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  • Why is my GUI unresponsive while a SwingWorker thread runs?

    - by Starchy
    Hello, I have a SwingWorker thread with an IOBound task which is totally locking up the interface while it runs. Swapping out the normal workload for a counter loop has the same result. The SwingWorker looks basically like this: public class BackupWorker extends SwingWorker<String, String> { private static String uname = null; private static String pass = null; private static String filename = null; static String status = null; BackupWorker (String uname, String pass, String filename) { this.uname = uname; this.pass = pass; this.filename = filename; } @Override protected String doInBackground() throws Exception { BackupObject bak = newBackupObject(uname,pass,filename); return "Done!"; } } The code that kicks it off lives in a class that extends JFrame: public void actionPerformed(ActionEvent event) { String cmd = event.getActionCommand(); if (BACKUP.equals(cmd)) { SwingUtilities.invokeLater(new Runnable() { public void run() { final StatusFrame statusFrame = new StatusFrame(); statusFrame.setVisible(true); SwingUtilities.invokeLater(new Runnable() { public void run () { statusFrame.beginBackup(uname,pass,filename); } }); } }); } } Here's the interesting part of StatusFrame: public void beginBackup(final String uname, final String pass, final String filename) { worker = new BackupWorker(uname, pass, filename); worker.execute(); try { System.out.println(worker.get()); } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } } } So far as I can see, everything "long-running" is handled by the worker, and everything that touches the GUI on the EDT. Have I tangled things up somewhere, or am I expecting too much of SwingWorker?

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  • How can I get the main thread to sleep while waiting for a delgate to be called?

    - by Erik B
    Consider a class with these methods: - (id) initWithFrame: (CGRect) frame { if (!(self = [super init])) return nil; webView = [[UIWebView alloc] initWithFrame:frame]; [webView setDelegate:self]; lock = [[NSConditionLock alloc] initWithCondition:LOCK_WAIT]; return self; } - (void) setHTML: (NSString *) html { [lock lockWhenCondition:LOCK_WAIT]; [webView loadHTMLString:html baseURL:nil]; [lock unlock]; } - (void)webViewDidFinishLoad:(UIWebView *)aWebView { [lock lockWhenCondition:LOCK_WAIT]; // Locking to be able to unlock and change the condition. [lock unlockWithCondition:LOCK_GO]; } - (NSString *) stringByEvaluatingJavaScriptFromString: (NSString *) jsCommand { [lock lockWhenCondition:LOCK_GO]; return [webView stringByEvaluatingJavaScriptFromString:jsCommand]; [lock unlock]; } Let's call this class SynchronousUIWebView. From the main thread I execute: webView = [[SynchronousUIWebView alloc] initWithFrame:frame]; [webView setHTML:html]; [webView stringByEvaluatingJavaScriptFromString:jsCommand]; The problem seems to be that the delegate is not called until I leave the current call stack, which I don't since I'm waiting for the delegate call to happen, aka deadlock. To me it seems like the delegate call is pushed to a queue that is called when the current call is done. So the question is can I modify this behavior? Note: The reason this is needed is that I can't execute the JavaScript until the HTML has loaded.

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  • Searching with a UISearchbar is slow and blocking the main thread.

    - by Robert
    I have a Table with over 3000 entries and searching is very slow. At the moment I am doing just like in the 'TableSearch' example code (but without scopes) - (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString { [self filterContentForSearchText: searchString]; // Return YES to cause the search result table view to be reloaded. return YES; } And the filterContentForSearchText method is as follows: - (void) filterContentForSearchText:(NSString*)searchText { // Update the filtered array based on the search text // First clear the filtered array. [filteredListContent removeAllObjects]; // Search the main list whose name matches searchText // add items that match to the filtered array. if (fetchedResultsController.fetchedObjects) { for (id object in fetchedResultsController.fetchedObjects) { NSString* searchTarget = [tableTypeDelegate getStringForSearchFilteringFromObject:object]; if ([searchTarget rangeOfString:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch)].location != NSNotFound) { [filteredListContent addObject:object]; } } } } My question is twofold: How do can I make the searching process faster? How can I stop the search from blocking the main thread? i.e. stop it preventing the user from typing more characters. For the second part, I tried "performSelector:withObject:afterDelay:" and "cancelPreviousPerformRequests..." without much success. I suspect that I will need to use threading instead, but I do not have much experience with it.

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  • How to prevent the other threads from accessing a method when one thread is accessing a method?

