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Articles indexed in September 2012

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  • Why fill() and copy() of Collections in java is implemented this way

    - by Priyank Doshi
    According to javadoc... Collections.fill() is written as below : public static <T> void fill(List<? super T> list, T obj) { int size = list.size(); if (size < FILL_THRESHOLD || list instanceof RandomAccess) { for (int i=0; i<size; i++) list.set(i, obj); } else { ListIterator<? super T> itr = list.listIterator(); for (int i=0; i<size; i++) { itr.next(); itr.set(obj); } } } Its easy to understand why they didn't use listIterator for if (size < FILL_THRESHOLD || list instanceof RandomAccess) condition as of RandomAccess. But whats the use of size < FILL_THRESHOLD in above? I mean is there any significant performance benefit over using iterator for size>=FILL_THRESHOLD and not for size < FILL_THRESHOLD ? I see the same approach for Collections.copy() also : public static <T> void copy(List<? super T> dest, List<? extends T> src) { int srcSize = src.size(); if (srcSize > dest.size()) throw new IndexOutOfBoundsException("Source does not fit in dest"); if (srcSize < COPY_THRESHOLD || (src instanceof RandomAccess && dest instanceof RandomAccess)) { for (int i=0; i<srcSize; i++) dest.set(i, src.get(i)); } else { ListIterator<? super T> di=dest.listIterator(); ListIterator<? extends T> si=src.listIterator(); for (int i=0; i<srcSize; i++) { di.next(); di.set(si.next()); } } } FYI: private static final int FILL_THRESHOLD = 25; private static final int COPY_THRESHOLD = 10;

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  • Any method to denote object assignment?

    - by Droogans
    I've been studying magic methods in Python, and have been wondering if there's a way to outline the specific action of: a = MyClass(*params).method() versus: MyClass(*params).method() In the sense that, perhaps, I may want to return a list that has been split on the '\n' character, versus dumping the raw list into the variable a that keeps the '\n' intact. Is there a way to ask Python if its next action is about to return a value to a variable, and change action, if that's the case? I was thinking: class MyClass(object): def __init__(*params): self.end = self.method(*params) def __asgn__(self): return self.method(*params).split('\n') def __str__(self): """this is the fallback if __asgn__ is not called""" return self.method(*params)

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  • Oracle Merge vs Select then Insert or Update

    - by DRTauli
    What is faster? the Merge statement MERGE INTO table USING dual ON (rowid = 'some_id') WHEN MATCHED THEN UPDATE SET colname = 'some_val' WHEN NOT MATCHED THEN INSERT (rowid, colname) VALUES ('some_id', 'some_val') or querying a select statement then using an update or insert statement. SELECT * FROM table where rowid = 'some_id' if rowCount == 0 INSERT INTO table (rowid,colname) VALUES ('some_id','some_val') else UPDATE table SET colname='some_val' WHERE rowid='some_id'

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  • rails - REST or create another method

    - by user1304740
    Let's assume we have two models linked with a 1-to-many relationship (like clients and invoices - a client can have many invoices). In a view of a 'client' (let's say the 'show' view), there is a form to capture an 'invoice'. I found 2 approaches: This form should be handled by the 'invoice' controller (method create), having client_id passed as a parameter This form should be handled by a new method in 'client' controller, probably a PUT method defined in routes.rb. Is there a 'Rails way', or both of them are good? Is there a preffered way? Thanks!

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  • How to get VC# to rebuild auto-generated .cs files?

    - by Jive Dadson
    I imagine this question has been asked and answered, but I cannot find it. I wanted to make a simple GUI to interface to a windows 7 command. I usually use Wx, but since this was to be a windows-only thing, I decided to see if I could whip it out real fast using Visual C# 2010 Express, which I had never used before. Things started off just great. I created a form, put a few buttons and text boxes and such on it, and hit Debug. It came up and ran just like that. No muss, no fuss. So I then designed the form just the way I wanted it, renamed the controls from "Button1" and so forth to meaningful names. But now it's a mess. By clicking around, I discovered that VC# had auto-generated two files called Form1.cs and Form1.Designer.cs. The later contains the bindings between functions and the events generated from user-clicks etc., and the former contains no-op code for those functions, for me to complete. Problem is, the names are all still the original "Button1" and so forth, not the new ones, and the new controls I added after running the first time do not appear at all. I want it to regenerate all that stuff afresh from the finished form. How to?

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  • Conditional Statements - If Then vs. Select Case

    - by cloyd800
    I'm a bit new to programming, and based on the few sources I've read both on the web and the books I'm learning to teach myself they are able to define what IF THEN and SELECT CASE conditional statements are, but have failed to give a comparison as to why I would use one over the other and what best practices decide this. If I'm understanding these conditional statements correctly, then both are based on a set of conditions with an outcome based around meeting these conditions, and if no conditions are met then an alternative outcome can be defined. I'm having trouble in understanding when I would use an IF THEN statement, and when I'd use a SELECT CASE statement, and what best practices are used to define this decision. Any insight on this would be greatly appreciated!

