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  • Exception: attempt to acquire a reference on a close SQLiteClosable

    - by CommonsWare
    I posted this back in May on the [android-developers] Google Group. I never heard back and was not able to reproduce the problem until one of my students did last week. I figured I'd post it here and see if it rang any bells for anyone. In one of my code samples, I have the following method: static Cursor getAll(SQLiteDatabase db, String orderBy) { return(db.rawQuery("SELECT * FROM restaurants "+orderBy, null)); } When I run it, sporadically, I get this: 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): java.lang.IllegalStateException: attempt to acquire a reference on a close SQLiteClosable 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:31) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:56) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1118) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1092) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at apt.tutorial.Restaurant.getAll(Restaurant.java:14) This makes no sense to me. The database is definitely open. The SQLiteClosable is the SQLiteQuery created by SQLiteQueryDriver, and I see no evidence that there is an object pool or something going on here that might explain how a "new" SQLiteClosable is already closed. The fact that it is sporadic (meaning the same UI operations sometimes trigger the exception, but not always) suggests some sort of pool, race condition, or something...but I'm not sure where. Thoughts? Thanks! UPDATE: The code in question is from the LunchList tutorials out of my Android Programming Tutorials book. It's a bit spread out and not terribly suitable for posting directly in SO. You can download the code for that book from the above link if you want to take a look at it. I do not recall exactly which edition of the tutorial the student was working on at the time, though it was in the Tutorial 12-Tutorial 16 range. I was mostly hoping to run across somebody who had tripped over this problem before and had a likely culprit. I'm fairly certain my database is open. Thanks again!

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  • HTML5 Video Tag in Chrome - Why is currentTime ignored when video downloaded from my webserver?

    - by larson4
    I want to be able to play back video from a specific time using the HTML5 video tag (and currently only need to worry about Chrome). This is possible by setting the currentTime property of a video element. That works fine in Chrome with a video sourced from html5rocks.com, but is ignored when the same file is loaded from my own local webserver. Using the sample code from http://playground.html5rocks.com/#video_tag, I have arrived at the following HTML: <!DOCTYPE html> <html> <body> <video id="video1" width="320" height="240" volume=".7" controls preload=true autobuffer> <source src="http://playground.html5rocks.com/samples/html5_misc/chrome_japan.webm" type='video/webm; codecs="vp8, vorbis"'/> </video> <input type=button onclick="play()" value="play"> <input type=button onclick="setTime()" value="setTime"> <input type=button onclick="pause()" value="pause"> <script> var play=function() { document.getElementById("video1").play(); } var setTime=function() { document.getElementById("video1").currentTime=2; } var pause=function() { document.getElementById("video1").pause(); } </script> </body> </html> Using Chrome, if you Wait for the video to download for a bit (until the progress bar is about 10% in) Press setTime - you should notice the time jump to 2 seconds press play ...the video will start at 2 seconds in. But if I download the webm file in the source src to my local webserver, and change src to point locally: <source src="chrome_japan.webm" type='video/webm; codecs="vp8, vorbis"'/> ...then setting currentTime is complete ignored. No errors are showing in the developer tools console. Now, my webserver is serving this with mime type "video/webm", but it will be served like any old file -- not streamed. Do I need a webserver that streams in some specific way? What else could be at fault here? Note: The webserver is a proprietary platform and won't have any of the same exact settings or controls one might expect of Tomcat or some other commonly used webserver, though there may be other ways to achieve the same effect.

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  • WLI domain with 3 servers - issues on JPD process startup

    - by XpiritO
    Hi there. I'm currently working on a clustered WLI environment which comprehends 3 servers: 1 admin server ("AdminServer") and 2 managed servers ("mn1" and "mn2") grouped as a cluster, as follows: Architecture diagram: http://img72.imageshack.us/img72/4112/clusterdiagram.jpg I've developed a JPD process to execute some scheduled tasks, invoked using a Message Broker. I've deployed this project into a single-server WLI domain (with AdminServer only) and it works as expected: the JPD process is invoked (I've configured a Timer Event Generator instance to start it up). Message broker: http://img532.imageshack.us/img532/1443/wlimessagebroker.jpg Timer event generator: http://img408.imageshack.us/img408/7358/wlitimereventgenerator.jpg In order to achieve fail-over and load-balancing capabilities, I'm currently trying to deploy this JPD process into this clustered WLI environment. Although, I'm having some issues with this, as I cannot get it to work properly, even if it still works. Here is a screenshot of the "WLI Process Instance Monitor" (with AdminServer and mn1 instances up and running): http://img710.imageshack.us/img710/8477/wliprocessinstancemonit.jpg According to this screen the process seems to be running, as it shows in this instance monitor screen. However, I don't see any output coming out neither at AdminServer console or mn1 console. In single-server domain it was visible output from JPD process "timeout" callback method, wich implementation is shown below: @com.bea.wli.control.broker.MessageBroker.StaticSubscription(xquery = "", filterValueMatch = "", channelName = "/SamplePrefix/Samples/SampleStringChannel", messageBody = "{x0}") public void subscription(java.lang.String x0) { String toReturn=""; try { Context myCtx = new InitialContext(); MBeanHome mbeanHome = (MBeanHome)myCtx.lookup("weblogic.management.home.localhome"); toReturn=mbeanHome.getMBeanServer().getServerName(); System.out.println("**** executed at **** " + System.currentTimeMillis() + " by: " + toReturn); } catch (Exception e) { System.out.println("Exception!"); e.printStackTrace(); } } (...) @org.apache.beehive.controls.api.events.EventHandler(field = "myT", eventSet = com.bea.control.WliTimerControl.Callback.class, eventName = "onTimeout") public void myT_onTimeout(long time, java.io.Serializable data) { // #START: CODE GENERATED - PROTECTED SECTION - you can safely add code above this comment in this method. #// // input transform System.out.println("**** published at **** " + System.currentTimeMillis()); publishControl.publish("aaaa"); // parameter assignment // #END : CODE GENERATED - PROTECTED SECTION - you can safely add code below this comment in this method. #// } and here is the output visible at "AdminServer" console in single-server domain testing: **** published at **** 1273238090713 **** executed at **** 1273238132123 by: AdminServer **** published at **** 1273238152462 **** executed at **** 1273238152562 by: AdminServer (...) What may be wrong with my clustered configuration? Am I missing something to accomplish clustered deployment? Thanks in advance for your help.

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  • how Can we get the output format to CSV instead of HTML in Alfresco using webscripts?