    - by geeta
    I want to search for a string in 10 files and write the matching lines to a single file. I wrote the matching lines from each file to 10 output files(o/p file1,o/p file2...) and then copied those to a single file using 10 threads. But the output single file has mixed output(one line from o/p file1,another line from o/p file 2 etc...) because its accessed simultaneously by many threads. If I wait for all threads to complete and then write the single file it will be much slower. I want the output file to be written by one thread at a time. What should i do? My source code:(only writing to single file method) public void WriteSingle(File output_file,File final_output) throws IOException { synchronized(output_file){ System.out.println("Writing Single file"); FileOutputStream fo = new FileOutputStream(final_output,true); FileChannel fi = fo.getChannel(); FileInputStream fs = new FileInputStream(output_file); FileChannel fc = fs.getChannel(); int maxCount = (64 * 1024 * 1024) - (32 * 1024); long size = fc.size(); long position = 0; while (position < size) { position += fc.transferTo(position, maxCount, fi); } } }

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  • "Exception in thread "main" java.lang.NoSuchMethodError Do i miss library in the installed JDk?

    - by Ahmad
    Hello every body I was using the JDK very well writing the code then i use "javac" to compile it then "java" to run it But Recently when i write a code and compile it then if i try to run it this exception appears to me "Exception in thread "main" java.lang.NoSuchMethodError " at first i thought there is something wrong in my code , i searched in the internet for a solving for this problem but i didn't find anything may help me Then i try to run the "HelloWorld" example i made it before, it runs i copied the code and pasted it in another file and changed the name to "HelloWorld2" and compile it by "javac" and tried to run it by "java" the same exception appears i was surprised why? it is the same code then i used the "javap" which decompile the code with both i found this difference in the first one (the old one) "public static void main(java.lang.String[])"; but in the second (the new one) "public static void main(String[])"; without java.lang then i compiled the old one which works and runs by "javac" and when i try to run it, it didn't run and give me the same exception i tried with some of my old codes it run and when i compile it by "javac" it doesn't work I searched to find a solution to this problem and i found nothing

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  • Does Socket open another thread? Does it return something?

    - by Roman
    In the client application I call new Socket(serverIP,serverPort). As a result the client application sends a request to the server application to open a socket. Does it start a new thread? I mean which of the following is true? Client application sends a request and immediately starts to execute following commands (not weighting for the answer). Client sends the request and weights for the answer. As soon as the answer is obtained, the client application continues to execute following commands. The second case seems to be more realistic and logical for me. However, I do not understand what happens if the server does not open a socket and it does not say that it does not "want" to open the second (it can happen if the server does not exist or network is broken). What will happen in this case? Will server weight forever? In general it would be nice for the client to know what is the result of its request for the socket. For example I can imagine the following situations: The socket is opened by the server. The server refuses to open a socket. So, server exists, it got the request from the client but it says "no". There is no response from the server. I know that new Socket(serverIP,serverPort) does not "return" this kind of information. But it throws exceptions. One of them is "UnkownHostException". When it is thrown? When the server is not responding for a while (for how long)? ADDED: I just found out that UnknownHostException is thrown to indicate that the IP address of a host could not be determined. So, it is unrelated with the above described situations (server is not responding, server refuses to open a socket).

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  • How to create a separate thread to do some operation periodically and update UI in WPF?I'm stack

    - by black sensei
    Hello Experts! I'm trying to do a periodic separated thread operation let's say check for internet connection or check for user's info via web service and update the user interface. i've tried with quartz.net to implement that.So i created an inner class for the window i need to update.That inner class does what is meant for but the problem is that i don't know how to access parent's(window class) members form the child(inner class). for example public partial class Window2 : Window { private int i; public Window2() { InitializeComponent(); } public string doMyOperation() { //code here return result; } public class Myclass :IJob { public void Execute(JobExecutionContext context) { string result = doMyOperation(); //Now here i could be able to call a label of name lblNotif //lblNotif.Content = result; } } } Well the whole idea works but i'm stacked at here i need to access a controls of Window2 Since i'm stacked i tried Spring.Net way of implementing Quartz hoping that i could use MethodInvokingJobDetailFactoryObject and rather have the Operation done on Window2 itself.But for some reason i'm having an exception Cannot resolve type [System.Windows.Window2,System.Windows];, could not load type from string value System.Windows.Window2,System.Windows and the wiring is done so <object name="UpdateLabelJob" type="System.Windows.Window2,System.Windows"/> What i'm i doing wrong here?Is that a way round? thanks for reading and for helping out

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  • PHP: Can pcntl_alarm() and socket_select() peacefully exist in the same thread?

