'gray');   An example of combining createLinearGradient() with addColorStop() is shown next:   Using createLinearGradient() var canvas = document.getElementById('myCanvas'); var ctx = canvas.getContext('2d'); var lgrad = ctx.createLinearGradient(0, 0, 200, 0); lgrad.addColorStop(0, 'white'); lgrad.addColorStop(1, 'gray'); ctx.fillStyle = lgrad; ctx.fillRect(0, 0, 200, 200); ctx.strokeRect(0, 0, 200, 200); This code renders a white to gray gradient as shown next: A live example of using createLinearGradient() is shown next. Click the Result tab to see the code in action.   In the next post on the HTML5 Canvas I’ll take a look at radial gradients and how they can be used. In the meantime, if you’re interested in learning more about the HTML5 Canvas and how it can be used in your Web or Windows 8 applications, check out my HTML5 Canvas Fundamentals course from Pluralsight. It has over 4 1/2 hours of canvas goodness packed in it.

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  • Another sound not working post

    - by Thomas Smart
    Tried all the other "sound not working" posts i think, lost count. purge/reinstall alsa and pulse, reboot, add user to audio group, various lines in the alsa config file such as "options snd-hda-intel model=" then tried different options like generic, auto, basic, default, etc. tried pulseaudio -k && sudo alsa force-reload a few times, with and without rebooting. Hardware: 16gb ram, core I7-4790, Intel Haswell mboard with onboard sound and graphics Multimedia: Audio Adapter: HDA-Intel-HDA Intel HDMI OS: Ubuntu server 14.04 with ubuntu-desktop installed. GUI sound settings lists only the dummy sound card alsamixer -c 0 ¦ Card: HDA Intel HDMI F1: Help ¦ ¦ Chip: Intel Haswell HDMI F2: System information ¦ ¦ View: F3:[Playback] F4: Capture F5: All F6: Select sound card ¦ ¦ Item: S/PDIF ¦ ¦ +--+ ¦ ¦ ¦OO¦ ¦ ¦ +--+ ¦ ¦ < S/PDIF > ¦ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 aplay -L default Playback/recording through the PulseAudio sound server null Discard all samples (playback) or generate zero samples (capture) pulse PulseAudio Sound Server hdmi:CARD=HDMI,DEV=0 HDA Intel HDMI, HDMI 0 HDMI Audio Output dmix:CARD=HDMI,DEV=3 HDA Intel HDMI, HDMI 0 Direct sample mixing device dsnoop:CARD=HDMI,DEV=3 HDA Intel HDMI, HDMI 0 Direct sample snooping device hw:CARD=HDMI,DEV=3 HDA Intel HDMI, HDMI 0 Direct hardware device without any conversions plughw:CARD=HDMI,DEV=3 HDA Intel HDMI, HDMI 0 Hardware device with all software conversions cat /proc/asound/cards 0 [HDMI ]: HDA-Intel - HDA Intel HDMI HDA Intel HDMI at 0xf7d14000 irq 46 cat /proc/asound/devices 1: : sequencer 2: [ 0- 3]: digital audio playback 3: [ 0- 0]: hardware dependent 4: [ 0] : control 33: : timer mplayer -ao alsa:device=hdmi /usr/share/sounds/ubuntu/stereo/system-ready.ogg MPlayer 1.1-4.8 (C) 2000-2012 MPlayer Team mplayer: could not connect to socket mplayer: No such file or directory Failed to open LIRC support. You will not be able to use your remote control. Playing /usr/share/sounds/ubuntu/stereo/system-ready.ogg. libavformat version 54.20.4 (external) Mismatching header version 54.20.3 libavformat file format detected. [lavf] stream 0: audio (vorbis), -aid 0 Load subtitles in /usr/share/sounds/ubuntu/stereo/ ========================================================================== Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders libavcodec version 54.35.0 (external) AUDIO: 44100 Hz, 1 ch, floatle, 80.0 kbit/5.67% (ratio: 10000->176400) Selected audio codec: [ffvorbis] afm: ffmpeg (FFmpeg Vorbis) ========================================================================== [AO_ALSA] alsa-lib: confmisc.c:768:(parse_card) cannot find card '1' [AO_ALSA] alsa-lib: conf.c:4248:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory [AO_ALSA] alsa-lib: confmisc.c:392:(snd_func_concat) error evaluating strings [AO_ALSA] alsa-lib: conf.c:4248:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory [AO_ALSA] alsa-lib: confmisc.c:1251:(snd_func_refer) error evaluating name [AO_ALSA] alsa-lib: conf.c:4248:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory [AO_ALSA] alsa-lib: conf.c:4727:(snd_config_expand) Evaluate error: No such file or directory [AO_ALSA] alsa-lib: pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM hdmi [AO_ALSA] Playback open error: No such file or directory Failed to initialize audio driver 'alsa:device=hdmi' Could not open/initialize audio device -> no sound. Audio: no sound Video: no video Exiting... (End of file) mplayer -ao alsa:device=hw=0.3 /usr/share/sounds/ubuntu/stereo/system-ready.ogg MPlayer 1.1-4.8 (C) 2000-2012 MPlayer Team mplayer: could not connect to socket mplayer: No such file or directory Failed to open LIRC support. You will not be able to use your remote control. Playing /usr/share/sounds/ubuntu/stereo/system-ready.ogg. libavformat version 54.20.4 (external) Mismatching header version 54.20.3 libavformat file format detected. [lavf] stream 0: audio (vorbis), -aid 0 Load subtitles in /usr/share/sounds/ubuntu/stereo/ ========================================================================== Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders libavcodec version 54.35.0 (external) AUDIO: 44100 Hz, 1 ch, floatle, 80.0 kbit/5.67% (ratio: 10000->176400) Selected audio codec: [ffvorbis] afm: ffmpeg (FFmpeg Vorbis) ========================================================================== [AO_ALSA] Format floatle is not supported by hardware, trying default. AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample) Video: no video Starting playback... A: 0.4 (00.4) of 0.8 (00.7) 0.1% Exiting... (End of file) Thank you for your time and help :)

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  • Am I right about the differences between Floyd-Warshall, Dijkstra's and Bellman-Ford algorithms?