    - by pavan123
    how Can we change the output format to CSV instead of HTML in Alfresco using webscripts? below are the my corresponding FTL and Webscript files recursive.get.html.ftl <#macro recurse_macro node depth> <#if node.isContainer> <tr> <td> ${node.properties.name} </td> <td></td> </tr> <#list node.children as child> <#if child.isContainer> <@recurse_macro node=child depth=depth+1/> <#list child.children as child2> <#if child2.isDocument> <tr><td></td><td>${child2.properties.name}</td></tr> </#if> </#list> </#if> </#list> </#if> </#macro> Recursive Listing of Spaces & Documents: Space Document recursive.get.desc.xml <webscript> <shortname>recurcive</shortname> <description>Recursive</description> <url>/sample/recursive/{recursive}</url> <format default="html">extension</format> <authentication>guest</authentication> </webscript> and html output is Recursive Listing of Spaces & Documents: Space Document Company Home Data Dictionary Space Templates Software Engineering Project Documentation Drafts Pending Approval Published Samples system-overview.html Discussions UI Design Presentations Quality Assurance Presentation Templates doc_info.ftl localizable.ftl my_docs.ftl my_spaces.ftl my_summary.ftl translatable.ftl recent_docs.ftl general_example.ftl my_docs_inline.ftl show_audit.ftl readme.ftl Email Templates notify_user_email.ftl invite_user_email.ftl RSS Templates RSS_2.0_recent_docs.ftl Saved Searches admin Scripts backup.js example test script.js backup and log.js append copyright.js alfresco docs.js test return value.js Web Scripts org alfresco sample blogsearch.get.js blogsearch.get.atom.ftl blogsearch.get.desc.xml blogsearch.get.html.ftl blogsearch.get.html.400.ftl blogsearch.get.atom.400.ftl categorysearch.get.js categorysearch.get.atom.ftl categorysearch.get.desc.xml categorysearch.get.html.ftl categorysearch.get.html.404.ftl categorysearch.get.atom.404.ftl folder.get.js folder.get.atom.ftl folder.get.desc.xml folder.get.html.ftl avmstores.get.desc.xml avmstores.get.html.ftl avmbrowse.get.js avmbrowse.get.desc.xml avmbrowse.get.html.ftl recursive.get.desc.xml recursive.get.html.ftl sgs.get.desc.xml sgs.get.csv.ftl sample1.get.desc.xml sample1.get.csv.ftl first.get.desc.xml first.get.text.ftl rag.get.html.ftl rag.get.desc.xml new1.get.desc.xml new1.get.html.ftl excel.get.html.ftl excel.get.desc.xml sgs1.get.desc.xml one.get.html.ftl one.get.desc.xml one.get.js readme.html Web Scripts Extensions readme.html Guest Home Alfresco-Tutorial.pdf User Homes isabel Users Home

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  • CoreData : App crashes when deleting last instance created

    - by Leo
    Hello, I have a 2 tabs application. In the first one, I'm creating objects of the "Sample" and "SampleList" entities. Each sampleList contains an ID and a set of samples. Each sample contains a date and temperature property. In the second tab, I'm displaying my data in a tableView. I implemented the - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath method in order to delete SampleLists. In my xcdatamodel the delete rule for my relationship between SampleList and Sample is Cascade. My problem is that when I try to delete SampleList I just created, the app crashes and I receive a EXC_BAD_ACCESS signal. If I restart it, then I'm able to delete "old" sampleList without any problems. Earlier, I had the following problem : I couldn't display the the sampleLists I created since I launched the app, because it crashed too. I received also the EXC_BAD_ACCESS signal. Actually, it seemed that the date of the last sample created of the set was nil. If I am not releasing the NSDate I'm using to set the sample's date, I don't have this problem anymore... If anyone could help me to find out what could cause my troubles it would be great !! Here is the method I'm using to create new instances : SampleList *newSampleList = (SampleList *)[NSEntityDescription insertNewObjectForEntityForName:@"SampleList" inManagedObjectContext:managedObjectContext]; [newSampleList setPatchID:patchID]; NSMutableSet *newSampleSet = [[NSMutableSet alloc] init]; NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; for (int i = 0; i < [byteArray count]; i=i+4, sampleCount++) { NSDateComponents *comps = [[NSDateComponents alloc] init]; [comps setYear:year]; [comps setMonth:month]; [comps setDay:day]; [comps setHour:hours]; [comps setMinute:minutes]; NSDate *sampleDate = [gregorian dateFromComponents:comps]; Sample *newSample = (Sample *)[NSEntityDescription insertNewObjectForEntityForName:@"Sample" inManagedObjectContext:managedObjectContext]; [newSample setSampleDate:sampleDate]; [newSample setSampleTemperature:[NSNumber numberWithInt:temperature]]; [newSampleSet addObject:newSample]; [comps release]; //[sampleDate release]; } [newSampleList setSampleSet:newSampleSet]; // [newSampleSet release]; NSError *error; if (![managedObjectContext save:&error]) { NSLog(@"Could not Save the context !!"); } [gregorian release];

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  • When to call glEnable(GL_FRAMEBUFFER_SRGB)?

    - by Steven Lu
    I have a rendering system where I draw to an FBO with a multisampled renderbuffer, then blit it to another FBO with a texture in order to resolve the samples in order to read off the texture to perform post-processing shading while drawing to the backbuffer (FBO index 0). Now I'd like to get some correct sRGB output... The problem is the behavior of the program is rather inconsistent between when I run it on OS X and Windows and this also changes depending on the machine: On Windows with the Intel HD 3000 it will not apply the sRGB nonlinearity but on my other machine with a Nvidia GTX 670 it does. On the Intel HD 3000 in OS X it will also apply it. So this probably means that I'm not setting my GL_FRAMEBUFFER_SRGB enable state at the right points in the program. However I can't seem to find any tutorials that actually tell me when I ought to enable it, they only ever mention that it's dead easy and comes at no performance cost. I am currently not loading in any textures so I haven't had a need to deal with linearizing their colors yet. To force the program to not simply spit back out the linear color values, what I have tried is simply comment out my glDisable(GL_FRAMEBUFFER_SRGB) line, which effectively means this setting is enabled for the entire pipeline, and I actually redundantly force it back on every frame. I don't know if this is correct or not. It certainly does apply a nonlinearization to the colors but I can't tell if this is getting applied twice (which would be bad). It could apply the gamma as I render to my first FBO. It could do it when I blit the first FBO to the second FBO. Why not? I've gone so far as to take screen shots of my final frame and compare raw pixel color values to the colors I set them to in the program: I set the input color to RGB(1,2,3) and the output is RGB(13,22,28). That seems like quite a lot of color compression at the low end and leads me to question if the gamma is getting applied multiple times. I have just now gone through the sRGB equation and I can verify that the conversion seems to be only applied once as linear 1/255, 2/255, and 3/255 do indeed map to sRGB 13/255, 22/255, and 28/255 using the equation 1.055*C^(1/2.4)+0.055. Given that the expansion is so large for these low color values it really should be obvious if the sRGB color transform is getting applied more than once. So, I still haven't determined what the right thing to do is. does glEnable(GL_FRAMEBUFFER_SRGB) only apply to the final framebuffer values, in which case I can just set this during my GL init routine and forget about it hereafter?

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  • Releasing the keyboard stops shake events. Why?

