concurrent queue - Page 51

HP Deskjet 3600: Offline and won't stop blinking and won't print.

- by George Bailey

Using Vista and an HP Deskjet 3600 on USB connection Normally when I unplug the printer, I open the printer queue and in the title bar it says "HP Deskjet 3600 - Use Printer Offline" then the offline message will go away and it will start printing. But for some reason, the bower button light is continually blinking. (this is the only light on the machine). The printer queue says "HP Deskjet 3600 - Offline" and when I unplug it it says "HP Deskjet 3600 - Offline - Use Printer Offline". I have tried unplugging it for a few hours, also tried turning it off for a few hours. Does anybody know what the single word Offline means? Does anybody know how I can clear out the memory in the Printer? (this is my guess as to what is causing the problem)

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Throwing TRIM support in Ubuntu guest at Win7-Virtualbox host

- by user141472

I have VirtualBox 4.1.14 on Windows 7 as host, and Ubuntu server 11.10 as guest. System was installed at traditional HDD years ago (and upgraded later), but now it's at SSD as expanding drive. There is "AHCI" and "it's SSD" features enabled in SATA controller. Problem is, this expanding drive growth to it's almost max size (90% of it), but actually in VM only about 50% spent. Also, guest VM does not recognize /dev/sda as SSD, /sys/block/sda/queue/rotational says "1", /sys/block/sda/queue/discard_* all says "0". And, of course, I cannot run fstrim /, it says that operation not supported. Is there some trick to enable TRIM support in my guest system without reinstalling it?

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Sporadic EXC_BAD_INSTRUCTION (SIGILL) when in 64 bit mode

- by Ger Teunis

For some reason for a low-number of users (say 1 in a few hundred) the application seem to crash when run in 64bit mode on a Snow Leopard 10.6.3 I've attached the code, but please remind IT IS NOT A CODE issue. The crashed seem to be random in com.apple.AppKit at random locations and random moments. Anyone else had any experiences? Using GCC compiler of Xcode 3.2.2 Crash #1 of user Code Type: X86-64 (Native) Parent Process: launchd [90] Date/Time: 2010-05-02 04:12:59.708 -0500 OS Version: Mac OS X 10.6.3 (10D573) Report Version: 6 Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Application Specific Information: objc[232]: alt handlers in objc runtime are buggy! Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 libobjc.A.dylib 0x00007fff874dd8b7 _objc_fatal + 238 1 libobjc.A.dylib 0x00007fff874de57c objc_addExceptionHandler + 1026 2 com.apple.CoreFoundation 0x00007fff83914212 _CFDoExceptionOperation + 402 3 com.apple.AppKit 0x00007fff87afc55d _NSAppKitLock + 79 4 com.apple.AppKit 0x00007fff87bd1f93 +[NSColorList _findColorListNamed:forDeviceType:] + 86 5 com.apple.AppKit 0x00007fff87b9d304 -[NSCatalogColor colorUsingColorSpaceName:device:] + 255 6 com.apple.AppKit 0x00007fff87c985ad -[NSLayoutManager(NSPrivate) _drawGlyphsForGlyphRange:atPoint:parameters:] + 4764 7 com.apple.AppKit 0x00007fff87c5d79c -[NSTextView drawRect:] + 1839 8 com.apple.AppKit 0x00007fff87c5ce2e -[NSTextView _drawRect:clip:] + 2343 9 com.apple.AppKit 0x00007fff87be4485 -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 1325 10 com.apple.AppKit 0x00007fff87be47ef -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 2199 11 com.apple.AppKit 0x00007fff87be2b57 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 767 12 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 13 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 14 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 15 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 16 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 17 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 18 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 19 com.apple.AppKit 0x00007fff87be3a23 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555 20 com.apple.AppKit 0x00007fff87be2678 -[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 254 21 com.apple.AppKit 0x00007fff87bdef27 -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] + 2683 22 com.apple.AppKit 0x00007fff87b58777 -[NSView displayIfNeeded] + 969 23 com.apple.AppKit 0x00007fff87b53622 _handleWindowNeedsDisplay + 678 24 com.apple.Foundation 0x00007fff8600fa4d __NSFireTimer + 114 25 com.apple.CoreFoundation 0x00007fff83908708 __CFRunLoopRun + 6488 26 com.apple.CoreFoundation 0x00007fff839068df CFRunLoopRunSpecific + 575 27 com.apple.HIToolbox 0x00007fff821b5ada RunCurrentEventLoopInMode + 333 28 com.apple.HIToolbox 0x00007fff821b58df ReceiveNextEventCommon + 310 29 com.apple.HIToolbox 0x00007fff821b5798 BlockUntilNextEventMatchingListInMode + 59 30 com.apple.AppKit 0x00007fff87b28a2a _DPSNextEvent + 708 31 com.apple.AppKit 0x00007fff87b28379 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155 32 com.apple.AppKit 0x00007fff87d37060 -[NSTextView mouseDown:] + 8426 33 com.apple.AppKit 0x00007fff87c21f1b -[NSWindow sendEvent:] + 5409 34 com.apple.AppKit 0x00007fff87b57662 -[NSApplication sendEvent:] + 4719 35 com.apple.AppKit 0x00007fff87aee0aa -[NSApplication run] + 474 36 com.apple.AppKit 0x00007fff87ae6d7c NSApplicationMain + 364 37 com.NZBVortex.NZBVortex 0x0000000100000fe0 start + 52 Crash #2 from same user moments later Code Type: X86-64 (Native) Parent Process: launchd [76] Date/Time: 2010-05-02 11:59:33.226 +0200 OS Version: Mac OS X 10.6.3 (10D573) Report Version: 6 Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Application Specific Information: objc[4360]: alt handlers in objc runtime are buggy! Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 libobjc.A.dylib 0x00007fff8015d8b7 _objc_fatal + 238 1 libobjc.A.dylib 0x00007fff8015e57c objc_addExceptionHandler + 1026 2 com.apple.CoreFoundation 0x00007fff85367212 _CFDoExceptionOperation + 402 3 com.apple.AppKit 0x00007fff840b5f2f -[NSViewHierarchyLock lockForReadingWithExceptionHandler:] + 478 4 com.apple.AppKit 0x00007fff8420753e -[NSConcreteTextStorage _lockForReading] + 243 5 com.apple.AppKit 0x00007fff841e1449 -[NSLayoutManager(NSPrivate) _fillGlyphHoleForCharacterRange:startGlyphIndex:desiredNumberOfCharacters:] + 320 6 com.apple.AppKit 0x00007fff840e204a _NSFastFillAllGlyphHolesForGlyphRange + 719 7 com.apple.AppKit 0x00007fff841e10e2 _NSFastFillAllLayoutHolesUpToEndOfContainerForGlyphIndex + 653 8 com.apple.AppKit 0x00007fff841e0c72 -[NSLayoutManager textContainerForGlyphAtIndex:effectiveRange:] + 243 9 com.apple.AppKit 0x00007fff840f6786 -[NSLayoutManager glyphRangeForTextContainer:] + 286 10 com.apple.AppKit 0x00007fff846664a9 -[NSToolTipStringDrawingLayoutManager _sizeWithSize:attributedString:] + 883 11 com.apple.AppKit 0x00007fff84665dad +[NSToolTipStringDrawingLayoutManager sizeForDisplayingAttributedString:] + 354 12 com.apple.AppKit 0x00007fff84667292 -[NSToolTipManager displayToolTip:] + 616 13 com.apple.AppKit 0x00007fff846657d4 toolTipTimerFired + 114 14 com.apple.CoreFoundation 0x00007fff8535b708 __CFRunLoopRun + 6488 15 com.apple.CoreFoundation 0x00007fff853598df CFRunLoopRunSpecific + 575 16 com.apple.HIToolbox 0x00007fff88510ada RunCurrentEventLoopInMode + 333 17 com.apple.HIToolbox 0x00007fff885108df ReceiveNextEventCommon + 310 18 com.apple.HIToolbox 0x00007fff88510798 BlockUntilNextEventMatchingListInMode + 59 19 com.apple.AppKit 0x00007fff840d1a2a _DPSNextEvent + 708 20 com.apple.AppKit 0x00007fff840d1379 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155 21 com.apple.AppKit 0x00007fff8409705b -[NSApplication run] + 395 22 com.apple.AppKit 0x00007fff8408fd7c NSApplicationMain + 364 23 com.NZBVortex.NZBVortex 0x0000000100000fe0 start + 52 Weirdly enough the crashes seem to go away for these users when running the code in 32 bit mode. Any suggestions other then running the application in 32 bit only? Please do not dilute the feedback by asking for or blaming the code, the code is 100% solid, guaranteed! No memory leaks, the crashes clearly are triggered in 32 bit mode only just after start inside the AppKit itself like deep inside NSThread sleep's callstack.