    - by Programming Noob
    I've been studying the three and I'm stating my inferences from them below. Could someone tell me if I have understood them accurately enough or not? Thank you. Dijkstra's algorithm is used only when you have a single source and you want to know the smallest path from one node to another, but fails in cases like this Floyd-Warshall's algorithm is used when any of all the nodes can be a source, so you want the shortest distance to reach any destination node from any source node. This only fails when there are negative cycles (this is the most important one. I mean, this is the one I'm least sure about:) 3.Bellman-Ford is used like Dijkstra's, when there is only one source. This can handle negative weights and its working is the same as Floyd-Warshall's except for one source, right? If you need to have a look, the corresponding algorithms are (courtesy Wikipedia): Bellman-Ford: procedure BellmanFord(list vertices, list edges, vertex source) // This implementation takes in a graph, represented as lists of vertices // and edges, and modifies the vertices so that their distance and // predecessor attributes store the shortest paths. // Step 1: initialize graph for each vertex v in vertices: if v is source then v.distance := 0 else v.distance := infinity v.predecessor := null // Step 2: relax edges repeatedly for i from 1 to size(vertices)-1: for each edge uv in edges: // uv is the edge from u to v u := uv.source v := uv.destination if u.distance + uv.weight < v.distance: v.distance := u.distance + uv.weight v.predecessor := u // Step 3: check for negative-weight cycles for each edge uv in edges: u := uv.source v := uv.destination if u.distance + uv.weight < v.distance: error "Graph contains a negative-weight cycle" Dijkstra: 1 function Dijkstra(Graph, source): 2 for each vertex v in Graph: // Initializations 3 dist[v] := infinity ; // Unknown distance function from 4 // source to v 5 previous[v] := undefined ; // Previous node in optimal path 6 // from source 7 8 dist[source] := 0 ; // Distance from source to source 9 Q := the set of all nodes in Graph ; // All nodes in the graph are 10 // unoptimized - thus are in Q 11 while Q is not empty: // The main loop 12 u := vertex in Q with smallest distance in dist[] ; // Start node in first case 13 if dist[u] = infinity: 14 break ; // all remaining vertices are 15 // inaccessible from source 16 17 remove u from Q ; 18 for each neighbor v of u: // where v has not yet been 19 removed from Q. 20 alt := dist[u] + dist_between(u, v) ; 21 if alt < dist[v]: // Relax (u,v,a) 22 dist[v] := alt ; 23 previous[v] := u ; 24 decrease-key v in Q; // Reorder v in the Queue 25 return dist; Floyd-Warshall: 1 /* Assume a function edgeCost(i,j) which returns the cost of the edge from i to j 2 (infinity if there is none). 3 Also assume that n is the number of vertices and edgeCost(i,i) = 0 4 */ 5 6 int path[][]; 7 /* A 2-dimensional matrix. At each step in the algorithm, path[i][j] is the shortest path 8 from i to j using intermediate vertices (1..k-1). Each path[i][j] is initialized to 9 edgeCost(i,j). 10 */ 11 12 procedure FloydWarshall () 13 for k := 1 to n 14 for i := 1 to n 15 for j := 1 to n 16 path[i][j] = min ( path[i][j], path[i][k]+path[k][j] );

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  • Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

    - by Goodsquirrel
    I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

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  • SQL SERVER – A Puzzle – Swap Value of Column Without Case Statement

    - by pinaldave
    For the last few weeks, I have been doing Friday Puzzles and I am really loving it. Yesterday I received a very interesting question by Navneet Chaurasia on Facebook Page. He was asked this question in one of the interview questions for job. Please read the original thread for a complete idea of the conversation. I am presenting the same question here. Puzzle Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Here is the quick setup script for the puzzle. USE tempdb GO CREATE TABLE SimpleTable (ID INT, Gender VARCHAR(10)) GO INSERT INTO SimpleTable (ID, Gender) SELECT 1, 'female' UNION ALL SELECT 2, 'male' UNION ALL SELECT 3, 'male' GO SELECT * FROM SimpleTable GO The above query will return following result set. The puzzle was to write a single update column which will generate following result set. There are multiple answers to this simple puzzle. Let me show you three different ways. I am assuming that the column will have either value ‘male’ or ‘female’ only. Method 1: Using CASE Statement I believe this is going to be the most popular solution as we are all familiar with CASE Statement. UPDATE SimpleTable SET Gender = CASE Gender WHEN 'male' THEN 'female' ELSE 'male' END GO SELECT * FROM SimpleTable GO Method 2: Using REPLACE  Function I totally understand it is the not cleanest solution but it will for sure work in giving situation. UPDATE SimpleTable SET Gender = REPLACE(('fe'+Gender),'fefe','') GO SELECT * FROM SimpleTable GO Method 3: Using IIF in SQL Server 2012 If you are using SQL Server 2012 you can use IIF and get the same effect as CASE statement. UPDATE SimpleTable SET Gender = IIF(Gender = 'male', 'female', 'male') GO SELECT * FROM SimpleTable GO You can read my article series on SQL Server 2012 various functions over here. SQL SERVER – Denali – Logical Function – IIF() – A Quick Introduction SQL SERVER – Detecting Leap Year in T-SQL using SQL Server 2012 – IIF, EOMONTH and CONCAT Function Let us clean up. DROP TABLE SimpleTable GO Question to you: I came up with three simple tricks where there is a single UPDATE statement which swaps the values in the column. Do you know any other simple trick? If yes, please post here in the comments. I will pick two random winners from all the valid answers. Winners will get 1) Print Copy of SQL Server Interview Questions and Answers 2) Free Learning Code for Online Video Courses I will announce the winners on coming Monday. Reference:  Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • How to inhibit suspend temporarily?

