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• Is this crash in libdispatch caused by Reachability?

  - by esilver

  Can anyone tell me if this crashing stack appears to be caused by Reachability? I am running apple's latest implementation of Reachability, downloadable at https://developer.apple.com/library/ios/samplecode/reachability/Introduction/Intro.html I have an app where ARC is not enabled by default (it is a legacy app) but I enable it on a per-file basis. I have enabled -fobjc-arc for Reachability.m When I look at these threads, my code is nowhere to be found. I see some activity happening because of a WebHTMLView (probably the ad network view code currently on screen; it's not mine). On Thread 10, I see a SCNetworkReachabilityDeallocate, then a dispatch_semaphore_wait_slow, and the crash happens on Thread 14 in libdispatch. Do you think this crash is being caused by that Reachability code, and have I erred in using -fobjc-arc with Reachability.m? Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Subtype: KERN_INVALID_ADDRESS at 0x2000000c Triggered by Thread: 14 Thread 0: 0 libsystem_kernel.dylib 0x39cafa84 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x39caf87c mach_msg + 36 2 CoreFoundation 0x2f3e255c __CFRunLoopServiceMachPort + 152 3 CoreFoundation 0x2f3e0cc2 __CFRunLoopRun + 858 4 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 5 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 6 GraphicsServices 0x340822e6 GSEventRunModal + 134 7 UIKit 0x31c021e0 UIApplicationMain + 1132 8 MyApp 0x00053ad4 main (main.m:33) 9 libdyld.dylib 0x39c0bab4 start + 0 Thread 1: 0 libsystem_kernel.dylib 0x39caf838 kevent64 + 24 1 libdispatch.dylib 0x39bfe0d0 _dispatch_mgr_invoke + 228 2 libdispatch.dylib 0x39bf863e _dispatch_mgr_thread + 34 Thread 2 name: com.apple.NSURLConnectionLoader Thread 2: 0 libsystem_kernel.dylib 0x39cb0910 close + 8 1 CoreFoundation 0x2f370ef6 CFSocketInvalidate + 434 2 CFNetwork 0x2f0122a2 Schedulables::_SchedulablesInvalidateApplierFunction(void const*, void*) + 14 3 CoreFoundation 0x2f34af6e CFArrayApplyFunction + 34 4 CFNetwork 0x2f011a94 SocketStream::close(void const*) + 280 5 CFNetwork 0x2f01194e CoreStreamBase::_streamInterface_Close() + 46 6 CFNetwork 0x2f030286 HTTPReadFilter::_streamImpl_Close() + 66 7 CFNetwork 0x2f01194e CoreStreamBase::_streamInterface_Close() + 46 8 CFNetwork 0x2f0301c6 NetConnection::shutdownConnectionStreams() + 98 9 CFNetwork 0x2f0309c8 NetConnection::closeStreamsIfPossibleOrSignalThatThatNeedsToBeDonePrettyPlease() + 56 10 CFNetwork 0x2f030d12 HTTPConnectionCacheEntry::removeUnauthConnection(NetConnection*) + 182 11 CoreFoundation 0x2f34af6e CFArrayApplyFunction + 34 12 CFNetwork 0x2f075678 HTTPConnectionCacheEntry::purgeIdleConnections(double, double) + 256 13 CFNetwork 0x2f030ad4 HTTPConnectionCache::performIdleSweep() + 156 14 CFNetwork 0x2f073b42 HTTPConnectionCache::timeoutIdleCellConnections() + 18 15 CFNetwork 0x2f0b3394 ___ZNK17CoreSchedulingSet13_performAsyncEPKcU13block_pointerFvvE_block_invoke + 16 16 CoreFoundation 0x2f34af6e CFArrayApplyFunction + 34 17 CFNetwork 0x2f019f10 RunloopBlockContext::perform() + 160 18 CFNetwork 0x2f019de2 MultiplexerSource::perform() + 218 19 CFNetwork 0x2f019c70 MultiplexerSource::_perform(void*) + 44 20 CoreFoundation 0x2f3e2f24 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 12 21 CoreFoundation 0x2f3e23ea __CFRunLoopDoSources0 + 202 22 CoreFoundation 0x2f3e0bda __CFRunLoopRun + 626 23 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 24 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 25 Foundation 0x2fd8664c +[NSURLConnection(Loader) _resourceLoadLoop:] + 316 26 Foundation 0x2fdfbdc2 __NSThread__main__ + 1058 27 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 28 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 29 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 3 name: WebThread Thread 3: 0 CoreGraphics 0x2f49163c CGRectIsEmpty + 0 1 WebCore 0x37291700 -[WAKView setNeedsDisplayInRect:] + 76 2 WebKit 0x37cad22a -[WebHTMLView setNeedsDisplayInRect:] + 214 3 WebCore 0x372915cc WebCore::ScrollView::platformRepaintContentRectangle(WebCore::IntRect const&, bool) + 148 4 WebCore 0x37291412 WebCore::ScrollView::repaintContentRectangle(WebCore::IntRect const&, bool) + 98 5 WebCore 0x37291272 WebCore::FrameView::doDeferredRepaints() + 90 6 WebCore 0x372dc96c WebCore::FrameView::layout(bool) + 1748 7 WebCore 0x3721fb94 WebCore::ThreadTimers::sharedTimerFiredInternal() + 132 8 WebCore 0x3721fae6 WebCore::timerFired(__CFRunLoopTimer*, void*) + 22 9 CoreFoundation 0x2f3e2e84 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 12 10 CoreFoundation 0x2f3e2a9e __CFRunLoopDoTimer + 790 11 CoreFoundation 0x2f3e0e26 __CFRunLoopRun + 1214 12 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 13 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 14 WebCore 0x372ae7d8 RunWebThread(void*) + 416 15 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 16 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 17 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 4: 0 libsystem_kernel.dylib 0x39cafa84 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x39caf87c mach_msg + 36 2 CoreFoundation 0x2f3e255c __CFRunLoopServiceMachPort + 152 3 CoreFoundation 0x2f3e0c7c __CFRunLoopRun + 788 4 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 5 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 6 libAVFAudio.dylib 0x2e3295ae GenericRunLoopThread::Entry(void*) + 126 7 libAVFAudio.dylib 0x2e31dbf4 CAPThread::Entry(CAPThread*) + 176 8 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 9 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 10 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 5 name: JavaScriptCore::BlockFree Thread 5: 0 libsystem_kernel.dylib 0x39cc1f38 __psynch_cvwait + 24 1 libsystem_pthread.dylib 0x39d28262 _pthread_cond_wait + 538 2 libsystem_pthread.dylib 0x39d2903c pthread_cond_wait + 36 3 JavaScriptCore 0x3036f408 JSC::BlockAllocator::blockFreeingThreadMain() + 204 4 JavaScriptCore 0x3036ca70 WTF::wtfThreadEntryPoint(void*) + 12 5 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 6 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 7 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 6 name: JavaScriptCore::Marking Thread 6: 0 libsystem_kernel.dylib 0x39cc1f38 __psynch_cvwait + 24 1 libsystem_pthread.dylib 0x39d28262 _pthread_cond_wait + 538 2 libsystem_pthread.dylib 0x39d2903c pthread_cond_wait + 36 3 JavaScriptCore 0x3050daf2 JSC::GCThread::waitForNextPhase() + 74 4 JavaScriptCore 0x3050db4c JSC::GCThread::gcThreadMain() + 48 5 JavaScriptCore 0x3036ca70 WTF::wtfThreadEntryPoint(void*) + 12 6 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 7 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 8 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 7 name: com.apple.CFSocket.private Thread 7: 0 libsystem_kernel.dylib 0x39cc2440 select$DARWIN_EXTSN + 20 1 CoreFoundation 0x2f3e645e __CFSocketManager + 482 2 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 3 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 4 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 8 name: AFNetworking Thread 8: 0 libsystem_kernel.dylib 0x39cafa84 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x39caf87c mach_msg + 36 2 CoreFoundation 0x2f3e255c __CFRunLoopServiceMachPort + 152 3 CoreFoundation 0x2f3e0c7c __CFRunLoopRun + 788 4 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 5 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 6 Foundation 0x2fd39822 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 250 7 Foundation 0x2fd8a664 -[NSRunLoop(NSRunLoop) run] + 76 8 MyApp 0x002c33d0 +[AFURLConnectionOperation networkRequestThreadEntryPoint:] (AFURLConnectionOperation.m:184) 9 Foundation 0x2fdfbdc2 __NSThread__main__ + 1058 10 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 11 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 12 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 9 name: WebCore: CFNetwork Loader Thread 9: 0 libsystem_kernel.dylib 0x39cafa84 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x39caf87c mach_msg + 36 2 CoreFoundation 0x2f3e255c __CFRunLoopServiceMachPort + 152 3 CoreFoundation 0x2f3e0c7c __CFRunLoopRun + 788 4 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 5 CoreFoundation 0x2f34b31e CFRunLoopRunInMode + 102 6 WebCore 0x372f7872 WebCore::runLoaderThread(void*) + 250 7 JavaScriptCore 0x3036ca70 WTF::wtfThreadEntryPoint(void*) + 12 8 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 9 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 10 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 10: 0 libsystem_kernel.dylib 0x39cafad4 semaphore_wait_trap + 8 1 libdispatch.dylib 0x39bfcdec _dispatch_semaphore_wait_slow + 172 2 libxpc.dylib 0x39d370d6 xpc_connection_send_message_with_reply_sync + 150 3 SystemConfiguration 0x31b77362 _reach_server_target_remove + 90 4 SystemConfiguration 0x31b772d2 __SCNetworkReachabilityServer_targetRemove + 38 5 SystemConfiguration 0x31b5e318 __SCNetworkReachabilityDeallocate + 92 6 CoreFoundation 0x2f347efc CFRelease + 464 7 libdispatch.dylib 0x39bfc7e0 _dispatch_root_queue_drain + 220 8 libdispatch.dylib 0x39bfc9cc _dispatch_worker_thread2 + 52 9 libsystem_pthread.dylib 0x39d26dfc _pthread_wqthread + 296 10 libsystem_pthread.dylib 0x39d26cc0 start_wqthread + 4 Thread 11: 0 libsystem_kernel.dylib 0x39cc2c7c __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x39d26e06 _pthread_wqthread + 306 2 libsystem_pthread.dylib 0x39d26cc0 start_wqthread + 4 Thread 12: 0 libsystem_kernel.dylib 0x39cc2c7c __workq_kernreturn + 8 1 libsystem_pthread.dylib 0x39d26e06 _pthread_wqthread + 306 2 libsystem_pthread.dylib 0x39d26cc0 start_wqthread + 4 Thread 13: 0 libsystem_kernel.dylib 0x39cafa84 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x39caf87c mach_msg + 36 2 CoreFoundation 0x2f3e255c __CFRunLoopServiceMachPort + 152 3 CoreFoundation 0x2f3e0c7c __CFRunLoopRun + 788 4 CoreFoundation 0x2f34b53c CFRunLoopRunSpecific + 520 5 CoreFoundation 0x2f38f1a6 CFRunLoopRun + 94 6 CoreMotion 0x2fa03394 ___lldb_unnamed_function1407$$CoreMotion + 724 7 libsystem_pthread.dylib 0x39d28c5a _pthread_body + 138 8 libsystem_pthread.dylib 0x39d28bca _pthread_start + 98 9 libsystem_pthread.dylib 0x39d26ccc thread_start + 4 Thread 14 Crashed: 0 libobjc.A.dylib 0x3970db66 objc_msgSend + 6 1 CoreFoundation 0x2f347f58 CFRelease + 556 2 libdispatch.dylib 0x39bf7100 _dispatch_call_block_and_release + 8 3 libdispatch.dylib 0x39bfbe72 _dispatch_queue_drain + 370 4 libdispatch.dylib 0x39bf8f96 _dispatch_queue_invoke + 38 5 libdispatch.dylib 0x39bfc74e _dispatch_root_queue_drain + 74 6 libdispatch.dylib 0x39bfc9cc _dispatch_worker_thread2 + 52 7 libsystem_pthread.dylib 0x39d26dfc _pthread_wqthread + 296 8 libsystem_pthread.dylib 0x39d26cc0 start_wqthread + 4

