class design - Page 142

Learn About Multiple C Class IP's One Step at a Time

Learning how SEO Hosting can help a webmaster can be a daunting task. This article explains the basics of SEO Hosting by stressing on the importance of Multiple C Class IPs.

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The Most Effective Way to Run a Professional Business is to Attend an SEO Class

There are numerous SEO colleges that offer fun, easy and affordable online SEO short courses as well as marketing subjects. There are no special requirements needed and these courses assume zero knowledge and do not require any previous HTML or programming background. In addition to an SEO class you will be provided with links for online tutorials which will supply you with valuable information.

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How to Use C Class IP Address Range

Another very important thing that you have to remember is that your site should be able to feature in the very first page of a search engine or else it is of no use. This is how you can use C Class IP address Ranges.

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Modifying a HTML page to fix several "bugs" add a function to next/previous on a option dropdown

- by Dennis Sylvian

SOF, I've got a few problems plaguing me at the moment and am wondering if anyone could assist me with them. I'm trying to get Next Class | Previous Class to act as buttons so that when Next Class is clicked it will go to the next item in the dropdown list and for previous it would go to back one. There used to be a scroll bar that allowed me to scroll the main window left and right, it's missing because (I think it was to do with the scroll left and scroll right function) The footer at the bottom doesn't show correctly on mobile devices; for some reason it appears completely differently to as it does on a computer. The "bar" practically and the Scroll Left and Scroll buttons don't appear at all on mobile devices. The scroll left button is unable to be clicked for some reason, I'm unsure what I've done wrong. Refreshing the page resets the horizontal scroll position to far left (I'm pretty sure this relates to the scroll bar) I want to also find a way so that on mobile devices the the header will not show the placeholder image, however I can't work out what CSS media tag(s) I should be using. Latest: http://jsfiddle.net/pwv7u/ Smaller HTML <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>DATA DATA DATA DATA DATA DATA DATA DATA</title> <style type="text/css">  </style> <script src="jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> $(document).ready( function() { for (var i=0;i<($("table").children().length);i++){ if(readCookie(i)) $($($("table").children()[i]).children()[(readCookie(i))]).toggleClass('selected').siblings().removeClass('selected'); } $("tr").click(function(){ $(this).toggleClass('selected').siblings().removeClass('selected'); if(readCookie($(this).parent().index())){ if(readCookie($(this).parent().index())==$(this).index()) eraseCookie($(this).parent().index()); else{ eraseCookie($(this).parent().index()); createCookie($(this).parent().index(),$(this).index(),1); } } else createCookie($(this).parent().index(),$(this).index(),1); }); // gather CLASS info var selector = $('.class-selector').on('change', function(){ var id = this.value; if (id!==''){ scrollToAnchor(id); } }); $('a[id^="CLASS"]').each(function(){ var id = this.id, option = $('<option>',{ value: this.id, text:this.id }); selector.append(option); }); function scrollToAnchor(aid) { var aTag = $("a[id='" + aid + "']"); $('html,body').animate({ scrollTop: aTag.offset().top - 80 }, 1); } $("a.TOPJS").click(function () { scrollToAnchor('TOP'); }); $("a.KEYJS").click(function () { scrollToAnchor('KEY'); }); $("a.def").click(function () { $('#container').animate({ "scrollLeft": "-=204" }, 200); }); $("a.abc").click(function () { $("#container").animate({ "scrollLeft": "+=204" }, 200); }); function createCookie(name,value,days) { var expires; if (days) { var date = new Date(); date.setMilliseconds(0); date.setSeconds(0); date.setMinutes(0); date.setHours(0); date.setDate(date.getDate()+days); expires = "; expires="+date.toGMTString(); } else expires = ""; document.cookie = name+"="+value+expires+"; path=/"; } function readCookie(name) { var nameEQ = name + "="; var ca = document.cookie.split(';'); for(var i=0;i < ca.length;i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1,c.length); if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length,c.length); } return null; } function eraseCookie(name) { createCookie(name,"",-1); } }); </script> </head> <body> <div id="header_container"> <div id="header"> <a href="http://site.x/" target="_blank"><img src="http://placehold.it/300x80"></a> <select class="class-selector"> <option value="">-select class-</option> </select> <div class="classcycler"> <a href="#TOP"><font color=#EFEFEF>Next Class</font></a> <font color=red>|</font> <a href="#TOP"><font color=#EFEFEF>Previous Class</font></a> </div> <div id="header1"> Semi-Transparent Image <a href="#TOP"><font color=#EFEFEF>Up to Top</font></a> | <a href="#KEY"><font color=#EFEFEF>Down to Key</font></a> </div> </div> </div> <a id="TOP"></a> <div id="container"> <table id="gradient-style"> <tbody> <thead> <tr> <th scope="col"><a id="CLASS1"></a>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class<br>Test 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class Data 1</th> <th scope="col">Class 1<br>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1<br>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1 Class 1</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> (data text)</th> <th scope="col">title text</th> <th scope="col">text</th> <th scope="col">text</th> <th scope="col">title text</th> <th scope="col">title text</th> </tr> </thead> <tr class="ft3"><td>testing data</td><td>testing data</td><td>test</td><td>class b</td><td>test4</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left"></div></td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><tr> <tr class="f3"><td>test</td><td>test</td><td>test</td><td>class a</td><td>test2</td><td><div align="left"> </div></td><td><div align="left"></div></td><td><div align="left"></div></td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><tr> <thead> <tr> <th scope="col"><a id="CLASS2"></a>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class<br>Test 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class Data 2</th> <th scope="col">Class 2<br>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2<br>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2 Class 2</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> (data text)</th> <th scope="col">title text</th> <th scope="col">text</th> <th scope="col">text</th> <th scope="col">title text</th> <th scope="col">title text</th> </tr> </thead> <tr class="ft3"><td>testing data</td><td>testing data</td><td>test</td><td>class f</td><td>test2</td><td><div align="left">data</div></td><td><div align="left"></div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr><td>test</td><td>testing data</td><td>test</td><td>class f</td><td>test4</td><td><div align="left">data</div></td><td><div align="left"></div></td><td><div align="left"></div></td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr class="f3"><td>test</td><td>testing data</td><td>testing data</td><td>class d</td><td>test5</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr><td>testing data</td><td>test</td><td>test</td><td>class f</td><td>test5</td><td><div align="left"></div></td><td><div align="left"></div></td><td><div align="left">data</div></td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><tr> <tr class="f2"><td>test</td><td>test</td><td>testing data</td><td>class a</td><td>test1</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><tr> </tbody> <tfoot> <tr> <th class="alt" colspan="34" scope="col"><a id="KEY"></a><img src="http://placehold.it/300x50"></th> </tr> <tr> <td colspan="34"><em><b>DATA DATA</b> - DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA </em></td> </tr> <tr> <td class="alt" colspan="34"><em><b>DAT DATA</b> - DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA </em></td> </tr> </tfoot> </table> </div> <div id="footer_container"> <div id="footer"> <a href="http://site.x/" target="_blank"><img src="http://placehold.it/300x80"></a> <div class="footleft"> <a class="def" href="javascript: void(0);"><font color="#EFEFEF">Scroll Left</font></a> </div> <div id="footer1"> <font color="darkblue">Semi-Transparent Image</font> <i>Copyright © 2013 <a href="http://site.x/" target="_blank" style="text-decoration: none"><font color=#ADD8E6>site</font></a>.</i> </div> <div id="footer2"> <i>All Rights Reserved.</i> </div> <div class="footright"> <a class="abc" href="javascript: void(0);"><font color="#EFEFEF">Scroll Right</font></a> </div> </div> </div> </body> </html> CSS gradient-style * { white-space: nowrap; } #header .class-selector { top: 10px; left: 20px; position: fixed; } #header .classcycler { top: 45px; left: 20px; position: fixed; font-size:20px; } body { line-height: 1.6em; background-color: #535353; overflow-x: scroll; } #gradient-style { font-family: "Lucida Sans Unicode", "Lucida Grande", Sans-Serif; font-size: 12px; margin: 0px; width: 100%; text-align: center; border-collapse: collapse; } #gradient-style th { font-size: 13px; font-weight: normal; line-height:250%; padding-left: 5px; padding-right: 5px; background: #535353 url('table-images/gradhead.png') repeat-x; border-top: 1px solid #fff; border-bottom: 1px solid #fff; color: #ffffff; } #gradient-style th.alt { font-family: "Times New Roman", Serif; text-align: left; padding: 10px; font-size: 26px; } #gradient-style td { padding-left: 5px; padding-right: 5px; border-bottom: 1px solid #fff; border-left: 1px solid #fff; border-right: 1px solid #fff; color: #00000; border-top: 1px solid #fff; background: #FFF url('table-images/gradback.png') repeat-x; } #gradient-style tr.ft3 td { color: #00000; background: #99cde7 url('table-images/gradoverallstudent.png') repeat-x; font-weight: bold; } #gradient-style tr.f1 td { color: #00000; background: #99cde7 url('table-images/gradbeststudent.png') repeat-x; } #gradient-style tr.f2 td { color: #00000; background: #b7e2b6 url('table-images/gradmostattentedstudent.png') repeat-x; } #gradient-style tr.f3 td { color: #00000; background: #a9cd6c url('table-images/gradleastlatestudtent.png') repeat-x; } #gradient-style tfoot tr td { background: #6FA275; font-size: 12px; color: #000; padding: 10; text-align: left; } #gradient-style tbody tr:hover td, #gradient-style tbody tr.selected td { background: #d0dafd url('table-images/gradhover.png') repeat-x; color: #339; } body { margin: 0; padding: 0; } #header_container { background: #000000 url('table-images/gradhead.png') repeat-x; border: 0px solid #666; height: 80px; left: 0; position: fixed; width: 100%; top: 0; } #header { position: relative; margin: 0 auto; width: 500px; height: 100%; text-align: center; color: #0c0aad; } #header1 { position: absolute; width: 125%; top: 50px; } #container { margin: 0 auto; overflow: auto; padding: 80px 0; width: 100%; } #content { } #footer_container { background: #000000 url('table-images/gradhead.png') repeat-x; border: 0px solid #666; bottom: 0; height: 95px; left: 0; position: fixed; width: 100%; } #footer { position: relative; margin: 0 auto; height: 100%; text-align: center; color: #FFF; } #footer1 { position: absolute; width: 103%; top: 50px; } #footer2 { position: absolute; width: 110%; top: 70px; } #footer .footleft { top: 45px; left: 2%; position: absolute; font-size:20px; } #footer .footright { top: 45px; right: 2%; position: absolute; font-size:20px; }