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How to directly rotate CVImageBuffer image in IOS 4 without converting to UIImage?

- by Ian Charnas

I am using OpenCV 2.2 on the iPhone to detect faces. I'm using the IOS 4's AVCaptureSession to get access to the camera stream, as seen in the code that follows. My challenge is that the video frames come in as CVBufferRef (pointers to CVImageBuffer) objects, and they come in oriented as a landscape, 480px wide by 300px high. This is fine if you are holding the phone sideways, but when the phone is held in the upright position I want to rotate these frames 90 degrees clockwise so that OpenCV can find the faces correctly. I could convert the CVBufferRef to a CGImage, then to a UIImage, and then rotate, as this person is doing: Rotate CGImage taken from video frame However that wastes a lot of CPU. I'm looking for a faster way to rotate the images coming in, ideally using the GPU to do this processing if possible. Any ideas? Ian Code Sample: -(void) startCameraCapture { // Start up the face detector faceDetector = [[FaceDetector alloc] initWithCascade:@"haarcascade_frontalface_alt2" withFileExtension:@"xml"]; // Create the AVCapture Session session = [[AVCaptureSession alloc] init]; // create a preview layer to show the output from the camera AVCaptureVideoPreviewLayer *previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session]; previewLayer.frame = previewView.frame; previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill; [previewView.layer addSublayer:previewLayer]; // Get the default camera device AVCaptureDevice* camera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; // Create a AVCaptureInput with the camera device NSError *error=nil; AVCaptureInput* cameraInput = [[AVCaptureDeviceInput alloc] initWithDevice:camera error:&error]; if (cameraInput == nil) { NSLog(@"Error to create camera capture:%@",error); } // Set the output AVCaptureVideoDataOutput* videoOutput = [[AVCaptureVideoDataOutput alloc] init]; videoOutput.alwaysDiscardsLateVideoFrames = YES; // create a queue besides the main thread queue to run the capture on dispatch_queue_t captureQueue = dispatch_queue_create("catpureQueue", NULL); // setup our delegate [videoOutput setSampleBufferDelegate:self queue:captureQueue]; // release the queue. I still don't entirely understand why we're releasing it here, // but the code examples I've found indicate this is the right thing. Hmm... dispatch_release(captureQueue); // configure the pixel format videoOutput.videoSettings = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA], (id)kCVPixelBufferPixelFormatTypeKey, nil]; // and the size of the frames we want // try AVCaptureSessionPresetLow if this is too slow... [session setSessionPreset:AVCaptureSessionPresetMedium]; // If you wish to cap the frame rate to a known value, such as 10 fps, set // minFrameDuration. videoOutput.minFrameDuration = CMTimeMake(1, 10); // Add the input and output [session addInput:cameraInput]; [session addOutput:videoOutput]; // Start the session [session startRunning]; } - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection { // only run if we're not already processing an image if (!faceDetector.imageNeedsProcessing) { // Get CVImage from sample buffer CVImageBufferRef cvImage = CMSampleBufferGetImageBuffer(sampleBuffer); // Send the CVImage to the FaceDetector for later processing [faceDetector setImageFromCVPixelBufferRef:cvImage]; // Trigger the image processing on the main thread [self performSelectorOnMainThread:@selector(processImage) withObject:nil waitUntilDone:NO]; } }

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Rx IObservable buffering to smooth out bursts of events

- by Dan

I have an Observable sequence that produces events in rapid bursts (ie: five events one right after another, then a long delay, then another quick burst of events, etc.). I want to smooth out these bursts by inserting a short delay between events. Imagine the following diagram as an example: Raw: --oooo--------------ooooo-----oo----------------ooo| Buffered: --o--o--o--o--------o--o--o--o--o--o--o---------o--o--o| My current approach is to generate a metronome-like timer via Observable.Interval() that signals when it's ok to pull another event from the raw stream. The problem is that I can't figure out how to then combine that timer with my raw unbuffered observable sequence. IObservable.Zip() is close to doing what I want, but it only works so long as the raw stream is producing events faster than the timer. As soon as there is a significant lull in the raw stream, the timer builds up a series of unwanted events that then immediately pair up with the next burst of events from the raw stream. Ideally, I want an IObservable extension method with the following function signature that produces the bevaior I've outlined above. Now, come to my rescue StackOverflow :) public static IObservable<T> Buffered(this IObservable<T> src, TimeSpan minDelay) PS. I'm brand new to Rx, so my apologies if this is a trivially simple question... 1. Simple yet flawed approach Here's my initial naive and simplistic solution that has quite a few problems: public static IObservable<T> Buffered<T>(this IObservable<T> source, TimeSpan minDelay) { Queue<T> q = new Queue<T>(); source.Subscribe(x => q.Enqueue(x)); return Observable.Interval(minDelay).Where(_ => q.Count > 0).Select(_ => q.Dequeue()); } The first obvious problem with this is that the IDisposable returned by the inner subscription to the raw source is lost and therefore the subscription can't be terminated. Calling Dispose on the IDisposable returned by this method kills the timer, but not the underlying raw event feed that is now needlessly filling the queue with nobody left to pull events from the queue. The second problem is that there's no way for exceptions or end-of-stream notifications to be propogated through from the raw event stream to the buffered stream - they are simply ignored when subscribing to the raw source. And last but not least, now I've got code that wakes up periodically regardless of whether there is actually any work to do, which I'd prefer to avoid in this wonderful new reactive world. 2. Way overly complex appoach To solve the problems encountered in my initial simplistic approach, I wrote a much more complicated function that behaves much like IObservable.Delay() (I used .NET Reflector to read that code and used it as the basis of my function). Unfortunately, a lot of the boilerplate logic such as AnonymousObservable is not publicly accessible outside the system.reactive code, so I had to copy and paste a lot of code. This solution appears to work, but given its complexity, I'm less confident that its bug free. I just can't believe that there isn't a way to accomplish this using some combination of the standard Reactive extensions. I hate feeling like I'm needlessly reinventing the wheel, and the pattern I'm trying to build seems like a fairly standard one.

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One letter game problem?