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• sort the "rollup" in group by

  - by shantanuo

  I found that the "with rollup" option used with group by is very useful. But it does not behave with "order by" clause. Is there any way to order by the way I want as well as calculate the sub-totals? CREATE TABLE `mygroup` ( `id` int(11) default NULL, `country` varchar(100) default NULL ) ENGINE=MyISAM ; INSERT INTO `mygroup` VALUES (1,'India'),(5,'India'),(8,'India'),(18,'China'),(28,'China'),(28,'China'); mysql>select country, sum(id) from mygroup group by country with rollup; +---------+---------+ | country | sum(id) | +---------+---------+ | China | 74 | | India | 14 | | NULL | 88 | +---------+---------+ 3 rows in set (0.00 sec) mysql>select country, sum(id) as cnt from mygroup group by country order by cnt ; +---------+------+ | country | cnt | +---------+------+ | India | 14 | | China | 74 | +---------+------+ 2 rows in set (0.00 sec) mysql>select country, sum(id) as cnt from mygroup group by country with rollup order by cnt; ERROR 1221 (HY000): Incorrect usage of CUBE/ROLLUP and ORDER BY Expected Result: +---------+------+ | country | cnt | +---------+------+ | India | 14 | | China | 74 | | NULL | 88 | +---------+---------+ 3 rows in set (0.00 sec)

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• Why is the class wrong for NSFetchRequest?