    - by Moshe
    1) How do I make a UITextField resign the keyboard and hide it? The keyboard is in a dynamically created subview whose superview looks for shake events. Resigning first responder seems to break the shake event handler. 2) how do you make the view holding the keyboard transparent, like see through glass? I have seen this done before. This part has been taken care of thanks guys. As always, code samples are appreciated. I've added my own to help explain the problem. EDIT: Basically, - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event; gets called in my main view controller to handle shaking. When a user taps on the "edit" icon (a pen, in the bottom of the screen - not the traditional UINavigationBar edit button), the main view adds a subview to itself and animates it on to the screen using a custom animation. This subview contains a UINavigationController which holds a UITableView. The UITableView, when a cell is tapped on, loads a subview into itself. This second subview is the culprit. For some reason, a UITextField in this second subview is causing problems. When a user taps on the view, the main view will not respond to shakes unless the UITextField is active (in editing mode?). Additional info: My Motion Event Handler: - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event { NSLog(@"%@", [event description]); SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"shake" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); [self genRandom:TRUE]; } The genRandom: Method: /* Generate random label and apply it */ -(void)genRandom:(BOOL)deviceWasShaken{ if(deviceWasShaken == TRUE){ decisionText.text = [NSString stringWithFormat: (@"%@", [shakeReplies objectAtIndex:(arc4random() % [shakeReplies count])])]; }else{ SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"string" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); decisionText.text = [NSString stringWithFormat: (@"%@", [pokeReplies objectAtIndex:(arc4random() % [pokeReplies count])])]; } } shakeReplies and pokeReplies are both NSArrays of strings. One is used for when a certain part of the screen is poked and one is for when the device is shaken. The app will randomly choose a string from the NSArray and display onscreen. For those of you who work graphically, here is a diagram of the view hierarchy: Root View -> UINavigationController -> UITableView -> Edit View -> Problem UITextfield

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  • Extending AdapterView

    - by Ander Webbs
    Hi, i'm trying to make (for learning purposes) my own implementation of a simple AdapterView where items comes from an basic Adapter (ImageAdapter from sdk samples). Actual code is like this: public class MyAdapterView extends AdapterView<ImageAdapter> implements AdapterView.OnItemClickListener{ private ImageAdapter mAdapter; public MyAdapterView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initThings(); } private void initThings(){ setOnItemClickListener(this); } @Override public ImageAdapter getAdapter() { // TODO Auto-generated method stub return mAdapter; } @Override public void setAdapter(ImageAdapter adapter) { // TODO Auto-generated method stub mAdapter=adapter; requestLayout(); } View obtainView(int position) { View child = mAdapter.getView(position, null, this); return child; } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { super.onLayout(changed, l, t, r, b); for(int i=0;i<mAdapter.getCount();i++){ View child = obtainView(i); child.layout(10, 70*i, 70, 70); addViewInLayout(child, i, null, true); } this.invalidate(); } @Override public void onItemClick(AdapterView<?> parent, View v, int position, long id) { Log.d("MYEXAMPLES","Clicked an item!"); } } This isn't a coding masterpiece, it just displays a pseudo-listview with pictures. I know i could've used ListView, GridView, Spinner, etc. but i'm relative new to android and i'm trying to figure out some things on it. Well, the question here is: Why is my onItemClick not firing? Using the same ImageAdapter with a GridView, everything works ok, but when i use with above class, i get nothing. Inside AdapterView.java there is code for those click, longclick, etc events... so why can't i just fire them? Maybe i'm misunderstanding basic things on how AdapterView works? Should I extend other base classes instead? And why? Hoping to find more experienced guidance on here, thanks in advance.

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  • Can I avoid a threaded UDP socket in Python dropping data?

    - by 666craig
    First off, I'm new to Python and learning on the job, so be gentle! I'm trying to write a threaded Python app for Windows that reads data from a UDP socket (thread-1), writes it to file (thread-2), and displays the live data (thread-3) to a widget (gtk.Image using a gtk.gdk.pixbuf). I'm using queues for communicating data between threads. My problem is that if I start only threads 1 and 3 (so skip the file writing for now), it seems that I lose some data after the first few samples. After this drop it looks fine. Even by letting thread 1 complete before running thread 3, this apparent drop is still there. Apologies for the length of code snippet (I've removed the thread that writes to file), but I felt removing code would just prompt questions. Hope someone can shed some light :-) import socket import threading import Queue import numpy import gtk gtk.gdk.threads_init() import gtk.glade import pygtk class readFromUDPSocket(threading.Thread): def __init__(self, socketUDP, readDataQueue, packetSize, numScans): threading.Thread.__init__(self) self.socketUDP = socketUDP self.readDataQueue = readDataQueue self.packetSize = packetSize self.numScans = numScans def run(self): for scan in range(1, self.numScans + 1): buffer = self.socketUDP.recv(self.packetSize) self.readDataQueue.put(buffer) self.socketUDP.close() print 'myServer finished!' class displayWithGTK(threading.Thread): def __init__(self, displayDataQueue, image, viewArea): threading.Thread.__init__(self) self.displayDataQueue = displayDataQueue self.image = image self.viewWidth = viewArea[0] self.viewHeight = viewArea[1] self.displayData = numpy.zeros((self.viewHeight, self.viewWidth, 3), dtype=numpy.uint16) def run(self): scan = 0 try: while True: if not scan % self.viewWidth: scan = 0 buffer = self.displayDataQueue.get(timeout=0.1) self.displayData[:, scan, 0] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 1] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 2] = numpy.fromstring(buffer, dtype=numpy.uint16) gtk.gdk.threads_enter() self.myPixbuf = gtk.gdk.pixbuf_new_from_data(self.displayData.tostring(), gtk.gdk.COLORSPACE_RGB, False, 8, self.viewWidth, self.viewHeight, self.viewWidth * 3) self.image.set_from_pixbuf(self.myPixbuf) self.image.show() gtk.gdk.threads_leave() scan += 1 except Queue.Empty: print 'myDisplay finished!' pass def quitGUI(obj): print 'Currently active threads: %s' % threading.enumerate() gtk.main_quit() if __name__ == '__main__': # Create socket (IPv4 protocol, datagram (UDP)) and bind to address socketUDP = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) host = '192.168.1.5' port = 1024 socketUDP.bind((host, port)) # Data parameters samplesPerScan = 256 packetsPerSecond = 1200 packetSize = 512 duration = 1 # For now, set a fixed duration to log data numScans = int(packetsPerSecond * duration) # Create array to store data data = numpy.zeros((samplesPerScan, numScans), dtype=numpy.uint16) # Create queue for displaying from readDataQueue = Queue.Queue(numScans) # Build GUI from Glade XML file builder = gtk.Builder() builder.add_from_file('GroundVue.glade') window = builder.get_object('mainwindow') window.connect('destroy', quitGUI) view = builder.get_object('viewport') image = gtk.Image() view.add(image) viewArea = (1200, samplesPerScan) # Instantiate & start threads myServer = readFromUDPSocket(socketUDP, readDataQueue, packetSize, numScans) myDisplay = displayWithGTK(readDataQueue, image, viewArea) myServer.start() myDisplay.start() gtk.gdk.threads_enter() gtk.main() gtk.gdk.threads_leave() print 'gtk.main finished!'