    - by Zorn
    I have searched around a bit for this and can't seem to find anything helpful. I have my PC running Ubuntu 12.10 set up to suspend after 30 minutes of inactivity. I don't want to change that, it works great most of the time. What I do want to do is disable the automatic suspend if a particular application is running. How can I do this? The closest thing I've found so far is to add a shell script in /usr/lib/pm-utils/sleep.d which checks if the application is running and returns 1 to indicate that suspend should be prevented. But it looks like the system then gives up on suspending automatically, instead of trying again after another 30 minutes. (As far as I can tell, if I move the mouse, that restarts the timer again.) It's quite likely the application will finish after a couple of hours, and I'd rather my PC then suspended automatically if I'm not using it at that point. (So I don't want to add a call to pm-suspend when the application finishes.) Is this possible? Any advice would be appreciated. Cheers. EDIT: As I noted in one of the comments below, what I actually wanted was to inhibit suspend when my PC was serving files over NFS; I just wanted to focus on the "suspend" part of the question because I already had an idea how to solve the NFS part. Using the 'xdotool' idea given in one of the answers, I have come up with the following script which I run from cron every few minutes. It's not ideal because it stops the screensaver kicking in as well, but it does work. I need to have a look at why 'caffeine' doesn't correctly re-enable suspend later on, then I could probably do better. Anyway, this does seem to work, so I'm including it here in case anyone else is interested. #!/bin/bash # If the output of this function changes between two successive runs of this # script, we inhibit auto-suspend. function check_activity() { /usr/sbin/nfsstat --server --list } # Prevent the automatic suspend from kicking in. function inhibit_suspend() { # Slightly jiggle the mouse pointer about; we do a small step and # reverse step to try to stop this being annoying to anyone using the # PC. TODO: This isn't ideal, apart from being a bit hacky it stops # the screensaver kicking in as well, when all we want is to stop # the PC suspending. Can 'caffeine' help? export DISPLAY=:0.0 xdotool mousemove_relative --sync -- 1 1 xdotool mousemove_relative --sync -- -1 -1 } LOG="$HOME/log/nfs-suspend-blocker.log" ACTIVITYFILE1="$HOME/tmp/nfs-suspend-blocker.current" ACTIVITYFILE2="$HOME/tmp/nfs-suspend-blocker.previous" echo "Started run at $(date)" >> "$LOG" if [ ! -f "$ACTIVITYFILE1" ]; then check_activity > "$ACTIVITYFILE1" exit 0; fi /bin/mv "$ACTIVITYFILE1" "$ACTIVITYFILE2" check_activity > "$ACTIVITYFILE1" if cmp --quiet "$ACTIVITYFILE1" "$ACTIVITYFILE2"; then echo "No activity detected since last run" >> "$LOG" else echo "Activity detected since last run; inhibiting suspend" >> "$LOG" inhibit_suspend fi

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  • Next Generation Mobile Clients for Oracle Applications & the role of Oracle Fusion Middleware

    - by Manish Palaparthy
    Oracle Enterprise Applications have been available with modern web browser based interfaces for a while now. The web browsers available in smart phones no longer require special markup language such as WML since the processing power of these handsets is quite near to that of a typical personal computer. Modern Mobile devices such as the IPhone, Android Phones, BlackBerry, Windows 8 devices can now render XHTML & HTML quite well. This means you could potentially use your mobile browser to access your favorite enterprise application. While the Mobile browser would render the UI, you might find it difficult to use it due to the formatting & Presentation of the Native UI. Smart phones offer a lot more than just a powerful web browser, they offer capabilities such as Maps, GPS, Multi touch, pinch zoom, accelerometers, vivid colors, camera with video, support for 3G, 4G networks, cloud storage, NFC, streaming media, tethering, voice based features, multi tasking, messaging, social networking web browsers with support for HTML 5 and many more features.  While the full potential of Enterprise Mobile Apps is yet to be realized, Oracle has published a few of its applications that take advantage of the above capabilities and are available for the IPhone natively. Here are some of them Iphone Apps  Oracle Business Approvals for Managers: Offers a highly intuitive user interface built as a native mobile application to conveniently access pending actions related to expenses, purchase requisitions, HR vacancies and job offers. You can even view BI reports related to the worklist actions. Works with Oracle E-Business Suite Oracle Business Indicators : Real-time secure access to OBI reports. Oracle Business Approvals for Sales Managers: Enables sales executives to review key targeted tasks, access relevant business intelligence reports. Works with Siebel CRM, Siebel Quote & Order Capture. Oracle Mobile Sales Assistant: CRM application that provides real-time, secure access to the information your sales organization needs, complete frequent tasks, collaborate with colleagues and customers. Works with Oracle CRMOracle Mobile Sales Forecast: Designed specifically for the mobile business user to view key opportunities. Works with Oracle CRM on demand Oracle iReceipts : Part of Oracle PeopleSoft Expenses, which allows users to create and submit expense lines for cash transactions in real-time. Works with Oracle PeopleSoft expenses Now, we have seen some mobile Apps that Oracle has published, I am sure you are intrigued as to how develop your own clients for the use-cases that you deem most fit. For that Oracle has ADF Mobile ADF Mobile You could develop Mobile Applications with the SDK available with the smart phone platforms!, but you'd really have to be a mobile ninja developer to develop apps with the rich user experience like the ones above. The challenges really multiply when you have to support multiple mobile devices. ADF Mobile framework is really handy to meet this challenge ADF Mobile can in be used to Develop Apps for the Mobile browser : An application built with ADF Mobile framework installs on a smart device, renders user interface via HTML5, and has access to device services. This means the programming model is primarily web-based, which offers consistency with other enterprise applications as well as easier migration to new platforms. Develop Apps for the Mobile Client (Native Apps): These applications have access to device services, enabling a richer experience for users than a browser alone can offer. ADF mobile enables rapid and declarative development of rich, on-device mobile applications. Developers only need to write an application once and then they can deploy the same application across multiple leading smart phone platforms. Oracle SOA Suite Although the Mobile users are using the smart phone apps, and actual transactions are being executed in the underlying app, there is lot of technical wizardry that is going under the surface. All of this key technical components to make 1. WebService calls 2. Authentication 3. Intercepting Webservice calls and adding security credentials to the request 4. Invoking the services of the enterprise application 5. Integrating with the Enterprise Application via the Adapter is all being implemented at the SOA infrastructure layer.  As you can see from the above diagram. The key pre-requisites to mobile enable an Enterprise application are The core enterprise application Oracle SOA Suite ADF Mobile

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  • 2D Rendering with OpenGL ES 2.0 on Android (matrices not working)