- by Alex K

Recently at a job interview I was given the following problem: Write a script capable of running on the command line as python It should take in two words on the command line (or optionally if you'd prefer it can query the user to supply the two words via the console). Given those two words: a. Ensure they are of equal length b. Ensure they are both words present in the dictionary of valid words in the English language that you downloaded. If so compute whether you can reach the second word from the first by a series of steps as follows a. You can change one letter at a time b. Each time you change a letter the resulting word must also exist in the dictionary c. You cannot add or remove letters If the two words are reachable, the script should print out the path which leads as a single, shortest path from one word to the other. You can /usr/share/dict/words for your dictionary of words. My solution consisted of using breadth first search to find a shortest path between two words. But apparently that wasn't good enough to get the job :( Would you guys know what I could have done wrong? Thank you so much. import collections import functools import re def time_func(func): import time def wrapper(*args, **kwargs): start = time.time() res = func(*args, **kwargs) timed = time.time() - start setattr(wrapper, 'time_taken', timed) return res functools.update_wrapper(wrapper, func) return wrapper class OneLetterGame: def __init__(self, dict_path): self.dict_path = dict_path self.words = set() def run(self, start_word, end_word): '''Runs the one letter game with the given start and end words. ''' assert len(start_word) == len(end_word), \ 'Start word and end word must of the same length.' self.read_dict(len(start_word)) path = self.shortest_path(start_word, end_word) if not path: print 'There is no path between %s and %s (took %.2f sec.)' % ( start_word, end_word, find_shortest_path.time_taken) else: print 'The shortest path (found in %.2f sec.) is:\n=> %s' % ( self.shortest_path.time_taken, ' -- '.join(path)) def _bfs(self, start): '''Implementation of breadth first search as a generator. The portion of the graph to explore is given on demand using get_neighboors. Care was taken so that a vertex / node is explored only once. ''' queue = collections.deque([(None, start)]) inqueue = set([start]) while queue: parent, node = queue.popleft() yield parent, node new = set(self.get_neighbours(node)) - inqueue inqueue = inqueue | new queue.extend([(node, child) for child in new]) @time_func def shortest_path(self, start, end): '''Returns the shortest path from start to end using bfs. ''' assert start in self.words, 'Start word not in dictionnary.' assert end in self.words, 'End word not in dictionnary.' paths = {None: []} for parent, child in self._bfs(start): paths[child] = paths[parent] + [child] if child == end: return paths[child] return None def get_neighbours(self, word): '''Gets every word one letter away from the a given word. We do not keep these words in memory because bfs accesses a given vertex only once. ''' neighbours = [] p_word = ['^' + word[0:i] + '\w' + word[i+1:] + '$' for i, w in enumerate(word)] p_word = '|'.join(p_word) for w in self.words: if w != word and re.match(p_word, w, re.I|re.U): neighbours += [w] return neighbours def read_dict(self, size): '''Loads every word of a specific size from the dictionnary into memory. ''' for l in open(self.dict_path): l = l.decode('latin-1').strip().lower() if len(l) == size: self.words.add(l) if __name__ == '__main__': import sys if len(sys.argv) not in [3, 4]: print 'Usage: python one_letter_game.py start_word end_word' else: g = OneLetterGame(dict_path = '/usr/share/dict/words') try: g.run(*sys.argv[1:]) except AssertionError, e: print e

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jQuery gallery scrolling effect with ease

- by Sebastian Otarola

So, I got this page from a friend and I think the gallery is amazingly done. Too bad it's in Flash ; http://selected.com/en/#/collection/homme/ Now, I'm trying to replicate the effect with jQuery. I've made all the loco searches on google one could think of. Zooming the picture is not a problem, the problem lies within the scrolling, how they come together at the ease part. I'm looking for solution in how to make the thumbnail animate when you scroll the page, they drag behind and infront of each other in a very subtle way - I've got (With a lot of help from Whirl3d in the jQuery-irc channel) this for the scrollup/down part of the mouse but the scrolling goes haywire; I Thought I post it here where I've come many times to get answers to a lot of questions and code-errors. This is my first post in stackoverflow and I know you guys are geniuses! Give it a shot! Thanks in advance! jQuery Part $(document).ready(function() { var fronts=$(".front"); var backs=$(".back"); var tempScrollTop, currentScrollTop = 0; $(document).scroll(function () { currentScrollTop = $(document).scrollTop(); if (tempScrollTop < currentScrollTop) { //Scroll down fronts.animate({marginTop:"-=100"},{duration:500, queue:false, easing:"easeOutBack"}); backs.animate({marginTop:"-=100"}, {duration:300, queue:false, easing:"easeOutBack"}); console.log('scroll down'); } else if (tempScrollTop > currentScrollTop) { //scroll up fronts.animate({marginTop:"+=100"},{duration:500, queue:false, easing:"easeOutBack"}); backs.animate({marginTop:"+=100"}, {duration:300, queue:false, easing:"easeOutBack"}); console.log('scroll up'); } tempScrollTop = currentScrollTop ;}) ;}); The HTML <html> <head> <link rel="stylesheet" type="text/css" href="style.css" /> <script type="text/javascript" src="http://code.jquery.com/jquery-1.7.2.min.js"></script> <script type="text/javascript" src="http://www.paigeharvey.net/assets/js/jquery.easing.js"></script> <script type="text/javascript" src="gallery.js"></script> <title>Parallax testing image gallery</title> </head> <body> <div class="container"> <div class='box front'>First Group</div> <div class='box back'>First Group</div> <div class='box front'>First Group</div> <div class='box back'>First Group</div> <br style="clear:both"/> <div class='box front'>Second Group</div> <div class='box back'>Second Group</div> <div class='box front'>Second Group</div> <div class='box back'>Second Group</div> <br style="clear:both"/> <div class='box front'>Third Group</div> <div class='box back'>Third Group</div> <div class='box front'>Third Group</div> <br style="clear:both"/> </div> </body> And finally the CSS Part .container {margin: auto; width: 410px; border: 1px solid red;} .box.front{border: 1px solid red;background-color:Black;color:white;z-Index:500;} .box.back {border: 1px solid green;z-Index:300;background-color:white;} .box {float:left; text-align:center; width:100px; height:100px;}

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Performance issues with jms and spring integration. What is wrong with the following configuration?

- by user358448

I have a jms producer, which generates many messages per second, which are sent to amq persistent queue and are consumed by single consumer, which needs to process them sequentially. But it seems that the producer is much faster than the consumer and i am having performance and memory problems. Messages are fetched very very slowly and the consuming seems to happen on intervals (the consumer "asks" for messages in polling fashion, which is strange?!) Basically everything happens with spring integration. Here is the configuration at the producer side. First stake messages come in stakesInMemoryChannel, from there, they are filtered throw the filteredStakesChannel and from there they are going into the jms queue (using executor so the sending will happen in separate thread) <bean id="stakesQueue" class="org.apache.activemq.command.ActiveMQQueue"> <constructor-arg name="name" value="${jms.stakes.queue.name}" /> </bean> <int:channel id="stakesInMemoryChannel" /> <int:channel id="filteredStakesChannel" > <int:dispatcher task-executor="taskExecutor"/> </int:channel> <bean id="stakeFilterService" class="cayetano.games.stake.StakeFilterService"/> <int:filter input-channel="stakesInMemoryChannel" output-channel="filteredStakesChannel" throw-exception-on-rejection="false" expression="true"/> <jms:outbound-channel-adapter channel="filteredStakesChannel" destination="stakesQueue" delivery-persistent="true" explicit-qos-enabled="true" /> <task:executor id="taskExecutor" pool-size="100" /> The other application is consuming the messages like this... The messages come in stakesInputChannel from the jms stakesQueue, after that they are routed to 2 separate channels, one persists the message and the other do some other stuff, lets call it "processing". <bean id="stakesQueue" class="org.apache.activemq.command.ActiveMQQueue"> <constructor-arg name="name" value="${jms.stakes.queue.name}" /> </bean> <jms:message-driven-channel-adapter channel="stakesInputChannel" destination="stakesQueue" acknowledge="auto" concurrent-consumers="1" max-concurrent-consumers="1" /> <int:publish-subscribe-channel id="stakesInputChannel" /> <int:channel id="persistStakesChannel" /> <int:channel id="processStakesChannel" /> <int:recipient-list-router id="customRouter" input-channel="stakesInputChannel" timeout="3000" ignore-send-failures="true" apply-sequence="true" > <int:recipient channel="persistStakesChannel"/> <int:recipient channel="processStakesChannel"/> </int:recipient-list-router> <bean id="prefetchPolicy" class="org.apache.activemq.ActiveMQPrefetchPolicy"> <property name="queuePrefetch" value="${jms.broker.prefetch.policy}" /> </bean> <bean id="connectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory"> <property name="targetConnectionFactory"> <bean class="org.apache.activemq.ActiveMQConnectionFactory"> <property name="brokerURL" value="${jms.broker.url}" /> <property name="prefetchPolicy" ref="prefetchPolicy" /> <property name="optimizeAcknowledge" value="true" /> <property name="useAsyncSend" value="true" /> </bean> </property> <property name="sessionCacheSize" value="10"/> <property name="cacheProducers" value="false"/> </bean>