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  • basic operations for modifying a source document with XSLT

    - by SpliFF
    All the tutorials and examples I've found of XSLT processing seem to assume your destination will be a significantly different format/structure to your source and that you know the structure of the source in advance. I'm struggling with finding out how to perform simple "in-place" modifications to a HTML document without knowing anything else about its existing structure. Could somebody show me a clear example that, given an arbitrary unknown HTML source will: 1.) delete the classname 'foo' from all divs 2.) delete a node if its empty (ie <p></p>) 3.) delete a <p> node if its first child is <br> 4.) add newattr="newvalue" to all H1 5.) replace 'heading' in text nodes with 'title' 6.) wrap all <u> tags in <b> tags (ie, <u>foo</u> -> <b><u>foo</u></b>) 7.) output the transformed document without changing anything else The above examples are the primary types of transform I wish to accomplish. Understanding how to do the above will go a long way towards helping me build more complex transforms. To help clarify/test the examples here is a sample source and output, however I must reiterate that I want to work with arbitrary samples without rewriting the XSLT for each source: <!doctype html> <html> <body> <h1>heading</h1> <p></p> <p><br>line</p> <div class="foo bar"><u>baz</u></div> <p>untouched</p> </body> </html> output: <!doctype html> <html> <body> <h1 newattr="newvalue">title</h1> <div class="bar"><b><u>baz</u></b></div> <p>untouched</p> </body> </html>

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  • Representing xml through a single class

    - by Charles
    I am trying to abstract away the difficulties of configuring an application that we use. This application takes a xml configuration file and it can be a bit bothersome to manually edit this file, especially when we are trying to setup some automatic testing scenarios. I am finding that reading xml is nice, pretty easy, you get a network of element nodes that you can just go through and build your structures quite nicely. However I am slowly finding that the reverse is not quite so nice. I want to be able to build a xml configuration file through a single easy to use interface and because xml is composed of a system of nodes I am having a lot of struggle trying to maintain the 'easy' part. Does anyone know of any examples or samples that easily and intuitively build xml files without declaring a bunch of element type classes and expect the user to build the network themselves? For example if my desired xml output is like so <cook version="1.1"> <recipe name="chocolate chip cookie"> <ingredients> <ingredient name="flour" amount="2" units="cups"/> <ingredient name="eggs" amount="2" units="" /> <ingredient name="cooking chocolate" amount="5" units="cups" /> </ingredients> <directions> <direction name="step 1">Preheat oven</direction> <direction name="step 2">Mix flour, egg, and chocolate</direction> <direction name="step 2">bake</direction> </directions> </recipe> <recipe name="hot dog"> ... How would I go about designing a class to build that network of elements and make one easy to use interface for creating recipes? Right now I have a recipe object, an ingredient object, and a direction object. The user must make each one, set the attributes in the class and attach them to the root object which assembles the xml elements and outputs the formatted xml. Its not very pretty and I just know there has to be a better way. I am using python so bonus points for pythonic solutions

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  • Output from OouraFFT correct sometimes but completely false other times. Why ?

    - by Yan
    Hi I am using Ooura FFT to compute the FFT of the accelerometer data in windows of 1024 samples. The code works fine, but then for some reason it produces very strange outputs, i.e. continuous spectrum with amplitudes of the order of 10^200. Here is the code: OouraFFT *myFFT=[[OouraFFT alloc] initForSignalsOfLength:1024 NumWindows:10]; // had to allocate it UIAcceleration *tempAccel = nil; double *input=(double *)malloc(1024 * sizeof(double)); double *frequency=(double *)malloc(1024*sizeof(double)); if (input) { //NSLog(@"%d",[array count]); for (int u=0; u<[array count]; u++) { tempAccel = (UIAcceleration *)[array objectAtIndex:u]; input[u]=tempAccel.z; //NSLog(@"%g",input[u]); } } myFFT.inputData=input; // specifies input data to myFFT [myFFT calculateWelchPeriodogramWithNewSignalSegment]; // calculates FFT for (int i=0;i<myFFT.dataLength;i++) // loop to copy output of myFFT, length of spectrumData is half of input data, so copy twice { if (i<myFFT.numFrequencies) { frequency[i]=myFFT.spectrumData[i]; // } else { frequency[i]=myFFT.spectrumData[myFFT.dataLength-i]; // copy twice } } for (int i=0;i<[array count];i++) { TransformedAcceleration *NewAcceleration=[[TransformedAcceleration alloc]init]; tempAccel=(UIAcceleration*)[array objectAtIndex:i]; NewAcceleration.timestamp=tempAccel.timestamp; NewAcceleration.x=tempAccel.x; NewAcceleration.y=tempAccel.z; NewAcceleration.z=frequency[i]; [newcurrentarray addObject:NewAcceleration]; // this does not work //[self replaceAcceleration:NewAcceleration]; //[NewAcceleration release]; [NewAcceleration release]; } TransformedAcceleration *a=nil;//[[TransformedAcceleration alloc]init]; // object containing fft of x,y,z accelerations for(int i=0; i<[newcurrentarray count]; i++) { a=(TransformedAcceleration *)[newcurrentarray objectAtIndex:i]; //NSLog(@"%d,%@",i,[a printAcceleration]); fprintf(fp,[[a printAcceleration] UTF8String]); //this is going wrong somewhow } fclose(fp); [array release]; [myFFT release]; //[array removeAllObjects]; [newcurrentarray release]; free(input); free(frequency);

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  • How do I 'globally' catch exceptions thrown in object instances.

    - by SleepyBobos
    I am currently writing a winforms application (C#). I am making use of the Enterprise Library Exception Handling Block, following a fairly standard approach from what I can see. IE : In the Main method of Program.cs I have wired up event handler to Application.ThreadException event etc. This approach works well and handles the applications exceptional circumstances. In one of my business objects I throw various exceptions in the Set accessor of one of the objects properties set { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum trim..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message..."); _minimumTrim = value; } My logic for this approach (without turning this into a 'when to throw exceptions' discussion) is simply that the business objects are responsible for checking business rule constraints and throwing an exception that can bubble up and be caught as required. It should be noted that in the UI of my application I do explictly check the values that the public property is being set to (and take action there displaying friendly dialog etc) but with throwing the exception I am also covering the situation where my business object may not be used by a UI eg : the Property is being set by another business object for example. Anyway I think you all get the idea. My issue is that these exceptions are not being caught by the handler wired up to Application.ThreadException and I don't understand why. From other reading I have done the Application.ThreadException event and it handler "... catches any exception that occurs on the main GUI thread". Are the exceptions being raised in my business object not in this thread? I have not created any new threads. I can get the approach to work if I update the code as follows, explicity calling the event handler that is wired to Application.ThreadException. This is the approach outlined in Enterprise Library samples. However this approach requires me to wrap any exceptions thrown in a try catch, something I was trying to avoid by using a 'global' handler to start with. try { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message"); _minimumTrim = value; } catch (Exception ex) { Program.ThreadExceptionHandler.ProcessUnhandledException(ex); } I have also investigated using wiring a handler up to AppDomain.UnhandledException event but this does not catch the exceptions either. I would be good if someone could explain to me why my exceptions are not being caught by my global exception handler in the first code sample. Is there another approach I am missing or am I stuck with wrapping code in try catch, shown above, as required?