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Can't build and run an android test project created using "ant create test-project" when tested proj

- by Mike

I have a module that builds an app called MyApp. I have another that builds some testcases for that app, called MyAppTests. They both build their own APKs, and they both work fine from within my IDE. I'd like to build them using ant so that I can take advantage of continuous integration. Building the app module works fine. I'm having difficulty getting the Test module to compile and run. Using Christopher's tip from a previous question, I used android create test-project -p MyAppTests -m ../MyApp -n MyAppTests to create the necessary build files to build and run my test project. This seems to work great (once I remove an unnecessary test case that it constructed for me and revert my AndroidManifest.xml to the one I was using before it got replaced by android create), but I have two problems. The first problem: The project doesn't compile because it's missing libraries. $ ant run-tests Buildfile: build.xml [setup] Project Target: Google APIs [setup] Vendor: Google Inc. [setup] Platform Version: 1.6 [setup] API level: 4 [setup] WARNING: No minSdkVersion value set. Application will install on all Android versions. -install-tested-project: [setup] Project Target: Google APIs [setup] Vendor: Google Inc. [setup] Platform Version: 1.6 [setup] API level: 4 [setup] WARNING: No minSdkVersion value set. Application will install on all Android versions. -compile-tested-if-test: -dirs: [echo] Creating output directories if needed... -resource-src: [echo] Generating R.java / Manifest.java from the resources... -aidl: [echo] Compiling aidl files into Java classes... compile: [javac] Compiling 1 source file to /Users/mike/Projects/myapp/android/MyApp/bin/classes -dex: [echo] Converting compiled files and external libraries into /Users/mike/Projects/myapp/android/MyApp/bin/classes.dex... [echo] -package-resources: [echo] Packaging resources [aaptexec] Creating full resource package... -package-debug-sign: [apkbuilder] Creating MyApp-debug-unaligned.apk and signing it with a debug key... [apkbuilder] Using keystore: /Users/mike/.android/debug.keystore debug: [echo] Running zip align on final apk... [echo] Debug Package: /Users/mike/Projects/myapp/android/MyApp/bin/MyApp-debug.apk install: [echo] Installing /Users/mike/Projects/myapp/android/MyApp/bin/MyApp-debug.apk onto default emulator or device... [exec] 1567 KB/s (288354 bytes in 0.179s) [exec] pkg: /data/local/tmp/MyApp-debug.apk [exec] Success -compile-tested-if-test: -dirs: [echo] Creating output directories if needed... [mkdir] Created dir: /Users/mike/Projects/myapp/android/MyAppTests/gen [mkdir] Created dir: /Users/mike/Projects/myapp/android/MyAppTests/bin [mkdir] Created dir: /Users/mike/Projects/myapp/android/MyAppTests/bin/classes -resource-src: [echo] Generating R.java / Manifest.java from the resources... -aidl: [echo] Compiling aidl files into Java classes... compile: [javac] Compiling 5 source files to /Users/mike/Projects/myapp/android/MyAppTests/bin/classes [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:4: package roboguice.test does not exist [javac] import roboguice.test.RoboUnitTestCase; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:8: package com.google.gson does not exist [javac] import com.google.gson.JsonElement; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:9: package com.google.gson does not exist [javac] import com.google.gson.JsonParser; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:11: cannot find symbol [javac] symbol: class RoboUnitTestCase [javac] public class GsonTest extends RoboUnitTestCase<MyApplication> { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:6: package roboguice.test does not exist [javac] import roboguice.test.RoboUnitTestCase; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:7: package roboguice.util does not exist [javac] import roboguice.util.RoboLooperThread; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:11: package com.google.gson does not exist [javac] import com.google.gson.JsonObject; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:15: cannot find symbol [javac] symbol: class RoboUnitTestCase [javac] public class HttpTest extends RoboUnitTestCase<MyApplication> { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/LinksTest.java:4: package roboguice.test does not exist [javac] import roboguice.test.RoboUnitTestCase; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/LinksTest.java:12: cannot find symbol [javac] symbol: class RoboUnitTestCase [javac] public class LinksTest extends RoboUnitTestCase<MyApplication> { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:4: package roboguice.test does not exist [javac] import roboguice.test.RoboUnitTestCase; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:5: package roboguice.util does not exist [javac] import roboguice.util.RoboAsyncTask; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:6: package roboguice.util does not exist [javac] import roboguice.util.RoboLooperThread; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:12: cannot find symbol [javac] symbol: class RoboUnitTestCase [javac] public class SafeAsyncTest extends RoboUnitTestCase<MyApplication> { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectResource': class file for roboguice.inject.InjectResource not found [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectResource' [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectView': class file for roboguice.inject.InjectView not found [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectView' [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectView' [javac] /Users/mike/Projects/myapp/android/MyApp/bin/classes/com/myapp/activity/Stories.class: warning: Cannot find annotation method 'value()' in type 'roboguice.inject.InjectView' [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:15: cannot find symbol [javac] symbol : class JsonParser [javac] location: class com.myapp.test.GsonTest [javac] final JsonParser parser = new JsonParser(); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:15: cannot find symbol [javac] symbol : class JsonParser [javac] location: class com.myapp.test.GsonTest [javac] final JsonParser parser = new JsonParser(); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:18: cannot find symbol [javac] symbol : class JsonElement [javac] location: class com.myapp.test.GsonTest [javac] final JsonElement e = parser.parse(s); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:20: cannot find symbol [javac] symbol : class JsonElement [javac] location: class com.myapp.test.GsonTest [javac] final JsonElement e2 = parser.parse(s2); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:19: cannot find symbol [javac] symbol : method getInstrumentation() [javac] location: class com.myapp.test.HttpTest [javac] assertEquals("MyApp", getInstrumentation().getTargetContext().getResources().getString(com.myapp.R.string.app_name)); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:62: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.HttpTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:82: cannot find symbol [javac] symbol : method assertTrue(java.lang.String,boolean) [javac] location: class com.myapp.test.HttpTest [javac] assertTrue(result[0], result[0].contains("Search")); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:87: cannot find symbol [javac] symbol : class JsonObject [javac] location: class com.myapp.test.HttpTest [javac] final JsonObject[] result = {null}; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:90: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.HttpTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:117: cannot find symbol [javac] symbol : class JsonObject [javac] location: class com.myapp.test.HttpTest [javac] final JsonObject[] result = {null}; [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/HttpTest.java:120: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.HttpTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/LinksTest.java:27: cannot find symbol [javac] symbol : method assertTrue(boolean) [javac] location: class com.myapp.test.LinksTest [javac] assertTrue(m.matches()); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/LinksTest.java:28: cannot find symbol [javac] symbol : method assertEquals(java.lang.String,java.lang.String) [javac] location: class com.myapp.test.LinksTest [javac] assertEquals( map.get(url), m.group(1) ); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:19: cannot find symbol [javac] symbol : method getInstrumentation() [javac] location: class com.myapp.test.SafeAsyncTest [javac] assertEquals("MyApp", getInstrumentation().getTargetContext().getString(com.myapp.R.string.app_name)); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:27: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.SafeAsyncTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:65: cannot find symbol [javac] symbol : method assertEquals(com.myapp.test.SafeAsyncTest.State,com.myapp.test.SafeAsyncTest.State) [javac] location: class com.myapp.test.SafeAsyncTest [javac] assertEquals(State.TEST_SUCCESS,state[0]); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:74: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.SafeAsyncTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:105: cannot find symbol [javac] symbol : method assertEquals(com.myapp.test.SafeAsyncTest.State,com.myapp.test.SafeAsyncTest.State) [javac] location: class com.myapp.test.SafeAsyncTest [javac] assertEquals(State.TEST_SUCCESS,state[0]); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:113: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.SafeAsyncTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:144: cannot find symbol [javac] symbol : method assertEquals(com.myapp.test.SafeAsyncTest.State,com.myapp.test.SafeAsyncTest.State) [javac] location: class com.myapp.test.SafeAsyncTest [javac] assertEquals(State.TEST_SUCCESS,state[0]); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:154: cannot find symbol [javac] symbol : class RoboLooperThread [javac] location: class com.myapp.test.SafeAsyncTest [javac] new RoboLooperThread() { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java:187: cannot find symbol [javac] symbol : method assertEquals(com.myapp.test.SafeAsyncTest.State,com.myapp.test.SafeAsyncTest.State) [javac] location: class com.myapp.test.SafeAsyncTest [javac] assertEquals(State.TEST_SUCCESS,state[0]); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/StoriesTest.java:11: cannot access roboguice.activity.GuiceListActivity [javac] class file for roboguice.activity.GuiceListActivity not found [javac] public class StoriesTest extends ActivityUnitTestCase<Stories> { [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/StoriesTest.java:21: cannot access roboguice.application.GuiceApplication [javac] class file for roboguice.application.GuiceApplication not found [javac] setApplication( new MyApplication( getInstrumentation().getTargetContext() ) ); [javac] ^ [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/StoriesTest.java:22: incompatible types [javac] found : com.myapp.activity.Stories [javac] required: android.app.Activity [javac] final Activity activity = startActivity(intent, null, null); [javac] ^ [javac] 39 errors [javac] 6 warnings BUILD FAILED /opt/local/android-sdk-mac/platforms/android-1.6/templates/android_rules.xml:248: Compile failed; see the compiler error output for details. Total time: 24 seconds That's not a hard problem to solve. I'm not sure it's the right thing to do, but I copied the missing libraries (roboguice and gson) from the MyApp/libs directory to the MyAppTests/libs directory and everything seems to compile fine. But that leads to the second problem, which I'm currently stuck on. The tests compile fine but they won't run: $ cp ../MyApp/libs/gson-r538.jar libs/ $ cp ../MyApp/libs/roboguice-1.1-SNAPSHOT.jar libs/ 0 10:23 /Users/mike/Projects/myapp/android/MyAppTests $ ant run-testsBuildfile: build.xml [setup] Project Target: Google APIs [setup] Vendor: Google Inc. [setup] Platform Version: 1.6 [setup] API level: 4 [setup] WARNING: No minSdkVersion value set. Application will install on all Android versions. -install-tested-project: [setup] Project Target: Google APIs [setup] Vendor: Google Inc. [setup] Platform Version: 1.6 [setup] API level: 4 [setup] WARNING: No minSdkVersion value set. Application will install on all Android versions. -compile-tested-if-test: -dirs: [echo] Creating output directories if needed... -resource-src: [echo] Generating R.java / Manifest.java from the resources... -aidl: [echo] Compiling aidl files into Java classes... compile: [javac] Compiling 1 source file to /Users/mike/Projects/myapp/android/MyApp/bin/classes -dex: [echo] Converting compiled files and external libraries into /Users/mike/Projects/myapp/android/MyApp/bin/classes.dex... [echo] -package-resources: [echo] Packaging resources [aaptexec] Creating full resource package... -package-debug-sign: [apkbuilder] Creating MyApp-debug-unaligned.apk and signing it with a debug key... [apkbuilder] Using keystore: /Users/mike/.android/debug.keystore debug: [echo] Running zip align on final apk... [echo] Debug Package: /Users/mike/Projects/myapp/android/MyApp/bin/MyApp-debug.apk install: [echo] Installing /Users/mike/Projects/myapp/android/MyApp/bin/MyApp-debug.apk onto default emulator or device... [exec] 1396 KB/s (288354 bytes in 0.201s) [exec] pkg: /data/local/tmp/MyApp-debug.apk [exec] Success -compile-tested-if-test: -dirs: [echo] Creating output directories if needed... -resource-src: [echo] Generating R.java / Manifest.java from the resources... -aidl: [echo] Compiling aidl files into Java classes... compile: [javac] Compiling 5 source files to /Users/mike/Projects/myapp/android/MyAppTests/bin/classes [javac] Note: /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/SafeAsyncTest.java uses unchecked or unsafe operations. [javac] Note: Recompile with -Xlint:unchecked for details. -dex: [echo] Converting compiled files and external libraries into /Users/mike/Projects/myapp/android/MyAppTests/bin/classes.dex... [echo] -package-resources: [echo] Packaging resources [aaptexec] Creating full resource package... -package-debug-sign: [apkbuilder] Creating MyAppTests-debug-unaligned.apk and signing it with a debug key... [apkbuilder] Using keystore: /Users/mike/.android/debug.keystore debug: [echo] Running zip align on final apk... [echo] Debug Package: /Users/mike/Projects/myapp/android/MyAppTests/bin/MyAppTests-debug.apk install: [echo] Installing /Users/mike/Projects/myapp/android/MyAppTests/bin/MyAppTests-debug.apk onto default emulator or device... [exec] 1227 KB/s (94595 bytes in 0.075s) [exec] pkg: /data/local/tmp/MyAppTests-debug.apk [exec] Success run-tests: [echo] Running tests ... [exec] [exec] android.test.suitebuilder.TestSuiteBuilder$FailedToCreateTests:INSTRUMENTATION_RESULT: shortMsg=Class ref in pre-verified class resolved to unexpected implementation [exec] INSTRUMENTATION_RESULT: longMsg=java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation [exec] INSTRUMENTATION_CODE: 0 BUILD SUCCESSFUL Total time: 38 seconds Any idea what's causing the "Class ref in pre-verified class resolved to unexpected implementation" error?