    - by DWilliams
    I have a PHP CLI script mostly written that functions as a chat server for chat clients to connect to (don't ask me why I'm doing it in PHP, thats another story haha). My script utilizes the socket_select() function to hang execution until something happens on a socket, at which point it wakes up, processes the event, and waits until the next event. Now, there are some routine tasks that I need performed every 30 seconds or so (check of tempbanned users should be unbanned, save user databases, other assorted things). From what I can tell, PHP doesn't have very great multi-threading support at all. My first thought was to compare a timestamp every time the socket generates an event and gets the program flowing again, but this is very inconsistent since the server could very well sit idle for hours and not have any of my cleanup routines executed. I came across the PHP pcntl extensions, and it lets me use assign a time interval for SIGALRM to get sent and a function get executed every time it's sent. This seems like the ideal solution to my problem, however pcntl_alarm() and socket_select() clash with each other pretty bad. Every time SIGALRM is triggered, all sorts of crazy things happen to my socket control code. My program is fairly lengthy so I can't post it all here, but it shouldn't matter since I don't believe I'm doing anything wrong code-wise. My question is: Is there any way for a SIGALRM to be handled in the same thread as a waiting socket_select()? If so, how? If not, what are my alternatives here? Here's some output from my program. My alarm function simply outputs "Tick!" whenever it's called to make it easy to tell when stuff is happening. This is the output (including errors) after allowing it to tick 4 times (there were no actual attempts at connecting to the server despite what it says): [05-28-10 @ 20:01:05] Chat server started on 192.168.1.28 port 4050 [05-28-10 @ 20:01:05] Loaded 2 users from file PHP Notice: Undefined offset: 0 in /home/danny/projects/PHPChatServ/ChatServ.php on line 112 PHP Warning: socket_select(): unable to select [4]: Interrupted system call in /home/danny/projects/PHPChatServ/ChatServ.php on line 116 [05-28-10 @ 20:01:15] Tick! PHP Warning: socket_accept(): unable to accept incoming connection [4]: Interrupted system call in /home/danny/projects/PHPChatServ/ChatServ.php on line 126 [05-28-10 @ 20:01:25] Tick! PHP Warning: socket_getpeername() expects parameter 1 to be resource, boolean given in /home/danny/projects/PHPChatServ/ChatServ.php on line 129 [05-28-10 @ 20:01:25] Accepting socket connection from PHP Notice: Undefined offset: 1 in /home/danny/projects/PHPChatServ/ChatServ.php on line 112 PHP Warning: socket_select(): unable to select [4]: Interrupted system call in /home/danny/projects/PHPChatServ/ChatServ.php on line 116 [05-28-10 @ 20:01:35] Tick! PHP Warning: socket_accept(): unable to accept incoming connection [4]: Interrupted system call in /home/danny/projects/PHPChatServ/ChatServ.php on line 126 [05-28-10 @ 20:01:45] Tick! PHP Warning: socket_getpeername() expects parameter 1 to be resource, boolean given in /home/danny/projects/PHPChatServ/ChatServ.php on line 129 [05-28-10 @ 20:01:45] Accepting socket connection from PHP Notice: Undefined offset: 2 in /home/danny/projects/PHPChatServ/ChatServ.php on line 112

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  • Segmentation fault when creating a Phonon MediaObject