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  • php regex guitar tab (tabs or tablature, a type of music notation)

    - by John
    I am in the process of creating a guitar tab to rtttl (Ring Tone Text Transfer Language) converter in PHP. In order to prepare a guitar tab for rtttl conversion I first strip out all comments (comments noted by #- and ended with -#), I then have a few lines that set tempo, note the tunning and define multiple instruments (Tempo 120\nDefine Guitar 1\nDefine Bass 1, etc etc) which are stripped out of the tab and set aside for later use. Now I essentially have nothing left except the guitar tabs. Each tab is prefixed with it's instrument name in conjunction with the instrument name noted prior. Some times we have tabs for 2 separate instruments that are linked because they are to be played together, ie a Guitar and a Bass Guitar playing together. Example 1, Standard Guitar Tab: |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| Example 2, Conjunction Tab: |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| | | |Bass 1 G|----------0-------0-----------0-------0--------| D|--------2-----------2-------2-----------2------| A|------3---------------3---3---------------3----| E|----3-------------------3-------------------3--| I have considered other methods of identifying the tabs with no solid results. I am hoping that someone who does regular expressions could help me find a way to identify a single guitar tab and if possible also be able to match a tab with multiple instruments linked together. Once the tabs are in an array I will go through them one line at a time and convert them into rtttl lines (exploded at each new line "\n"). I do not want to separate the guitar tabs in the document via explode "\n\n" or something similar because it does not identify the guitar tab, rather, it is identifying the space between the tabs - not on the tabs themselves. I have been messing with this for about a week now and this is the only major hold up I have. Everything else is fairly simple. As of current, I have tried many variations of the regex pattern. Here is one of the most recent test samples: <?php $t = " |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| | | |Bass 1 G|----------0-------0-----------0-------0--------| D|--------2-----------2-------2-----------2------| A|------3---------------3---3---------------3----| E|----3-------------------3-------------------3--| "; preg_match_all("/^.*?(\\|).*?(\\|)/is",$t,$p); print_r($p); ?> It is also worth noting that inside the tabs, where the dashes and #'s are, you may also have any variation of letters, numbers and punctuation. The beginning of each line marks the tuning of each string with one of the following case insensitive: a,a#,b,c,c#,d,d#,e,f,f#,g or g. Thanks in advance for help with this most difficult problem.

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  • Copy image to BLOB from client pc aka Java function in Oracle

    - by mumich
    Hi guys, I've been stuck with this for past two days. I've go java function stored in Oracle system which is supposed to copy image from local drive do remote database and store it in BLOB - it's called CopyBLOB and looks like this: import java.sql.*; import oracle.sql.*; import java.io.*; public class CopyBLOB { static int id; static String fileName = null; static Connection conn = null; public CopyBLOB(int idz, String f) { id = idz; fileName = f; } public static void copy(int ident, String path) throws SQLException, FileNotFoundException { CopyBLOB cpB = new CopyBLOB(ident, path); cpB.getConnection(); cpB.callUpdate(id, fileName); } public void getConnection() throws SQLException { DriverManager.registerDriver (new oracle.jdbc.OracleDriver()); try { conn = DriverManager.getConnection("jdbc:oracle:thin:@oraserv.ms.mff.cuni.cz:1521:db", "xxx", "xxx"); } catch (SQLException sqlex) { System.out.println("SQLException while getting db connection: "+sqlex); if (conn != null) conn.close(); } catch (Exception ex) { System.out.println("Exception while getting db connection: "+ex); if (conn != null) conn.close(); } } public void callUpdate(int id, String file ) throws SQLException, FileNotFoundException { CallableStatement cs = null; try { conn.setAutoCommit(false); File f = new File(file); FileInputStream fin = new FileInputStream(f); cs = (CallableStatement) conn.prepareCall( "begin add_image(?,?); end;" ); cs.setInt(1, id ); cs.setBinaryStream(2, fin, (int) f.length()); cs.execute(); conn.setAutoCommit(true); } catch ( SQLException sqlex ) { System.out.println("SQLException in callUpdateUsingStream method of given status : " + sqlex.getMessage() ); } catch ( FileNotFoundException fnex ) { System.out.println("FileNotFoundException in callUpdateUsingStream method of given status : " + fnex.getMessage() ); } finally { try { if (cs != null) cs.close(); if (conn != null) conn.close(); } catch ( Exception ex ) { System.out.println("Some exception in callUpdateUsingStream method of given status : " + ex.getMessage( ) ); } } } } The wrapper function is defined in package "MyPackage" as folows: procedure image_adder( id varchar2, path varchar2 ) AS language java name 'CopyBLOB.copy(java.lang.String, java.lang.String)'; And the inserting function called image_add is as simple as this: procedure add_image( id numeric(10), pic blob) AS BEGIN insert into pictures values (seq_pic.nextval, id, pic); END add_image; Now the problem: When I type call MyPackage.image_adder(1, 'd:\samples\img.jpg'); I get the ORA-29531 Error: No method copy in class CopyBLOB. Can you help me, please?

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  • Javascript: Writing a firefox extension with sockets

    - by Johnny Grass
    I need to write a firefox extension that creates a server socket (I think that's what it's called) and returns the browser's current url when a client application (running on the same computer) sends it a request. The thing is that I have no Java/Javascript background at all and I'm pressed for time so I am trying to hack something together from code samples. So far I've been mildly successful. I've been working with code from this question which is used in the open source Firefox exension PolyChrome I have the following code: var reader = { onInputStreamReady : function(input) { var input_stream = Components.classes["@mozilla.org/scriptableinputstream;1"] .createInstance(Components.interfaces.nsIScriptableInputStream); input_stream.init(input); input_stream.available(); var request = ''; while (input_stream.available()) { request = request + input_stream.read(512); } var checkString = "foo" if (request.toString() == checkString.toString()) { output_console('URL: ' + content.location.href); } else output_console("nothing"); var thread_manager = Components.classes["@mozilla.org/thread-manager;1"].getService(); input.asyncWait(reader,0,0,thread_manager.mainThread); } } var listener = { onSocketAccepted: function(serverSocket, clientSocket) { output_console("Accepted connection on "+clientSocket.host+":"+clientSocket.port); input = clientSocket.openInputStream(0, 0, 0).QueryInterface(Components.interfaces.nsIAsyncInputStream); output = clientSocket.openOutputStream(Components.interfaces.nsITransport.OPEN_BLOCKING, 0, 0); var thread_manager = Components.classes["@mozilla.org/thread-manager;1"].getService(); input.asyncWait(reader,0,0,thread_manager.mainThread); } } var serverSocket = Components.classes["@mozilla.org/network/server-socket;1"]. createInstance(Components.interfaces.nsIServerSocket); serverSocket.init(9999, true, 5); output_console("Opened socket on " + serverSocket.port); serverSocket.asyncListen(listener); I have a few questions. So far I can telnet into localhost and get a response, but my string comparison in the reader seems to fail even if I enter "foo". I don't get why. What am I missing? The sample code I'm using opens up a console window and prints output when I telnet into localhost. Ideally I would like the output to be returned as a response when the client sends a request to the server socket with a passphrase. How do I go about doing that? Is doing this a good idea? Does it create security vulnerabilities on the computer? How can I block connections to the socket from other computers? What is a good place to read about javascript sockets? My google searches have been pretty fruitless but then maybe I'm not using the right keywords.