    - by TranquilMarmot
    So I'm trying to render two moving quads, each at different locations. My shaders are as simple as possible (vertices are only transformed by the modelview-projection matrix, there's only one color). Whenever I try and render something, I only end up with slivers of color! I've only done work with 3D rendering in OpenGL before so I'm having issues with 2D stuff. Here's my basic rendering loop, simplified a bit (I'm using the Matrix manipulation methods provided by android.opengl.Matrix and program is a custom class I created that just calls GLES20.glUniformMatrix4fv()): Matrix.orthoM(projection, 0, 0, windowWidth, 0, windowHeight, -1, 1); program.setUniformMatrix4f("Projection", projection); At this point, I render the quads (this is repeated for each quad): Matrix.setIdentityM(modelview, 0); Matrix.translateM(modelview, 0, quadX, quadY, 0); program.setUniformMatrix4f("ModelView", modelview); quad.render(); // calls glDrawArrays and all I see is a sliver of the color each quad is! I'm at my wits end here, I've tried everything I can think of and I'm at the point where I'm screaming at my computer and tossing phones across the room. Anybody got any pointers? Am I using ortho wrong? I'm 100% sure I'm rendering everything at a Z value of 0. I tried using frustumM instead of orthoM, which made it so that I could see the quads but they would get totally skewed whenever they got moved, which makes sense if I correctly understand the way frustum works (it's more for 3D rendering, anyway). If it makes any difference, I defined my viewport with GLES20.glViewport(0, 0, windowWidth, windowHeight); Where windowWidth and windowHeight are the same values that are pased to orthoM It might be worth noting that the android.opengl.Matrix methods take in an offset as the second parameter so that multiple matrices can be shoved into one array, so that'w what the first 0 is for For reference, here's my vertex shader code: uniform mat4 ModelView; uniform mat4 Projection; attribute vec4 vPosition; void main() { mat4 mvp = Projection * ModelView; gl_Position = vPosition * mvp; } I tried swapping Projection * ModelView with ModelView * Projection but now I just get some really funky looking shapes... EDIT Okay, I finally figured it out! (Note: Since I'm new here (longtime lurker!) I can't answer my own question for a few hours, so as soon as I can I'll move this into an actual answer to the question) I changed Matrix.orthoM(projection, 0, 0, windowWidth, 0, windowHeight, -1, 1); to float ratio = windowWwidth / windowHeight; Matrix.orthoM(projection, 0, 0, ratio, 0, 1, -1, 1); I then had to scale my projection matrix to make it a lot smaller with Matrix.scaleM(projection, 0, 0.05f, 0.05f, 1.0f);. I then added an offset to the modelview translations to simulate a camera so that I could center on my action (so Matrix.translateM(modelview, 0, quadX, quadY, 0); was changed to Matrix.translateM(modelview, 0, quadX + camX, quadY + camY, 0);) Thanks for the help, all!

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  • Project structure: where to put business logic

    - by Mister Smith
    First of all, I'm not asking where does business logic belong. This has been asked before and most answers I've read agree in that it belongs in the model: Where to put business logic in MVC design? How much business logic should be allowed to exist in the controller layer? How accurate is "Business logic should be in a service, not in a model"? Why put the business logic in the model? What happens when I have multiple types of storage? However people disagree in the way this logic should be distributed across classes. There seem to exist three major currents of thought: Fat model with business logic inside entity classes. Anemic model and business logic in "Service" classes. It depends. I find all of them problematic. The first option is what most Fowlerites stick to. The problem with a fat model is that sometimes a business logic funtion is not only related to a class, and instead uses a bunch of other classes. If, for example, we are developing a web store, there should be a function that calcs an order's total. We could think of putting this function inside the Order class, but what actually happens is that the logic needs to use different classes, not only data contained in the Order class, but also in the User class, the Session class, and maybe the Tax class, Country class, or Giftcard, Payment, etc. Some of these classes could be composed inside the Order class, but some others not. Sorry if the example is not very good, but I hope you understand what I mean. Putting such a function inside the Order class would break the single responsibility principle, adding unnecesary dependences. The business logic would be scattered across entity classes, making it hard to find. The second option is the one I usually follow, but after many projects I'm still in doubt about how to name the class or classes holding the business logic. In my company we usually develop apps with offline capabilities. The user is able to perform entire transactions offline, so all validation and business rules should be implemented in the client, and then there's usually a background thread that syncs with the server. So we usually have the following classes/packages in every project: Data model (DTOs) Data Access Layer (Persistence) Web Services layer (Usually one class per WS, and one method per WS method). Now for the business logic, what is the standard approach? A single class holding all the logic? Multiple classes? (if so, what criteria is used to distribute the logic across them?). And how should we name them? FooManager? FooService? (I know the last one is common, but in our case it is bad naming because the WS layer usually has classes named FooWebService). The third option is probably the right one, but it is also devoid of any useful info. To sum up: I don't like the first approach, but I accept that I might have been unable to fully understand the Zen of it. So if you advocate for fat models as the only and universal solution you are welcome to post links explaining how to do it the right way. I'd like to know what is the standard design and naming conventions for the second approach in OO languages. Class names and package structure, in particular. It would also be helpful too if you could include links to Open Source projects showing how it is done. Thanks in advance.

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  • Speeding up procedural texture generation

    - by FalconNL
    Recently I've begun working on a game that takes place in a procedurally generated solar system. After a bit of a learning curve (having neither worked with Scala, OpenGL 2 ES or Libgdx before), I have a basic tech demo going where you spin around a single procedurally textured planet: The problem I'm running into is the performance of the texture generation. A quick overview of what I'm doing: a planet is a cube that has been deformed to a sphere. To each side, a n x n (e.g. 256 x 256) texture is applied, which are bundled in one 8n x n texture that is sent to the fragment shader. The last two spaces are not used, they're only there to make sure the width is a power of 2. The texture is currently generated on the CPU, using the updated 2012 version of the simplex noise algorithm linked to in the paper 'Simplex noise demystified'. The scene I'm using to test the algorithm contains two spheres: the planet and the background. Both use a greyscale texture consisting of six octaves of 3D simplex noise, so for example if we choose 128x128 as the texture size there are 128 x 128 x 6 x 2 x 6 = about 1.2 million calls to the noise function. The closest you will get to the planet is about what's shown in the screenshot and since the game's target resolution is 1280x720 that means I'd prefer to use 512x512 textures. Combine that with the fact the actual textures will of course be more complicated than basic noise (There will be a day and night texture, blended in the fragment shader based on sunlight, and a specular mask. I need noise for continents, terrain color variation, clouds, city lights, etc.) and we're looking at something like 512 x 512 x 6 x 3 x 15 = 70 million noise calls for the planet alone. In the final game, there will be activities when traveling between planets, so a wait of 5 or 10 seconds, possibly 20, would be acceptable since I can calculate the texture in the background while traveling, though obviously the faster the better. Getting back to our test scene, performance on my PC isn't too terrible, though still too slow considering the final result is going to be about 60 times worse: 128x128 : 0.1s 256x256 : 0.4s 512x512 : 1.7s This is after I moved all performance-critical code to Java, since trying to do so in Scala was a lot worse. Running this on my phone (a Samsung Galaxy S3), however, produces a more problematic result: 128x128 : 2s 256x256 : 7s 512x512 : 29s Already far too long, and that's not even factoring in the fact that it'll be minutes instead of seconds in the final version. Clearly something needs to be done. Personally, I see a few potential avenues, though I'm not particularly keen on any of them yet: Don't precalculate the textures, but let the fragment shader calculate everything. Probably not feasible, because at one point I had the background as a fullscreen quad with a pixel shader and I got about 1 fps on my phone. Use the GPU to render the texture once, store it and use the stored texture from then on. Upside: might be faster than doing it on the CPU since the GPU is supposed to be faster at floating point calculations. Downside: effects that cannot (easily) be expressed as functions of simplex noise (e.g. gas planet vortices, moon craters, etc.) are a lot more difficult to code in GLSL than in Scala/Java. Calculate a large amount of noise textures and ship them with the application. I'd like to avoid this if at all possible. Lower the resolution. Buys me a 4x performance gain, which isn't really enough plus I lose a lot of quality. Find a faster noise algorithm. If anyone has one I'm all ears, but simplex is already supposed to be faster than perlin. Adopt a pixel art style, allowing for lower resolution textures and fewer noise octaves. While I originally envisioned the game in this style, I've come to prefer the realistic approach. I'm doing something wrong and the performance should already be one or two orders of magnitude better. If this is the case, please let me know. If anyone has any suggestions, tips, workarounds, or other comments regarding this problem I'd love to hear them.