    - by Luke Hansford
    I have music playing program made using PySide which uses Phonon to playback audio. I updated to MacOS X Mavericks a few days ago, which meant I needed to reinstall PySide. I'm not sure which of these actions has caused this, but now whenever I try to create a Phonon MediaObject I get a Segmentation Fault: 11 from Python. It's not just in my program, it happens when trying to create a MediaObject in Python without any other actions. I'm getting the following error message from my Mac whenever it crashes: Process: Python [13711] Path: /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python Identifier: org.python.python Version: 2.7.5 (2.7.5) Code Type: X86-64 (Native) Parent Process: bash [13707] Responsible: Terminal [13704] User ID: 501 Date/Time: 2013-11-01 19:47:53.164 +1000 OS Version: Mac OS X 10.9 (13A603) Report Version: 11 Anonymous UUID: C2686854-18CA-9D37-26E9-60050E3C4DA6 Sleep/Wake UUID: BB983BF6-CCE2-44D1-82A0-1C73382DFFE4 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000008 VM Regions Near 0x8: --> __TEXT 00000001082e8000-00000001082e9000 [ 4K] r-x/rwx SM=COW /usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 QtCore 0x000000010a1b34cb QObject::moveToThread(QThread*) + 17 1 QtDBus 0x000000010d55f98b QDBusDefaultConnection::QDBusDefaultConnection(QDBusConnection::BusType, char const*) + 171 2 QtDBus 0x000000010d55ebdf QDBusConnection::sessionBus() + 71 3 phonon 0x000000010d50228d Phonon::FactoryPrivate::FactoryPrivate() + 189 4 phonon 0x000000010d5024d5 Phonon::$_249::operator->() + 99 5 phonon 0x000000010d502991 Phonon::Factory::registerFrontendObject(Phonon::MediaNodePrivate*) + 17 6 phonon 0x000000010d50b27e Phonon::MediaNodePrivate::MediaNodePrivate(Phonon::MediaNodePrivate::CastId) + 80 7 phonon 0x000000010d50f570 Phonon::MediaObjectPrivate::MediaObjectPrivate() + 24 8 phonon 0x000000010d50be9d Phonon::MediaObject::MediaObject(QObject*) + 45 9 phonon.so 0x000000010d42f24a Sbk_Phonon_MediaObject_Init + 458 10 org.python.python 0x0000000108338707 type_call + 189 11 org.python.python 0x00000001082f74fd PyObject_Call + 101 12 org.python.python 0x00000001083714f0 PyEval_EvalFrameEx + 15525 13 org.python.python 0x0000000108373aaf fast_function + 182 14 org.python.python 0x0000000108370919 PyEval_EvalFrameEx + 12494 15 org.python.python 0x000000010836d721 PyEval_EvalCodeEx + 1638 16 org.python.python 0x000000010836d0b5 PyEval_EvalCode + 54 17 org.python.python 0x000000010838beb8 run_mod + 53 18 org.python.python 0x000000010838bf5f PyRun_FileExFlags + 137 19 org.python.python 0x000000010838baad PyRun_SimpleFileExFlags + 718 20 org.python.python 0x000000010839c58b Py_Main + 3039 21 libdyld.dylib 0x00007fff8e4fb5fd start + 1 Thread 1:: Dispatch queue: com.apple.libdispatch-manager 0 libsystem_kernel.dylib 0x00007fff8c938662 kevent64 + 10 1 libdispatch.dylib 0x00007fff923e743d _dispatch_mgr_invoke + 239 2 libdispatch.dylib 0x00007fff923e7152 _dispatch_mgr_thread + 52 Thread 2: 0 libsystem_kernel.dylib 0x00007fff8c937e6a __workq_kernreturn + 10 1 libsystem_pthread.dylib 0x00007fff90bd8f08 _pthread_wqthread + 330 2 libsystem_pthread.dylib 0x00007fff90bdbfb9 start_wqthread + 13 Thread 3: 0 libsystem_kernel.dylib 0x00007fff8c937e6a __workq_kernreturn + 10 1 libsystem_pthread.dylib 0x00007fff90bd8f08 _pthread_wqthread + 330 2 libsystem_pthread.dylib 0x00007fff90bdbfb9 start_wqthread + 13 Thread 4: 0 libsystem_kernel.dylib 0x00007fff8c937e6a __workq_kernreturn + 10 1 libsystem_pthread.dylib 0x00007fff90bd8f08 _pthread_wqthread + 330 2 libsystem_pthread.dylib 0x00007fff90bdbfb9 start_wqthread + 13 Thread 0 crashed with X86 Thread State (64-bit): rax: 0x00007feba0d19700 rbx: 0x000000010d5b7098 rcx: 0x00000000002f4180 rdx: 0x000000000012c040 rdi: 0x0000000000000000 rsi: 0x00007feba0d19700 rbp: 0x00007fff57917210 rsp: 0x00007fff579171d0 r8: 0x00007feba0fd5d10 r9: 0x00007feba0ff5310 r10: 0x0000000019c04cbe r11: 0x0000000070769b38 r12: 0x00007fff57917220 r13: 0x00007feba0c07190 r14: 0x0000000000000000 r15: 0x00007feba0fe1430 rip: 0x000000010a1b34cb rfl: 0x0000000000010202 cr2: 0x0000000000000008 Logical CPU: 0 Error Code: 0x00000004 Trap Number: 14 Anyone have any ideas about what is happening?

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  • Strange exception of Httpcore nio in java

    - by bruce dou
    Exception in thread "Thread-0" java.lang.NullPointerException at org.apache.http.impl.nio.reactor.AbstractIOReactor.closeActiveChannels(AbstractIOReactor.java:532) at org.apache.http.impl.nio.reactor.AbstractIOReactor.hardShutdown(AbstractIOReactor.java:564) at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.doShutdown(AbstractMultiworkerIOReactor.java:411) at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:340) at com.***.clawer.Clawer$1.run(Clawer.java:81) at java.lang.Thread.run(Unknown Source) Exception in thread "Thread-1" java.lang.IllegalStateException: I/O reactor has been shut down at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.connect(DefaultConnectingIOReactor.java:190) at com.***.clawer.Run.run(Run.java:29)

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  • Which credentials should I put in for Google App Engine BulkLoader at development server?