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  • Hibernate Persistence problems with Bean Mapping (Dozer)

    - by BuffaloBuffalo
    I am using Hibernate 3, and having a particular issue when persisting a new Entity which has an association with an existing detached entity. Easiest way to explain this is via code samples. I have two entities, FooEntity and BarEntity, of which a BarEntity can be associated with many FooEntity: @Entity public class FooEntity implements Foo{ @Id private Long id; @ManyToOne(targetEntity = BarEntity.class) @JoinColumn(name = "bar_id", referencedColumnName = "id") @Cascade(value={CascadeType.ALL}) private Bar bar; } @Entity public class BarEntity implements Bar{ @Id private Long id; @OneToMany(mappedBy = "bar", targetEntity = FooEntity.class) private Set<Foo> foos; } Foo and Bar are interfaces that loosely define getters for the various fields. There are corresponding FooImpl and BarImpl classes that are essentially just the entity objects without the annotations. What I am trying to do is construct a new instance of FooImpl, and persist it after setting a number of fields. The new Foo instance will have its 'bar' member set to an existing Bar (runtime being a BarEntity) from the database (retrieved via session.get(..)). After the FooImpl has all of its properties set, Apache Dozer is used to map between the 'domain' object FooImpl and the Entity FooEntity. What Dozer is doing in the background is instantiating a new FooEntity and setting all of the matching fields. BarEntity is cloned as well via instantiation and set the FooEntity's 'bar' member. After this occurs, passing the new FooEntity object to persist. This throws the exception: org.hibernate.PersistentObjectException: detached entity passed to persist: com.company.entity.BarEntity Below is in code the steps that are occurring FooImpl foo = new FooImpl(); //returns at runtime a persistent BarEntity through session.get() Bar bar = BarService.getBar(1L); foo.setBar(bar); ... //This constructs a new instance of FooEntity, with a member 'bar' which itself is a new instance that is detached) FooEntity entityToPersist = dozerMapper.map(foo, FooEntity.class); ... session.persist(entityToPersist); I have been able to resolve this issue by either removing or changing the @Cascade annotation, but that limits future use for say adding a new Foo with a new Bar attached to it already. Is there some solution here I am missing? I would be surprised if this issue hasn't been solved somewhere before, either by altering how Dozer Maps the children of Foo or how Hibernate reacts to a detached Child Entity.

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  • What is the best way to reduce code and loop through a hierarchial commission script?

    - by JM4
    I have a script which currently "works" but is nearly 3600 lines of code and makes well over 50 database calls within a single script. From my experience, there is no way to really "loop" the script and minimize it because each call to the database is a subquery of the ones before based on referral ids. Perhaps I can give a very simple example of what I am trying to accomplish and see if anybody has experience with something similar. In my example, there are three tables: Table 1 - Sellers ID | Comm_level | Parent ----------------------------------- 1 | 4 | NULL 2 | 3 | 1 3 | 2 | 1 4 | 2 | 2 5 | 2 | 2 6 | 1 | 3 Where ID is the id of one of our sales agents, comm_level will determine what his commission percentage is for each product he sells, parent indicates the ID for whom recruited that particular agent. In the example above, 1 is the top agent, he recruited two agents, 2 and 3. 2 recruited two agents, 4 and 5. 3 recruited one agent, 6. NOTE: An agent can NEVER recruit anybody equal to or higher than their own level. Table 2 - Commissions Level | Item 1 | Item 2 | Item 3 ----------------------------------------------------- 4 | .5 | .4 | .3 3 | .45 | .35 | .25 2 | .4 | .3 | .2 1 | .35 | .25 | .15 This table lays out the commission percentages for each agent based on their actual comm_level (if an agent is at a level 4, he will receive 50% on every item 1 sold, 40% on every item 2, 30% on every item 3 and so on. Table 3 - Items Sold ID | Item --------------------- 4 | item_1 4 | item_2 1 | item_1 2 | item_3 6 | item_2 1 | item_3 This table pairs the actual item sold with the seller who sold the item. When generating the commission report, calculating individual values is very simple. Calculating their commission based on their sub_sellers however is very difficult. In this example, Seller ID 1 gets a piece of every single item sold. The commission percentages indicate individual sales or the height of their commission. For example: When seller ID 6 sold one of item_2 above, the tree for commissions will look like the following: -ID 6 - 25% of cost(item_1) -ID 3 - 5% of cost(item_1) - (30% is his comm - 25% comm of seller id 6) -ID 1 - 10% of cost(item_1) - (40% is his comm - 30% of seller id 3) This must be calculated for every agent in the system from the top down (hence the DB calls within while loops throughout my enormous script). Anybody have a good suggestion or samples they may have used in the past?

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  • 4 table query / join. getting duplicate rows