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  • Java iterative vs recursive

    - by user1389813
    Can anyone explain why the following recursive method is faster than the iterative one (Both are doing it string concatenation) ? Isn't the iterative approach suppose to beat up the recursive one ? plus each recursive call adds a new layer on top of the stack which can be very space inefficient. private static void string_concat(StringBuilder sb, int count){ if(count >= 9999) return; string_concat(sb.append(count), count+1); } public static void main(String [] arg){ long s = System.currentTimeMillis(); StringBuilder sb = new StringBuilder(); for(int i = 0; i < 9999; i++){ sb.append(i); } System.out.println(System.currentTimeMillis()-s); s = System.currentTimeMillis(); string_concat(new StringBuilder(),0); System.out.println(System.currentTimeMillis()-s); } I ran the program multiple time, and the recursive one always ends up 3-4 times faster than the iterative one. What could be the main reason there that is causing the iterative one slower ?

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  • sequencing function calls in javascript - are callbacks the only way?

    - by tim
    I read through various threads like this one for example. But it really escapes me how to accomplish the following: I have 4 functions, and want them happen one after another in sequence. Notice they are in incorrect order, to get my point across. I want the result that will output "1, 2, 3, 4' function firstFunction(){ // some very time consuming asynchronous code... console.log('1'); } function thirdFunction(){ // definitely dont wanna do this until secondFunction is finished console.log('3'); } function secondFunction(){ // waits for firstFunction to be completed console.log('2'); } function fourthFunction(){ // last function, not executed until the other 3 are done. console.log('4'); } I tried to figure out callbacks but am getting lost :( Isn't there some simple way to do this? Like looping through an array...

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  • Organizing github repository for java 6 and 7

    - by Edmon
    I am wanting to create a gihub repository that offers benchmarking code that works for concurrent features available only in JDK 1.7 (Fork/Join) as well as for older ones found in JDK 1.6. Offering both options is important for what I need. Does anyone have a recommendation how should I structure the repository. I was planning on having a repo called and under it: jdk17 build src mycode ... jdk16 build src mycode Please suggest any alternatives, possibly use of Maven or other more practical approaches, if any.

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  • Is there a way to redirect ONLY stderr to stdout (not combine the two) so it can be piped to other programs

    - by James K
    I'm working in a Windows CMD.EXE environment and would like to change the output of stdout to match that of stderr so that I can pipe error messages to other programs without the intermediary of a file. I'm aware of the 2>&1 notation, but that combines stdout and stderr into a single stream. What I'm thinking of would be something like this: program.exe 2>&1 | find " " But that combines stdout and stderr just like: program.exe | find " " 2>&1 I realize that I could do... program 2>file type file | find " " del file But this does not have the flexibility and power of a program | find " " sort of notation. Doing this requires that program has finished with it's output before that output can be processed.

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  • Cannot get list of elements using Linq to XML

    - by Blackator
    Sample XML: <CONFIGURATION> <Files> <File>D:\Test\TestFolder\TestFolder1\TestFile.txt</File> <File>D:\Test\TestFolder\TestFolder1\TestFile01.txt</File> <File>D:\Test\TestFolder\TestFolder1\TestFile02.txt</File> <File>D:\Test\TestFolder\TestFolder1\TestFile03.txt</File> <File>D:\Test\TestFolder\TestFolder1\TestFile04.txt</File> </Files> <SizeMB>3</SizeMB> <BackupLocation>D:\Log backups\File backups</BackupLocation> </CONFIGURATION> I've been doing some tutorials but I am unable to get all the list of file inside the files element. It only shows the first element and doesn't display the rest. This is my code: var fileFolders = from file in XDocument.Load(@"D:\Hello\backupconfig1.xml").Descendants("Files") select new { File = file.Element("File").Value }; foreach (var fileFolder in fileFolders) { Console.WriteLine("File = " + fileFolder.File); } How do I display all the File in the Files element, the SizeMB and BackupLocation? Thanks

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  • localhost yes but phpmyadmin blank