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  • Motorola Droid App Recommendations

    - by Brian Jackett
    Just as a disclaimer, the views and opinions expressed in this post are solely my own and I’m not getting paid or compensated for anything.     Ok, so I’m one of the crazy few who went out and bought a Droid the week it was released a few months back.  The Motorola Droid was a MAJOR upgrade in phone capabilities for me as my previous phone had no GPS, no web access, limited apps, etc.  I now use my Droid for so much of my life from work to personal to community based events.  Since I’ve been using my Droid for awhile, a number of friends (@toddklindt, @spmcdonough, @jfroushiii, and many more) who later got a Droid asked me which apps I recommended.  While there are a few sites on the web listing out useful Android apps, here’s my quick list (with a few updates since first put together.) Note: * denotes a highly recommended app     Android App Recommendations for Motorola Droid (Updated after 2.1 update) RemoteDroid – install a thin client on another computer and Droid becomes mouse pad / keyboard, control computer remotely PdaNet – free version allows tethering (only to HTTP, no HTTPS) without paying extra monthly charge.  A paid version allows HTTPS access. SportsTap – keep track of about a dozen sports, favorite teams, etc *Movies – setup favorite theaters, find movie times, buy tickets, etc WeatherBug elite – paid app, but gives weather alerts, 4 day forecast, etc.  Free version also exists.  (Update: Android 2.1 offers free weather app, but I still prefer WeatherBug.) *Advanced Task Killer – manually free up memory and kill apps not needed Google Voice – have to have a Google Voice account to really use, but allows visual voice mail, sending calls to specific phones, and too many other things to list AndroZip – access your phone memory like a file system Twidroid – best Twitter client I’ve found so far, but personal preference varies.  I’m using free version and suits me just fine. Skype (beta) – I only use this to send chat messages, not sure how/if phone calls works on this. (Update: Skype Mobile app just released, but uninstalled after few days as it kept launching in background and using up memory when not wanted.) *NewsRob – RSS reader syncs to Google Reader.  I use this multiple times a day, excellent app. (Update: this app does ask for your Google username and password, so security minded folks be cautioned.) ConnectBot – don’t use often myself, but allows SSH into remote computer.  Great if you have a need for remote manage server. Speed Test – same as the online website, allows finding upload/download speeds. WiFinder – store wifi preferences and find wifi spots in area. TagReader – simple Microsoft Tag Reader, works great. *Google Listen – audible podcast catcher that allows putting items into a queue, sync with Google Reader RSS, etc. I personally love this app which has now replaced the iPod I used to use in my car, but have heard mixed reviews from others. Robo Defense – (paid app) tower defense game but with RPG elements to upgrade towers over lifetime playing. I’ve never played FieldRunners but I’m told very similar in offering. Nice distraction when in airport or have some time to burn. Phit Droid 3rd Edition – drag and drop block shapes into a rectangle box, simple game to pass the time with literally 1000s of levels. Note this game has been updated dozens of times with numerous editions so unsure exactly which are still on the market. Google Sky Map – impress your friends by holding Droid up to sky and viewing constellations using Droid screen. wootCheck Lite – check up on daily offerings on Woot.com and affiliated wine, sellout, shirt, and kids sites.   Side notes: I’ve seen that Glympse and TripIt have recently come out with Android apps.  I’ve installed but haven’t gotten to use either yet, but I hear good things.  Will try out on 2 upcoming trips in May and update with impressions.         -Frog Out   Image linked from http://images.tolmol.com/images/grpimages/200910191814100_motorola-droid.gif

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  • How to use a list of values in Excel as filter in a query