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What exactly is a so called "Class Cluster" in Objective-C?

- by openfrog

I was reading that NSArray is just such a thing. Sounds heavy. I have 7 really fat books here on my desk about Objective-C, Cocoa and C. None of them mention Class Cluster at all, at least I can't find it in the Index at the back of the books. So what's that?

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How does versioning work when using Boost Serialization for Derived Classes?

- by Venkata Adusumilli

When a Client serializes the following data: InternationalStudent student; student.id("Client ID"); student.firstName("Client First Name"); student.country("Client Country"); the Server receives the following: ID = "Client ID" Country = "Client First Name" instead of the following: ID = "Client ID" Country = "Client Country" The only difference between the Server and Client classes is the First Name of the Student. How can we make the Server ignore First Name recieved from the Client and process the Country? Server Side Classes class Student { public: Student(){} virtual ~Student(){} public: std::string id() { return idM; } void id(std::string id) { idM = id; } protected: friend class boost::serialization::access; protected: std::string idM; protected: template<class A> void serialize(A& archive, const unsigned int /*version*/) { archive & BOOST_SERIALIZATION_NVP(idM); } }; class InternationalStudent : public Student { public: InternationalStudent() {} ~InternationalStudent() {} public: std::string country() { return countryM; } void country(std::string country) { countryM = country; } protected: friend class boost::serialization::access; protected: std::string countryM; protected: template<class A> void serialize(A& archive, const unsigned int /*version*/) { archive & BOOST_SERIALIZATION_NVP(boost::serialization::base_object<Student>(*this)); archive & BOOST_SERIALIZATION_NVP(countryM); } }; Client Side Classes class Student { public: Student(){} virtual ~Student(){} public: std::string id() { return idM; } void id(std::string id) { idM = id; } std::string firstName() { return firstNameM; } void firstName(std::string name) { firstNameM = name; } protected: friend class boost::serialization::access; protected: std::string idM; std::string firstNameM; protected: template<class A> void serialize(A& archive, const unsigned int /*version*/) { archive & BOOST_SERIALIZATION_NVP(idM); if (version >=1) { archive & BOOST_SERIALIZATION_NVP(firstNameM); } } }; BOOST_CLASS_VERSION(Student, 1) class InternationalStudent : public Student { public: InternationalStudent() {} ~InternationalStudent() {} public: std::string country() { return countryM; } void country(std::string country) { countryM = country; } protected: friend class boost::serialization::access; protected: std::string countryM; protected: template<class A> void serialize(A& archive, const unsigned int /*version*/) { archive & BOOST_SERIALIZATION_NVP(boost::serialization::base_object<Student>(*this)); archive & BOOST_SERIALIZATION_NVP(countryM); } };

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How to Submit Form Given Specific Json Response