    - by Giskin Leow
    WAMP people having problem with both localhost and phpmyadmin loads blank which usually the port problem. Mine is only phpmyadmin blank. sqlbuddy and phpinfo no problem. tried uninstall reinstalled wamp. tried xampp, same problem, all works well, not phpmyadmin. mysql log: 120905 8:03:08 [Note] Plugin 'FEDERATED' is disabled. 120905 8:03:08 InnoDB: The InnoDB memory heap is disabled 120905 8:03:08 InnoDB: Mutexes and rw_locks use Windows interlocked functions 120905 8:03:08 InnoDB: Compressed tables use zlib 1.2.3 120905 8:03:09 InnoDB: Initializing buffer pool, size = 128.0M 120905 8:03:09 InnoDB: Completed initialization of buffer pool 120905 8:03:09 InnoDB: highest supported file format is Barracuda. 120905 8:03:09 InnoDB: Waiting for the background threads to start 120905 8:03:10 InnoDB: 1.1.8 started; log sequence number 1595675 120905 8:03:11 [Note] Server hostname (bind-address): '(null)'; port: 3306 120905 8:03:11 [Note] - '(null)' resolves to '::'; 120905 8:03:11 [Note] - '(null)' resolves to '0.0.0.0'; 120905 8:03:11 [Note] Server socket created on IP: '0.0.0.0'. 120905 8:03:13 [Note] Event Scheduler: Loaded 0 events 120905 8:03:13 [Note] wampmysqld: ready for connections. apache log [Wed Sep 05 08:03:09 2012] [notice] Apache/2.2.22 (Win32) PHP/5.4.3 configured -- resuming normal operations [Wed Sep 05 08:03:09 2012] [notice] Server built: May 13 2012 13:32:42 [Wed Sep 05 08:03:09 2012] [notice] Parent: Created child process 3812 [Wed Sep 05 08:03:09 2012] [notice] Child 3812: Child process is running [Wed Sep 05 08:03:09 2012] [notice] Child 3812: Acquired the start mutex. [Wed Sep 05 08:03:09 2012] [notice] Child 3812: Starting 64 worker threads. [Wed Sep 05 08:03:09 2012] [notice] Child 3812: Starting thread to listen on port 80. [Wed Sep 05 08:03:09 2012] [notice] Child 3812: Starting thread to listen on port 80. [Wed Sep 05 08:04:14 2012] [error] [client 127.0.0.1] File does not exist: C:/wamp/www/favicon.ico [Wed Sep 05 08:09:50 2012] [error] [client 127.0.0.1] File does not exist: C:/wamp/www/favicon.ico [Wed Sep 05 08:41:03 2012] [error] [client 127.0.0.1] File does not exist: C:/wamp/www/phpMyAdmin

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  • sherlock actionbar menu

    - by user1647443
    I am trying to setup a menu programatically and my method gets com.actionbarsherlock.view.Menu menu as a parameter. As I want to change the styling of the menu item I am trying to setup a SpannableString spannable and pass it to add. menu.add(0, MENU_ABOUT, 0, spannable); This is causing a crash only in ICS when I cick that menu item. Any ideas if I am missing something. Thanks Here is the code I am trying and it crashes when I run the app and select "About Application". FYI, I am using SpannableString because I want to add some styling and color to the menu item. The crash does NOT happen if I use a regular string, but then I cant do styling public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) { SpannableString spannable = new SpannableString("About Application"); menu.add(0, MENU_ABOUT, 0, spannable); return true; } Here is the stack trace: 09-05 02:25:32.849: E/AndroidRuntime(684): FATAL EXCEPTION: main 09-05 02:25:32.849: E/AndroidRuntime(684): java.lang.IllegalArgumentException: Invalid payload item type 09-05 02:25:32.849: E/AndroidRuntime(684): at android.util.EventLog.writeEvent(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.Activity.onMenuItemSelected(Activity.java:2501) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:351) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:950) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:163) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AdapterView.performItemClick(AdapterView.java:292) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.performItemClick(AbsListView.java:1058) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.onTouchEvent(AbsListView.java:3180) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchTouchEvent(View.java:5541) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1951) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1712) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1726) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1860) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchPointerEvent(View.java:5721) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2890) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2466) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.processInputEvents(ViewRootImpl.java:845) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2475) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Handler.dispatchMessage(Handler.java:99) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Looper.loop(Looper.java:137) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.ActivityThread.main(ActivityThread.java:4424) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invokeNative(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invoke(Method.java:511) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 09-05 02:25:32.849: E/AndroidRuntime(684): at dalvik.system.NativeStart.main(Native Method) Thanks

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  • How to trigger an action from a NSTableCellView in view based NSTableView when using bindings

    - by user1075752
    I'm facing a problem with a view-based NSTableView running on 10.8 (target is 10.7, but I think this is not relevant). I'm using an NSTableView, and I get content values for my custom NSTableCellView through bindings. I use the obejctValue of the NSTableCellView to get my data. I added a button to my cell, and I'd like it to trigger some action when clicked. So far I have only been able to trigger an action within the custom NSTableCellView's subclass. I can get the row that was clicked like this, using the chain: NSButton *myButton = (NSButton*)sender; NSTableView *myView = (NSTableView*)myButton.superview.superview.superview; NSInteger rowClicked = [myView rowForView:myButton.superview]; From there I don't know how to reach my App Delegate or controller where the action is defined. As I am using cocoa bindings, I do not have a delegate on the NSTableView that I could use to trigger my action. Do you have any idea how I could talked back to controller ? Many thanks in advance!

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  • jQuery Mobile: How to run a callback-function before $.mobile.changePage?