    - by Luca Zavarella
    It often happens that a customer provides us with a list of items for which to extract certain information. Imagine, for example, that our clients wish to have the header information of the sales orders only for certain orders. Most likely he will give us a list of items in a column in Excel, or, less probably, a simple text file with the identification code:     As long as the given values ??are at best a dozen, it costs us nothing to copy and paste those values ??in our SSMS and place them in a WHERE clause, using the IN operator, making sure to include the quotes in the case of alphanumeric elements (the database sample is AdventureWorks2008R2): SELECT * FROM Sales.SalesOrderHeader AS SOH WHERE SOH.SalesOrderNumber IN ( 'SO43667' ,'SO43709' ,'SO43726' ,'SO43746' ,'SO43782' ,'SO43796') Clearly, the need to add commas and quotes becomes an hassle when dealing with hundreds of items (which of course has happened to us!). It’d be comfortable to do a simple copy and paste, leaving the items as they are pasted, and make sure the query works fine. We can have this commodity via a User Defined Function, that returns items in a table. Simply we’ll provide the function with an input string parameter containing the pasted items. I give you directly the T-SQL code, where comments are there to clarify what was written: CREATE FUNCTION [dbo].[SplitCRLFList] (@List VARCHAR(MAX)) RETURNS @ParsedList TABLE ( --< Set the item length as your needs Item VARCHAR(255) ) AS BEGIN DECLARE --< Set the item length as your needs @Item VARCHAR(255) ,@Pos BIGINT --< Trim TABs due to indentations SET @List = REPLACE(@List, CHAR(9), '') --< Trim leading and trailing spaces, then add a CR\LF at the end of the list SET @List = LTRIM(RTRIM(@List)) + CHAR(13) + CHAR(10) --< Set the position at the first CR/LF in the list SET @Pos = CHARINDEX(CHAR(13) + CHAR(10), @List, 1) --< If exist other chars other than CR/LFs in the list then... IF REPLACE(@List, CHAR(13) + CHAR(10), '') <> '' BEGIN --< Loop while CR/LFs are over (not found = CHARINDEX returns 0) WHILE @Pos > 0 BEGIN --< Get the heading list chars from the first char to the first CR/LF and trim spaces SET @Item = LTRIM(RTRIM(LEFT(@List, @Pos - 1))) --< If the so calulated item is not empty... IF @Item <> '' BEGIN --< ...insert it in the @ParsedList temporary table INSERT INTO @ParsedList (Item) VALUES (@Item) --(CAST(@Item AS int)) --< Use the appropriate conversion if needed END --< Remove the first item from the list... SET @List = RIGHT(@List, LEN(@List) - @Pos - 1) --< ...and set the position to the next CR/LF SET @Pos = CHARINDEX(CHAR(13) + CHAR(10), @List, 1) --< Repeat this block while the upon loop condition is verified END END RETURN END At this point, having created the UDF, our query is transformed trivially in: SELECT * FROM Sales.SalesOrderHeader AS SOH WHERE SOH.SalesOrderNumber IN ( SELECT Item FROM SplitCRLFList('SO43667 SO43709 SO43726 SO43746 SO43782 SO43796') AS SCL) Convenient, isn’t it? You can find the script DBA_SplitCRLFList.sql here. Bye!!

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  • jqGrid - customizing the multi-select option (restrict single selection and adding custom events)

    - by Renso
    Goal: Using the jgGrid to enable a selection of a checkbox for row selection - which is easy to set in the jqGrid - but also only allowing a single row to be selectable at a time while adding events based on whether the row was selected or de-selected. Environment: jQuery 1.4.4 jqGrid 3.4.4a Issue: The jqGrid does not support the option to restrict the multi-select to only allow for a single selection. You may ask, why bother with the multi-select checkbox function if you only want to allow for the selection of a single row? Good question, as an example, you want to reserve the selection of a row to trigger another kind of event and use the checkbox multi-select to handle a different kind of event; in other words, when I select the row I want something entirely different to happen than when I select to check off the checkbox for that row. Also the setSelection method of the jqGrid is a toggle and has no support for determining whether the checkbox has already been selected or not, So it will simply act as a switch - which it is designed to do - but with no way out of the box to only check off the box (as in not to de-select) rather than act like a switch. Furthermore, the getGridParam('selrow') does not indicate if the row was selected or de-selected, which seems a bit strange and is the main reason for this blog post. Solution: How this will act: When you check off a multi-select checkbox in the gird, and then commence to select another row by checking off that row's multi-select checkbox - I'm not talking there about clicking on the row but using the grid's multi-select checkbox - it will de-select the previous selection so that you are always left with only a single selection. Furthermore, once you select or de-select a multi-select checkbox, fire off an event that will be determined by whether or not the row was selected or de-selected, not just merely clicked on. So if I de-select the row do one thing but when selecting it do another. Implementation (this of course is only a partial code snippet):             multiselect: true,             multiboxonly: true,             onSelectRow: function (rowId) {                 var gridSelRow = $(item).getGridParam('selrow');                 var s;                 s = $(item).getGridParam('selarrrow');                 if (!s || !s[0]) {                     $(item).resetSelection();                     $('#productLineDetails').fadeOut();                     lastsel = null;                     return;                 }                 var selected = $.inArray(rowId, s) != -1;                 if (selected) {                     $('#productLineDetails').show();                 }                 else {                     $('#productLineDetails').fadeOut();                 }                 if (rowId && rowId !== lastsel && selected) {                     $(item).GridToForm(gridSelRow, '#productLineDetails');                     if (lastsel) $(item).setSelection(lastsel, false);                 }                 lastsel = rowId;             }, In the example code above: The "item" property is the id of the jqGrid. The following to settings ensure that the jqGrid will add the new column to select rows with a checkbox and also the not allow for the selection by clicking on the row but to force the user to have to click on the multi-select checkbox to select the row: multiselect: true, multiboxonly: true, Unfortunately the var gridSelRow = $(item).getGridParam('selrow') function will only return the row the user clicked on or rather that the row's checkbox was clicked on and NOT whether or not it was selected nor de-selected, but it retrieves the row id, which is what we will need. The following piece get's all rows that have been selected so far, as in have a checked off multi-select checkbox: var s; s = $(item).getGridParam('selarrrow'); Now determine if the checkbox the user just clicked on was selected or de-selected: var selected = $.inArray(rowId, s) != -1; If it was selected then show a container "#productLineDetails", if not hide that container away. The following instruction populates a form with the grid data using the built-in GridToForm method (just mentioned here as an example) ONLY if the row has been selected and NOT de-selected but more importantly to de-select any other multi-select checkbox that may have been selected: if (rowId && rowId !== lastsel && selected) {                     $(item).GridToForm(gridSelRow, '#productLineDetails');                     if (lastsel) $(item).setSelection(lastsel, false); }

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  • Managing Scripts in Oracle SQL Developer