- by dentalhero

I'm new to Json, so please excuse the newb question. I have a form in which I'm conducting an Ajax post to submit address information to a backend script for validation. Here's the form: <form name="Form" id="Forms" method="post" action="WebCatPageServer.exe" class="uniForm"> <input name="Action" type="hidden" value="SHIPTOVALIDATE"/> <input name="IsAjax" type="hidden" value="Yes"/>  <fieldset class="inlineLabels top"> <h2>Order Details</h2> <div class="ctrlHolder first"> <label for="orderdesc">Order Description</label> <input name="Order Desc" id="OrderDesc" type="text" class="textInput small" tabindex="1" value=""/> </div> <div class="ctrlHolder"> <label for="po">PO # <span class="redasterisk">*</span></label> <input name="Cust Po" id="PoJobNo" type="text" class="textInput small required" maxlength="20" tabindex="2" value="dgnfg"/> </div>  <div class="ctrlHolder"> <label for="shipvia">Ship Via <span class="redasterisk">*</span></label> <select name="Ship Via" id="shipvia" class="selectInput small required" tabindex="4"/> <option value="" class="default">Select Ship Method</option> <option value="OT - Our Truck" class="del" selected>Our Truck</option> <option value="WC - Will Call" class="pick">Will Call</option> </select> </div> <div class="ctrlHolder" id="pickupdate"> <label for="datepickup">Requested Pickup Date <span class="redasterisk">*</span></label> <input name="datepickup" id="datepickup" type="text" class="textInput small" tabindex="5" value="11/09/2012"> </div> <div class="ctrlHolder" id="shipdate"> <label for="dateship">Requested Delivery Date <span class="redasterisk">*</span></label> <input name="dateship" id="dateship" type="text" class="textInput small" value="" tabindex="6"> </div> <div class="ctrlHolder" id="shipto"> <label for="ShipTo">Ship To <span class="redasterisk">*</span></label> <select name="ShipTos" id="ShipTos" class="selectInput auto required" tabindex="7"> <option value="">Select an Option</option> <option value="ShipToManual" class="manual">Manually Enter Address</option> <option value="0">A ACTION AIR*, 5241 YANCEYVILLE, COLUMBIA, SC 29214-0001</option> <option value="1">A ACTION AIR*, 649 spring lane, sanford, NC 27330</option> <option value="2">A ACTION AIR*, 1313 south briggs avenue, durham, NC 27703</option> <option value="3">A ACTION AIR*, 112 cricket hill lane, cary, NC 27513</option> <option value="4">A ACTION AIR*, 2911 duke homestead road, durham, NC 27705</option> <option value="5">A ACTION AIR*, chickem poop, atlanta, GA 60609</option> </select> <br /> </div> </fieldset> <fieldset class="inlineLabels" id="shipinfo"> <h2>Shipping Information</h2> <div class="ctrlHolder first"> <label for="YourName">Your Name <span class="redasterisk">*</span></label> <input name="Your Name" id="Your_Name" type="text" class="textInput small required" tabindex="8" value="" /> </div> <div class="ctrlHolder"> <label for="CompanyName">Company Name <span class="redasterisk">*</span></label> <input name="Company Name" id="CompanyName" type="text" class="textInput small required" tabindex="9" value="A ACTION AIR*"/> </div> <div class="ctrlHolder"> <label for="Address1">Address 1 <span class="redasterisk">*</span></label> <input name="Address_1" id="Address_1" type="text" maxlength="30" class="textInput small required" tabindex="10" value="5241 YANCEYVILLE"/> </div> <div class="ctrlHolder"> <label for="Address2">Address 2</label> <input name="Address_2" id="Address_2" type="text" maxlength="30" class="textInput small" tabindex="11" value=""/> </div> <div class="ctrlHolder"> <label for="City">City <span class="redasterisk">*</span></label> <input name="City" id="City" type="text" maxlength="25" class="textInput small required" tabindex="12" value="COLUMBIA"/> </div> <div class="ctrlHolder"> <label for="State">State <span class="redasterisk">*</span></label> <select name="State" id="State" class="selectInput small required" tabindex="13"> <option value="">Select State</option> <option value="AL">Alabama</option> <option value="AK">Alaska</option> <option value="AZ">Arizona</option> <option value="AR">Arkansas</option> <option value="CA">California</option> <option value="CO">Colorado</option> <option value="CT">Connecticut</option> <option value="DE">Delaware</option> <option value="FL">Florida</option> <option value="GA">Georgia</option> <option value="HI">Hawaii</option> <option value="ID">Idaho</option> <option value="IL">Illinois</option> <option value="IN">Indiana</option> <option value="IA">Iowa</option> <option value="KS">Kansas</option> <option value="KY">Kentucky</option> <option value="LA">Louisiana</option> <option value="ME">Maine</option> <option value="MD">Maryland</option> <option value="MA">Massachussetts</option> <option value="MI">Michigan</option> <option value="MN">Minnesota</option> <option value="MS">Mississippi</option> <option value="MO">Missouri</option> <option value="MT">Montana</option> <option value="NE">Nebraska</option> <option value="NV">Nevada</option> <option value="NH">New Hampshire</option> <option value="NJ">New Jersey</option> <option value="NM">New Mexico</option> <option value="NY">New York</option> <option value="NC">North Carolina</option> <option value="ND">North Dakota</option> <option value="OH">Ohio</option> <option value="OK">Oklahoma</option> <option value="OR">Oregon</option> <option value="PA">Pennsylvania</option> <option value="RI">Rhode Island</option> <option value="SC" selected>South Carolina</option> <option value="SD">South Dakota</option> <option value="TN">Tennessee</option> <option value="TX">Texas</option> <option value="UT">Utah</option> <option value="VT">Vermont</option> <option value="VA">Virginia</option> <option value="WA">Washington</option> <option value="WV">West Virginia</option> <option value="WI">Wisconsin</option> <option value="WY">Wyoming</option> </select> </div> <div class="ctrlHolder"> <label for="ZipCode">Zip Code <span class="redasterisk">*</span></label> <input name="Zip" id="Zip" type="text" maxlength="10" class="textInput small required zipcode" tabindex="14" value=""/> </div> <div class="ctrlHolder"> <label for="Phone">Phone <span class="redasterisk">*</span></label> <input name="Phone Number" id="Phone" type="text" class="textInput small required phone" alt="phone-us" tabindex="15" value="(336)954-5009"/> </div> <div class="ctrlHolder"> <label for="Fax">Fax</label> <input name="FaxNumber" id="Fax Number" type="text" class="textInput small fax" alt="phone-us" tabindex="16" value=""/> </div> <div class="ctrlHolder"> <label for="">E-mail <span class="redasterisk">*</span></label> <input name="Email" id="Email" type="text" class="textInput small required email" tabindex="17" value=""/> </div> </fieldset> <fieldset class="inlineLabels"> <h2>Order/Shipping Notes</h2> <div class="ctrlHolder first"> <label for="notes">Order Notes </label> <textarea name="OrderNotes" id="ta" cols="26" rows="7" tabindex="18"></textarea><br /> <p class="formHint"><b>(Maximum characters: 175)   <span id="charLeft"></span>   Characters left</b><br /> (Cross streets, special instructions, etc.)</p> <br /> </div> </fieldset> <fieldset class="inlineLabels"> <h2>Continue To Next Step</h2> <div class="buttonHolder"> <label for="freightmsg">**Applicable freight charges will be applied at the time of invoicing.**</label> <input name="continuetocheckout" type="submit" class="button red smallrounded" value="Continue >" alt="Continue to Next Step" tabindex="20"/> </div> </fieldset> </form> AJAX Call Here's the AJAX call: $(function() { $("#Forms").submit(function() { $.ajax({ type: 'post', url: 'WebCatPageServer.exe', dataType : 'json', data: $("#Forms").serialize(), complete:function(data){ alert(data); } }); return false; }); }); JSON Response Here's the JSON response: {"DidValidate":true,"Company Name":"A ACTION AIR*","AddrLine1":"5241 YANCEYVILLE","AddrLine2":"","City":"COLUMBIA","State":"SC","Zip":"","Modified":false,"AddressError":false,"ZipError":false} Question: How do I submit the form programatically if both AddressError and ZipError return with a false?

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OOP: class based and prototype based, are there other alternatives?

- by Gabriel Šcerbák

I know of class-based and protype based object oriented programming languages, are there any other alternatives? What are they?

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Fitting it together, database, reporting, applications in C#

- by alvonellos

Introduction Preamble I was hesitant to post this, since it's an application whose intricate details are defined elsewhere, and answers may not be helpful to others. Within the past few weeks (I was actually going to write a blog post about this after I finished) I've discovered that the barrier I'm encountering is one that's actually quite common for newer developers. This question is not so much about a specific thing as it is about piecing those things together. I've searched the internet far and wide, and found many tutorials on how to create applications that are kind of similar to what I'm looking for. I've also looked at hiring another, more experienced, developer to help me along, but all I've gotten are unqualified candidates that don't have the experience necessary and won't take care of the client or project like I will. I'd rather have the project never transpire than to release a solution that is half-baked. I've asked professors at my school, but they've not turned up answers to my question. I'm an experienced developer, and I've written many applications that are -- very abstractly -- close to what I'm doing, but my experiences from those applications aren't giving me enough leverage to solve this particular problem. I just hope that posting this article isn't a mistake for me to write. Project Description I have a project I'm working on for a client that is a rewrite of an application, originally written in Foxpro 2.6 by someone before me, that performs some analysis (which, sadly, I'm not allowed to disclose as per of my employment contract) on financial data. One day, after a long talk between the client and I -- where he intimately described his frustrations with all the bugs I've been hacking out of this code for 6 months now -- he told me to just rewrite it and gave me a month to write a good 1/8 of this 65k LOC Foxpro monstrosity. this 65k line of code foxpro monstrosity. It'll take me a good 3 - 6 months to rewrite this software (I know things the original programmer did not, like inheritance) going as I am right now, but I'm quickly discovering that I'm going to need to use databases. Prior to this contract I didn't even know about foxpro, and so I've had to learn foxpro on the fly, write procedures and make modifications to the database. I've actually come to like it, and this project would be rewritten in Foxpro if it were still a supported language, because over the past few months, I've come to like the features of Foxpro that make it so easy to develop data-driven applications. I once perfomed an experiment, comparing C# to Foxpro. What took me 45 minutes in C# took me two in Foxpro, and I knew C# prior to Foxpro. I was hoping to leverage the power of C#, but it intimidates me that in foxpro, you can have one line of code and be using a database. Prior to this, I have never written any serious database development from scratch. All the applications that I've written are in a different league. They are either completely data-naive or data-naive enough that I can get away with not using a database through serialization or by designing algorithms that work with the data in a manner that is stateless, so there is no need to worry about databases. I've come to realize, very quickly, that serialization and my efficacy with data structures has been my crutch all these years that's prevented me from adventuring into databases, and has consequently hindered my success in real-world programming. Sure, I've written some database stuff in Perl and Python, and I've done forms and worked with relational databases and tables, I'm a wizard in Access and Excel (seriously) and can do just about anything, but it just feels unnatural writing SQL code in another language... I don't mind writing SQL, and I don't It's that bridge between the database and the program code that drives me absolutely bonkers. I hope I'm not the only one to think this, but it bothers me that I have to create statements like the following string sSql = "SELECT * from tablename" When there's really no reason for that kind of unchecked language binding between two languages and two API's. Don't get my wrong, SQL is great, but I don't like the idea that, when executing commands on a SQL database, that one must intermix database and application software, and there's no database independence, which means that different versions of different databases can break code. This isn't very nice. The nicest thing about Foxpro is the cohesiveness between programming language and database. It's so easy, and Foxpro makes it easy, because the tool just fits the task. I can see why so many developers have created a career with this language, because it lowered the barrier of entry to data-driven applications that so many businesses need. It was wonderful. For my purposes today, with the demands and need for community support, extensibility, and language features, Foxpro isn't a solution that I feel would be the right tool for the job. I'm also worried about working too heavy with the database, because I've seen data-driven .NET applications have issues with database caches, running out of memory, and objects in the database not being collected. (Memory leaks) And OH the queries. Which one, how, and why? There are a plethora of different ways that a database can be setup, I think I counted 5 or 6 different kinds of database applications alone that I can chose from. That is a great mountain for me to climb when I don't even know where to begin when it comes to writing data-driven applications. The problem isn't that I don't know SQL or that I don't know C#. I know both and have worked with both extensively. It's making them work together that's the problem, and it's something I've never done in C# before. Reports The client likes paper. The data needs to be printed out in a format that is extensible, layered, and easy to use. I have never done reporting before, and so this is a bit of a problem. From the data source comes crystal reports, and so there's a dependency on the database, from what I understand. Code reuse A large part of the design decision that I've gone through so far is to break the task of writing a piece of this software into routines and modular DLL's and so forth such that much of the code can be reused. For example, when I setup this database, I want to be able to reuse the same database code over and over again. I also want to make sure that when the day comes that another developer is here, that he/she will be able to pick up just where I left off. The quicker I develop these applications, the better off I am. Tasks & Goals In my project, I need to write routines that apply algorithms and look for predefined patterns in financial data. Additionally, I need to simulate trading based on predefined algorithms and data. Then I need to prepare reports on that data. Additionally, I need to have a way to change the code base for this application quickly and effectively, without hacking together some band-aid solution for a problem that really needs a trauma ward. Special Considerations The solution must be fast, run quickly on existing hardware, and not be too much of a pain to maintain and write. I understand that anything I write I'm married to -- I'm responsible for the things that I write because my reputation and livelihood is dependent on it. Do I really need a database? What about performance? Performance was such a big issue that I hand wrote a data structure that is capable of performing 2 billion operations, using a total of 4 gigs of memory in under 1/4 of a second using the standard core two duo processor. I could not find a similar, pre-written data structure in C# to perform this task. What setup do I use in terms of database? What about reporting? I'd prefer to have PDF's generated, but I'd like to be able to visually sketch those reports and then just have a ReportFactory of some sort, that when I pass some variables in, it just does that data. About Me I'm a lone developer for a small business in this area. This is the first time I've done this and I've never had the breadth and depth of my knowledge tested. I'm incredibly frustrated with this project because I feel incredibly overwhelmed with the task at hand. I'm looking for that entry level point where I can draw a line and say "this is what I need to do" Conclusion I may have not been clear enough on my post. I'm still new to this whole thing, and I've been doing my best to contribute back to the community that I've leached so much knowledge from. I'd be glad to edit my post and add more information if possible. I'm looking for a big-picture solution or design process that helps me get off the ground in this world of data-driven applications, because I have a feeling that it's going to be concentric to my entire career as a programmer for some time. Specifically, if you didn't get it from the rest of the post (I may not have been clear enough) I really need some guidance as to where to go in terms of the design decisions for this project. Some things that'll be useful will be a pro/con list for the different kinds of database projects available in VS2010. I've tried, but generating that list has been as hard as solving the problem itself... If you could walk a developer writing a data-driven application for the first time in C#, how would you do that? Where would you point them to?