  - by Stephen Furlani

  Hello, I am working with an undocumented API (Osirix) and I have a sister-question to the one I posted here. I am having trouble loading objects from a managed object context. With loading from API, using their instance of _context and _model 2010-05-28 14:05:13.588 OsiriX[44012:a0f] Entity: Study 2010-05-28 14:05:13.589 OsiriX[44012:a0f] EntityClassName: DicomStudy 2010-05-28 14:05:13.589 OsiriX[44012:a0f] ClassName: DicomStudy With loading from Fetch Request (and my own instance of _context, and _model) 2010-05-28 14:19:09.956 rcOsirix[44431:7a03] Entity: Study 2010-05-28 14:19:09.957 rcOsirix[44431:7a03] EntityClassName: DicomStudy 2010-05-28 14:19:09.958 rcOsirix[44431:7a03] ClassName: NSManagedObject output given by: NSLog(@"Entity: %@",[[item entity] name]); NSLog(@"EntityClassName: %@", [[item entity] managedObjectClassName]); NSLog(@"ClassName: %s", class_getName(object_getClass([item class]))); So it is obvious that even though the Entity thinks it is a DicomSeries - it is not. It is just a NSManagedObject. DicomSeries has some "hard-coded" KVC stuff that I ran into a problem with in my other question. I'm pursuing a different line of reasoning in this thread - with the loading of the objects. The following is their code: - (NSManagedObjectModel *)managedObjectModel { if (managedObjectModel) return managedObjectModel; NSMutableSet *allBundles = [[NSMutableSet alloc] init]; [allBundles addObject: [NSBundle mainBundle]]; [allBundles addObjectsFromArray: [NSBundle allFrameworks]]; managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL: [NSURL fileURLWithPath: [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"/OsiriXDB_DataModel.mom"]]]; [allBundles release]; return managedObjectModel; } - (NSManagedObjectContext *) managedObjectContextLoadIfNecessary:(BOOL) loadIfNecessary { NSError *error = nil; NSString *localizedDescription; NSFileManager *fileManager; if( currentDatabasePath == nil) return nil; if (managedObjectContext) return managedObjectContext; if( loadIfNecessary == NO) return nil; fileManager = [NSFileManager defaultManager]; [persistentStoreCoordinator release]; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: self.managedObjectModel]; managedObjectContext = [[NSManagedObjectContext alloc] init]; [managedObjectContext setPersistentStoreCoordinator: persistentStoreCoordinator]; NSURL *url = [NSURL fileURLWithPath: currentDatabasePath]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:&error]) { NSLog(@"********** managedObjectContextLoadIfNecessary FAILED: %@", error); localizedDescription = [error localizedDescription]; error = [NSError errorWithDomain:@"OsiriXDomain" code:0 userInfo:[NSDictionary dictionaryWithObjectsAndKeys:error, NSUnderlyingErrorKey, [NSString stringWithFormat:@"Store Configuration Failure: %@", ((localizedDescription != nil) ? localizedDescription : @"Unknown Error")], NSLocalizedDescriptionKey, nil]]; } [[managedObjectContext undoManager] setLevelsOfUndo: 1]; [[managedObjectContext undoManager] disableUndoRegistration]; // This line is very important, if there is NO database.sql file [self saveDatabase: currentDatabasePath]; return managedObjectContext; } This is my code: NSManagedObjectModel* DataModule::managedObjectModel() { if (_managedObjectModel) return _managedObjectModel; NSMutableSet *allBundles = [[NSMutableSet alloc] init]; [allBundles addObject: [NSBundle mainBundle]]; [allBundles addObjectsFromArray: [NSBundle allFrameworks]]; _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL: [NSURL fileURLWithPath: [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"/OsiriXDB_DataModel.mom"]]]; [allBundles release]; return [_managedObjectModel retain]; } ... NSError *error = nil; [_storeCoordinator release]; _storeCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: managedObjectModel()]; _context = [[NSManagedObjectContext alloc] init]; [_context setPersistentStoreCoordinator: _storeCoordinator]; NSURL *url = [NSURL fileURLWithPath: [[NSString alloc] initWithCString:_DBPath.c_str()]]; if (url == nil) { [pool release]; _loadLock = false; return nil; } if (![_storeCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:&error]) { NSLog(@"********** managedObjectContextLoadIfNecessary FAILED: %@", error); NSString *localizedDescription = [error localizedDescription]; error = [NSError errorWithDomain:@"OsiriXDomain" code:0 userInfo:[NSDictionary dictionaryWithObjectsAndKeys:error, NSUnderlyingErrorKey, [NSString stringWithFormat:@"Store Configuration Failure: %@", ((localizedDescription != nil) ? localizedDescription : @"Unknown Error")], NSLocalizedDescriptionKey, nil]]; //Exit Failure [pool release]; _loadLock = false; return nil; } [[_context undoManager] setLevelsOfUndo: 1]; [[_context undoManager] disableUndoRegistration]; ... I am including all the same frameworks.... but _allBundles isn't even used to create the managedObjectModel so I don't know what it's supposed to do except load them into memory so that the mom can look at them while loading. Totally lost. Help! Why would objects returned by my FetchRequest with the same Entity come out as NSManagedObjects and not DicomStudys? I'm including DicomStudy.h so it should see the object during creation of the model, context, and fetch request. [request setEntity: [[managedObjectModel() entitiesByName] objectForKey:@"Study"]]; Thanks in advance, -Stephen

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• Help with game development. Render loop?

  - by John

  Hello, I'm working on a simple game, this is my first game project. Most of the samples I find have a Render Loop where all the game logic is made too and I just don't like this. Let's say I have a ball with X=0, and a wall in X=10 and in a slow machine, the first loop places the ball in X=7 and in a second loop, it places the ball in X=14. It would just crash the game! Is this "render loop" the right way to make games? Should I write code to check for things like this in every frame? Example, new frame X=14, last frame have X=7, so I should check if there's anything from X=7 to X=14?? I was thinking that I should have a separated thread for the game logic and in the render loop, I should just "take a snapshot" of the current game logic and display that, no? How do you guys, experienced game developers work around this? thanks!

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• ruby on rails group by with null values problem

  - by winter sun

  I have an hour table in witch I store user time tracking information, the table consists from the following cells project_id task_id (optional can be null) worker_id reported_date working_hours each worker enters sevral records per day so generally the table is looking like this id project_id worker_id task_id reported_date working hours; == =========== ========= ========= ============= ============== 1 1 1 1 10/10/2011 4 2 1 1 1 10/10/2011 14 3 1 1 10/10/2011 4 4 1 1 10/10/2011 14 the task_id is not a must field so there can be times when the user is not selecting it and ther task_id cell is empty now i need to display the data by using group by clouse so the resualt will be somthing like this project_id worker_id task_id working hours ========== ========= ========= ============== 1 1 1 18 1 1 18 I did the folowing group by condition @group_hours=Hour.group('project_id,worker_id,task_id)').select('project_id, task_id ,worker_id,sum(working_hours)as working_hours_sum') My view looks like this <% @group_hours.each do |b| % <%= b.project.name if b.project % <%= b.worker.First_name if b.worker % <%= b.task.name if b.task % <%= b.working_hours_sum % <%end% This it is working but only if the task_id is not null when task id is null it present all the records without grouping them like this project_id worker_id task_id working hours =========== ========= ========= ============== 1 1 1 18 1 1 4 1 1 14 I will appreciate any kind of solution to this problem

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• MSSQL choosing row (from group) with max value

  - by sriehl

  I have a large database and am putting together a report of the data. I have aggregated and summed the data from many tables to get two tables that look like the following. id | code | value id | code | value 13 | AA | 0.5 13 | AC | 2.0 13 | AB | 1.0 14 | AB | 1.5 14 | AA | 2.0 13 | AA | 0.5 15 | AB | 0.5 15 | AB | 3.0 15 | AD | 1.5 15 | AA | 1.0 I need to get a list of id's, with the code (sumed from both tables) with the largest value. 13 | AC 14 | AA 15 | AB There are 4-6 thousand records and it is not possible to change the original tables. I'm not too worried about performance as I only need to run it a few times a year.

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• how to substract numbers from levels

  - by romunov

  Dear SOFers, I would like to cut a vector of values ranging 0-70 to x number of categories, and would like the upper limit of each category. So far, I have tried this using cut() and am trying to extract the limits from levels. I have a list of levels, from which I would like to extract the second number from each level. How can I extract the values between space and ] (which is the number I'm interested in)? I have: > levels(bins) [1] "(-0.07,6.94]" "(6.94,14]" "(14,21]" "(21,28]" "(28,35]" [6] "(35,42]" "(42,49]" "(49,56]" "(56,63.1]" "(63.1,70.1]" and would like to get: [1] 6.94 14 21 28 35 42 49 56 63.1 70.1 Or is there a better way of calculating the upper bounds of categories?

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• How to use group by for grouping varchar data.

  - by Shantanu Gupta

  I have a table that contains some data given below pk_map_id preferences ImmediateParent Department_Id -------------------- -------------------- -------------------- -------------------- 20 14 5 1 21 15 5 1 22 16 6 1 23 9 4 2 24 4 3 2 25 24 20 2 26 25 20 2 27 23 13 2 I want to group my records on behalf of department then immediate parent then preferences each seperated by ',' i.e. department Immediate Parent preferences 1 5,6 14,15,16 2 4,3,20,13 9,4,24,25,23 and this table also Immediate parent preferences 5 14,15 6 16 4 9 3 4 20 24,25 13 13 In actual scenario all these are my ids which are to be replaced by their string fields. I am using sql server 2k5

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• How to Import data from Excel 2010 to SQL table

  - by user2950101

  I am using this , Insert into smst(id,mobile,day,month,year,time,model,imie1,imie2,FullMessage)select * FROM OPENROWSET('Microsoft.Ace.OLEDB.14.0','Excel 14.0;Database=L:\SMS.xlsx;HDR=YES', 'SELECT id,mobile,day,month,year,time,model,imie1,imie2,FullMessage FROM [Sheet2]') Could you please help and find the error? sql error : 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('Microsoft.Ace.OLEDB.14.0','Excel 14.0;Database=L:\SMS.xlsx;HDR=YES', 'SELECT i' at line 1 i am using excel 2010.