    - by Jugi84
    I'm setting up a mobile app with jQuery Mobile and PhoneGap. What I want to do is that when I click link with id "news_link" I want jQuery to fetch data from database and put it to jQm's collapsible set. In my solution, I've wanted to use $.mobile.changePage inside callback functions because I want to wait until the data has been fetched and put inside the container before the code changes page. Here's the code: $(function() { $('#news_link').click(function(){ loadNewsFromDB(function(){ $.mobile.changePage( $("#news"), { transition: "slideup"} ); }); }); loadNewsFromDB is PhoneGap's SQLite database function which would fetch the data with more callback functions from database. The contents would be put to desired container with .html-function function loadNewsFromDB(){ //some code here theDB.transaction(function(tx) { tx.executeSql(sqlStr, [], onLoadNewsSuccess, onLoadNewsError); },onTxError, onTxSuccess); function onLoadNewsSuccess(tx, results){ //some code here $("#newsSet").html(htmlCodeAndContentToPut); Html is jQm's basic ui-modules: <!-- some html code here --!> <div data-role="page" id="news"> <div data-role="content"> <div id="newsSet" data-role="collapsible-set" data-mini="true"> With debugging I know that the code work up until it works very well unti it arrives to $.mobile.changePage-function. Somehow it doesn't change the page. I've checked the function it works well in other occasions, but not inside callback-functions. I would be very grateful if someone would give me a hand am I not seeing something obviously wrong or is something more specific? What other workarounds there is for fetching the data from SQLite, waiting for data to be fetched, putting the data to container and then changing the pages?

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  • validation functions in google apps script is not working properly

    - by chocka
    I create a i/p form in google site using Apps Script and i did the validation using the Apps Script coding. Validation functions available in Apps script is not satisfying all the possibility of checking the error. function validate(e) { var app = UiApp.getActiveApplication(); var flag=0; var text = app.getElementById('name'); var textrequired = app.getElementById('namerequired'); var number = app.getElementById('number'); var numberrequired = app.getElementById('numberrequired'); var email = app.getElementById('email'); var emailrequired = app.getElementById('emailrequired'); var submit = app.getElementById('submit_button'); var valid = app.createClientHandler() .validateNumber(number) .validateNotInteger(text) .validateEmail(email) .forTargets(submit).setEnabled(true) .forTargets(number,text,email).setStyleAttribute("color","black") .forTargets(numberrequired,textrequired,emailrequired).setText('*').setStyleAttribute("color", "red").setVisible(true); var invalidno = app.createClientHandler().validateNotNumber(number).validateMatches(number, '').forTargets(number).setStyleAttribute("color", "red").forTargets(submit).setEnabled(false).forTargets(numberrequired).setText('Please Enter a Valid No.').setStyleAttribute("color", "red").setVisible(true); var validno = app.createClientHandler().validateNumber(number).forTargets(number).setStyleAttribute("color","black").forTargets(numberrequired).setText('*').setStyleAttribute("color", "red").setVisible(true); var invalidText=app.createClientHandler().validateNumber(text).validateMatches(text, '').forTargets(text).setStyleAttribute("color", "red").forTargets(submit).setEnabled(false).forTargets(textrequired).setText('Please Enter a Valid Name.').setStyleAttribute("color", "red").setVisible(true); var validText=app.createClientHandler().validateNotNumber(text).forTargets(text).setStyleAttribute("color","black").forTargets(textrequired).setText('*').setStyleAttribute("color", "red").setVisible(true); var invalidemail=app.createClientHandler().validateNotEmail(email).validateMatches(email, '').forTargets(email).setStyleAttribute("color", "red").forTargets(submit).setEnabled(false).forTargets(emailrequired).setText('Please Enter a Valid Mail-Id.').setStyleAttribute("color", "red").setVisible(true); var validemail=app.createClientHandler().validateEmail(email).forTargets(email).setStyleAttribute("color","black").forTargets(emailrequired).setText('*').setStyleAttribute("color", "red").setVisible(true); number.addKeyPressHandler(invalidno).addKeyPressHandler(validno).addKeyPressHandler(valid).addKeyPressHandler(invalidText).addKeyPressHandler(invalidemail); text.addKeyPressHandler(invalidText).addKeyPressHandler(validText).addKeyPressHandler(valid).addKeyPressHandler(invalidno).addKeyPressHandler(invalidemail); email.addKeyPressHandler(invalidemail).addKeyPressHandler(validemail).addKeyPressHandler(valid).addKeyPressHandler(invalidno).addKeyPressHandler(invalidText); if (text == ''){flag = 1;} if (email == ''){flag = 1;} if (number == ''){flag = 1;} if(flag == 1){submit.setEnabled(false);} return app; } I just placed my Validation function using Apps Script. I don't know why its not satisfying all the possibilities of the validation. And also i have to do is to enable the submit button after all the fields satisfy the validation. After once it enabled, if i make any error in any field it will not get disable correctly. I wrote the coding correctly i think so. Please take a look at my validation function and give me some suggestion to make it possible. Please guide me, Thanks & Regards, chocka.