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Using jQuery validation plugin with tabbed navigation

- by user3438917

I have a tabbed navigation wizard, for which the first section needs to be validated before proceeding to the next tab. The validation should trigger when the user hits the "next" button. I am unable to get the validation to trigger though: <form id="target-group" novalidate="novalidate"> <div class="box"> <div class='box-header-main'><h2><img src="assets/img/list.png" /> Target Group Information</h2></div> <br /> <div class='box'> <div class='box-header-property'><h2><span data-bind="text:Name">New Target Group</span> | <i class='fa fa-file'></i></h2></div> <br /> <div class='row'> <div id='flight-wizard'> <div id='content' class='col-lg-12'> <div class='col-lg-12'> <div id='tabs'> <ul> <li id="targetgroup-info-tab"><a href='#tabs-1'><i class="fa fa-info-circle"></i>Target Group Info</a></li> <li id="zone-tab"><a href='#tabs-2'><i class="fa fa-map-marker"></i>Zones</a></li> </ul> <div id='tabs-1'> <div class='row'> <div class='col-xs-6'> <div class='form-group'> Name<sup>*</sup> <input id="selectError0" name="name" class='form-control col-xs-12' data-bind="value: asdf" placeholder='Enter Name ...' /> </div> <form class='form-horizontal'> <div class='form-group'> Product(s)<sup>*</sup> <div class='controls' id='products'> <select id='selectError3' class='form-control' data-bind="options:test, optionsText: 'Name', optionsValue : 'test', value: test, optionsCaption: 'Choose Product...'"></select> </div> </div> </form> </div>  <div class='col-xs-6'> <div class='form-group'> Platform<sup>*</sup> <div class='controls'> <select id="selectError2" class='form-control' data-bind="options:test, optionsText: 'Name', optionsValue: 'test', value : test, optionsCaption: 'Choose Platform...'"></select> </div> </div> <form class='form-horizontal'> <div class='form-group'> AdTypes(s)<sup>*</sup> <div class='controls' id='adtypes'> <select multiple="" id='adtypesselect' class='form-control' data-rel="chosen" data-bind="options:test, optionsText: 'Name', optionsValue : 'test', selectedOptions: test, optionsCaption: 'test...'"></select> </div> </div> </form> <button id="btn_cancel_large" class='btn btn-large btn-primary btn-round'><i class='fa fa-ban' /></i> Cancel</button> <button id="btn-next-large" class='btn btn-large btn-primary btn-round'>Next <i class='fa fa-arrow-circle-right'></i></button> </div>  </div> </div> <div id='tabs-2'> <div class='row'> <div class='col-lg-12'> <div class='row'> <div class='col-lg-12'> <div id='zones_list' class='box-content'> <div id='add-new-targetgroupzone' class='add-new'><i class='fa fa-plus-circle'></i><a href='/#/inventory/targeting/' onclick="return false;">Add Zone</a></div> <table id="results" width="100%"> <thead> <tr> <th>Publisher</th> <th>Property</th> <th>Zone</th> <th>AdTypes</th> <th width='10%'>Quick Actions</th> </tr> </thead> </table> </div> </div> </div> </div> </div> <br /> <div class="btn_row"> <button id="btn_cancel_large2" class='btn btn-large btn-primary btn-round'><i class='fa fa-ban' /></i> Cancel</button> <button id="btn-submit-large" class='btn btn-large btn-primary btn-round'>Submit <i class='fa fa-arrow-circle-down'></i></button> </div> </div> </div> </div> </div> </div> </div> </div> </div> </form> <form id="zones-form" style="display: none;" novalidate="novalidate" class="slideup-form"> <div class="box"> <div class="box-header-panel"> <h2>Add Target Group Zone</h2> <div class="box-icon" id="zones-form-close"> <i class="fa fa-arrow-circle-down"></i> </div> </div> <div class="box-content clearfix"> <div class="box-content"> <table id="zones-list" width="100%"> <thead> <tr> <th>Publisher</th> <th>Property</th> <th>Zone</th> <th>AdTypes</th> <th width='10%'>Quick Actions</th> </tr> </thead> </table> </div> </div> </div> </div> </form> jQuery: $("#target-group").validate({ rules: { name: { required: true } }, messages: { name: "Name required", } }); $('#btn-next-large').click(function () { if ($('#target-group').valid()) $tabs.tabs('select', $(this).attr("rel")); });

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How do I target a div without a class or id but with all these specific style-attributes

- by Ben

I'm restyling a certain page where I don't have access to all the source-HTML. So I'm left over with some hard to target elements within a page I need removed. For example the page is swamped with <div style="float: left; width: 10.25px; height: 284px;"></div>. To get rid of them I tried this in CSS: div[style="float: left; width: 10.25px; height: 284px;"] { display:none !important; } I'd like to fix this using CSS, because the the HTML that needs to be removed is updated using ajax. How do I target a div without a class or id but with all these specific style-attributes? Some more of the source-code (took a while to organize the parsed source): <div> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760187/Le-Coq-Sportif-Angers-Low.html.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036303.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Angers-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760187/Le-Coq-Sportif-Angers-Low.html.html"> Le Coq Sportif Angers Low </a> </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 89,95 </span> </span> <div style="float: left; width: 10.25px; height: 284px; border-right: 1px dashed #A0A0A0;" class="BigPhotoList_Stippel"></div> <div style="float: left; width: 10.25px; height: 284px;"></div> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760185/Le-Coq-Sportif-Auveurne-Low.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036301.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Auveurne-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760185/Le-Coq-Sportif-Auveurne-Low.html"> Le Coq Sportif Auveurne Low </a> </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 79,95 </span> </span> <div style="float: left; width: 10.25px; height: 284px; border-right: 1px dashed #A0A0A0;" class="BigPhotoList_Stippel"></div> <div style="float: left; width: 10.25px; height: 284px;"></div> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760191/Le-Coq-Sportif-Bordeaux-Low.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036307.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Bordeaux-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760191/Le-Coq-Sportif-Bordeaux-Low.html"> Le Coq Sportif Bordeaux Low </a> </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 99,95 </span> </span> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760181/Le-Coq-Sportif-Cannet-Low.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036297.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Cannet-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760181/Le-Coq-Sportif-Cannet-Low.html"> Le Coq Sportif Cannet Low </a> </span> <span class="Discount BigPhotoList_Discount" style="font-size: 120%;"> € 99,95 </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 94,95 </span> </span> <div style="float: left; width: 10.25px; height: 284px; border-right: 1px dashed #A0A0A0;" class="BigPhotoList_Stippel"></div> <div style="float: left; width: 10.25px; height: 284px;"></div> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760183/Le-Coq-Sportif-Rodez-Low.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036299.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Rodez-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760183/Le-Coq-Sportif-Rodez-Low.html"> Le Coq Sportif Rodez Low </a> </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 99,95 </span> </span> <div style="float: left; width: 10.25px; height: 284px; border-right: 1px dashed #A0A0A0;" class="BigPhotoList_Stippel"></div> <div style="float: left; width: 10.25px; height: 284px;"></div> <span class="Block BigPhotoList_Block"> <span class="Photo BigPhotoList_Photo" style="height: 200px"> <a href="/Webwinkel-Product-83760189/Le-Coq-Sportif-Sedan-Low.html"> <span style="background-image:url(http://61955.static.securearea.eu/Files/2/61000/61955/ProductPhotos/MaxContent/144036305.jpg);" class="Canvas BigPhotoList_Canvas" title="Le-Coq-Sportif-Sedan-Low"></span> </a> </span> <span class="Title BigPhotoList_Title"> <a href="/Webwinkel-Product-83760189/Le-Coq-Sportif-Sedan-Low.html"> Le Coq Sportif Sedan Low </a> </span> <span class="Discount BigPhotoList_Discount" style="font-size: 120%;"> € 109,95 </span> <span class="Price BigPhotoList_Price" style="font-size: 120%;"> € 99,95 </span> </span> </div>

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C#. Struct design. Why 16 byte is recommended size?