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• Fastest way to get an Excel Range of Rows

  - by gayan

  In a VSTO C# project I want to get a range of rows from a set of row indexes. The row indexes can be for example like "7,8,9,12,14". Then I want the range "7:9,12,14" rows. I now do this: Range rng1 = sheet.get_Range("A7:A9,A12,A14", Type.Missing); rng1 = rng1.EntireRow; But it's a bit inefficient due to string handling in range specification. sheet.Rows["7:9"] works but I can't give this sheet.Rows["7:9,12,14"] // Fails

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• Mysql query: count and distinct

  - by Azevedo

  I have this hypotetical MySQL table: TABLE cars: (year, color, brand) How do I count # of cars grouped by brand and year? I mean, how can I get to know how many colors are there grouped by brand like: brand "GM": total # of colors: 8. brand "GM": total # of years (grouped together): 14 (meaning there are count of 14 different years). brand "TOYOTA": total # of colors: 3. brand "TOYOTA": total # of years (grouped together): 10 (meaning there are count of 14 different years) I tried playing some queries with COUNT, DISTINCT, GROUP BY but I can't get to it. Actually I'm trying to get the 2 queries... +-------+---------------+ | brand | count(colors) | +-------+---------------+ +-------+--------------+ | brand | count(years) | +-------+--------------+ thanks a lot!

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• How might I assume a "default value" when parsing using boost::spirit?

  - by tJener

  Let's say I have a grammar defined to something like: a b c d where c, and d are optional and default to 14 if not given. Can I get it to automatically return the 14 if the value isn't given? The closest I've come is like the following: qi::rule<Iterator, std::vector<int>(), ascii::space_type> some_rule; some_rule %= >> int_ >> int_ >> -int_ >> -int_; // ... some_other_rule = some_rule[&some_callback_for_int_vectors]; which will then get 0 for the optional values that didn't show up (I believe). I then change consecutive 0s at the end into 14. Not only is this horribly wrong, but its also just not elegant. Is there a better way to do this?

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• A hard Question ?

  - by the-ifl

  Hi Guys , I try To find a solution to a question .... we have a number , example : 20 ... and we have 6 number :{ a ,b , c , d , e , f} < 20 , t try to find all values of these numbers , but only if we can combinate (whit + or -) whit 2 of this numbers and getting all the value below to 20 : for example we choose 31 : a = 22 b = 21 c = 14 d = 11 e = 9 f = 5 we have : 22 - 21 = 1 ; 11 - 9 = 2 ; 14 - 11 = 3 ; 9 - 5 = 4 ; f = 5 ; 11 - 5 = 6 ; 21 - 14 = 7 ; .... .... .... .... .... 21 + 9 = 30 ; 9 + 22 = 31 ;

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• Can't run the ActionBarCompat sample

  - by David Miler

  I am having trouble compiling and running the ActionBarCompat sample of Android 16. I have API level 16 as the build target selected, which seems to build fine, but when I try to debug these errors pop up. Of course I could change the min API level in the manifest, but what would be the point of that? I have made no changes to the sample, so how come it is not working properly? Class requires API level 14 (current min is 3): android.view.ActionProvider SimpleMenuItem.java /ActionBarCompat/src/com/example/android/actionbarcompat line 129 Android Lint Problem Class requires API level 14 (current min is 3): android.view.ActionProvider SimpleMenuItem.java /ActionBarCompat/src/com/example/android/actionbarcompat line 134 Android Lint Problem Class requires API level 14 (current min is 3): android.view.MenuItem.OnActionExpandListener SimpleMenuItem.java /ActionBarCompat/src/com/example/android/actionbarcompat line 155 Android Lint Problem I am thoroughly confused, any help would be appreciated.

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• Converting arrays into another format (PHP)

  - by apis17

  Hi.. i want to convert this array Array ( [2] => Array ( ) [4] => Array ( [12] => Array ( ) [13] => Array ( [16] => Array ( ) ) ) [5] => Array ( ) [10] => Array ( ) [14] => Array ( ) ) into this format Array ( [2] => 2 [4] => Array ( [0] => 12 [13] => Array ( [0] => 16 ) ) [5] => 5 [10] => 10 [14] => 14 ) can anybody help? thanks.

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• Working by group by for grouping data into string format

  - by Shantanu Gupta

  I have a table that contains some data given below. It uses a tree like structure i.e. Department SubD1, SubD2 ..... PreSubD1, PreSubD1... PreSubD2, PreSubD2... pk_map_id preferences ImmediateParent Department_Id -------------------- -------------------- -------------------- -------------------- 20 14 5 1 21 15 5 1 22 16 6 1 23 9 4 2 24 4 3 2 25 24 20 2 26 25 20 2 27 23 13 2 I want to group my records on behalf of department then immediate parent then preferences each seperated by ',' i.e. department Immediate Parent preferences 1 5,6 14,15,16 2 4,3,20,13 9,4,24,25,23 and this table also Immediate parent preferences 5 14,15 6 16 4 9 3 4 20 24,25 13 13 In actual scenario all these are my ids which are to be replaced by their string fields. I am using sql server 2k5

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• question on revrse array

  - by davit-datuashvili

  we know algorithm how reverse array of n integers for (int i=0;i<n/2;i++){ swap(a[i],a[n-1-i]): } is this method better according the speed of algorithm or not because swap using xor is more fast then in other method here is code public class swap{ public static void main(String[]args){ int a[]=new int[]{2,4,5,7,8,11,13,12,14,24}; System.out.println(" array at the begining:"); for (int i=0;i<a.length;i++){ System.out.println(a[i]); } for (int j=0;j<a.length/2;j++){ a[j]^=a[a.length-1-j]; a[a.length-1-j]^=a[j]; a[j]^=a[a.length-1-j]; } System.out.println("reversed array:"); for (int j=0;j<a.length;j++){ System.out.println(a[j]); } } } //result array at the begining: 2 4 5 7 8 11 13 12 14 24 reversed array: 24 14 12 13 11 8 7 5 4 2

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• question on reverse array

  - by davit-datuashvili

  we know algorithm how reverse array of n integers for (int i=0;i<n/2;i++){ swap(a[i],a[n-1-i]): } is this method better according the speed of algorithm or not because swap using xor is more fast then in other method here is code public class swap { public static void main(String[]args){ int a[]=new int[]{2,4,5,7,8,11,13,12,14,24}; System.out.println(" array at the begining:"); for (int i=0;i<a.length;i++){ System.out.println(a[i]); } for (int j=0;j<a.length/2;j++){ a[j]^=a[a.length-1-j]; a[a.length-1-j]^=a[j]; a[j]^=a[a.length-1-j]; } System.out.println("reversed array:"); for (int j=0;j<a.length;j++){ System.out.println(a[j]); } } } Result: array at the begining: 2 4 5 7 8 11 13 12 14 24 reversed array: 24 14 12 13 11 8 7 5 4 2

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• PC hangs and reboots from time to time