    - by thatjeffsmith
    You backup your databases, right? You backup you home computer – your media collection, tax documents, bank accounts, etc, right? You backup your handy-dandy SQL scripts, right? Ok, now that I’ve got your head nodding, I want to answer a question I get every so often: How can I manage my scripts in SQL Developer? This is an interesting question. First, it assumes that one SHOULD manage their scripts in their IDE. Now, what I think the question generally gets around to is, how can we: Navigate to our scripts Open them Execute them What a good IDE should have is an interface to your existing Version Control System (VCS.) SQL Developer supports out-of-the-box both Subversion and Git. You can also download an extension via check-for-updates to get support for CVS. Now, what I’m about to show you COULD be done without versioning and controlling your scripts – but I want to ask you why you wouldn’t want to do this? So, I’m going to proceed and assume that you do INDEED version your scripts already. Seeing what scripts you’ve already got in your repository This is very straightforward – just open the Team Versions panel. Then connect to your repository. Shows you the files in your source control system. Now, I could ‘preview’ said file right away. If I open the file from here, we get a temp file copy down from the server to the local machine. This is a local temp copy of the controlled script – I can read/execute, but not write to it. And that might be all you need. But, if your script calls other scripts, then you’re going to want to check out the server copy of your stuff down your local SVN working copy directory. That way when your script calls another script – you’re executing the PRODUCTION APPROVED copies of said scripts. And if you do SPOOL or other file I/O stuff, it will work as expected. To get to those said client copies of your scripts… Enter the Files Panel The Files panel is accessible from the View menu. You can get to your files, one of two ways. If you’ve touched the file recently, you can see it under the Recent tree. Otherwise, you can navigate to your local ‘checked out’ copies of your script(s). Open your local copies, see what’s changed, etc. And I can access the change history and see what’s been touched… What changes am I going to ‘push out’ if I commit this back to the server? Most of us work on teams, yes? This panel also gives me a heads up if someone else is making changes to the same file. I can see the ‘incoming’ changes as well. To Sum It Up… If I want to get a script to run: do a full get to your local directory open the script(s) The files panel will tell you if your local copy is out of date from the server and if you have made local changes you’ve forgotten to commit back up to the server and your fellow teammates. Now, if you’re the selfish type and don’t want to share, that’s fine. But you should still be backing up your scripts, and you can still use the Files panel to manage your scripts.

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  • SQL SERVER – Partition Parallelism Support in expressor 3.6

    - by pinaldave
    I am very excited to learn that there is a new version of expressor’s data integration platform coming out in March of this year.  It will be version 3.6, and I look forward to using it and telling everyone about it.  Let me describe a little bit more about what will be so great in expressor 3.6: Greatly enhanced user interface Parallel Processing Bulk Artifact Upgrading The User Interface First let me cover the most obvious enhancements. The expressor Studio user interface (UI) has had some significant work done. Kudos to the expressor Engineering team; the entire UI is a visual masterpiece that is very responsive and intuitive. The improvements are more than just eye candy; they provide significant productivity gains when developing expressor Dataflows. Operator shape icons now include a description that identifies the function of each operator, instead of having to guess at the function by the icon. Operator shapes and highlighting depict the current function and status: Disabled, enabled, complete, incomplete, and error. Each status displays an appropriate message in the message panel with correction suggestions. Floating or docking property panels provide descriptive tool tips for each property as well as auto resize when adjusting the canvas, without having to search Help or the need to scroll around to get access to the property. Progress and status indicators let you know when an operation is working. “No limit” canvas with snap-to-grid allows automatic sizing and accurate positioning when you have numerous operators in the Dataflow. The inline tool bar offers quick access to pan, zoom, fit and overview functions. Selecting multiple artifacts with a right click context allows you to easily manage your workspace more efficiently. Partitioning and Parallel Processing Partitioning allows each operator to process multiple subsets of records in parallel as opposed to processing all records that flow through that operator in a single sequential set. This capability allows the user to configure the expressor Dataflow to run in a way that most efficiently utilizes the resources of the hardware where the Dataflow is running. Partitions can exist in most individual operators. Using partitions increases the speed of an expressor data integration application, therefore improving performance and load times. With the expressor 3.6 Enterprise Edition, expressor simplifies enabling parallel processing by adding intuitive partition settings that are easy to configure. Bulk Artifact Upgrading Bulk Artifact Upgrading sounds a bit intimidating, but it actually is not and it is a welcome addition to expressor Studio. In past releases, users were prompted to confirm that they wanted to upgrade their individual artifacts only when opened. This was a cumbersome and repetitive process. Now with bulk artifact upgrading, a user can easily select what artifact or group of artifacts to upgrade all at once. As you can see, there are many new features and upgrade options that will prove to make expressor Studio quicker and more efficient.  I hope I’m not the only one who is excited about all these new upgrades, and that I you try expressor and share your experience with me. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • ResourceSerializable: an alternate to ORM and ActiveRecord

    - by Levi Morrison
    A few opinionated reasons I don't like the traditional ORM and ActiveRecord patterns: They work only with a database. Sometimes I'm dealing with objects from an API and other objects from a database. All the implementations I have seen don't allow for that. Feel free to clue me in if I'm wrong on this. They are brittle. Changes in the database will likely break your implemenation. Some implementations can help reduce this, but a few of the ones I've seen don't. Their very design is influenced by the database. If I want to switch to using an API, I'll have to redesign the object to get it to work (likely). It seems to violate the single-responsibility pattern. They know what they are and how they act, but they also know how they are created, destroyed and saved? Seems a bit much. What about an approach that is somewhat more familiar in PHP: implementing an interface? In php 5.4, we'll have the JsonSerializable interface that defines the data to be json_encoded, so users will become accustomed to this type of thing. What if there was a ResourceSerializable interface? This is still an ORM by name, but certainly not by tradition. interface ResourceSerializable { /** * Returns the id that identifies the resource. */ function resourceId(); /** * Returns the 'type' of the resource. */ function resourceType(); /** * Returns the data to be serialized. */ function resourceSerialize(); } Things might be poorly named, I'll take suggestions. Notes: ResourceId will work for API's and databases. As long as your primary key in the database is the same as the resource ID in the API, there is no conflict. All of the API's I've worked with have a unique ID for the resource, so I don't see any issues there. ResourceType is the group or type associated with the resource. You can use this to map the resource to an API call or a database table. If the ResourceType was person, it could map to /api/1/person/{resourceId} and the table persons (or people, if it's smart enough). resourceSerialize() returns the data to be stored. Keys would identify API parameters and database table columns. This also seems easier to test than ActiveRecord / Orm implemenations. I haven't done much automated testing on traditional ActiveRecord/ORM implemenations, so this is merely a guess. But it seems that I being able to create objects independently of the library helps me. I don't have to use load() to get an existing resource, I can simply create one and set all the right properties. This is not so easy in the ActiveRecord / Orm implemenations I've dealt with. Downsides: You need another object to serialize it. This also means you have more code in general as you have to use more objects. You have to map resource types to API calls and database tables. This is even more work, but some ORMs and ActiveRecord implementations require you to map objects to table names anyway. Are there other downsides that you see? Does this seem feasible to you? How would you improve it? Note: I almost asked this on StackOverflow because it might be too vague for their standards, but I'm still not really familiar with programmers.stackexchange.com, so please help me improve my question if it doesn't shape up to standards here.