- by maxima120

I read Cwalina book (recommendations on development and design of .NET apps). He says that good designed struct has to be less than 16 bytes in size (for performance purpose). My questions is - why exactly is this? And (more important) can I have larger struct with same efficiency if I run my .NET 3.5 (soon to be .NET 4.0) 64-bit application on i7 under Win7 x64 (is this limitation CPU / OS based)? Just to stress again - I need as efficient struct as it is possible. I try to keep it in stack all the time, the application is heavily multi-threaded and runs on sub-millisecond intervals, the current size of the struct is 64 byte.

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design a large scale network for an organization

- by Essam

i want to design a large scale network for an organization with HQ and two branches. i want to use a class A subnet. if i am using the network address 30.0.0.0 for the whole organization how can it be different from another organization company or whatever which is using the same address in another country? now i have the three locations for this organization,so i need 5 subnets [one for the HQ,two for branch A and branch B , one for connecting A to HQ and one for connecting branch B with HQ since i will use central DHCP server at the HQ,is that (number of subnetting) right? is it advisable to use class A or class B for this organization it term of address that will be wasted (let's say it is a university with two branches in two different states)?!

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Tips to Make Your Website Cell Phone Friendly

- by Aditi

Working on a new website design? or Redesigning your website? There is a lot more to consider now a days not just user experience, clean code, CSS etc. one of the important attribute one must not miss, which is making them mobile friendly! With the growing use of handhelds & unlimited data plans, people browse on their cellphones! and All come in different sizes! it is tough to make a website that would look great not just on a high resolution widescreen monitor/LCD, but also should look equally impressive on the low resolutions of cellphones. We are today going to discuss about such factors that can help you make a website Cellphone Friendly. Fluid Width Layouts As we start discussing about this, Most people speak of the Fluid Width Layouts as vital step in moving your website to be mobile friendly. Fluid width allows the width of your website stretch or shrink depending on the browser size. However, having a layout which flows with the width of the screen’s resolution is certainly convenient, more often than not the website was originally laid out for a desktop in mind. Compressing a fluid layout to 320 pixels can do some serious damage to layout, Thus some people strongly believe it is far better to have a mobile style sheet and lay out the content specifically for that screen and have more control on the display. The best thing to do is to detect the type of platform that is connected to your website and disabling or changing some tools and effects to make it look better if not perfect. Keep Your Web Pages Short length One must avoid long pages on their website, a lot of scroll makes it very non user friendly for people, especially on mobile devices this is a huge draw back because of the longer load time it takes to download the webpage. Everyone likes crisp & concise content such pages are easier to load & browse. This makes your website accessible across all platforms. Also try to keep shorter urls, if they have to type..save them from that much work especially if someone is using a cellphone with no QWERTY keyboard it can be tough. Usable Navigation & Search Unlike Desktops, your website’s Navigation won’t super work on a cellphone. Keep in mind the user experience for cellphone users as you design your Navigation. Try to keep your content centered as they do have difficulty in reading the webpage. I always look upto Google and their pages as available on mobile as a great example. Keeping a functional & very visible search bar helps mobile users navigate by searching. Understanding Clean Website Code : Evolved for Mobile Clean code is important when you consider the diversity out there for handheld devices. Some cell phones may only understand WAP. More capable phones may understand WAP2, which allows rendering websites with XHTML and CSS. Most mobiles won’t display tables, floats, frames, JavaScript, and dynamic menus. Most cellphone will not support cookies. Devices at the high end of the mobile market such as BlackBerry, Palm, or the upcoming iPhone are highly capable and support nearly as much as a standard computer..but masses still do not have such phones. You can use specific emulators to test your website on mobile devices. Make sure your color combinations provide good contrast between foreground and background colors, particularly for devices with fewer color options.

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How to get rid of grub menu after boot?

- by umpirsky

Here is my /etc/default/grub: # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. GRUB_DEFAULT=0 GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=10 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_LINUX_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" I tried various things including: How do I hide the GRUB menu showing up in the beginning of boot? How to disable Grub's menu from showing up after failed boot http://www.itworld.com/software/306238/disable-grub-boot-menu-ubuntu-1210 But I still get grub menu each time I boot. My generated /boot/grub/grub.cfg: # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi if [ "${next_entry}" ] ; then set default="${next_entry}" set next_entry= save_env next_entry set boot_once=true else set default="0" fi if [ x"${feature_menuentry_id}" = xy ]; then menuentry_id_option="--id" else menuentry_id_option="" fi export menuentry_id_option if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { if [ x$feature_all_video_module = xy ]; then insmod all_video else insmod efi_gop insmod efi_uga insmod ieee1275_fb insmod vbe insmod vga insmod video_bochs insmod video_cirrus fi } if [ x$feature_default_font_path = xy ] ; then font=unicode else insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi font="/usr/share/grub/unicode.pf2" fi if loadfont $font ; then set gfxmode=auto load_video insmod gfxterm set locale_dir=$prefix/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ] ; then set timeout=-1 else if [ x$feature_timeout_style = xy ] ; then set timeout_style=hidden set timeout=0 # Fallback hidden-timeout code in case the timeout_style feature is # unavailable. elif sleep --interruptible 0 ; then set timeout=0 fi fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 45,51,53; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-ed6b32bc-ec1d-444c-a000-282fddd6d460' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-ed6b32bc-ec1d-444c-a000-282fddd6d460' { menuentry 'Ubuntu, with Linux 3.13.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-advanced-ed6b32bc-ec1d-444c-a000-282fddd6d460' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-recovery-ed6b32bc-ec1d-444c-a000-282fddd6d460' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-advanced-ed6b32bc-ec1d-444c-a000-282fddd6d460' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-recovery-ed6b32bc-ec1d-444c-a000-282fddd6d460' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry 'Ubuntu 14.04 LTS (14.04) (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-simple-ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro splash quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } submenu 'Advanced options for Ubuntu 14.04 LTS (14.04) (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' $menuentry_id_option 'osprober-gnulinux-advanced-ed6b32bc-ec1d-444c-a000-282fddd6d460' { menuentry 'Ubuntu (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-/boot/vmlinuz-3.13.0-29-generic.efi.signed--ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro splash quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-29-generic (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-/boot/vmlinuz-3.13.0-29-generic.efi.signed--ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro splash quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-29-generic (recovery mode) (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-/boot/vmlinuz-3.13.0-29-generic.efi.signed-root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset splash quiet-ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-29-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset splash quiet initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-/boot/vmlinuz-3.13.0-24-generic.efi.signed--ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro splash quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-24-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic (recovery mode) (on /dev/mapper/isw_beaaegcdjh_ASUS_OS2)' --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-/boot/vmlinuz-3.13.0-24-generic.efi.signed-root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset splash quiet-ed6b32bc-ec1d-444c-a000-282fddd6d460' { insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 else search --no-floppy --fs-uuid --set=root ed6b32bc-ec1d-444c-a000-282fddd6d460 fi linux /boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=ed6b32bc-ec1d-444c-a000-282fddd6d460 ro recovery nomodeset splash quiet initrd /boot/initrd.img-3.13.0-24-generic } } set timeout_style=menu if [ "${timeout}" = 0 ]; then set timeout=10 fi ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/30_uefi-firmware ### menuentry 'System setup' $menuentry_id_option 'uefi-firmware' { fwsetup } ### END /etc/grub.d/30_uefi-firmware ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f ${config_directory}/custom.cfg ]; then source ${config_directory}/custom.cfg elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ###

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How would you gather client's data on Google App Engine without using Datastore/Backend Instances too much?

- by ruslan

I'm relatively new to StackExchange and not sure if it's appropriate place to ask design question. Site gives me a hint "The question you're asking appears subjective and is likely to be closed". Please let me know. Anyway.. One of the projects I'm working on is online survey engine. It's my first big commercial project on Google App Engine. I need your advice on how to collect stats and efficiently record them in DataStore without bankrupting me. Initial requirements are: After user finishes survey client sends list of pairs [ID (int) + PercentHit (double)]. This list shows how close answers of this user match predefined answers of reference answerers (which identified by IDs). I call them "target IDs". Creator of the survey wants to see aggregated % for given IDs for last hour, particular timeframe or from the beginning of the survey. Some surveys may have thousands of target/reference answerers. So I created entity public class HitsStatsDO implements Serializable { @Id transient private Long id; transient private Long version = (long) 0; transient private Long startDate; @Parent transient private Key parent; // fake parent which contains target id @Transient int targetId; private double avgPercent; private long hitCount; } But writing HitsStatsDO for each target from each user would give a lot of data. For instance I had a survey with 3000 targets which was answered by ~4 million people within one week with 300K people taking survey in first day. Even if we assume they were answering it evenly for 24 hours it would give us ~1040 writes/second. Obviously it hits concurrent writes limit of Datastore. I decided I'll collect data for one hour and save that, that's why there are avgPercent and hitCount in HitsStatsDO. GAE instances are stateless so I had to use dynamic backend instance. There I have something like this: // Contains stats for one hour private class Shard { ReadWriteLock lock = new ReentrantReadWriteLock(); Map<Integer, HitsStatsDO> map = new HashMap<Integer, HitsStatsDO>(); // Key is target ID public void saveToDatastore(); public void updateStats(Long startDate, Map<Integer, Double> hits); } and map with shard for current hour and previous hour (which doesn't stay here for long) private HashMap<Long, Shard> shards = new HashMap<Long, Shard>(); // Key is HitsStatsDO.startDate So once per hour I dump Shard for previous hour to Datastore. Plus I have class LifetimeStats which keeps Map<Integer, HitsStatsDO> in memcached where map-key is target ID. Also in my backend shutdown hook method I dump stats for unfinished hour to Datastore. There is only one major issue here - I have only ONE backend instance :) It raises following questions on which I'd like to hear your opinion: Can I do this without using backend instance ? What if one instance is not enough ? How can I split data between multiple dynamic backend instances? It hard because I don't know how many I have because Google creates new one as load increases. I know I can launch exact number of resident backend instances. But how many ? 2, 5, 10 ? What if I have no load at all for a week. Constantly running 10 backend instances is too expensive. What do I do with data from clients while backend instance is dead/restarting? Thank you very much in advance for your thoughts.