  - by Bevor

  Hello, I have a very strange problem: Since I have my new PC, I have always had problems with it. From time to time the computer freezes for some seconds and suddendly reboots by itself. I've had this problem since Ubuntu 9.10. The same with 10.04 and 10.10. That's why I don't think it's a software failure because the problem persist too long. It doesn't have anything to do with what I'm doing at this time. Sometimes I listen to music, sometimes I only use Firefox, sometimes I'm running 2 or 3 VMs, sometimes I watch DVD. So it's not isolatable. I could freeze once a day or once a week. I put the PC to the vendor twice(!). The first time they changed my power supply but the problem persisted. The second time they told me that they made some heavy performance tests 50 hours long but they didn't find anything. (How can that be that I have daily freezes with normal usage). The vendor didn't check the hard discs because they used their own disc with Windows. (So they never checked the Linux installation). Yesterday I made some intensive hard disc scans with "SMART" but no errors were found. I ran memtest for 3 times but no errors found. I already had this problem in my old flat, so I doubt that I has something to do with current fluctuation. I already tried another electrical socket and changed to connector strip but the problem persists. At the moment I removed 2 of the RAMs (2x 2GB). In all I have 6GB, 2x2GB and 2x1GB. Could this difference maybe be a problem? Here is a list of my components. I hope that anybody find something I didn't think about yet. And here a list of my components: 1x AMD Phenom II X4 965 Black Edition, 3,4Ghz, Quad Core, S-AM3, Boxed 2x DDR3-RAM 2048MB, PC3-1333 Mhz, CL9, Kingston ValueRAM 2x DDR3-RAM 1024MB, PC3-1333 Mhz, CL9, Kingston ValueRAM 2x SATA II Seagate Barracuda 7200.12, 1TB 32MB Cache = RAID 1 1x DVD ROM SATA LG DH16NSR, 16x/52x 1x DVD-+R/-+RW SATA LG GH-22NS50 1x Cardreader 18in1 1x PCI-E 2.0 GeForce GTS 250, Retail, 1024MB 1x Power Supply ATX 400 Watt, CHIEFTEC APS-400S, 80 Plus 1x Network card PCI Intel PRO/1000GT 10/100/1000 MBit 1x Mainboard Socket-AM3 ASUS M4A79XTD EVO, ATX lshw: description: Desktop Computer product: System Product Name vendor: System manufacturer version: System Version serial: System Serial Number width: 64 bits capabilities: smbios-2.5 dmi-2.5 vsyscall64 vsyscall32 configuration: boot=normal chassis=desktop uuid=80E4001E-8C00-002C-AA59-E0CB4EBAC29A *-core description: Motherboard product: M4A79XTD EVO vendor: ASUSTeK Computer INC. physical id: 0 version: Rev X.0X serial: MT709CK11101196 slot: To Be Filled By O.E.M. *-firmware description: BIOS vendor: American Megatrends Inc. physical id: 0 version: 0704 (11/25/2009) size: 64KiB capacity: 960KiB capabilities: isa pci pnp apm upgrade shadowing escd cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb ls120boot zipboot biosbootspecification *-cpu description: CPU product: AMD Phenom(tm) II X4 965 Processor vendor: Advanced Micro Devices [AMD] physical id: 4 bus info: cpu@0 version: AMD Phenom(tm) II X4 965 Processor serial: To Be Filled By O.E.M. slot: AM3 size: 800MHz capacity: 3400MHz width: 64 bits clock: 200MHz capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp x86-64 3dnowext 3dnow constant_tsc rep_good nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock nrip_save cpufreq *-cache:0 description: L1 cache physical id: 5 slot: L1-Cache size: 512KiB capacity: 512KiB capabilities: pipeline-burst internal varies data *-cache:1 description: L2 cache physical id: 6 slot: L2-Cache size: 2MiB capacity: 2MiB capabilities: pipeline-burst internal varies unified *-cache:2 description: L3 cache physical id: 7 slot: L3-Cache size: 6MiB capacity: 6MiB capabilities: pipeline-burst internal varies unified *-memory description: System Memory physical id: 36 slot: System board or motherboard size: 2GiB *-bank:0 description: DIMM Synchronous 1333 MHz (0.8 ns) product: ModulePartNumber00 vendor: Manufacturer00 physical id: 0 serial: SerNum00 slot: DIMM0 size: 1GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: DIMM Synchronous 1333 MHz (0.8 ns) product: ModulePartNumber01 vendor: Manufacturer01 physical id: 1 serial: SerNum01 slot: DIMM1 size: 1GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:2 description: DIMM [empty] product: ModulePartNumber02 vendor: Manufacturer02 physical id: 2 serial: SerNum02 slot: DIMM2 *-bank:3 description: DIMM [empty] product: ModulePartNumber03 vendor: Manufacturer03 physical id: 3 serial: SerNum03 slot: DIMM3 *-pci:0 description: Host bridge product: RD780 Northbridge only dual slot PCI-e_GFX and HT1 K8 part vendor: ATI Technologies Inc physical id: 100 bus info: pci@0000:00:00.0 version: 00 width: 32 bits clock: 66MHz *-pci:0 description: PCI bridge product: RD790 PCI to PCI bridge (external gfx0 port A) vendor: ATI Technologies Inc physical id: 2 bus info: pci@0000:00:02.0 version: 00 width: 32 bits clock: 33MHz capabilities: pci pm pciexpress msi ht normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:a000(size=4096) memory:f8000000-fbbfffff ioport:d0000000(size=268435456) *-display description: VGA compatible controller product: G92 [GeForce GTS 250] vendor: nVidia Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a2 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nvidia latency=0 resources: irq:18 memory:fa000000-faffffff memory:d0000000-dfffffff memory:f8000000-f9ffffff ioport:ac00(size=128) memory:fbbe0000-fbbfffff *-pci:1 description: PCI bridge product: RD790 PCI to PCI bridge (PCI express gpp port C) vendor: ATI Technologies Inc physical id: 6 bus info: pci@0000:00:06.0 version: 00 width: 32 bits clock: 33MHz capabilities: pci pm pciexpress msi ht normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:41 ioport:b000(size=4096) memory:fbc00000-fbcfffff ioport:f6f00000(size=1048576) *-network description: Ethernet interface product: RTL8111/8168B PCI Express Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 03 serial: e0:cb:4e:ba:c2:9a size: 10MB/s capacity: 1GB/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half latency=0 link=no multicast=yes port=MII speed=10MB/s resources: irq:45 ioport:b800(size=256) memory:f6fff000-f6ffffff memory:f6ff8000-f6ffbfff memory:fbcf0000-fbcfffff *-pci:2 description: PCI bridge product: RD790 PCI to PCI bridge (PCI express gpp port D) vendor: ATI Technologies Inc physical id: 7 bus info: pci@0000:00:07.0 version: 00 width: 32 bits clock: 33MHz capabilities: pci pm pciexpress msi ht normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:42 ioport:c000(size=4096) memory:fbd00000-fbdfffff *-firewire description: FireWire (IEEE 1394) product: VT6315 Series Firewire Controller vendor: VIA Technologies, Inc. physical id: 0 bus info: pci@0000:03:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress ohci bus_master cap_list configuration: driver=firewire_ohci latency=0 resources: irq:19 memory:fbdff800-fbdfffff ioport:c800(size=256) *-pci:3 description: PCI bridge product: RD790 PCI to PCI bridge (PCI express gpp port E) vendor: ATI Technologies Inc physical id: 9 bus info: pci@0000:00:09.0 version: 00 width: 32 bits clock: 33MHz capabilities: pci pm pciexpress msi ht normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:43 ioport:d000(size=4096) memory:fbe00000-fbefffff *-ide description: IDE interface product: 88SE6121 SATA II Controller vendor: Marvell Technology Group Ltd. physical id: 0 bus info: pci@0000:04:00.0 version: b2 width: 32 bits clock: 33MHz capabilities: ide pm msi pciexpress bus_master cap_list configuration: driver=pata_marvell latency=0 resources: irq:17 ioport:dc00(size=8) ioport:d880(size=4) ioport:d800(size=8) ioport:d480(size=4) ioport:d400(size=16) memory:fbeffc00-fbefffff *-storage description: SATA controller product: SB700/SB800 SATA Controller [IDE mode] vendor: ATI Technologies Inc physical id: 11 bus info: pci@0000:00:11.0 logical name: scsi0 logical name: scsi2 version: 00 width: 32 bits clock: 66MHz capabilities: storage msi ahci_1.0 bus_master cap_list emulated configuration: driver=ahci latency=64 resources: irq:44 ioport:9000(size=8) ioport:8000(size=4) ioport:7000(size=8) ioport:6000(size=4) ioport:5000(size=16) memory:f7fffc00-f7ffffff *-disk:0 description: ATA Disk product: ST31000528AS vendor: Seagate physical id: 0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: CC38 serial: 9VP3WD9Z size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=000ad206 *-volume:0 UNCLAIMED description: Linux filesystem partition vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 version: 1.0 serial: 81839235-21ea-4853-90a4-814779f49000 size: 972MiB capacity: 972MiB capabilities: primary ext2 initialized configuration: filesystem=ext2 modified=2010-12-06 18:32:58 mounted=2010-11-01 07:05:10 state=unknown *-volume:1 UNCLAIMED description: Linux swap volume physical id: 2 bus info: scsi@0:0.0.0,2 version: 1 serial: 