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  • SQL Sentry Truth-Telling and Disk Configuration

    - by AjarnMark
    Recently, SQL Sentry told me something about my SQL Server disk configurations that I just didn’t want to believe, but alas, it was true. Several days ago I posted my First Impressions of the SQL Sentry Power Suite.  Today’s post could fall into the category of, “Hey, as long as you have that fancy tool…”  Unfortunately, it also falls into the category of an overloaded worker taking someone else’s word for the truth, not verifying it with independent fact-checking, and then making decisions based on that.  Here’s my story… I’m not exactly an Accidental DBA (or Involuntary DBA as Paul Randal calls it).  I came to this company five years ago as a lead application developer with extensive experience in database design and development.  I worked my way into management, and along the way, took over the DBA responsibilities.  Fortunately, our systems run pretty smoothly most of the time, but I’m always looking for ways to make them better and to fit into my understanding of best practices.  When I took over as DBA, I inherited a SQL 2000 server with about 30 databases on it supporting our main systems, and a SQL 2005 server with multiple instances.  Both of these servers were configured with the Operating System and Application files on the C drive, data files on a different drive letter, and log files on a third drive letter.  Even before I took over as DBA, I verified that this was true with a previous server administrator, and that these represented actual separate disks.  He stated that they did, and I thought that all was well. Then one day, I’m poking around inside the SQL Sentry Performance Advisor, checking out features as I am evaluating whether to purchase the product, and I come across a Disk Configuration section.  The first thing I notice is that the drives do not have the proper partition offset, which was not at all surprising to me given the age of the installation and the relative newness of that topic.  But what threw me for a loop was that the graphic display appeared to be telling me that I did not in fact have three separate drives (or arrays) but rather had two, and that the log files were merely on a separate volume on the same physical array as the OS.  I figured that I must be reading it wrong so I scanned the Help file, but that just seemed to confirm my interpretation.  Then I thought, “there must be something wrong with the demo version of the software!  This can’t be right!”  But just to double-check, I went to our current server admin to talk it over with him, and sure enough, SQL Sentry was telling the truth! I was stunned!  I quickly went through the grieving process…denial…anger…reconciliation.  Here was something that I thought was such a basic truth that was turned upside down.  OK, granted, this wasn’t disastrous.  Our databases didn’t suddenly grind to a halt.  I didn’t get calls late at night inquiring about the sudden downturn in performance.  But it was a bit of a shock to the system, in a good way, to jolt me out of taking what I had believed as the truth for granted, and instead to Trust, but Verify! Yes, before someone else points it out, I know that there are”free” disk management tools built-in to Windows that would have told me the same thing if I had only looked at them; I did not have to buy a fancy tool to tell me that, but the fact is, until I was evaluating the tool, I had just gone with what I was told, and never bothered to check what was actually there. So, what things do you believe to be true but you actually never verified?

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  • Why you shouldn't add methods to interfaces in APIs

    - by Simon Cooper
    It is an oft-repeated maxim that you shouldn't add methods to a publically-released interface in an API. Recently, I was hit hard when this wasn't followed. As part of the work on ApplicationMetrics, I've been implementing auto-reporting of MVC action methods; whenever an action was called on a controller, ApplicationMetrics would automatically report it without the developer needing to add manual ReportEvent calls. Fortunately, MVC provides easy hook when a controller is created, letting me log when it happens - the IControllerFactory interface. Now, the dll we provide to instrument an MVC webapp has to be compiled against .NET 3.5 and MVC 1, as the lowest common denominator. This MVC 1 dll will still work when used in an MVC 2, 3 or 4 webapp because all MVC 2+ webapps have a binding redirect redirecting all references to previous versions of System.Web.Mvc to the correct version, and type forwards taking care of any moved types in the new assemblies. Or at least, it should. IControllerFactory In MVC 1 and 2, IControllerFactory was defined as follows: public interface IControllerFactory { IController CreateController(RequestContext requestContext, string controllerName); void ReleaseController(IController controller); } So, to implement the logging controller factory, we simply wrap the existing controller factory: internal sealed class LoggingControllerFactory : IControllerFactory { private readonly IControllerFactory m_CurrentController; public LoggingControllerFactory(IControllerFactory currentController) { m_CurrentController = currentController; } public IController CreateController( RequestContext requestContext, string controllerName) { // log the controller being used FeatureSessionData.ReportEvent("Controller used:", controllerName); return m_CurrentController.CreateController(requestContext, controllerName); } public void ReleaseController(IController controller) { m_CurrentController.ReleaseController(controller); } } Easy. This works as expected in MVC 1 and 2. However, in MVC 3 this type was throwing a TypeLoadException, saying a method wasn't implemented. It turns out that, in MVC 3, the definition of IControllerFactory was changed to this: public interface IControllerFactory { IController CreateController(RequestContext requestContext, string controllerName); SessionStateBehavior GetControllerSessionBehavior( RequestContext requestContext, string controllerName); void ReleaseController(IController controller); } There's a new method in the interface. So when our MVC 1 dll was redirected to reference System.Web.Mvc v3, LoggingControllerFactory tried to implement version 3 of IControllerFactory, was missing the GetControllerSessionBehaviour method, and so couldn't be loaded by the CLR. Implementing the new method Fortunately, there was a workaround. Because interface methods are normally implemented implicitly in the CLR, if we simply declare a virtual method matching the signature of the new method in MVC 3, then it will be ignored in MVC 1 and 2 and implement the extra method in MVC 3: internal sealed class LoggingControllerFactory : IControllerFactory { ... public virtual SessionStateBehaviour GetControllerSessionBehaviour( RequestContext requestContext, string controllerName) {} ... } However, this also has problems - the SessionStateBehaviour type only exists in .NET 4, and we're limited to .NET 3.5 by support for MVC 1 and 2. This means that the only solutions to support all MVC versions are: Construct the LoggingControllerFactory type at runtime using reflection Produce entirely separate dlls for MVC 1&2 and MVC 3. Ugh. And all because of that blasted extra method! Another solution? Fortunately, in this case, there is a third option - System.Web.Mvc also provides a DefaultControllerFactory type that can provide the implementation of GetControllerSessionBehaviour for us in MVC 3, while still allowing us to override CreateController and ReleaseController. However, this does mean that LoggingControllerFactory won't be able to wrap any calls to GetControllerSessionBehaviour. This is an acceptable bug, given the other options, as very few developers will be overriding GetControllerSessionBehaviour in their own custom controller factory. So, if you're providing an interface as part of an API, then please please please don't add methods to it. Especially if you don't provide a 'default' implementing type. Any code compiled against the previous version that can't be updated will have some very tough decisions to make to support both versions.

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