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  • PHP cache header override

    - by Soyo
    I've been through over 100 answers here, lots to try, NOTHING working?? Have a PHP based site. I need caching OFF for all .php files EXCEPT A SELECT FEW. So, in .htaccess, I have the following: ExpiresActive On # Eliminate caching for certain dynamic files <FilesMatch "\.(php|cgi|pl)$"> ExpiresDefault A0 Header set Cache-Control "no-cache, no-store, must-revalidate, max-age=0, proxy-revalidate, no-transform" Header set Pragma "no-cache" </FilesMatch> Using Firebug, I see the following: Cache-Control no-cache, no-store, must-revalidate, max-age=0, proxy-revalidate, no-transform Connection Keep-Alive Content-Type text/html Date Sun, 02 Sep 2012 19:22:27 GMT Expires Sun, 02 Sep 2012 19:22:27 GMT Keep-Alive timeout=3, max=100 Pragma no-cache Server Apache Transfer-Encoding chunked X-Powered-By PHP/5.2.17 Hey, Looks great! BUT, I have a couple .php pages I need some very short caching on. I thought the simple answer was having this added to the very top of each php page in which I want caching enabled: <?php header("Cache-Control: max-age=360"); ?> Nope. Then I tried various versions of the above. Nope. Then I tried meta http-equiv variations. Nope. Then I tried variations of the .htaccess code along with the above variations, such as limiting it to: # Eliminate caching for certain dynamic files <FilesMatch "\.(php|cgi|pl)$"> Header set Cache-Control "no-cache, max-age=0" </FilesMatch> Nope. It seems nothing I do will allow a single .php to be cache enabled with the .htaccess code in place, short of removing the statements from the .htaccess file altogether. Where am I going wrong? What do I have to do to get individual php pages to be cacheable while the rest remain off?? Thank you for any thoughts.

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  • How to detect back button or forward button navigation in a silverlight navigation application

    - by parapura rajkumar
    When a Page is navigated to in silverlight you can override this method. protected override void OnNavigatedTo(NavigationEventArgs e) { base.OnNavigatedTo(e); } The NavigationEventArgs has a NavigationMode enumeration which is defined as public enum NavigationMode { New = 0, Back = 1, Forward = 2, Refresh = 3, } But calling e.NavigationMode always throws a NotImplementedException Is there a way in silverlight to detect a page is being navigated to because the user hit the forward/back browser button. What I am trying to achieve is some kind of state that can be preserved when the user hits the back button. For example assume you have a customer page which is showing a list of customers in a datagrid. The user can select a customer and there is a detail view which shows all the orders for that customer. Now within an order item you can click a hyperlink link that takes you to the shipping history of the order which is a separate page. When the user hits the back button I want to go back to the customers page and automatically select the customer he was viewing. Is this possible at all ? I also tried out the fragment navigation feature NavigationService.Navigate(new Uri("#currentcustomerid=" + customer.Id.ToString(), UriKind.Relative)); when the customer selection changes but this adds too many items to the history when the user clicks various customers on the customer page. EDIT There is also an method you can override protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) { } which is the same as handling the NavigationService.Navigating event as indicated by BugFinder's answer. In this method e.NavigationMode always returns New when when you hit the Back or Forward Button. The only time this method returns Back is when you explicitly call NavigationService.GoBack()

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  • 3d cube using canvas. Need a little improvement

    - by TimeManx
    I made this 3d cube using the following code Matrix mMatrix = canvas.getMatrix(); canvas.save(); camera.save(); camera.rotateY(-angle); camera.getMatrix(mMatrix); mMatrix.preTranslate(-width, 0); mMatrix.postTranslate(width, 0); canvas.concat(mMatrix); canvas.drawBitmap(bmp1, 0, 0, null); camera.restore(); canvas.restore(); camera.rotateY(90 - angle); camera.getMatrix(mMatrix); mMatrix.preTranslate(-width, 0); mMatrix.postTranslate(width2, 0); canvas.concat(mMatrix); canvas.drawBitmap(bmp2, width, 0, null); This is what it gives But what I need is It's because when Camera rotates the images, some part of the image gets hidden. Like this But I think this can be done.

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  • Alternatives to Java bytecode instrumentation

    - by Rafael Regis
    I'm starting a project that will have to instrument java applications for coverage purposes (definition-usage of variables, etc). It has to add trace statements and some logic to the application and maybe remove statements. I have searched for ways of instrument Java code and what I always find is about bytecode instrumentation. My question is: It's the only way to instrument Java applications? There is any other way to do that? What are the advantages of bytecode instrumentation over the others? I'll probably use the bytecode solution, but I want to know what are the problems with the other approaches (if any) to decide precisely. Thanks!