22b881d5-6f5c-484d-94e8-e231896fa91b size: 486MiB capacity: 486MiB capabilities: primary nofs swap initialized configuration: filesystem=swap pagesize=4096 *-volume:2 UNCLAIMED description: EXT3 volume vendor: Linux physical id: 3 bus info: scsi@0:0.0.0,3 version: 1.0 serial: ad5b0daf-11e8-4f8f-8598-4e89da9c0d84 size: 47GiB capacity: 47GiB capabilities: primary journaled extended_attributes large_files recover ext3 ext2 initialized configuration: created=2010-02-16 20:42:29 filesystem=ext3 modified=2010-11-29 17:02:34 mounted=2010-12-06 18:32:50 state=clean *-volume:3 UNCLAIMED description: Extended partition physical id: 4 bus info: scsi@0:0.0.0,4 size: 882GiB capacity: 882GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume UNCLAIMED description: Linux filesystem partition physical id: 5 capacity: 882GiB *-disk:1 description: ATA Disk product: ST31000528AS vendor: Seagate physical id: 1 bus info: scsi@2:0.0.0 logical name: /dev/sdb version: CC38 serial: 9VP3SCPF size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=000ad206 *-volume:0 UNCLAIMED description: Linux filesystem partition vendor: Linux physical id: 1 bus info: scsi@2:0.0.0,1 version: 1.0 serial: 81839235-21ea-4853-90a4-814779f49000 size: 972MiB capacity: 972MiB capabilities: primary ext2 initialized configuration: filesystem=ext2 modified=2010-12-06 18:32:58 mounted=2010-11-01 07:05:10 state=unknown *-volume:1 UNCLAIMED description: Linux swap volume physical id: 2 bus info: scsi@2:0.0.0,2 version: 1 serial: 22b881d5-6f5c-484d-94e8-e231896fa91b size: 486MiB capacity: 486MiB capabilities: primary nofs swap initialized configuration: filesystem=swap pagesize=4096 *-volume:2 UNCLAIMED description: EXT3 volume vendor: Linux physical id: 3 bus info: scsi@2:0.0.0,3 version: 1.0 serial: ad5b0daf-11e8-4f8f-8598-4e89da9c0d84 size: 47GiB capacity: 47GiB capabilities: primary journaled extended_attributes large_files recover ext3 ext2 initialized configuration: created=2010-02-16 20:42:29 filesystem=ext3 modified=2010-11-29 17:02:34 mounted=2010-12-06 18:32:50 state=clean *-volume:3 UNCLAIMED description: Extended partition physical id: 4 bus info: scsi@2:0.0.0,4 size: 882GiB capacity: 882GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume UNCLAIMED description: Linux filesystem partition physical id: 5 capacity: 882GiB *-usb:0 description: USB Controller product: SB700/SB800 USB OHCI0 Controller vendor: ATI Technologies Inc physical id: 12 bus info: pci@0000:00:12.0 version: 00 width: 32 bits clock: 66MHz capabilities: ohci bus_master configuration: driver=ohci_hcd latency=64 resources: irq:16 memory:f7ffd000-f7ffdfff *-usb:1 description: USB Controller product: SB700 USB OHCI1 Controller vendor: ATI Technologies Inc physical id: 12.1 bus info: pci@0000:00:12.1 version: 00 width: 32 bits clock: 66MHz capabilities: ohci bus_master configuration: driver=ohci_hcd latency=64 resources: irq:16 memory:f7ffe000-f7ffefff *-usb:2 description: USB Controller product: SB700/SB800 USB EHCI Controller vendor: ATI Technologies Inc physical id: 12.2 bus info: pci@0000:00:12.2 version: 00 width: 32 bits clock: 66MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=64 resources: irq:17 memory:f7fff800-f7fff8ff *-usb:3 description: USB Controller product: SB700/SB800 USB OHCI0 Controller vendor: ATI Technologies Inc physical id: 13 bus info: pci@0000:00:13.0 version: 00 width: 32 bits clock: 66MHz capabilities: ohci bus_master configuration: driver=ohci_hcd latency=64 resources: irq:18 memory:f7ffb000-f7ffbfff *-usb:4 description: USB Controller product: SB700 USB OHCI1 Controller vendor: ATI Technologies Inc physical id: 13.1 bus info: pci@0000:00:13.1 version: 00 width: 32 bits clock: 66MHz capabilities: ohci bus_master configuration: driver=ohci_hcd latency=64 resources: irq:18 memory:f7ffc000-f7ffcfff *-usb:5 description: USB Controller product: SB700/SB800 USB EHCI Controller vendor: ATI Technologies Inc physical id: 13.2 bus info: pci@0000:00:13.2 version: 00 width: 32 bits clock: 66MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=64 resources: irq:19 memory:f7fff400-f7fff4ff *-serial UNCLAIMED description: SMBus product: SBx00 SMBus Controller vendor: ATI Technologies Inc physical id: 14 bus info: pci@0000:00:14.0 version: 3c width: 32 bits clock: 66MHz capabilities: ht cap_list configuration: latency=0 *-ide description: IDE interface product: SB700/SB800 IDE Controller vendor: ATI Technologies Inc physical id: 14.1 bus info: pci@0000:00:14.1 logical name: scsi5 version: 00 width: 32 bits clock: 66MHz capabilities: ide msi bus_master cap_list emulated configuration: driver=pata_atiixp latency=64 resources: irq:16 ioport:1f0(size=8) ioport:3f6 ioport:170(size=8) ioport:376 ioport:ff00(size=16) *-cdrom:0 description: DVD reader product: DVDROM DH16NS30 vendor: HL-DT-ST physical id: 0.0.0 bus info: scsi@5:0.0.0 logical name: /dev/cdrom1 logical name: /dev/dvd1 logical name: /dev/scd0 logical name: /dev/sr0 version: 1.00 capabilities: removable audio dvd configuration: ansiversion=5 status=nodisc *-cdrom:1 description: DVD-RAM writer product: DVDRAM GH22NS50 vendor: HL-DT-ST physical id: 0.1.0 bus info: scsi@5:0.1.0 logical name: /dev/cdrom logical name: /dev/cdrw logical name: /dev/dvd logical name: /dev/dvdrw logical name: /dev/scd1 logical name: /dev/sr1 version: TN02 capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram configuration: ansiversion=5 status=nodisc *-multimedia description: Audio device product: SBx00 Azalia (Intel HDA) vendor: ATI Technologies Inc physical id: 14.2 bus info: pci@0000:00:14.2 version: 00 width: 64 bits clock: 33MHz capabilities: pm bus_master cap_list configuration: driver=HDA Intel latency=64 resources: irq:16 memory:f7ff4000-f7ff7fff *-isa description: ISA bridge product: SB700/SB800 LPC host controller vendor: ATI Technologies Inc physical id: 14.3 bus info: pci@0000:00:14.3 version: 00 width: 32 bits clock: 66MHz capabilities: isa bus_master configuration: latency=0 *-pci:4 description: PCI bridge product: SBx00 PCI to PCI Bridge vendor: ATI Technologies Inc physical id: 14.4 bus info: pci@0000:00:14.4 version: 00 width: 32 bits clock: 66MHz capabilities: pci subtractive_decode bus_master resources: ioport:e000(size=4096) memory:fbf00000-fbffffff *-network description: Ethernet interface product: 82541PI Gigabit Ethernet Controller vendor: Intel Corporation physical id: 5 bus info: pci@0000:05:05.0 logical name: eth1 version: 05 serial: 00:1b:21:56:f3:60 size: 100MB/s capacity: 1GB/s width: 32 bits clock: 66MHz capabilities: pm pcix bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000 driverversion=7.3.21-k6-NAPI duplex=full firmware=N/A ip=192.168.1.2 latency=64 link=yes mingnt=255 multicast=yes port=twisted pair speed=100MB/s resources: irq:20 memory:fbfe0000-fbffffff memory:fbfc0000-fbfdffff ioport:ec00(size=64) memory:fbfa0000-fbfbffff *-usb:6 description: USB Controller product: SB700/SB800 USB OHCI2 Controller vendor: ATI Technologies Inc physical id: 14.5 bus info: pci@0000:00:14.5 version: 00 width: 32 bits clock: 66MHz capabilities: ohci bus_master configuration: driver=ohci_hcd latency=64 resources: irq:18 memory:f7ffa000-f7ffafff *-pci:1 description: Host bridge product: Family 10h Processor HyperTransport Configuration vendor: Advanced Micro Devices [AMD] physical id: 101 bus info: pci@0000:00:18.0 version: 00 width: 32 bits clock: 33MHz *-pci:2 description: Host bridge product: Family 10h Processor Address Map vendor: Advanced Micro Devices [AMD] physical id: 102 bus info: pci@0000:00:18.1 version: 00 width: 32 bits clock: 33MHz *-pci:3 description: Host bridge product: Family 10h Processor DRAM Controller vendor: Advanced Micro Devices [AMD] physical id: 103 bus info: pci@0000:00:18.2 version: 00 width: 32 bits clock: 33MHz *-pci:4 description: Host bridge product: Family 10h Processor Miscellaneous Control vendor: Advanced Micro Devices [AMD] physical id: 104 bus info: pci@0000:00:18.3 version: 00 width: 32 bits clock: 33MHz configuration: driver=k10temp resources: irq:0 *-pci:5 description: Host bridge product: Family 10h Processor Link Control vendor: Advanced Micro Devices [AMD] physical id: 105 bus info: pci@0000:00:18.4 version: 00 width: 32 bits clock: 33MHz *-scsi physical id: 1 bus info: usb@2:3 logical name: scsi8 capabilities: emulated scsi-host configuration: driver=usb-storage *-disk:0 description: SCSI Disk physical id: 0.0.0 bus info: scsi@8:0.0.0 logical name: /dev/sdc *-disk:1 description: SCSI Disk physical id: 0.0.1 bus info: scsi@8:0.0.1 logical name: /dev/sdd *-disk:2 description: SCSI Disk physical id: 0.0.2 bus info: scsi@8:0.0.2 logical name: /dev/sde *-disk:3 description: SCSI Disk physical id: 0.0.3 bus info: scsi@8:0.0.3 logical name: /dev/sdf *-network DISABLED description: Ethernet interface physical id: 1 logical name: vboxnet0 serial: 0a:00:27:00:00:00 capabilities: ethernet physical configuration: broadcast=yes multicast=yes