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Ubuntu 13.10 install ISO crashes on VirtualBox Mac 4.3

- by John Allsup

Does anybody know what to do about this? Machine is a 2008 Core 2 Duo iMac with 4GB RAM. (And 64bit Debian 7 boots OK, but I've not tried installing under the latest version of VirtualBox as I have just upgraded VBox today.) VirtualBox 4.3, upon trying to boot a machine with the Ubuntu 13.10 (64bit) iso (with the VM configured for Ubuntu 64bit) crashes, with the following information: Failed to open a session for the virtual machine Ubuntu64. The VM session was aborted. Result Code: NS_ERROR_FAILURE (0x80004005) Component: SessionMachine Interface: ISession {12f4dcdb-12b2-4ec1-b7cd-ddd9f6c5bf4d} === Head of crash dump is below Process: VirtualBoxVM [716] Path: /Applications/VirtualBox.app/Contents/MacOS/VirtualBoxVM Identifier: VirtualBoxVM Version: ??? (???) Code Type: X86 (Native) Parent Process: VBoxSVC [644] Date/Time: 2013-10-17 22:58:23.679 +0100 OS Version: Mac OS X 10.6.8 (10K549) Report Version: 6 Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000040 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 com.apple.CoreFoundation 0x92a25c03 CFSetApplyFunction + 83 1 com.apple.framework.IOKit 0x95557ad4 __IOHIDManagerInitialEnumCallback + 69 2 com.apple.CoreFoundation 0x92a2442b __CFRunLoopDoSources0 + 1563 3 com.apple.CoreFoundation 0x92a21eef __CFRunLoopRun + 1071 4 com.apple.CoreFoundation 0x92a213c4 CFRunLoopRunSpecific + 452 5 com.apple.CoreFoundation 0x92a211f1 CFRunLoopRunInMode + 97 6 com.apple.HIToolbox 0x98eb5e04 RunCurrentEventLoopInMode + 392 7 com.apple.HIToolbox 0x98eb5af5 ReceiveNextEventCommon + 158 8 com.apple.HIToolbox 0x98eb5a3e BlockUntilNextEventMatchingListInMode + 81 9 com.apple.AppKit 0x9971b595 _DPSNextEvent + 847 10 com.apple.AppKit 0x9971add6 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 156 11 com.apple.AppKit 0x996dd1f3 -[NSApplication run] + 821 12 QtGuiVBox 0x019f19e1 QEventDispatcherMac::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 1505 13 QtCoreVBox 0x018083b1 QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 65 14 QtCoreVBox 0x018086fa QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 170 15 QtGuiVBox 0x01eea9e5 QDialog::exec() + 261 16 VirtualBox.dylib 0x011234b8 TrustedMain + 1108104 17 VirtualBox.dylib 0x01126d68 TrustedMain + 1122616 18 VirtualBox.dylib 0x010fac19 TrustedMain + 942057 19 VirtualBox.dylib 0x010f9b3d TrustedMain + 937741 20 VirtualBox.dylib 0x010f81dd TrustedMain + 931245 21 VirtualBox.dylib 0x010f85b8 TrustedMain + 932232 22 VirtualBox.dylib 0x0109d4f8 TrustedMain + 559304 23 VirtualBox.dylib 0x0101521e TrustedMain + 1518 24 ...virtualbox.app.VirtualBoxVM 0x00002e7e start + 2766 25 ...virtualbox.app.VirtualBoxVM 0x000024b5 start + 261 26 ...virtualbox.app.VirtualBoxVM 0x000023e5 start + 53 ==== And please somebody fix the code so that you can just delimit large blocks of code at the start and the end without indenting every line manually by 4 spaces.

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Extended JMS Support

- by ACShorten

In a previous post I discussed the real time JMS integration we added in FW4.1 and also as patches for FW2.2. There are some additional aspects of this integration I did not mention which may be of interest: JMS Topic Support - In the post I concentrated on talking about JMS Queue support but failed to mention that the MDB and outgoing real time JMS also supports JMS Topics. JMS Queues are typically used for point to point decoupled integration and JMS Topics are used for hub integration that uses Publish and Subscribe. JMS Selector Support - By default the MDB will process every message from a JMS resource (Queue or Topic). If you want to alter this behaviour to selectively filter JMS messages then you can use JMS Selectors to specify the conditions for the MDB to selectively process JMS messages based upon conditions. JMS Selectors allow filters to be specified on elements in the JMS Header and JMS Message Properties using SQL like syntax. Note: JMS Selectors do not support filters on the body elements. JMS Header Support - It is possible to place custom information in the JMS Header and JMS Message Properties for outgoing messages (so that other applications can use JMS selectors if necessary as well). This is only available when installing Patches 11888040 (FW4.1) and 11850795 (FW2.2). These facilities coupled with the JMS facilities described in the previous posts gives the product integration capabilities in JMS which can be used with configuration rather than coding. Of course, the JMS facility I have described can also be used in conjunction with SOA Suite to provide greater levels of traceability and management.

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2 way SSL between SOA and OSB