    - by Horse
    So I have written a query that will grab an order (this is for an ecommerce type site), and from that order id it will get all order items (ecom_order_items), print options (c_print_options) and images (images). The eoi_p_id is currently a foreign key from the images table. This works fine and the query is: SELECT eoi_parentid, eoi_p_id, eoi_po_id, eoi_quantity, i_id, i_parentid, po_name, po_price FROM ecom_order_items, images, c_print_options WHERE eoi_parentid = '1' AND i_id = eoi_p_id AND po_id = eoi_po_id; The above would grab all the stuff I need for order #1 Now to complicate things I added an extra table (ecom_products), which needs to act in a similar way to the images table. The eoi_p_id can also point at a foreign key in this table too. I have added an extra field 'eoi_type' which will either have the value 'image', or 'product'. Now items in the order could be made up of a mix of items from images or ecom_products. Whatever I try it either ends up with too many records, wont actually output any with eoi_type = 'product', and just generally wont work. Any ideas on how to achieve what I am after? Can provide SQL samples if needed? SELECT eoi_id, eoi_parentid, eoi_p_id, eoi_po_id, eoi_po_id_2, eoi_quantity, eoi_type, i_id, i_parentid, po_name, po_price, po_id, ep_id FROM ecom_order_items, images, c_print_options, ecom_products WHERE eoi_parentid = '9' AND i_id = eoi_p_id AND po_id = eoi_po_id The above outputs duplicate rows and doesnt work as expected. Am I going about this the wrong way? Should I have seperate foreign key fields for the eoi_p_id depending it its an image or a product? Should I be using JOINs? Here is a mysql explain of the tables in question ecom_products +-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | ep_id | int(8) | NO | PRI | NULL | auto_increment | | ep_title | varchar(255) | NO | | NULL | | | ep_link | text | NO | | NULL | | | ep_desc | text | NO | | NULL | | | ep_imgdrop | text | NO | | NULL | | | ep_price | decimal(6,2) | NO | | NULL | | | ep_category | varchar(255) | NO | | NULL | | | ep_hide | tinyint(1) | NO | | 0 | | | ep_featured | tinyint(1) | NO | | 0 | | +-------------+--------------+------+-----+---------+----------------+ ecom_order_items +--------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+----------------+ | eoi_id | int(8) | NO | PRI | NULL | auto_increment | | eoi_parentid | int(8) | NO | | NULL | | | eoi_type | varchar(32) | NO | | NULL | | | eoi_p_id | int(8) | NO | | NULL | | | eoi_po_id | int(8) | NO | | NULL | | | eoi_quantity | int(4) | NO | | NULL | | +--------------+-------------+------+-----+---------+----------------+ c_print_options +------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | po_id | int(8) | NO | PRI | NULL | auto_increment | | po_name | varchar(255) | NO | | NULL | | | po_price | decimal(6,2) | NO | | NULL | | +------------+--------------+------+-----+---------+----------------+ images +--------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+----------------+ | i_id | int(8) | NO | PRI | NULL | auto_increment | | i_filename | varchar(255) | NO | | NULL | | | i_data | longtext | NO | | NULL | | | i_parentid | int(8) | NO | | NULL | | +--------------+--------------+------+-----+---------+----------------+

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  • Can I avoid a threaded UDP socket in Pyton dropping data?

    - by 666craig
    First off, I'm new to Python and learning on the job, so be gentle! I'm trying to write a threaded Python app for Windows that reads data from a UDP socket (thread-1), writes it to file (thread-2), and displays the live data (thread-3) to a widget (gtk.Image using a gtk.gdk.pixbuf). I'm using queues for communicating data between threads. My problem is that if I start only threads 1 and 3 (so skip the file writing for now), it seems that I lose some data after the first few samples. After this drop it looks fine. Even by letting thread 1 complete before running thread 3, this apparent drop is still there. Apologies for the length of code snippet (I've removed the thread that writes to file), but I felt removing code would just prompt questions. Hope someone can shed some light :-) import socket import threading import Queue import numpy import gtk gtk.gdk.threads_init() import gtk.glade import pygtk class readFromUDPSocket(threading.Thread): def __init__(self, socketUDP, readDataQueue, packetSize, numScans): threading.Thread.__init__(self) self.socketUDP = socketUDP self.readDataQueue = readDataQueue self.packetSize = packetSize self.numScans = numScans def run(self): for scan in range(1, self.numScans + 1): buffer = self.socketUDP.recv(self.packetSize) self.readDataQueue.put(buffer) self.socketUDP.close() print 'myServer finished!' class displayWithGTK(threading.Thread): def __init__(self, displayDataQueue, image, viewArea): threading.Thread.__init__(self) self.displayDataQueue = displayDataQueue self.image = image self.viewWidth = viewArea[0] self.viewHeight = viewArea[1] self.displayData = numpy.zeros((self.viewHeight, self.viewWidth, 3), dtype=numpy.uint16) def run(self): scan = 0 try: while True: if not scan % self.viewWidth: scan = 0 buffer = self.displayDataQueue.get(timeout=0.1) self.displayData[:, scan, 0] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 1] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 2] = numpy.fromstring(buffer, dtype=numpy.uint16) gtk.gdk.threads_enter() self.myPixbuf = gtk.gdk.pixbuf_new_from_data(self.displayData.tostring(), gtk.gdk.COLORSPACE_RGB, False, 8, self.viewWidth, self.viewHeight, self.viewWidth * 3) self.image.set_from_pixbuf(self.myPixbuf) self.image.show() gtk.gdk.threads_leave() scan += 1 except Queue.Empty: print 'myDisplay finished!' pass def quitGUI(obj): print 'Currently active threads: %s' % threading.enumerate() gtk.main_quit() if __name__ == '__main__': # Create socket (IPv4 protocol, datagram (UDP)) and bind to address socketUDP = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) host = '192.168.1.5' port = 1024 socketUDP.bind((host, port)) # Data parameters samplesPerScan = 256 packetsPerSecond = 1200 packetSize = 512 duration = 1 # For now, set a fixed duration to log data numScans = int(packetsPerSecond * duration) # Create array to store data data = numpy.zeros((samplesPerScan, numScans), dtype=numpy.uint16) # Create queue for displaying from readDataQueue = Queue.Queue(numScans) # Build GUI from Glade XML file builder = gtk.Builder() builder.add_from_file('GroundVue.glade') window = builder.get_object('mainwindow') window.connect('destroy', quitGUI) view = builder.get_object('viewport') image = gtk.Image() view.add(image) viewArea = (1200, samplesPerScan) # Instantiate & start threads myServer = readFromUDPSocket(socketUDP, readDataQueue, packetSize, numScans) myDisplay = displayWithGTK(readDataQueue, image, viewArea) myServer.start() myDisplay.start() gtk.gdk.threads_enter() gtk.main() gtk.gdk.threads_leave() print 'gtk.main finished!'

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  • Postfix/SMTPD Relay Access Denied when sending outside the network