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Parallel Classloading Revisited: Fully Concurrent Loading

- by davidholmes

Java 7 introduced support for parallel classloading. A description of that project and its goals can be found here: http://openjdk.java.net/groups/core-libs/ClassLoaderProposal.html The solution for parallel classloading was to add to each class loader a ConcurrentHashMap, referenced through a new field, parallelLockMap. This contains a mapping from class names to Objects to use as a classloading lock for that class name. This was then used in the following way: protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException { synchronized (getClassLoadingLock(name)) { // First, check if the class has already been loaded Class c = findLoadedClass(name); if (c == null) { long t0 = System.nanoTime(); try { if (parent != null) { c = parent.loadClass(name, false); } else { c = findBootstrapClassOrNull(name); } } catch (ClassNotFoundException e) { // ClassNotFoundException thrown if class not found // from the non-null parent class loader } if (c == null) { // If still not found, then invoke findClass in order // to find the class. long t1 = System.nanoTime(); c = findClass(name); // this is the defining class loader; record the stats sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); sun.misc.PerfCounter.getFindClasses().increment(); } } if (resolve) { resolveClass(c); } return c; } } Where getClassLoadingLock simply does: protected Object getClassLoadingLock(String className) { Object lock = this; if (parallelLockMap != null) { Object newLock = new Object(); lock = parallelLockMap.putIfAbsent(className, newLock); if (lock == null) { lock = newLock; } } return lock; } This approach is very inefficient in terms of the space used per map and the number of maps. First, there is a map per-classloader. As per the code above under normal delegation the current classloader creates and acquires a lock for the given class, checks if it is already loaded, then asks its parent to load it; the parent in turn creates another lock in its own map, checks if the class is already loaded and then delegates to its parent and so on till the boot loader is invoked for which there is no map and no lock. So even in the simplest of applications, you will have two maps (in the system and extensions loaders) for every class that has to be loaded transitively from the application's main class. If you knew before hand which loader would actually load the class the locking would only need to be performed in that loader. As it stands the locking is completely unnecessary for all classes loaded by the boot loader. Secondly, once loading has completed and findClass will return the class, the lock and the map entry is completely unnecessary. But as it stands, the lock objects and their associated entries are never removed from the map. It is worth understanding exactly what the locking is intended to achieve, as this will help us understand potential remedies to the above inefficiencies. Given this is the support for parallel classloading, the class loader itself is unlikely to need to guard against concurrent load attempts - and if that were not the case it is likely that the classloader would need a different means to protect itself rather than a lock per class. Ultimately when a class file is located and the class has to be loaded, defineClass is called which calls into the VM - the VM does not require any locking at the Java level and uses its own mutexes for guarding its internal data structures (such as the system dictionary). The classloader locking is primarily needed to address the following situation: if two threads attempt to load the same class, one will initiate the request through the appropriate loader and eventually cause defineClass to be invoked. Meanwhile the second attempt will block trying to acquire the lock. Once the class is loaded the first thread will release the lock, allowing the second to acquire it. The second thread then sees that the class has now been loaded and will return that class. Neither thread can tell which did the loading and they both continue successfully. Consider if no lock was acquired in the classloader. Both threads will eventually locate the file for the class, read in the bytecodes and call defineClass to actually load the class. In this case the first to call defineClass will succeed, while the second will encounter an exception due to an attempted redefinition of an existing class. It is solely for this error condition that the lock has to be used. (Note that parallel capable classloaders should not need to be doing old deadlock-avoidance tricks like doing a wait() on the lock object\!). There are a number of obvious things we can try to solve this problem and they basically take three forms: Remove the need for locking. This might be achieved by having a new version of defineClass which acts like defineClassIfNotPresent - simply returning an existing Class rather than triggering an exception. Increase the coarseness of locking to reduce the number of lock objects and/or maps. For example, using a single shared lockMap instead of a per-loader lockMap. Reduce the lifetime of lock objects so that entries are removed from the map when no longer needed (eg remove after loading, use weak references to the lock objects and cleanup the map periodically). There are pros and cons to each of these approaches. Unfortunately a significant "con" is that the API introduced in Java 7 to support parallel classloading has essentially mandated that these locks do in fact exist, and they are accessible to the application code (indirectly through the classloader if it exposes them - which a custom loader might do - and regardless they are accessible to custom classloaders). So while we can reason that we could do parallel classloading with no locking, we can not implement this without breaking the specification for parallel classloading that was put in place for Java 7. Similarly we might reason that we can remove a mapping (and the lock object) because the class is already loaded, but this would again violate the specification because it can be reasoned that the following assertion should hold true: Object lock1 = loader.getClassLoadingLock(name); loader.loadClass(name); Object lock2 = loader.getClassLoadingLock(name); assert lock1 == lock2; Without modifying the specification, or at least doing some creative wordsmithing on it, options 1 and 3 are precluded. Even then there are caveats, for example if findLoadedClass is not atomic with respect to defineClass, then you can have concurrent calls to findLoadedClass from different threads and that could be expensive (this is also an argument against moving findLoadedClass outside the locked region - it may speed up the common case where the class is already loaded, but the cost of re-executing after acquiring the lock could be prohibitive. Even option 2 might need some wordsmithing on the specification because the specification for getClassLoadingLock states "returns a dedicated object associated with the specified class name". The question is, what does "dedicated" mean here? Does it mean unique in the sense that the returned object is only associated with the given class in the current loader? Or can the object actually guard loading of multiple classes, possibly across different class loaders? So it seems that changing the specification will be inevitable if we wish to do something here. In which case lets go for something that more cleanly defines what we want to be doing: fully concurrent class-loading. Note: defineClassIfNotPresent is already implemented in the VM as find_or_define_class. It is only used if the AllowParallelDefineClass flag is set. This gives us an easy hook into existing VM mechanics. Proposal: Fully Concurrent ClassLoaders The proposal is that we expand on the notion of a parallel capable class loader and define a "fully concurrent parallel capable class loader" or fully concurrent loader, for short. A fully concurrent loader uses no synchronization in loadClass and the VM uses the "parallel define class" mechanism. For a fully concurrent loader getClassLoadingLock() can return null (or perhaps not - it doesn't matter as we won't use the result anyway). At present we have not made any changes to this method. All the parallel capable JDK classloaders become fully concurrent loaders. This doesn't require any code re-design as none of the mechanisms implemented rely on the per-name locking provided by the parallelLockMap. This seems to give us a path to remove all locking at the Java level during classloading, while retaining full compatibility with Java 7 parallel capable loaders. Fully concurrent loaders will still encounter the performance penalty associated with concurrent attempts to find and prepare a class's bytecode for definition by the VM. What this penalty is depends on the number of concurrent load attempts possible (a function of the number of threads and the application logic, and dependent on the number of processors), and the costs associated with finding and preparing the bytecodes. This obviously has to be measured across a range of applications. Preliminary webrevs: http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.hotspot/ http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.jdk/ Please direct all comments to the mailing list [email protected].

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Improving Click and Drag with C++

- by Josh

I'm currently using SFML 2.0 to develop a game in C++. I have a game sprite class that has a click and drag method. The method works, but there is a slight problem. If the mouse moves too fast, the object the user selected can't keep up and is left behind in the spot where the mouse left its bounds. I will share the class definition and the given function implementation. Definition: class codePeg { protected: FloatRect bounds; CircleShape circle; int xPos, yPos, xDiff, yDiff, once; int xBase, yBase; Vector2i mousePos; Vector2f circlePos; public: void init(RenderWindow& Window); void draw(RenderWindow& Window); void drag(RenderWindow& Window); void setPegPosition(int x, int y); void setPegColor(Color pegColor); void mouseOver(RenderWindow& Window); friend int isPegSelected(void); }; Implementation of the "drag" function: void codePeg::drag(RenderWindow& Window) { mousePos = Mouse::getPosition(Window); circlePos = circle.getPosition(); if(Mouse::isButtonPressed(Mouse::Left)) { if(mousePos.x > xPos && mousePos.y > yPos && mousePos.x - bounds.width < xPos && mousePos.y - bounds.height < yPos) { if(once) { xDiff = mousePos.x - circlePos.x; yDiff = mousePos.y - circlePos.y; once = 0; } xPos = mousePos.x - xDiff; yPos = mousePos.y - yDiff; circle.setPosition(xPos, yPos); } } else { once = 1; xPos = xBase; yPos = yBase; xDiff = 0; yDiff = 0; circle.setPosition(xBase, yBase); } Window.draw(circle); } Like I said, the function works, but to me, the code is very ugly and I think it could be improved and could be more efficient. The only thing I can think of as to why the object cannot keep up with the mouse is that there are too many function calls and/or checks. The user does not really have to mouse the mouse "fast" for it to happen, I would say at an average pace the object is left behind. How can I improve the code so that the object remains with the mouse when it is selected? Any help improving this code or giving advice is greatly appreciated.

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How can I gather client's data on Google App Engine without using Datastore/Backend Instances too much?