- by Johnny Shum

If you have a need to use 2 way SSL between SOA composite and external partner links, you can follow these steps. Create the identity keystores, trust keystores, and server certificates. Setup keystores and SSL on WebLogic Setup server to use 2 way SSL Configure your SOA composite's partner link to use 2 way SSL Configure SOA engine two ways SSL In this case, I use SOA and OSB for the test. I started with a separate OSB and SOA domains. I deployed two soap based proxies on OSB and two composites on SOA. In SOA, one composite invokes a OSB proxy service, the other is invoked by the OSB. Similarly, in OSB, one proxy invokes a SOA composite and the other is invoked by SOA. 1. Create the identity keystores, trust keystores and the server certificates Since this is a development environment, I use JDK's keytool to create the stores and use self signing certificate. For production environment, you should use certificates from a trusted certificate authority like Verisign. I created a script below to show what is needed in this step. The only requirement is when creating the SOA identity certificate, you MUST use the alias mykey. STOREPASS=welcome1KEYPASS=welcome1# generate identity keystore for soa and osb. Note: For SOA, you MUST use alias mykeyecho "creating stores"keytool -genkey -alias mykey -keyalg "RSA" -sigalg "SHA1withRSA" -dname "CN=soa, C=US" -keystore soa-default-keystore.jks -storepass $STOREPASS -keypass $KEYPASS keytool -genkey -alias osbkey -keyalg "RSA" -sigalg "SHA1withRSA" -dname "CN=osb, C=US" -keystore osb-default-keystore.jks -storepass $STOREPASS -keypass $KEYPASS# listing keystore contentsecho "listing stores contents"keytool -list -alias mykey -keystore soa-default-keystore.jks -storepass $STOREPASSkeytool -list -alias osbkey -keystore osb-default-keystore.jks -storepass $STOREPASS# exporting certs from storesecho "export certs from stores"keytool -exportcert -alias mykey -keystore soa-default-keystore.jks -storepass $STOREPASS -file soacert.derkeytool -exportcert -alias osbkey -keystore osb-default-keystore.jks -storepass $STOREPASS -file osbcert.der # import certs to trust storesecho "import certs"keytool -importcert -alias osbkey -keystore soa-trust-keystore.jks -storepass $STOREPASS -file osbcert.der -keypass $KEYPASSkeytool -importcert -alias mykey -keystore osb-trust-keystore.jks -storepass $STOREPASS -file soacert.der -keypass $KEYPASS SOA suite uses the JDK's SSL implementation for outbound traffic instead of the WebLogic's implementation. You will need to import the partner's public cert into the trusted keystore used by SOA. The default trusted keystore for SOA is DemoTrust.jks and it is located in $MW_HOME/wlserver_10.3/server/lib. (This is set in the startup script -Djavax.net.ssl.trustStore). If you use your own trusted keystore, then you will need to import it into your own trusted keystore. keytool -importcert -alias osbkey -keystore $MW_HOME/wlserver_10.3/server/lib/DemoTrust.jks -storepass DemoTrustKeyStorePassPhrase -file osbcert.der -keypass $KEYPASS If you do not perform this step, you will encounter this exception in runtime when SOA invokes OSB service using 2 way SSL Message send failed: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target 2. Setup keystores and SSL on WebLogic First, you will need to login to the WebLogic console, navigate to the server's configuration->Keystore's tab. Change the Keystores type to Custom Identity and Custom Trust and enter the rest of the fields. Then you navigate to the SSL tab, enter the fields in the identity section and expand the Advanced section. Since I am using self signing cert on my VM enviornment, I disabled Hostname verification. In real production system, this should not be the case. I also enabled the option "Use Server Certs", so that the application uses the server cert to initiate https traffic (it is important to enable this in OSB). Last, you enable SSL listening port in the Server's configuration->General tab. 3. Setup server to use 2 way SSL If you follow the screen shot in previous step, you can see in the Server->Configuration->SSL->Advanced section, there is an option for Two Way Client Cert Behavior, you should set this to Client Certs Requested and Enforced. Repeat step 2 and 3 done on OSB. After all these configurations, you have to restart all the servers. 4. Configure your SOA composite's partner link to use 2 way SSL You do this by modifying the composite.xml in your project, locate the partner's link reference and add the property oracle.soa.two.way.ssl.enabled. <reference name="callosb" ui:wsdlLocation="helloword.wsdl"> <interface.wsdl interface="http://www.examples.com/wsdl/HelloService.wsdl#wsdl.interface(Hello_PortType)"/> <binding.ws port="http://www.examples.com/wsdl/HelloService.wsdl#wsdl.endpoint(Hello_Service/Hello_Port)" location="helloword.wsdl" soapVersion="1.1"> <property name="weblogic.wsee.wsat.transaction.flowOption" type="xs:string" many="false">WSDLDriven</property> <property name="oracle.soa.two.way.ssl.enabled">true</property> </binding.ws> </reference> In OSB, you should have checked the HTTPS required flag in the proxy's transport configuration. After this, rebuilt the composite jar file and ready to deploy in the EM console later. 5. Configure SOA engine two ways SSL Oracle SOA Suite uses both Oracle WebLogic Server and Sun Secure Socket Layer (SSL) stacks for two-way SSL configurations. For the inbound web service bindings, Oracle SOA Suite uses the Oracle WebLogic Server infrastructure and, therefore, the Oracle WebLogic Server libraries for SSL. This is already done by step 2 and 3 in the previous section. For the outbound web service bindings, Oracle SOA Suite uses JRF HttpClient and, therefore, the Sun JDK libraries for SSL. You do this by configuring the SOA Engine in the Enterprise Manager Console, select soa-infra->SOA Administration->Common Properties Then click at the link at the bottom of the page: "More SOA Infra Advances Infrastructure Configuration Properties" and then enter the full path of soa identity keystore in the value field of the KeyStoreLocation attribute. Click Apply and Return then navigate to the domain->security->credential. Here, you provide the password to the keystore. Note: the alias of the certficate must be mykey as described in step 1, so you only need to provide the password to the identity keystore. You accomplish this by: Click Create Map In the Map Name field, enter SOA, and click OK Click Create Key Enter the following details where the password is the password for the SOA identity keystore. 6. Test and Trouble Shooting Once the setup is complete and server restarted, you can deploy the composite in the EM console and test it. In case of error, you can read the server log file to determine the cause of the error. For example, If you have not setup step 5 and test 2 way SSL, you will see this in the log when invoking OSB from BPEL: java.lang.Exception: oracle.sysman.emSDK.webservices.wsdlapi.SoapTestException: oracle.fabric.common.FabricInvocationException: Unable to access the following endpoint(s): https://localhost.localdomain:7002/default/helloword ####<Sep 22, 2012 2:07:37 PM CDT> <Error> <oracle.soa.bpel.engine.ws> <rhel55> <AdminServer> <[ACTIVE] ExecuteThread: '1' for queue: 'weblogic.kernel.Default (self-tuning)'> <<anonymous>> <BEA1-0AFDAEF20610F8FD89C5> ............ <11d1def534ea1be0:-4034173:139ef56d9f0:-8000-00000000000002ec> <1348340857956> <BEA-000000> <got FabricInvocationException sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target If you have not enable WebLogic SSL to use server certificate in the console and invoke SOA composite from OSB using two ways SSL, you will see this error: ####<Sep 22, 2012 2:07:37 PM CDT> <Warning> <Security> <rhel55> <AdminServer> <[ACTIVE] ExecuteThread: '6' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <11d1def534ea1be0:-51f5c76a:139ef5e1e1a:-8000-00000000000000e2> <1348340857776> <BEA-090485> <CERTIFICATE_UNKNOWN alert was received from localhost.localdomain - 127.0.0.1. The peer has an unspecified issue with the certificate. SSL debug tracing should be enabled on the peer to determine what the issue is.> ####<Sep 22, 2012 2:07:37 PM CDT> <Warning> <Security> <rhel55> <AdminServer> <[ACTIVE] ExecuteThread: '6' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <11d1def534ea1be0:-51f5c76a:139ef5e1e1a:-8000-00000000000000e4> <1348340857786> <BEA-090485> <CERTIFICATE_UNKNOWN alert was received from localhost.localdomain - 127.0.0.1. The peer has an unspecified issue with the certificate. SSL debug tracing should be enabled on the peer to determine what the issue is.> ####<Sep 22, 2012 2:27:21 PM CDT> <Warning> <Security> <rhel55> <AdminServer> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<anonymous>> <> <11d1def534ea1be0:-51f5c76a:139ef5e1e1a:-8000-0000000000000124> <1348342041926> <BEA-090497> <HANDSHAKE_FAILURE alert received from localhost - 127.0.0.1. Check both sides of the SSL configuration for mismatches in supported ciphers, supported protocol versions, trusted CAs, and hostname verification settings.> References http://docs.oracle.com/cd/E23943_01/admin.1111/e10226/soacompapp_secure.htm#CHDCFABB Section 5.6.4 http://docs.oracle.com/cd/E23943_01/web.1111/e13707/ssl.htm#i1200848

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Ubuntu One file sync error: SSL Handshake

- by Jay Ó Broin

Ubuntu One repeatedly tries to sync my files but keeps disconnecting before anything is uploaded. Here are some of the messages from syncdaemon.log: 2012-01-08 12:12:34,068 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection started to host fs-2.ubuntuone.com, port 443. 2012-01-08 12:12:34,256 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection made. 2012-01-08 12:12:34,257 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection made. 2012-01-08 12:13:08,832 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection lost, reason: [Failure instance: Traceback (failure with no frames): <class 'OpenSSL.SSL.Error'>: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')]]. 2012-01-08 12:13:08,833 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'protocol_version' failed with the error: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')] 2012-01-08 12:13:08,844 - ubuntuone.SyncDaemon.ActionQueue - WARNING - Connection lost: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')] 2012-01-08 12:13:38,550 - ubuntuone.SyncDaemon.Main - NOTE - ---- MARK (state: <State: 'WAITING' (queues WORKING connection 'With User With Network')>; queue: 1378; hash: 0) ---- 2012-01-08 12:15:08,870 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection started to host fs-2.ubuntuone.com, port 443. 2012-01-08 12:15:09,033 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection made. 2012-01-08 12:15:09,034 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection made. 2012-01-08 12:15:33,676 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection lost, reason: [Failure instance: Traceback (failure with no frames): <class 'OpenSSL.SSL.Error'>: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')]]. 2012-01-08 12:15:33,677 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'protocol_version' failed with the error: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')] 2012-01-08 12:15:33,692 - ubuntuone.SyncDaemon.ActionQueue - WARNING - Connection lost: [('SSL routines', 'SSL23_READ', 'ssl handshake failure')] 2012-01-08 12:15:38,551 - ubuntuone.SyncDaemon.Main - NOTE - ---- MARK (state: <State: 'WAITING' (queues WORKING connection 'With User With Network')>; queue: 1378; hash: 0) ---- I'm using Ubuntu 11.10.