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  • Actionscript - Adding EventListener to multiple buttons on stage

    - by Chev
    I have a little problem with adding EventListener to multiple objects on stage. I have above 40 buttons on stage named "Button01","Button02" .. "Button40", and i'm looking for easiest way to add EventListener to all of them. Creating something like Button01.addEventListener(MouseEvent.CLICK, doSomething) Button02.addEventListener(MouseEvent.CLICK, doSomething) .. Button40.addEventListener(MouseEvent.Click, doSomething) (Notice the same function). isn't solution i'm looking for :(. Thanks in advice.

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  • ASP.NET Frameworks and Raw Throughput Performance

    - by Rick Strahl
    A few days ago I had a curious thought: With all these different technologies that the ASP.NET stack has to offer, what's the most efficient technology overall to return data for a server request? When I started this it was mere curiosity rather than a real practical need or result. Different tools are used for different problems and so performance differences are to be expected. But still I was curious to see how the various technologies performed relative to each just for raw throughput of the request getting to the endpoint and back out to the client with as little processing in the actual endpoint logic as possible (aka Hello World!). I want to clarify that this is merely an informal test for my own curiosity and I'm sharing the results and process here because I thought it was interesting. It's been a long while since I've done any sort of perf testing on ASP.NET, mainly because I've not had extremely heavy load requirements and because overall ASP.NET performs very well even for fairly high loads so that often it's not that critical to test load performance. This post is not meant to make a point  or even come to a conclusion which tech is better, but just to act as a reference to help understand some of the differences in perf and give a starting point to play around with this yourself. I've included the code for this simple project, so you can play with it and maybe add a few additional tests for different things if you like. Source Code on GitHub I looked at this data for these technologies: ASP.NET Web API ASP.NET MVC WebForms ASP.NET WebPages ASMX AJAX Services  (couldn't get AJAX/JSON to run on IIS8 ) WCF Rest Raw ASP.NET HttpHandlers It's quite a mixed bag, of course and the technologies target different types of development. What started out as mere curiosity turned into a bit of a head scratcher as the results were sometimes surprising. What I describe here is more to satisfy my curiosity more than anything and I thought it interesting enough to discuss on the blog :-) First test: Raw Throughput The first thing I did is test raw throughput for the various technologies. This is the least practical test of course since you're unlikely to ever create the equivalent of a 'Hello World' request in a real life application. The idea here is to measure how much time a 'NOP' request takes to return data to the client. So for this request I create the simplest Hello World request that I could come up for each tech. Http Handler The first is the lowest level approach which is an HTTP handler. public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public bool IsReusable { get { return true; } } } WebForms Next I added a couple of ASPX pages - one using CodeBehind and one using only a markup page. The CodeBehind page simple does this in CodeBehind without any markup in the ASPX page: public partial class HelloWorld_CodeBehind : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Response.Write("Hello World. Time is: " + DateTime.Now.ToString() ); Response.End(); } } while the Markup page only contains some static output via an expression:<%@ Page Language="C#" AutoEventWireup="false" CodeBehind="HelloWorld_Markup.aspx.cs" Inherits="AspNetFrameworksPerformance.HelloWorld_Markup" %> Hello World. Time is <%= DateTime.Now %> ASP.NET WebPages WebPages is the freestanding Razor implementation of ASP.NET. Here's the simple HelloWorld.cshtml page:Hello World @DateTime.Now WCF REST WCF REST was the token REST implementation for ASP.NET before WebAPI and the inbetween step from ASP.NET AJAX. I'd like to forget that this technology was ever considered for production use, but I'll include it here. Here's an OperationContract class: [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World" + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } } WCF REST can return arbitrary results by returning a Stream object and a content type. The code above turns the string result into a stream and returns that back to the client. ASP.NET AJAX (ASMX Services) I also wanted to test ASP.NET AJAX services because prior to WebAPI this is probably still the most widely used AJAX technology for the ASP.NET stack today. Unfortunately I was completely unable to get this running on my Windows 8 machine. Visual Studio 2012  removed adding of ASP.NET AJAX services, and when I tried to manually add the service and configure the script handler references it simply did not work - I always got a SOAP response for GET and POST operations. No matter what I tried I always ended up getting XML results even when explicitly adding the ScriptHandler. So, I didn't test this (but the code is there - you might be able to test this on a Windows 7 box). ASP.NET MVC Next up is probably the most popular ASP.NET technology at the moment: MVC. Here's the small controller: public class MvcPerformanceController : Controller { public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } } ASP.NET WebAPI Next up is WebAPI which looks kind of similar to MVC. Except here I have to use a StringContent result to return the response: public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } } Testing Take a minute to think about each of the technologies… and take a guess which you think is most efficient in raw throughput. The fastest should be pretty obvious, but the others - maybe not so much. The testing I did is pretty informal since it was mainly to satisfy my curiosity - here's how I did this: I used Apache Bench (ab.exe) from a full Apache HTTP installation to run and log the test results of hitting the server. ab.exe is a small executable that lets