    - by Hoang Pham
    Hello everyone, I would like to ask which kind of credentials do I need to put on for importing data using the Google App Engine BulkLoader class appcfg.py upload_data --config_file=models.py --filename=listcountries.csv --kind=CMSCountry --url=http://localhost:8178/remote_api vit/ And then it asks me for credentials: Please enter login credentials for localhost Here is an extraction of the content of the models.py, I use this listcountries.csv file class CMSCountry(db.Model): sortorder = db.StringProperty() name = db.StringProperty(required=True) formalname = db.StringProperty() type = db.StringProperty() subtype = db.StringProperty() sovereignt = db.StringProperty() capital = db.StringProperty() currencycode = db.StringProperty() currencyname = db.StringProperty() telephonecode = db.StringProperty() lettercode = db.StringProperty() lettercode2 = db.StringProperty() number = db.StringProperty() countrycode = db.StringProperty() class CMSCountryLoader(bulkloader.Loader): def __init__(self): bulkloader.Loader.__init__(self, 'CMSCountry', [('sortorder', str), ('name', str), ('formalname', str), ('type', str), ('subtype', str), ('sovereignt', str), ('capital', str), ('currencycode', str), ('currencyname', str), ('telephonecode', str), ('lettercode', str), ('lettercode2', str), ('number', str), ('countrycode', str) ]) loaders = [CMSCountryLoader] Every tries to enter the email and password result in "Authentication Failed", so I could not import the data to the development server. I don't think that I have any problem with my files neither my models because I have successfully uploaded the data to the appspot.com application. So what should I put in for localhost credentials? I also tried to use Eclipse with Pydev but I still got the same message :( Here is the output: Uploading data records. [INFO ] Logging to bulkloader-log-20090820.121659 [INFO ] Opening database: bulkloader-progress-20090820.121659.sql3 [INFO ] [Thread-1] WorkerThread: started [INFO ] [Thread-2] WorkerThread: started [INFO ] [Thread-3] WorkerThread: started [INFO ] [Thread-4] WorkerThread: started [INFO ] [Thread-5] WorkerThread: started [INFO ] [Thread-6] WorkerThread: started [INFO ] [Thread-7] WorkerThread: started [INFO ] [Thread-8] WorkerThread: started [INFO ] [Thread-9] WorkerThread: started [INFO ] [Thread-10] WorkerThread: started Password for [email protected]: [DEBUG ] Configuring remote_api. url_path = /remote_api, servername = localhost:8178 [DEBUG ] Bulkloader using app_id: abc [INFO ] Connecting to /remote_api [ERROR ] Exception during authentication Traceback (most recent call last): File "D:\Projects\GoogleAppEngine\google_appengine\google\appengine\tools\bulkloader.py", line 2802, in Run request_manager.Authenticate() File "D:\Projects\GoogleAppEngine\google_appengine\google\appengine\tools\bulkloader.py", line 1126, in Authenticate remote_api_stub.MaybeInvokeAuthentication() File "D:\Projects\GoogleAppEngine\google_appengine\google\appengine\ext\remote_api\remote_api_stub.py", line 488, in MaybeInvokeAuthentication datastore_stub._server.Send(datastore_stub._path, payload=None) File "D:\Projects\GoogleAppEngine\google_appengine\google\appengine\tools\appengine_rpc.py", line 344, in Send f = self.opener.open(req) File "C:\Python25\lib\urllib2.py", line 381, in open response = self._open(req, data) File "C:\Python25\lib\urllib2.py", line 399, in _open '_open', req) File "C:\Python25\lib\urllib2.py", line 360, in _call_chain result = func(*args) File "C:\Python25\lib\urllib2.py", line 1107, in http_open return self.do_open(httplib.HTTPConnection, req) File "C:\Python25\lib\urllib2.py", line 1082, in do_open raise URLError(err) URLError: <urlopen error (10061, 'Connection refused')> [INFO ] Authentication Failed Thank you!

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  • InvokeRequired not reliable?

    - by marocanu2001
    InvalidOperationException: Cross-thread operation not valid: Control 'progressBar' accessed from a thread other than the thread it was created ... Now this is not a nice way to start a day! not even if it's a Monday! So you have seen this and already thought, come on, this is an old one, just ask whether InvokeRequired before calling the method in the control, something like this: if (progressBar.InvokeRequired) {           progressBar.Invoke  ( new MethodInvoker( delegate {  progressBar.Value = 50;    }) ) }else      progressBar.Value = 50;    Unfortunately this was not working the way I would have expected, I got this error, debugged and though in debugging the InvokeRequired had become true , the error was thrown on the branch that did not required Invoke. So there was a scenario where InvokeRequired returned false and still accessing the control was not on the right thread ... Problem was that I kept showing and hiding the little form showing the progressbar. The progressbar was updating on an event  , ProgressChanged and I could not guarantee the little form was loaded by the time the event was thrown. So , spotted the problem, if none of the parents of the control you try to modify is created at the time of the method invoking, the InvokeRequired returns true! That causes your code to execute on the woring thread. Of course, updating UI before the win dow was created is not a legitimate action either, still I would have expected a different error. MSDN: "If the control's handle does not yet exist, InvokeRequired searches up the control's parent chain until it finds a control or form that does have a window handle. If no appropriate handle can be found, the InvokeRequired method returns false. This means that InvokeRequired can return false if Invoke is not required (the call occurs on the same thread), or if the control was created on a different thread but the control's handle has not yet been created." Have  a look at InvokeRequired's implementation: public bool InvokeRequired {     get     {         HandleRef hWnd;         int lpdwProcessId;         if (this.IsHandleCreated)         {             hWnd = new HandleRef(this, this.Handle);         }         else         {             Control wrapper = this.FindMarshallingControl();             if (!wrapper.IsHandleCreated)             {                 return false; // <==========             }             hWnd = new HandleRef(wrapper, wrapper.Handle);         }         int windowThreadProcessId = SafeNativeMethods.GetWindowThreadProcessId(hWnd, out lpdwProcessId);         int currentThreadId = SafeNativeMethods.GetCurrentThreadId();         return (windowThreadProcessId != currentThreadId);     } } Here 's a good article about this and a workaround http://www.ikriv.com/en/prog/info/dotnet/MysteriousHang.html