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Reminder: True WCF Asynchronous Operation

- by Sean Feldman

A true asynchronous service operation is not the one that returns void, but the one that is marked as IsOneWay=true using BeginX/EndX asynchronous operations (thanks Krzysztof). To support this sort of fire-and-forget invocation, Windows Communication Foundation offers one-way operations. After the client issues the call, Windows Communication Foundation generates a request message, but no correlated reply message will ever return to the client. As a result, one-way operations can't return values, and any exception thrown on the service side will not make its way to the client. One-way calls do not equate to asynchronous calls. When one-way calls reach the service, they may not be dispatched all at once and may be queued up on the service side to be dispatched one at a time, all according to the service configured concurrency mode behavior and session mode. How many messages (whether one-way or request-reply) the service is willing to queue up is a product of the configured channel and the reliability mode. If the number of queued messages has exceeded the queue's capacity, then the client will block, even when issuing a one-way call. However, once the call is queued, the client is unblocked and can continue executing while the service processes the operation in the background. This usually gives the appearance of asynchronous calls.

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Refactor This (Ugly Code)!

- by Alois Kraus

Ayende has put on his blog some ugly code to refactor. First and foremost it is nearly impossible to reason about other peoples code without knowing the driving forces behind the current code. It is certainly possible to make it much cleaner when potential sources of errors cannot happen in the first place due to good design. I can see what the intention of the code is but I do not know about every brittle detail if I am allowed to reorder things here and there to simplify things. So I decided to make it much simpler by identifying the different responsibilities of the methods and encapsulate it in different classes. The code we need to refactor seems to deal with a handler after a message has been sent to a message queue. The handler does complete the current transaction if there is any and does handle any errors happening there. If during the the completion of the transaction errors occur the transaction is at least disposed. We can enter the handler already in a faulty state where we try to deliver the complete event in any case and signal a failure event and try to resend the message again to the queue if it was not inside a transaction. All is decorated with many try/catch blocks, duplicated code and some state variables to route the program flow. It is hard to understand and difficult to reason about. In other words: This code is a mess and could be written by me if I was under pressure. Here comes to code we want to refactor: private void HandleMessageCompletion( Message message, TransactionScope tx, OpenedQueue messageQueue, Exception exception, Action<CurrentMessageInformation, Exception> messageCompleted, Action<CurrentMessageInformation> beforeTransactionCommit) { var txDisposed = false; if (exception == null) { try { if (tx != null) { if (beforeTransactionCommit != null) beforeTransactionCommit(currentMessageInformation); tx.Complete(); tx.Dispose(); txDisposed = true; } try { if (messageCompleted != null) messageCompleted(currentMessageInformation, exception); } catch (Exception e) { Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e); } return; } catch (Exception e) { Trace.TraceWarning("Failed to complete transaction, moving to error mode"+ e); exception = e; } } try { if (txDisposed == false && tx != null) { Trace.TraceWarning("Disposing transaction in error mode"); tx.Dispose(); } } catch (Exception e) { Trace.TraceWarning("Failed to dispose of transaction in error mode."+ e); } if (message == null) return; try { if (messageCompleted != null) messageCompleted(currentMessageInformation, exception); } catch (Exception e) { Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e); } try { var copy = MessageProcessingFailure; if (copy != null) copy(currentMessageInformation, exception); } catch (Exception moduleException) { Trace.TraceError("Module failed to process message failure: " + exception.Message+ moduleException); } if (messageQueue.IsTransactional == false)// put the item back in the queue { messageQueue.Send(message); } } You can see quite some processing and handling going on there. Yes this looks like real world code one did put together to make things work and he does not trust his callbacks. I guess these are event handlers which are optional and the delegates were extracted from an event to call them back later when necessary. Lets see what the author of this code did intend: private void HandleMessageCompletion( TransactionHandler transactionHandler, MessageCompletionHandler handler, CurrentMessageInformation messageInfo, ErrorCollector errors ) { // commit current pending transaction transactionHandler.CallHandlerAndCommit(messageInfo, errors); // We have an error for a null message do not send completion event if (messageInfo.CurrentMessage == null) return; // Send completion event in any case regardless of errors handler.OnMessageCompleted(messageInfo, errors); // put message back if queue is not transactional transactionHandler.ResendMessageOnError(messageInfo.CurrentMessage, errors); } I did not bother to write the intention here again since the code should be pretty self explaining by now. I have used comments to explain the still nontrivial procedure step by step revealing the real intention about all this complex program flow. The original complexity of the problem domain does not go away but by applying the techniques of SRP (Single Responsibility Principle) and some functional style but we can abstract the necessary complexity away in useful abstractions which make it much easier to reason about it. Since most of the method seems to deal with errors I thought it was a good idea to encapsulate the error state of our current message in an ErrorCollector object which stores all exceptions in a list along with a description what the error all was about in the exception itself. We can log it later or not depending on the log level or whatever. It is really just a simple list that encapsulates the current error state. class ErrorCollector { List<Exception> _Errors = new List<Exception>(); public void Add(Exception ex, string description) { ex.Data["Description"] = description; _Errors.Add(ex); } public Exception Last { get { return _Errors.LastOrDefault(); } } public bool HasError { get { return _Errors.Count > 0; } } } Since the error state is global we have two choices to store a reference in the other helper objects (TransactionHandler and MessageCompletionHandler)or pass it to the method calls when necessary. I did chose the latter one because a second argument does not hurt and makes it easier to reason about the overall state while the helper objects remain stateless and immutable which makes the helper objects much easier to understand and as a bonus thread safe as well. This does not mean that the stored member variables are stateless or thread safe as well but at least our helper classes are it. Most of the complexity is located the transaction handling I consider as a separate responsibility that I delegate to the TransactionHandler which does nothing if there is no transaction or Call the Before Commit Handler Commit Transaction Dispose Transaction if commit did throw In fact it has a second responsibility to resend the message if the transaction did fail. I did see a good fit there since it deals with transaction failures. class TransactionHandler { TransactionScope _Tx; Action<CurrentMessageInformation> _BeforeCommit; OpenedQueue _MessageQueue; public TransactionHandler(TransactionScope tx, Action<CurrentMessageInformation> beforeCommit, OpenedQueue messageQueue) { _Tx = tx; _BeforeCommit = beforeCommit; _MessageQueue = messageQueue; } public void CallHandlerAndCommit(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { if (_Tx != null && !errors.HasError) { try { if (_BeforeCommit != null) { _BeforeCommit(currentMessageInfo); } _Tx.Complete(); _Tx.Dispose(); } catch (Exception ex) { errors.Add(ex, "Failed to complete transaction, moving to error mode"); Trace.TraceWarning("Disposing transaction in error mode"); try { _Tx.Dispose(); } catch (Exception ex2) { errors.Add(ex2, "Failed to dispose of transaction in error mode."); } } } } public void ResendMessageOnError(Message message, ErrorCollector errors) { if (errors.HasError && !_MessageQueue.IsTransactional) { _MessageQueue.Send(message); } } } If we need to change the handling in the future we have a much easier time to reason about our application flow than before. After we did complete our transaction and called our callback we can call the completion handler which is the main purpose of the HandleMessageCompletion method after all. The responsiblity o the MessageCompletionHandler is to call the completion callback and the failure callback when some error has occurred. class MessageCompletionHandler { Action<CurrentMessageInformation, Exception> _MessageCompletedHandler; Action<CurrentMessageInformation, Exception> _MessageProcessingFailure; public MessageCompletionHandler(Action<CurrentMessageInformation, Exception> messageCompletedHandler, Action<CurrentMessageInformation, Exception> messageProcessingFailure) { _MessageCompletedHandler = messageCompletedHandler; _MessageProcessingFailure = messageProcessingFailure; } public void OnMessageCompleted(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { try { if (_MessageCompletedHandler != null) { _MessageCompletedHandler(currentMessageInfo, errors.Last); } } catch (Exception ex) { errors.Add(ex, "An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"); } if (errors.HasError) { SignalFailedMessage(currentMessageInfo, errors); } } void SignalFailedMessage(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { try { if (_MessageProcessingFailure != null) _MessageProcessingFailure(currentMessageInfo, errors.Last); } catch (Exception moduleException) { errors.Add(moduleException, "Module failed to process message failure"); } } } If for some reason I did screw up the logic and we need to call the completion handler from our Transaction handler we can simple add to the CallHandlerAndCommit method a third argument to the MessageCompletionHandler and we are fine again. If the logic becomes even more complex and we need to ensure that the completed event is triggered only once we have now one place the completion handler to capture the state. During this refactoring I simple put things together that belong together and came up with useful abstractions. If you look at the original argument list of the HandleMessageCompletion method I have put many things together: Original Arguments New Arguments Encapsulate Message message CurrentMessageInformation messageInfo Message message TransactionScope tx Action<CurrentMessageInformation> beforeTransactionCommit OpenedQueue messageQueue TransactionHandler transactionHandler TransactionScope tx OpenedQueue messageQueue Action<CurrentMessageInformation> beforeTransactionCommit Exception exception, ErrorCollector errors Action<CurrentMessageInformation, Exception> messageCompleted MessageCompletionHandler handler Action<CurrentMessageInformation, Exception> messageCompleted Action<CurrentMessageInformation, Exception> messageProcessingFailure The reason is simple: Put the things that have relationships together and you will find nearly automatically useful abstractions. I hope this makes sense to you. If you see a way to make it even more simple you can show Ayende your improved version as well.