you hit a URL repeatedly and provides counter information about the number of requests, requests per second etc. ab.exe and the batch file are located in the \LoadTests folder of the project. An ab.exe command line  looks like this: ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld which hits the specified URL 100,000 times with a load factor of 20 concurrent requests. This results in output like this:   It's a great way to get a quick and dirty performance summary. Run it a few times to make sure there's not a large amount of varience. You might also want to do an IISRESET to clear the Web Server. Just make sure you do a short test run to warm up the server first - otherwise your first run is likely to be skewed downwards. ab.exe also allows you to specify headers and provide POST data and many other things if you want to get a little more fancy. Here all tests are GET requests to keep it simple. I ran each test: 100,000 iterations Load factor of 20 concurrent connections IISReset before starting A short warm up run for API and MVC to make sure startup cost is mitigated Here is the batch file I used for the test: IISRESET REM make sure you add REM C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin REM to your path so ab.exe can be found REM Warm up ab.exe -n100 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJsonab.exe -n100 -c20 http://localhost/aspnetperf/api/HelloWorldJson ab.exe -n100 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld ab.exe -n100000 -c20 http://localhost/aspnetperf/handler.ashx > handler.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_CodeBehind.aspx > AspxCodeBehind.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_Markup.aspx > AspxMarkup.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld > Wcf.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldCode > Mvc.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld > WebApi.txt I ran each of these tests 3 times and took the average score for Requests/second, with the machine otherwise idle. I did see a bit of variance when running many tests but the values used here are the medians. Part of this has to do with the fact I ran the tests on my local machine - result would probably more consistent running the load test on a separate machine hitting across the network. I ran these tests locally on my laptop which is a Dell XPS with quad core Sandibridge I7-2720QM @ 2.20ghz and a fast SSD drive on Windows 8. CPU load during tests ran to about 70% max across all 4 cores (IOW, it wasn't overloading the machine). Ideally you can try running these tests on a separate machine hitting the local machine. If I remember correctly IIS 7 and 8 on client OSs don't throttle so the performance here should be Results Ok, let's cut straight to the chase. Below are the results from the tests… It's not surprising that the handler was fastest. But it was a bit surprising to me that the next fastest was WebForms and especially Web Forms with markup over a CodeBehind page. WebPages also fared fairly well. MVC and WebAPI are a little slower and the slowest by far is WCF REST (which again I find surprising). As mentioned at the start the raw throughput tests are not overly practical as they don't test scripting performance for the HTML generation engines or serialization performances of the data engines. All it really does is give you an idea of the raw throughput for the technology from time of request to reaching the endpoint and returning minimal text data back to the client which indicates full round trip performance. But it's still interesting to see that Web Forms performs better in throughput than either MVC, WebAPI or WebPages. It'd be interesting to try this with a few pages that actually have some parsing logic on it, but that's beyond the scope of this throughput test. But what's also amazing about this test is the sheer amount of traffic that a laptop computer is handling. Even the slowest tech managed 5700 requests a second, which is one hell of a lot of requests if you extrapolate that out over a 24 hour period. Remember these are not static pages, but dynamic requests that are being served. Another test - JSON Data Service Results The second test I used a JSON result from several of the technologies. I didn't bother running WebForms and WebPages through this test since that doesn't make a ton of sense to return data from the them (OTOH, returning text from the APIs didn't make a ton of sense either :-) In these tests I have a small Person class that gets serialized and then returned to the client. The Person class looks like this: public class Person { public Person() { Id = 10; Name = "Rick"; Entered = DateTime.Now; } public int Id { get; set; } public string Name { get; set; } public DateTime Entered { get; set; } } Here are the updated handler classes that use Person: Handler public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { var action = context.Request.QueryString["action"]; if (action == "json") JsonRequest(context); else TextRequest(context); } public void TextRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public void JsonRequest(HttpContext context) { var json = JsonConvert.SerializeObject(new Person(), Formatting.None); context.Response.ContentType = "application/json"; context.Response.Write(json); } public bool IsReusable { get { return true; } } } This code adds a little logic to check for a action query string and route the request to an optional JSON result method. To generate JSON, I'm using the same JSON.NET serializer (JsonConvert.SerializeObject) used in Web API to create the JSON response. WCF REST   [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World " + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } [OperationContract] [WebGet(ResponseFormat=WebMessageFormat.Json,BodyStyle=WebMessageBodyStyle.WrappedRequest)] public Person HelloWorldJson() { // Add your operation implementation here return new Person(); } } For WCF REST all I have to do is add a method with the Person result type.   