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  • Safe non-tamperable URL component in Perl using symmetric encryption?

    - by Randal Schwartz
    OK, I'm probably just having a bad Monday, but I have the following need and I'm seeing lots of partial solutions but I'm sure I'm not the first person to need this, so I'm wondering if I'm missing the obvious. $client has 50 to 500 bytes worth of binary data that must be inserted into the middle of a URL and roundtrip to their customer's browser. Since it's part of the URL, we're up against the 1K "theoretical" limit of a GET URL. Also, $client doesn't want their customer decoding the data, or tampering with it without detection. $client would also prefer not to store anything server-side, so this must be completely standalone. Must be Perl code, and fast, in both encoding and decoding. I think the last step can be base64. But what are the steps for encryption and hashing that make the most sense?

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  • [Ruby] Why do I have to URI.encode even safe characters for Net::HTTP requests?

    - by Matthias
    I was trying to send a GET request to Twitter (user ID replaced for privacy reasons) using Net::HTTP: url = URI.parse("http://api.twitter.com/1/friends/ids.json?user_id=12345") resp = Net::HTTP.get_response(url) this throws an exception in Net::HTTP: NoMethodError: undefined method empty?' for #<URI::HTTP:0x59f5c04> from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/net/http.rb:1470:ininitialize' just by coincidence, I stumbled upon a similar code snippet, which used URI.encode prior to URI.parse, so I copied that and tried again: url = URI.parse(URI.encode("http://api.twitter.com/1/friends/ids.json?user_id=12345")) resp = Net::HTTP.get_response(url) now it works fine, but why? There are no reserved characters that need escaping in the URL I mentioned, so why do I have to call URI.encode for get_response to succeed?

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  • What is a good dumbed-down, safe template system for PHP?

    - by Wilhelm
    (Summary: My users need to be able to edit the structure of their dynamically generated web pages without being able to do any damage.) Greetings, ladies and gentlemen. I am currently working on a service where customers from a specific demographic can create a specific type of web site and fill it with their own content. The system is written in PHP. Many of the users of this system wish to edit how their particular web site looks, or, more commonly, have a designer do it for them. Editing the CSS is fine and dandy, but sometimes that's not enough. Sometimes they want to shuffle the entire page structure around by editing the raw HTML of the dynamically created web pages. The templating system used by WordPress is, as far as I can see, perfect for my use. Except for one thing which is critically important. In addition to being able to edit how comments are displayed or where the menu goes, someone editing a template can have that template execute arbitrary PHP code. As the same codebase runs all these different sites, with all content in the same databse, allowing my users to run arbitrary code is clearly out of the question. So what I need, is a dumbed-down, idiot-proof templating system where my users can edit most of the page structure on their own, pulling in the dynamic sections wherever, without being able to even echo 1+1;. Observe the following psuedocode: <!DOCTYPE html> <title><!-- $title --></title> <!-- header() --> <!-- menu() --> <div>Some random custom crap added by the user.</div> <!-- page_content() --> That's the degree of power I'd like to grant my users. They don't need to do their own loops or calculations or anything. Just include my variables and functions and leave the rest to me. I'm sure I'm not the only person on the planet that needs something like this. Do you know of any ready-made templating systems I could use? Thanks in advance for your reply.

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  • Best open source alternative for MS Visual Source Safe?