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• Why is Java EE 6 better than Spring ?

  - by arungupta

  Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V    at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20)    at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies.  I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite  2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly.  Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

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• C#: System.Lazy&lt;T&gt; and the Singleton Design Pattern

  - by James Michael Hare

  So we've all coded a Singleton at one time or another.  It's a really simple pattern and can be a slightly more elegant alternative to global variables.  Make no mistake, Singletons can be abused and are often over-used -- but occasionally you find a Singleton is the most elegant solution. For those of you not familiar with a Singleton, the basic Design Pattern is that a Singleton class is one where there is only ever one instance of the class created.  This means that constructors must be private to avoid users creating their own instances, and a static property (or method in languages without properties) is defined that returns a single static instance. 1: public class Singleton 2: { 3: // the single instance is defined in a static field 4: private static readonly Singleton _instance = new Singleton(); 5:  6: // constructor private so users can't instantiate on their own 7: private Singleton() 8: { 9: } 10:  11: // read-only property that returns the static field 12: public static Singleton Instance 13: { 14: get 15: { 16: return _instance; 17: } 18: } 19: } This is the most basic singleton, notice the key features: Static readonly field that contains the one and only instance. Constructor is private so it can only be called by the class itself. Static property that returns the single instance. Looks like it satisfies, right?  There's just one (potential) problem.  C# gives you no guarantee of when the static field _instance will be created.  This is because the C# standard simply states that classes (which are marked in the IL as BeforeFieldInit) can have their static fields initialized any time before the field is accessed.  This means that they may be initialized on first use, they may be initialized at some other time before, you can't be sure when. So what if you want to guarantee your instance is truly lazy.  That is, that it is only created on first call to Instance?  Well, there's a few ways to do this.  First we'll show the old ways, and then talk about how .Net 4.0's new System.Lazy<T> type can help make the lazy-Singleton cleaner. Obviously, we could take on the lazy construction ourselves, but being that our Singleton may be accessed by many different threads, we'd need to lock it down. 1: public class LazySingleton1 2: { 3: // lock for thread-safety laziness 4: private static readonly object _mutex = new object(); 5:  6: // static field to hold single instance 7: private static LazySingleton1 _instance = null; 8:  9: // property that does some locking and then creates on first call 10: public static LazySingleton1 Instance 11: { 12: get 13: { 14: if (_instance == null) 15: { 16: lock (_mutex) 17: { 18: if (_instance == null) 19: { 20: _instance = new LazySingleton1(); 21: } 22: } 23: } 24:  25: return _instance; 26: } 27: } 28:  29: private LazySingleton1() 30: { 31: } 32: } This is a standard double-check algorithm so that you don't lock if the instance has already been created.  However, because it's possible two threads can go through the first if at the same time the first time back in, you need to check again after the lock is acquired to avoid creating two instances. Pretty straightforward, but ugly as all heck.  Well, you could also take advantage of the C# standard's BeforeFieldInit and define your class with a static constructor.  It need not have a body, just the presence of the static constructor will remove the BeforeFieldInit attribute on the class and guarantee that no fields are initialized until the first static field, property, or method is called.   1: public class LazySingleton2 2: { 3: // because of the static constructor, this won't get created until first use 4: private static readonly LazySingleton2 _instance = new LazySingleton2(); 5:  6: // Returns the singleton instance using lazy-instantiation 7: public static LazySingleton2 Instance 8: { 9: get { return _instance; } 10: } 11:  12: // private to prevent direct instantiation 13: private LazySingleton2() 14: { 15: } 16:  17: // removes BeforeFieldInit on class so static fields not 18: // initialized before they are used 19: static LazySingleton2() 20: { 21: } 22: } Now, while this works perfectly, I hate it.  Why?  Because it's relying on a non-obvious trick of the IL to guarantee laziness.  Just looking at this code, you'd have no idea that it's doing what it's doing.  Worse yet, you may decide that the empty static constructor serves no purpose and delete it (which removes your lazy guarantee).  Worse-worse yet, they may alter the rules around BeforeFieldInit in the future which could change this. So, what do I propose instead?  .Net 4.0 adds the System.Lazy type which guarantees thread-safe lazy-construction.  Using System.Lazy<T>, we get: 1: public class LazySingleton3 2: { 3: // static holder for instance, need to use lambda to construct since constructor private 4: private static readonly Lazy<LazySingleton3> _instance 5: = new Lazy<LazySingleton3>(() => new LazySingleton3()); 6:  7: // private to prevent direct instantiation. 8: private LazySingleton3() 9: { 10: } 11:  12: // accessor for instance 13: public static LazySingleton3 Instance 14: { 15: get 16: { 17: return _instance.Value; 18: } 19: } 20: } Note, you need your lambda to call the private constructor as Lazy's default constructor can only call public constructors of the type passed in (which we can't have by definition of a Singleton).  But, because the lambda is defined inside our type, it has access to the private members so it's perfect. Note how the Lazy<T> makes it obvious what you're doing (lazy construction), instead of relying on an IL generation side-effect.  This way, it's more maintainable.  Lazy<T> has many other uses as well, obviously, but I really love how elegant and readable it makes the lazy Singleton.