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WebLogic Weekly for June 20th, 2011

- by james.bayer

Welcome the first the first edition of the WebLogic Weekly. The WebLogic Server team has been trying to extend our community outreach to new mediums like an Oracle WebLogic Youtube Channel (how-to videos and feature showcases), Twitter (sharing WebLogic links, typically blogs), and a Facebook page to do a better job sharing information, providing learning alternatives to product documentation and perhaps most importantly collecting feedback from all of our users using the tools they prefer. This is our attempt to provide a round-up what has been going on in WebLogic over the past week. If you would like to have something shared here, use the #weblogic tag on tweets, post on the Oracle WebLogic facebook page, or comment on these blog entries. Blogs WebLogic Server: Listing Groups of an Authenticated User by Steve Button Weblogic, QBrowser And Topics by Eric Elzinga Weblogic, Topics And (Non)-Durable Subscribers by Eric Elzinga Database Web Service using Toplink DB Provider by Vishal Jain WebLogic Server – Use the Execution Context ID in Applications – Lessons From Hansel and Gretel by James Bayer Getting All Server’s Lifecycle State in a Domain by Jay SenSharma Steps to Move Messages From One Queue To Another Queue Using WLST (Updated Version) by Ravish Mody Events If you want to share a story of something innovative you or your organization has done with WebLogic Server or other Fusion Middleware, you could win a pass to Oracle Open World 2011 and share the story there. See Ruma Sanyal's posting on the Application Grid blog for details. The deadline for submissions is July 22nd, 2011.

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Autoscaling in a modern world…. Part 1

- by Steve Loethen

It has been a while since I have had time to sit down and blog. I need to make sure I take the time. It helps me to focus on technology and not let the administrivia keep me from doing the things I love. I have been focusing on the cloud for the last couple of years. Specifically the PaaS platform from Microsoft called Azure. Time to dig in.. I wanted to explore Autoscaling. Autoscaling is not native part of Azure. The platform has the needed connection points. You can write code that looks at the health and performance of your application components and react to needed scaling changes. But that means you have to write all the code. Luckily, an add on to the Enterprise Library provides a lot of code that gets you a long way to being able to autoscale without having to start from scratch. The tool set is primarily composed of a Autoscaler object that you need to host. This object, when hosted and configured, looks at the performance criteria you specify and adjusts your application based on your needs. Sounds perfect. I started with the a set of HOL’s that gave me a good basis to understand the mechanics. I worked through labs 1 and 2 just to get the feel, but let’s start our saga at the end of lab3. Lab3 end results in a web application, hosted in Azure and a console app running on premise. The web app has a few buttons on it. One set adds messages to a queue, another removes them. A second set of buttons drives processor utilization to 100%. If you want to guess, a safe bet is that the Autoscaler is configured to react to a queue that has filled up or high cpu usage. We will continue our saga in the next post…

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Git-based storage and publishing, infrastructure advice

- by Joel Martinez

I wanted to get some advice on moving a system to "the cloud" ... specifically, I'm looking to move into some of Windows Azure's managed services, as right now I'm managing a VM. Basically, the system operates on some data stored in a github git repository. I'll describe the current architecture: Current system (all hosted on a single server): GitHub - configured with a webhook pointing at ... ASP.NET MVC application - to accept the webhook from git. It pushes a message onto ... Azure service bus Queue - which is drained by ... Windows Service - pulls the message from the queue and ... Fetches the latest data from the git repository (using GitLib2Sharp) onto the local disk and finally ... Operates on the data in git to produce a static HTML website hosted/served by IIS. The system works really well, actually ... but I would like to get out of the business of managing the VM, and move to using some combination of Azure web and worker roles. But because the system relies so heavily on the git repository on the local filesystem, I'm finding it difficult to figure out how to architect in the cloud. I know you can get file system access, so in theory I could just fetch the repository if there's nothing on disk ... but the performance/responsiveness of the system sort of depends on the repository being available and only having to fetch diffs, which is relatively quick. As opposed to periodically having to fetch the entire (somewhat large) git repository if the web or worker role was recycled, or something. So I would love some advice on how you would architect such a system :) Ultimately, the only real requirement is to be able to serve HTML content that's been produced from the contents of a git repository (in a relatively responsive manner, from a publishing perspective) ... please feel free to ask any clarifying questions if there's something I omitted. Thanks!

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Catch Me If You Can

- by Knut Vatsendvik

Suppose you have a Proxy based Web Service using Oracle Service Bus. In a stage in the request pipeline, you are using a Publish action to publish the incoming message to a JMS queue using a Business Service. What if the outbound transport provider throws an exception (outside of your pipeline)? Is your pipeline able to catch the error with an error handler?? This situation could occur because of a faulty connection, suspended queue, or some other reason. Here is the Request Pipeline in our simple test case. With an Error Handler added to the message flow containing a simple Log action. By default, the Publish action will invoke the service in a fire and forget fashion. Therefore any exception that occurs in the outbound transport will go unnoticed as shown in the following Invocation Trace. So what now? In a message flow, you can apply a Routing Options action to modify any or all of the following properties in the outbound request: URI, Quality of Service, Mode, Retry parameters, Message Priority. Now add the Routing Options action to the Request Action as shown below. Click the Routing Options to display its properties in the Properties View. Select the QoS option to set the Quality of Service element. Select Exactly Once to override the default setting, and Republish the project. The invocation will now block until the message is completely processed. Trying the same test case as earlier generates the following Invocation Trace showing that the Error Handler is now triggered.

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Designing a Content-Based ETL Process with .NET and SFDC

- by Patrick

As my firm makes the transition to using SFDC as our main operational system, we've spun together a couple of SFDC portals where we can post customer-specific documents to be viewed at will. As such, we've had the need for pseudo-ETL applications to be implemented that are able to extract metadata from the documents our analysts generate internally (most are industry-standard PDFs, XML, or MS Office formats) and place in networked "queue" folders. From there, our applications scoop of the queued documents and upload them to the appropriate SFDC CRM Content Library along with some select pieces of metadata. I've mostly used DbAmp to broker communication with SFDC (DbAmp is a Linked Server provider that allows you to use SQL conventions to interact with your SFDC Org data). I've been able to create [console] applications in C# that work pretty well, and they're usually structured something like this: static void Main() { // Load parameters from app.config. // Get documents from queue. var files = someInterface.GetFiles(someFilterOrRegexPattern); foreach (var file in files) { // Extract metadata from the file. // Validate some attributes of the file; add any validation errors to an in-memory // structure (e.g. List<ValidationErrors>). if (isValid) { var fileData = File.ReadAllBytes(file); // Upload using some wrapper for an ORM or DAL someInterface.Upload(fileData, meta.Param1, meta.Param2, ...); } else { // Bounce the file } } // Report any validation errors (via message bus or SMTP or some such). } And that's pretty much it. Most of the time I wrap all these operations in a "Worker" class that takes the needed interfaces as constructor parameters. This approach has worked reasonably well, but I just get this feeling in my gut that there's something awful about it and would love some feedback. Is writing an ETL process as a C# Console app a bad idea? I'm also wondering if there are some design patterns that would be useful in this scenario that I'm clearly overlooking. Thanks in advance!