    - by afsharm
    We are leaving VSS for TFS or any other alternatives. I'm the one who persists to go for an open source alternative like SVN. Now I'm searching for a good open source Version Control regarding following aspects: We are in love with open source movement and cross-platform. Could it be possible to use it with Mono, SharpDevelop and Express editions of VS instead of Visual Studio itself? What about backup? Is it integrated with VS without serious problems? Any API or command prompt access? Please notice I've read following previous texts about it but still need more help: http://stackoverflow.com/questions/690766/vss-or-svn-for-a-net-project http://stackoverflow.com/questions/61959/tfs-vs-open-source-alternatives http://stackoverflow.com/questions/44588/how-to-convince-a-company-to-switch-their-source-control

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  • Is it safe to lock a static variable in a non-static class?

    - by Dario Solera
    I've got a class that manages a shared resource. Now, since access to the resource depends on many parameters, this class is instantiated and disposed several times during the normal execution of the program. The shared resource does not support concurrency, so some kind of locking is needed. The first thing that came into my mind is having a static instance in the class, and acquire locks on it, like this: // This thing is static! static readonly object MyLock = new object(); // This thing is NOT static! MyResource _resource = ...; public DoSomeWork() { lock(MyLock) { _resource.Access(); } } Does that make sense, or would you use another approach?

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  • How can I make these images download on a seperate thread?

    - by Andy Barlow
    Hello!! I have the following code running on my Android device. It works great and displays my list items wonderfully. It's also clever in the fact it only downloads the data when it's needed by the ArrayAdapter. However, whilst the download of the thumbnail is occurring, the entire list stalls and you cannot scroll until it's finished downloading. Is there any way of threading this so it'll still scroll happily, maybe show a place holder for the downloading image, finish the download, and then show? Any help with this would be really apreciated. Thank-you kindly. Andy Barlow private class CatalogAdapter extends ArrayAdapter { private ArrayList<SingleQueueResult> items; //Must research what this actually does! public CatalogAdapter(Context context, int textViewResourceId, ArrayList<SingleQueueResult> items) { super(context, textViewResourceId, items); this.items = items; } /** This overrides the getview of the ArrayAdapter. It should send back our new custom rows for the list */ @Override public View getView(int position, View convertView, ViewGroup parent) { View v = convertView; if (v == null) { LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE); v = vi.inflate(R.layout.mylists_rows, null); } final SingleQueueResult result = items.get(position); // Sets the text inside the rows as they are scrolled by! if (result != null) { TextView title = (TextView)v.findViewById(R.id.mylist_title); TextView format = (TextView)v.findViewById(R.id.mylist_format); title.setText(result.getTitle()); format.setText(result.getThumbnail()); // Download Images ImageView myImageView = (ImageView)v.findViewById(R.id.mylist_thumbnail); downloadImage(result.getThumbnail(), myImageView); } return v; } } // This should run in a seperate thread public void downloadImage(String imageUrl, ImageView myImageView) { try { url = new URL(imageUrl); URLConnection conn = url.openConnection(); conn.connect(); InputStream is = conn.getInputStream(); BufferedInputStream bis = new BufferedInputStream(is); Bitmap bm = BitmapFactory.decodeStream(bis); bis.close(); is.close(); myImageView.setImageBitmap(bm); } catch (IOException e) { /* Reset to Default image on any error. */ //this.myImageView.setImageDrawable(getResources().getDrawable(R.drawable.default)); } }

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  • Need help with Java Producer Consumer Problem, NullPointerException

    - by absk
    This is my code: package test; import java.util.logging.Level; import java.util.logging.Logger; class Data{ int ar[]=new int[50]; int ptr; Data() { for(int i=0;i<50;i++) ar[i]=0; ptr=0; } public int produce() { if(this.ptr<50) { this.ar[this.ptr]=1; this.ptr++; return this.ptr; } else return -1; } public int consume() { if(this.ptr>0) { this.ar[this.ptr]=0; this.ptr--; return this.ptr; } else return -1; } } class Prod implements Runnable{ private Main m; Prod(Main mm) { m=mm; } public void run() { int r = m.d.produce(); if (r != -1) { System.out.println("Produced, total elements: " + r); } else { try { wait(); } catch (InterruptedException ex) { Logger.getLogger(Prod.class.getName()).log(Level.SEVERE, null, ex); } } } } class Cons implements Runnable{ private Main m; Cons(Main mm) { m=mm; } public void run() { int r=m.d.consume(); if(r!=-1) System.out.println("Consumed, total elements: " + r); else { try { wait(); } catch (InterruptedException ex) { Logger.getLogger(Prod.class.getName()).log(Level.SEVERE, null, ex); } } notify(); } } public class Main{ Data d; public static void main(String s[]) throws InterruptedException{ Main m = new Main(); Prod p = new Prod(m); Cons c = new Cons(m); new Thread(p).start(); new Thread(c).start(); } } It is giving following errors: Exception in thread "Thread-0" Exception in thread "Thread-1" java.lang.NullPointerException at test.Cons.run(Main.java:84) at java.lang.Thread.run(Thread.java:619) java.lang.NullPointerException at test.Prod.run(Main.java:58) at java.lang.Thread.run(Thread.java:619) I am new to Java. Any help will be appreciated.