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• Getting time in ubuntu

  - by user2578666

  include #include <stdio.h> int GetTime() { struct timespec tsp; clock_gettime(CLOCK_REALTIME, &tsp); //Call clock_gettime to fill tsp fprintf(stdout, "time=%d.%d\n", tsp.tv_sec, tsp.tv_nsec); fflush(stdout); } I am trying to compile the above code but it keeps throwing the error: time.c: In function ‘GetTime’: time.c:12:4: warning: implicit declaration of function ‘clock_gettime’ [-Wimplicit-function-declaration] time.c:12:18: error: ‘CLOCK_REALTIME’ undeclared (first use in this function) time.c:12:18: note: each undeclared identifier is reported only once for each function it appears in time.c:14:4: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘__time_t’ [-Wformat] time.c:14:4: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long int’ [-Wformat] I have tried compiling with -lrt flag and -std=gnu99. Nothing works.

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• SQL SERVER – Finding Shortest Distance between Two Shapes using Spatial Data Classes – Ramsetu or Adam’s Bridge

  - by pinaldave

  Recently I was reading excellent blog post by Lenni Lobel on Spatial Database. He has written very interesting function ShortestLineTo in Spatial Data Classes. I really loved this new feature of the finding shortest distance between two shapes in SQL Server. Following is the example which is same as Lenni talk on his blog article . DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -26, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -22, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) GO When you run this script SQL Server finds out the shortest distance between two shapes and draws the line. We are using STBuffer so we can see the connecting line clearly. Now let us modify one of the object and then we see how the connecting shortest line works. DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -30, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -22, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) GO Now once again let us modify one of the script and see how the shortest line to works. DECLARE @Shape1 geometry = 'POLYGON ((-20 -30, -3 -30, 14 -28, 20 -40, -20 -30))' DECLARE @Shape2 geometry = 'POLYGON ((-18 -20, 0 -10, 4 -12, 10 -20, 2 -18, -18 -20))' SELECT @Shape1 UNION ALL SELECT @Shape2 UNION ALL SELECT @Shape1.ShortestLineTo(@Shape2).STBuffer(.25) SELECT @Shape1.STDistance(@Shape2) GO You can see as the objects are changing the shortest lines are moving at appropriate place. I think even though this is very small feature this is really cool know. While I was working on this example, I suddenly thought about distance between Sri Lanka and India. The distance is very short infect it is less than 30 km by sea. I decided to map India and Sri Lanka using spatial data classes. To my surprise the plotted shortest line is the same as Adam’s Bridge or Ramsetu. Adam’s Bridge starts as chain of shoals from the Dhanushkodi tip of India’s Pamban Island and ends at Sri Lanka’s Mannar Island. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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• C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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• nvidia driver problem after update

  - by baltasar

  I know there are a lot of posts about nvdia driver, but I am not able to solve this. I updated my configuration yesterday, September 27th, and it seems that a new nvidia driver was involved. The updated completed with an error, and invited me to send a bug report automatically. I send it, but it finally said that there was no place to send the bug report to. Today I updated again, and a new kernel was there. Then I rebooted. I found a desktop in 640x480 with a horrible, unreadable font. I run jockey and tried to go back to another version of the nvidia driver, but it seems that none of the drivers listed there are suddenly valid. I have the x-swat repository enabled, because I remember that I had a similar issue in the past that was only to be solved with the newest driver. jockey log: 2012-09-28 11:22:24,747 DEBUG: Selecting previously unselected package nvidia-173. (Reading database ... 536311 files and directories currently installed.) Unpacking nvidia-173 (from .../nvidia-173_173.14.35-0ubuntu0.2_i386.deb) ... Processing triggers for man-db ... Setting up nvidia-173 (173.14.35-0ubuntu0.2) ... Loading new nvidia-173-173.14.35 DKMS files... Building only for 3.2.0-32-generic-pae Building for architecture i686 Building initial module for 3.2.0-32-generic-pae Error! Bad return status for module build on kernel: 3.2.0-32-generic-pae (i686) Consult /var/lib/dkms/nvidia-173/173.14.35/build/make.log for more information. Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... 2012-09-28 11:22:25,143 WARNING: modinfo for module nvidia_173 failed: ERROR: modinfo: could not find module nvidia_173 2012-09-28 11:22:25,143 ERROR: XorgDriverHandler.enable(): package or module not installed, aborting 2012-09-28 11:22:53,613 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:22:53,613 DEBUG: KMH enabled: False 2012-09-28 11:22:53,629 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:22:53,629 DEBUG: KMH enabled: False 2012-09-28 11:23:01,943 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:01,943 DEBUG: KMH enabled: False 2012-09-28 11:23:01,962 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:01,963 DEBUG: KMH enabled: False 2012-09-28 11:23:01,998 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-173/ld.so.conf other target alt None other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:01,998 DEBUG: nvidia_173_updates is not the alternative in use 2012-09-28 11:23:02,044 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,044 DEBUG: nvidia_current is not the alternative in use 2012-09-28 11:23:02,066 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,066 DEBUG: nvidia_current is not the alternative in use 2012-09-28 11:23:02,106 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-173/ld.so.conf other target alt None other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,106 DEBUG: nvidia_current_updates is not the alternative in use 2012-09-28 11:23:02,157 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,157 DEBUG: KMH enabled: False 2012-09-28 11:23:02,177 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,178 DEBUG: KMH enabled: False 2012-09-28 11:23:02,245 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,245 DEBUG: KMH enabled: False 2012-09-28 11:23:02,272 DEBUG: NVidia(nvidia_173).enabled(): target_alt /usr/lib/nvidia-173/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-173/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,273 DEBUG: KMH enabled: False 2012-09-28 11:23:02,303 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-173/ld.so.conf other target alt None other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,303 DEBUG: nvidia_173_updates is not the alternative in use 2012-09-28 11:23:02,330 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,410 DEBUG: nvidia_current is not the alternative in use 2012-09-28 11:23:02,427 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-173/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,428 DEBUG: nvidia_current is not the alternative in use 2012-09-28 11:23:02,457 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-173/ld.so.conf other target alt None other current alt /usr/lib/nvidia-173/alt_ld.so.conf 2012-09-28 11:23:02,458 DEBUG: nvidia_current_updates is not the alternative in use

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