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Distribute Sort Sample Service

- by kaleidoscope

How it works? Using the front-end of the service, a user can specify a size in MB for the input data set to sort. Algorithm CreateAndSplit The CreateAndSplit task generates the input data and stores them as 10 blobs in the utility storage. The URLs to these blobs are packaged as Separate work items and written to the queue. · Separate The Separate task reads the blobs with the random numbers created in the CreateAndSplit task and places the random numbers into buckets. The interval of the numbers that go into one bucket is chosen so that the expected amount of numbers (assuming a uniform distribution of the numbers in the original data set) is around 100 kB. Each bucket is represented as a blob container in utility storage. Whenever there are 10 blobs in one bucket (i.e., the placement in this bucket is complete because we had 10 original splits), the separate task will generate a new Sort task and write the task into the queue. · Sort The Sort task merges all blobs in a single bucket and sorts them using a standard sort algorithm. The result is stored as a blob in utility storage. · Concat The concat task merges the results of all Sort tasks into a single blob. This blob can be downloaded as a text file using this Web page. As the resulting file is presented in text format, the size of the file is likely to be larger than the specified input file. Anish

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Message Driven Bean JMS integration

- by Anthony Shorten

In Oracle Utilities Application Framework V4.1 and above the product introduced the concept of real time JMS integration within the Framework for interfacing. Customer familiar with older versions of the Framework will recall that we used a component called the Multi-purpose Listener (MPL) which was a very light service bus for calling interface channels (including JMS). The MPL is not supplied with all products and customers prefer to use Oracle SOA Suite and native methods rather then MPL. In Oracle Utilities Application Framework V4.1 (and for Oracle Utilities Application Framework V2.2 via Patches 9454971, 9256359, 9672027 and 9838219) we introduced real time JMS integration natively for outbound JMS integration and using Message Driven Beans (MDB) for incoming integration. The outbound integration has not changed a lot between releases where you create an Outbound Message Type to indicate the record types to send out, create a JMS sender (though now you use the Real Time Sender) and then create an External System definition to complete the configuration. When an outbound message appears in the table of the type and external system configured (via a business event such as an algorithm or plug-in script) the Oracle Utilities Application Framework will place the message on the configured Queue linked to the JMS Sender. The inbound integration has changed. In the past you created XAI Receivers and specified configuration about what types of transactions to process. This is now all configuration file driven. The configuration files for the Business Application Server (ejb-jar.xml and weblogic-ejb-jar.xml) define Message Driven Beans and the queues to monitor. When a message appears on the queue, the MDB processes it through our web services interface. Configuration of the MDB can be native (via editing the configuration files) or through the new user exit capabilities (which is aimed at maintaining custom configuration across upgrades). The latter is better as you build fragments of configuration to make it easier to maintain. In the next few weeks a number of new whitepaper will be released to illustrate the features of the Oracle WebLogic JMS and Oracle SOA Suite integration capabilities.

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Designing Content-Based ETL Process with .NET and SFDC

- by Patrick

As my firm makes the transition to using SFDC as our main operational system, we've spun together a couple of SFDC portals where we can post customer-specific documents to be viewed at will. As such, we've had the need for pseudo-ETL applications to be implemented that are able to extract metadata from the documents our analysts generate internally (most are industry-standard PDFs, XML, or MS Office formats) and place in networked "queue" folders. From there, our applications scoop of the queued documents and upload them to the appropriate SFDC CRM Content Library along with some select pieces of metadata. I've mostly used DbAmp to broker communication with SFDC (DbAmp is a Linked Server provider that allows you to use SQL conventions to interact with your SFDC Org data). I've been able to create [console] applications in C# that work pretty well, and they're usually structured something like this: static void Main() { // Load parameters from app.config. // Get documents from queue. var files = someInterface.GetFiles(someFilterOrRegexPattern); foreach (var file in files) { // Extract metadata from the file. // Validate some attributes of the file; add any validation errors to an in-memory // structure (e.g. List<ValidationErrors>). if (isValid) { // Upload using some wrapper for an ORM an someInterface.Upload(meta.Param1, meta.Param2, ...); } else { // Bounce the file } } // Report any validation errors (via message bus or SMTP or some such). } And that's pretty much it. Most of the time I wrap all these operations in a "Worker" class that takes the needed interfaces as constructor parameters. This approach has worked reasonably well, but I just get this feeling in my gut that there's something awful about it and would love some feedback. Is writing an ETL process as a C# Console app a bad idea? I'm also wondering if there are some design patterns that would be useful in this scenario that I'm clearly overlooking. Thanks in advance!

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OpenGL ES Loading

- by kuroutadori

I want to know what is the norm of loading rendering code. Take a button. When the application is loaded, a texture is loaded which has the image of the button on it. When the button is tapped, it then adds a loader into a queue, which is loaded on render thread. It then loads up an array buffer with vertexes and tex coords when render is called. It then adds to a render tree. Then it renders. the render function looks like this void render() { update(); mBaseRenderer->render(); } update() is when the queue is checked to see if anything needs loading. mBaseRenderer->render() is the render tree. What I am asking then is, should I even have the update() there at all and instead have everything preloaded before it renders? If I can have it loaded when need, for instance when there is tap, then how can it be done (My current code causes an dequeueing buffer error (Unknown error: -75) which I assume is to do with OpenGL ES and the context)?

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How should I host our scalable worker processes?

- by Pieter Breed

We are designing a new architecture for an enterprise business. The principles we've followed so far is not to develop what you can (possible buy and) deploy, ie, don't reinvent any wheels. In this way we've decided on CQRS, RabbitMQ, Riak and a bunch of other things. We still need to write /some/ business code though and these will be in the form of worker processes, which will consume commands from a message queue and after any side-effects, produce events onto another message queue. The idea behind this is that via the competing-consumers design we will have a scalable design right out of the box. One option is of writing a management infrastructure that will know how to: deploy code instantiate processes kill processes update configuration etc IE provide fault tolerance and scalability. Also, this is exactly what something like GAE and Heroku does for you, but in a public setting and in our organization, public is bad. My question is, is there an out-of-the-box solution that we can use to host our consumers in? Like a private cloud or private platform-as-a-service. Private Heroku or GAE. Is there some kind of software or software product with which we can do all of these things and thereby get scalability and fault tolerance over our consumers?

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print jobs are held until the VirtualBox guest OS is reboot

- by broiyan

Here is the setup: VirtualBox 4.1.20 (which the Help window describes as 4.1.12_Ubuntu) Extension Pack 4.1.20 (for USB support) Windows 7 Home Premium as a guest operating system on VirtualBox Ubuntu 12.04 with dist-upgrade's to September 2012 as the host operating system. Fuji Xerox DocuPrint P205b, which I believe is a GDI printer, connected via USB. The problem is that often print jobs will sit in the print queue and nothing comes out of the printer. The printer status for the first item in the queue will be Printing even though nothing happens. Then upon rebooting Windows, the print jobs get printed, seemingly simultaneous to the rebooting process; that is as Windows reloads. One way to avoid this problem is to reboot Windows with the printer cable attached, and then submit the print jobs. The print jobs get printed in a timely manner. Perhaps VirtualBox has a problem with USB being plug-n-play and hot pluggable. It's not convenient to have the printer plugged in when Windows boots because: One, this is a laptop, and Two, I may be boot Windows for a purpose other than printing and not anticipate needing to print. Are there any recommendable fixes for this problem?

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