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  • 1 oracle schema support large reques per day , is this safe ?

    - by Hlex
    I 'm java system designer. As we have large project to do tightly, Those projects are java api without webpage. I design to create general flow engine to support all project. This idea use 1 oracle schema , having general transaction table . And others control routing table. They all nearly complete. But DBA Team concern that he is suffered to maintain very large request to 1 schema. 1 reason is if there are problem is some table. He must offline tablespace to fix. This is problem because all project will be affected. I try to convince by split data of each table to partition by project_code & "month number to delete" . Eaxmple partition: PROJ1_05 PROJ1_06 PROJ1_07 PROJ2_05 PROJ2_06 PROJ2_07 and all transaction table will store on its partition. So, If there are problem on any part of tablespace then he should offline some partition and another project with use same table should able to service Transaction per day should around 10Meg Record per day. Is this a good idea? If I must use 1 schema, what is strategy to do? Do you have any comment?

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  • Subterranean IL: Volatile

    - by Simon Cooper
    This time, we'll be having a look at the volatile. prefix instruction, and one of the differences between volatile in IL and C#. The volatile. prefix volatile is a tricky one, as there's varying levels of documentation on it. From what I can see, it has two effects: It prevents caching of the load or store value; rather than reading or writing to a cached version of the memory location (say, the processor register or cache), it forces the value to be loaded or stored at the 'actual' memory location, so it is then immediately visible to other threads. It forces a memory barrier at the prefixed instruction. This ensures instructions don't get re-ordered around the volatile instruction. This is slightly more complicated than it first seems, and only seems to matter on certain architectures. For more details, Joe Duffy has a blog post going into the details. For this post, I'll be concentrating on the first aspect of volatile. Caching field accesses To demonstrate this, I created a simple multithreaded IL program. It boils down to the following code: .class public Holder { .field public static class Holder holder .field public bool stop .method public static specialname void .cctor() { newobj instance void Holder::.ctor() stsfld class Holder Holder::holder ret }}.method private static void Main() { .entrypoint // Thread t = new Thread(new ThreadStart(DoWork)) // t.Start() // Thread.Sleep(2000) // Console.WriteLine("Stopping thread...") ldsfld class Holder Holder::holder ldc.i4.1 stfld bool Holder::stop call instance void [mscorlib]System.Threading.Thread::Join() ret}.method private static void DoWork() { ldsfld class Holder Holder::holder // while (!Holder.holder.stop) {} DoWork: dup ldfld bool Holder::stop brfalse DoWork pop ret} If you compile and run this code, you'll find that the call to Thread.Join() never returns - the DoWork spinlock is reading a cached version of Holder.stop, which is never being updated with the new value set by the Main method. Adding volatile to the ldfld fixes this: dupvolatile.ldfld bool Holder::stopbrfalse DoWork The volatile ldfld forces the field access to read direct from heap memory, which is then updated by the main thread, rather than using a cached copy. volatile in C# This highlights one of the differences between IL and C#. In IL, volatile only applies to the prefixed instruction, whereas in C#, volatile is specified on a field to indicate that all accesses to that field should be volatile (interestingly, there's no mention of the 'no caching' aspect of volatile in the C# spec; it only focuses on the memory barrier aspect). Furthermore, this information needs to be stored within the assembly somehow, as such a field might be accessed directly from outside the assembly, but there's no concept of a 'volatile field' in IL! How this information is stored with the field will be the subject of my next post.

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  • How to make safe cast using generics in C#?

    - by TN
    I want to implement a generic method on a generic class which would allow to cast safely, see example: public class Foo<T> : IEnumerable<T> { ... public IEnumerable<R> SafeCast<R>() where T : R { return this.Select(item => (R)item); } } However, the compiler tells me that Foo<T>.SafeCast<R>() does not define parameter 'T'. I understand this message that I cannot specify a constraint on T in the method since it is not defined in the method. But how can I specify an inverse constraint?

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  • WCF: Is it safe to override the Client's Dispose method using a partial class?

    - by pdiddy
    I'd like to override the Dispose method of generated proxy (ClientBase) because of the fact that disposing of a proxy calls Close and can throw an exception when the channel is faulted. The only way I came up was to create a partial class to my generated proxy, make it inherit from IDisposable: public partial class MyServiceProxy : IDisposable { #region IDisposable Members public void Dispose() { if (State != System.ServiceModel.CommunicationState.Faulted) Close(); else Abort(); } #endregion } I did some test and my Dispose method is indeed called. Do you see any issue with this strategy? Also, I don't like the fact that I'll have to create this partial class for every generated proxy. It be nice if I was able to make my proxy inherit from a base class...

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