ASP.NET MVC public class MvcPerformanceController : Controller { // // GET: /MvcPerformance/ public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } public JsonResult HelloWorldJson() { return Json(new Person(), JsonRequestBehavior.AllowGet); } } For MVC all I have to do for a JSON response is return a JSON result. ASP.NET internally uses JavaScriptSerializer. ASP.NET WebAPI public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } [HttpGet] public Person HelloWorldJson() { return new Person(); } [HttpGet] public HttpResponseMessage HelloWorldJson2() { var response = new HttpResponseMessage(HttpStatusCode.OK); response.Content = new ObjectContent<Person>(new Person(), GlobalConfiguration.Configuration.Formatters.JsonFormatter); return response; } } Testing and Results To run these data requests I used the following ab.exe commands:REM JSON RESPONSES ab.exe -n100000 -c20 http://localhost/aspnetperf/Handler.ashx?action=json > HandlerJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJson > MvcJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorldJson > WebApiJson.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorldJson > WcfJson.txt The results from this test run are a bit interesting in that the WebAPI test improved performance significantly over returning plain string content. Here are the results:   The performance for each technology drops a little bit except for WebAPI which is up quite a bit! From this test it appears that WebAPI is actually significantly better performing returning a JSON response, rather than a plain string response. Snag with Apache Benchmark and 'Length Failures' I ran into a little snag with Apache Benchmark, which was reporting failures for my Web API requests when serializing. As the graph shows performance improved significantly from with JSON results from 5580 to 6530 or so which is a 15% improvement (while all others slowed down by 3-8%). However, I was skeptical at first because the WebAPI test reports showed a bunch of errors on about 10% of the requests. Check out this report: Notice the Failed Request count. What the hey? Is WebAPI failing on roughly 10% of requests when sending JSON? Turns out: No it's not! But it took some sleuthing to figure out why it reports these failures. At first I thought that Web API was failing, and so to make sure I re-ran the test with Fiddler attached and runiisning the ab.exe test by using the -X switch: ab.exe -n100 -c10 -X localhost:8888 http://localhost/aspnetperf/api/HelloWorldJson which showed that indeed all requests where returning proper HTTP 200 results with full content. However ab.exe was reporting the errors. After some closer inspection it turned out that the dates varying in size altered the response length in dynamic output. For example: these two results: {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.841926-10:00"} {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.8519262-10:00"} are different in length for the number which results in 68 and 69 bytes respectively. The same URL produces different result lengths which is what ab.exe reports. I didn't notice at first bit the same is happening when running the ASHX handler with JSON.NET result since it uses the same serializer that varies the milliseconds. Moral: You can typically ignore Length failures in Apache Benchmark and when in doubt check the actual output with Fiddler. Note that the other failure values are accurate though. Another interesting Side Note: Perf drops over Time As I was running these tests repeatedly I was finding that performance steadily dropped from a startup peak to a 10-15% lower stable level. IOW, with Web API I'd start out with around 6500 req/sec and in subsequent runs it keeps dropping until it would stabalize somewhere around 5900 req/sec occasionally jumping lower. For these tests this is why I did the IIS RESET and warm up for individual tests. This is a little puzzling. Looking at Process Monitor while the test are running memory very quickly levels out as do handles and threads, on the first test run. Subsequent runs everything stays stable, but the performance starts going downwards. This applies to all the technologies - Handlers, Web Forms, MVC, Web API - curious to see if others test this and see similar results. Doing an IISRESET then resets everything and performance starts off at peak again… Summary As I stated at the outset, these were informal to satiate my curiosity not to prove that any technology is better or even faster than another. While there clearly are differences in performance the differences (other than WCF REST which was by far the slowest and the raw handler which was by far the highest) are relatively minor, so there is no need to feel that any one technology is a runaway standout in raw performance. Choosing a technology is about more than pure performance but also about the adequateness for the job and the easy of implementation. The strengths of each technology will make for any minor performance difference we see in these tests. However, to me it's important to get an occasional reality check and compare where new technologies are heading. Often times old stuff that's been optimized and designed for a time of less horse power can utterly blow the doors off newer tech and simple checks like this let you compare. Luckily we're seeing that much of the new stuff performs well even in V1.0 which is great. To me it was very interesting to see Web API perform relatively badly with plain string content, which originally led me to think that Web API might not be properly optimized just yet. For those that caught my Tweets late last week regarding WebAPI's slow responses was with String content which is in fact considerably slower. Luckily where it counts with serialized JSON and XML WebAPI actually performs better. But I do wonder what would make generic string content slower than serialized code? This stresses another point: Don't take a single test as the final gospel and don't extrapolate out from a single set of tests. Certainly Twitter can make you feel like a fool when you post something immediate that hasn't been fleshed out a little more <blush>. Egg on my face. As a result I ended up screwing around with this for a few hours today to compare different scenarios. Well worth the time… I hope you found this useful, if not for the results, maybe for the process of quickly testing a few requests for performance and charting out a comparison. Now onwards with more serious stuff… Resources Source Code on GitHub Apache HTTP Server Project (ab.exe is part of the binary distribution)© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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