- by ruslan

One of the projects I'm working on is online survey engine. It's my first big commercial project on Google App Engine. I need your advice on how to collect stats and efficiently record them in DataStore without bankrupting me. Initial requirements are: After user finishes survey client sends list of pairs [ID (int) + PercentHit (double)]. This list shows how close answers of this user match predefined answers of reference answerers (which identified by IDs). I call them "target IDs". Creator of the survey wants to see aggregated % for given IDs for last hour, particular timeframe or from the beginning of the survey. Some surveys may have thousands of target/reference answerers. So I created entity public class HitsStatsDO implements Serializable { @Id transient private Long id; transient private Long version = (long) 0; transient private Long startDate; @Parent transient private Key parent; // fake parent which contains target id @Transient int targetId; private double avgPercent; private long hitCount; } But writing HitsStatsDO for each target from each user would give a lot of data. For instance I had a survey with 3000 targets which was answered by ~4 million people within one week with 300K people taking survey in first day. Even if we assume they were answering it evenly for 24 hours it would give us ~1040 writes/second. Obviously it hits concurrent writes limit of Datastore. I decided I'll collect data for one hour and save that, that's why there are avgPercent and hitCount in HitsStatsDO. GAE instances are stateless so I had to use dynamic backend instance. There I have something like this: // Contains stats for one hour private class Shard { ReadWriteLock lock = new ReentrantReadWriteLock(); Map<Integer, HitsStatsDO> map = new HashMap<Integer, HitsStatsDO>(); // Key is target ID public void saveToDatastore(); public void updateStats(Long startDate, Map<Integer, Double> hits); } and map with shard for current hour and previous hour (which doesn't stay here for long) private HashMap<Long, Shard> shards = new HashMap<Long, Shard>(); // Key is HitsStatsDO.startDate So once per hour I dump Shard for previous hour to Datastore. Plus I have class LifetimeStats which keeps Map<Integer, HitsStatsDO> in memcached where map-key is target ID. Also in my backend shutdown hook method I dump stats for unfinished hour to Datastore. There is only one major issue here - I have only ONE backend instance :) It raises following questions on which I'd like to hear your opinion: Can I do this without using backend instance ? What if one instance is not enough ? How can I split data between multiple dynamic backend instances? It hard because I don't know how many I have because Google creates new one as load increases. I know I can launch exact number of resident backend instances. But how many ? 2, 5, 10 ? What if I have no load at all for a week. Constantly running 10 backend instances is too expensive. What do I do with data from clients while backend instance is dead/restarting?

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Writing a method to 'transform' an immutable object: how should I approach this?

- by Prog

(While this question has to do with a concrete coding dilemma, it's mostly about what's the best way to design a function.) I'm writing a method that should take two Color objects, and gradually transform the first Color into the second one, creating an animation. The method will be in a utility class. My problem is that Color is an immutable object. That means that I can't do color.setRGB or color.setBlue inside a loop in the method. What I can do, is instantiate a new Color and return it from the method. But then I won't be able to gradually change the color. So I thought of three possible solutions: 1- The client code includes the method call inside a loop. For example: int duration = 1500; // duration of the animation in milliseconds int steps = 20; // how many 'cycles' the animation will take for(int i=0; i<steps; i++) color = transformColor(color, targetColor, duration, steps); And the method would look like this: Color transformColor(Color original, Color target, int duration, int steps){ int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted return new Color(newRed, newGreen, newBlue); } The disadvantage of this approach is that the client code has to "do part of the method's job" and include a for loop. The method doesn't do it's work entirely on it's own, which I don't like. 2- Make a mutable Color subclass with methods such as setRed, and pass objects of this class into transformColor. Then it could look something like this: void transformColor(MutableColor original, Color target, int duration){ final int STEPS = 20; int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. for(int i=0; i<STEPS; i++){ original.setRed(original.getRed() + redAddition); // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted } } Then the calling code would usually look something like this: // The method will usually transform colors of JComponents JComponent someComponent = ... ; // setting the Color in JComponent to be a MutableColor Color mutableColor = new MutableColor(someComponent.getForeground()); someComponent.setForeground(mutableColor); // later, transforming the Color in the JComponent transformColor((MutableColor)someComponent.getForeground(), new Color(200,100,150), 2000); The disadvantage is - the need to create a new class MutableColor, and also the need to do casting. 3- Pass into the method the actual mutable object that holds the color. Then the method could do object.setColor or similar every iteration of the loop. Two disadvantages: A- Not so elegant. Passing in the object that holds the color just to transform the color feels unnatural. B- While most of the time this method will be used to transform colors inside JComponent objects, other kinds of objects may have colors too. So the method would need to be overloaded to receive other types, or receive Objects and have instanceof checks inside.. Not optimal. Right now I think I like solution #2 the most, than solution #1 and solution #3 the least. However I'd like to hear your opinions and suggestions regarding this.

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C++ non-member functions for nested template classes

- by beldaz

I have been writing several class templates that contain nested iterator classes, for which an equality comparison is required. As I believe is fairly typical, the comparison is performed with a non-member (and non-friend) operator== function. In doing so, my compiler (I'm using Mingw32 GCC 4.4 with flags -O3 -g -Wall) fails to find the function and I have run out of possible reasons. In the rather large block of code below there are three classes: a Base class, a Composed class that holds a Base object, and a Nested class identical to the Composed class except that it is nested within an Outer class. Non-member operator== functions are supplied for each. These classes are in templated and untemplated forms (in their own respective namespaces), with the latter equivalent to the former specialised for unsigned integers. In main, two identical objects for each class are compared. For the untemplated case there is no problem, but for the templated case the compiler fails to find operator==. What's going on? #include <iostream> namespace templated { template<typename T> class Base { T t_; public: explicit Base(const T& t) : t_(t) {} bool equal(const Base& x) const { return x.t_==t_; } }; template<typename T> bool operator==(const Base<T> &x, const Base<T> &y) { return x.equal(y); } template<typename T> class Composed { typedef Base<T> Base_; Base_ base_; public: explicit Composed(const T& t) : base_(t) {} bool equal(const Composed& x) const {return x.base_==base_;} }; template<typename T> bool operator==(const Composed<T> &x, const Composed<T> &y) { return x.equal(y); } template<typename T> class Outer { public: class Nested { typedef Base<T> Base_; Base_ base_; public: explicit Nested(const T& t) : base_(t) {} bool equal(const Nested& x) const {return x.base_==base_;} }; }; template<typename T> bool operator==(const typename Outer<T>::Nested &x, const typename Outer<T>::Nested &y) { return x.equal(y); } } // namespace templated namespace untemplated { class Base { unsigned int t_; public: explicit Base(const unsigned int& t) : t_(t) {} bool equal(const Base& x) const { return x.t_==t_; } }; bool operator==(const Base &x, const Base &y) { return x.equal(y); } class Composed { typedef Base Base_; Base_ base_; public: explicit Composed(const unsigned int& t) : base_(t) {} bool equal(const Composed& x) const {return x.base_==base_;} }; bool operator==(const Composed &x, const Composed &y) { return x.equal(y); } class Outer { public: class Nested { typedef Base Base_; Base_ base_; public: explicit Nested(const unsigned int& t) : base_(t) {} bool equal(const Nested& x) const {return x.base_==base_;} }; }; bool operator==(const Outer::Nested &x, const Outer::Nested &y) { return x.equal(y); } } // namespace untemplated int main() { using std::cout; unsigned int testVal=3; { // No templates first typedef untemplated::Base Base_t; Base_t a(testVal); Base_t b(testVal); cout << "a=b=" << testVal << "\n"; cout << "a==b ? " << (a==b ? "TRUE" : "FALSE") << "\n"; typedef untemplated::Composed Composed_t; Composed_t c(testVal); Composed_t d(testVal); cout << "c=d=" << testVal << "\n"; cout << "c==d ? " << (c==d ? "TRUE" : "FALSE") << "\n"; typedef untemplated::Outer::Nested Nested_t; Nested_t e(testVal); Nested_t f(testVal); cout << "e=f=" << testVal << "\n"; cout << "e==f ? " << (e==f ? "TRUE" : "FALSE") << "\n"; } { // Now with templates typedef templated::Base<unsigned int> Base_t; Base_t a(testVal); Base_t b(testVal); cout << "a=b=" << testVal << "\n"; cout << "a==b ? " << (a==b ? "TRUE" : "FALSE") << "\n"; typedef templated::Composed<unsigned int> Composed_t; Composed_t c(testVal); Composed_t d(testVal); cout << "c=d=" << testVal << "\n"; cout << "d==c ? " << (c==d ? "TRUE" : "FALSE") << "\n"; typedef templated::Outer<unsigned int>::Nested Nested_t; Nested_t e(testVal); Nested_t f(testVal); cout << "e=f=" << testVal << "\n"; cout << "e==f ? " << (e==f ? "TRUE" : "FALSE") << "\n"; // Above line causes compiler error: // error: no match for 'operator==' in 'e == f' } cout << std::endl; return 0; }

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PHP Classes Extend

- by John

I have two classes that work seperate from another, but they extend the same class. Is it possible to have them work the same instance of the extended class. I'm wanting the constructor of the extended class to run only once. I know this isn't right but something like this: <?php $oApp = new app; class a extends $oApp {} class b extends $oApp {}

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Why can't you call abstract functions from abstract classes in PHP?

- by incrediman

I've set up an abstract parent class, and a concrete class which extends it. Why can the parent class not call the abstract function? //foo.php <?php abstract class AbstractFoo{ abstract public static function foo(); public static function getFoo(){ return self::foo();//line 5 } } class ConcreteFoo extends AbstractFoo{ public static function foo(){ return "bar"; } } echo ConcreteFoo::getFoo(); ?> Error: Fatal error: Cannot call abstract method AbstractFoo::foo() in foo.php on line 5

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Auto-needed classes?

- by fsdfa

Suppose I have a class A and a class B. The .h of A, needs the .h of B, and the .h of B needs the .h of A. (need = #include). All .h have the guards: #ifndef _classX_ #define _classX_ ... ... #endif But if I compile the .cpp of A, then when it includes the .h of B, the B class cannot include the .h of A class because the A class has already use the guard. How can i solve this?

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