    - by David
    I asked a very similar question some 4 or 5 months ago, but haven't tracked down a suitable answer. I decided to post a new question so that I can ... a) Post updated info b) post my most current postconf -n output When a user sends mail from inside the network (via webmail) to email addresses both inside and outside the network, the email is delivered. When a user with an email account on the system sends mail from outside the network, using the server as the relay, to addresses inside the network, the email is delivered. But [sometimes] when a user connects via SMTPD to send email to an external address, a Relay Access Denied error is returned: Feb 25 19:33:49 myers postfix/smtpd[8044]: NOQUEUE: reject: RCPT from host-68-169-158-182.WISOLT2.epbfi.com[68.169.158.182]: 554 5.7.1 <host-68-169-158-182.WISOLT2.epbfi.com[68.169.158.182]>: Client host rejected: Access denied; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<my-computer-name> Feb 25 19:33:52 myers postfix/smtpd[8044]: disconnect from host-68-169-158-182.WISOLT2.epbfi.com[68.169.158.182] Sending this through Microsoft Outlook 2003 generates the above log. However, sending through my iPhone, with the exact same settings, goes through fine: Feb 25 19:37:18 myers postfix/qmgr[3619]: A2D861302C9: from=<[email protected]>, size=1382, nrcpt=1 (queue active) Feb 25 19:37:18 myers amavis[2799]: (02799-09) FWD via SMTP: <[email protected]> -> <[email protected]>,BODY=7BIT 250 2.0.0 Ok, id=02799-09, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as A2D861302C9 Feb 25 19:37:18 myers amavis[2799]: (02799-09) Passed CLEAN, [68.169.158.182] [68.169.158.182] <[email protected]> -> <[email protected]>, Message-ID: <[email protected]>, mail_id: yMLvzVQJloFV, Hits: -9.607, size: 897, queued_as: A2D861302C9, 6283 ms Feb 25 19:37:18 myers postfix/lmtp[8752]: 2ED3A1302C8: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=6.6, delays=0.25/0.01/0.19/6.1, dsn=2.0.0, status=sent (250 2.0.0 Ok, id=02799-09, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as A2D861302C9) Feb 25 19:37:18 myers postfix/qmgr[3619]: 2ED3A1302C8: removed Outgoing Settings on Outlook 2003 match the settings on my iPhone: SMTP server: mail.my-domain.com Username: My full email address Uses SSL Server Port 587 Now, here's postconf -n. I realize the "My Networks" Parameter is a bit nasty. I have these IP addresses in here for just this reason, as others have been complaining of this problem too: alias_database = hash:/etc/postfix/aliases alias_maps = $alias_database append_dot_mydomain = no biff = no broken_sasl_auth_clients = yes command_directory = /usr/sbin config_directory = /etc/postfix content_filter = amavisfeed:[127.0.0.1]:10024 daemon_directory = /usr/libexec/postfix debug_peer_level = 2 disable_vrfy_command = yes html_directory = no inet_interfaces = all mail_owner = postfix mail_spool_directory = /var/spool/mail mailbox_size_limit = 0 mailq_path = /usr/bin/mailq manpage_directory = /usr/share/man message_size_limit = 20480000 mydestination = $myhostname, localhost, localhost.$mydomain mydomain = my-domain.com myhostname = myers.my-domain.com mynetworks = 127.0.0.0/8, 74.125.113.27, 74.125.82.49, 74.125.79.27, 209.85.161.0/24, 209.85.214.0/24, 209.85.216.0/24, 209.85.212.0/24, 209.85.160.0/24 myorigin = $myhostname newaliases_path = /usr/bin/newaliases queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES receive_override_options = no_address_mappings recipient_delimiter = + relay_domains = $mydestination sample_directory = /usr/share/doc/postfix-2.3.3/samples sendmail_path = /usr/sbin/sendmail setgid_group = postdrop smtp_bind_address = my-primary-server's IP address smtpd_banner = mail.my-domain.com smtpd_helo_required = yes smtpd_sasl_auth_enable = yes smtpd_sasl_path = private/auth smtpd_sasl_type = dovecot smtpd_tls_auth_only = yes smtpd_tls_cert_file = /etc/ssl/mailserver/postfix.pem smtpd_tls_key_file = /etc/ssl/mailserver/private/postfix.pem smtpd_tls_loglevel = 3 smtpd_tls_received_header = no smtpd_tls_session_cache_timeout = 3600s smtpd_use_tls = yes tls_random_source = dev:/dev/urandom unknown_local_recipient_reject_code = 554 virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf,mysql:/etc/postfix/mysql-email2email.cf virtual_gid_maps = static:5000 virtual_mailbox_base = /var/vmail virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf virtual_minimum_uid = 5000 virtual_transport = dovecot virtual_uid_maps = static:5000 If anyone has any ideas and can help me finally solve this issue once and for all, I'd be eternally grateful.

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  • Postfix : relay access denied

    - by kfa
    Since I can't find a solution that works with my config, I lean on you guys to help me out with this. I've installed postfix and dovecot on a CentOS server. Everything's running well. But when I try to send an e-mail from Outlook to tld that is not .com, server returns : Relay access denied. Here's the result from the postconf -n command alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix data_directory = /var/lib/postfix debug_peer_level = 2 home_mailbox = Maildir/ html_directory = no inet_protocols = all mailbox_size_limit = 104857600 mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man message_size_limit = 20971520 mydestination = $myhostname, $mydomain, localhost, localhost.$mydomain newaliases_path = /usr/bin/newaliases.postfix readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES sample_directory = /usr/share/doc/postfix-2.6.6/samples sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop smtp_tls_loglevel = 3 smtpd_tls_auth_only = yes smtpd_tls_cert_file = /etc/postfix/mailserver.pem smtpd_tls_key_file = /etc/postfix/mailserver.pem smtpd_tls_received_header = yes smtpd_tls_security_level = encrypt smtpd_tls_session_cache_timeout = 3600s tls_random_source = dev:/dev/urandom unknown_local_recipient_reject_code = 550 Here's the maillog error : Nov 23 13:26:24 website_name postfix/smtpd[16391]: extract_addr: input: <mrm@website_name.com> Nov 23 13:26:24 website_name postfix/smtpd[16391]: smtpd_check_addr: addr=mrm@website_name.com Nov 23 13:26:24 website_name postfix/smtpd[16391]: ctable_locate: move existing entry key mrm@website_name.com Nov 23 13:26:24 website_name postfix/smtpd[16391]: extract_addr: in: <mrm@website_name.com>, result: mrm@website_name.com Nov 23 13:26:24 website_name postfix/smtpd[16391]: fsspace: .: block size 4096, blocks free 23679665 Nov 23 13:26:24 website_name postfix/smtpd[16391]: smtpd_check_queue: blocks 4096 avail 23679665 min_free 0 msg_size_limit 20971520 Nov 23 13:26:24 website_name postfix/smtpd[16391]: > unknown[178.193.xxx.xxx]: 250 2.1.0 Ok Nov 23 13:26:24 website_name postfix/smtpd[16391]: < unknown[178.193.xxx.xxx]: RCPT TO:<[email protected]> Nov 23 13:26:24 website_name postfix/smtpd[16391]: extract_addr: input: <[email protected]> Nov 23 13:26:24 website_name postfix/smtpd[16391]: smtpd_check_addr: [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: ctable_locate: move existing entry key [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: extract_addr: in: <[email protected]>, result: [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: >>> START Recipient address RESTRICTIONS <<< Nov 23 13:26:24 website_name postfix/smtpd[16391]: generic_checks: name=permit_sasl_authenticated Nov 23 13:26:24 website_name postfix/smtpd[16391]: generic_checks: name=permit_sasl_authenticated status=0 Nov 23 13:26:24 website_name postfix/smtpd[16391]: generic_checks: name=reject_unauth_destination Nov 23 13:26:24 website_name postfix/smtpd[16391]: reject_unauth_destination: [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: permit_auth_destination: [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: ctable_locate: leave existing entry key [email protected] Nov 23 13:26:24 website_name postfix/smtpd[16391]: NOQUEUE: reject: RCPT from unknown[178.193.xxx.xxx]: 554 5.7.1 <[email protected]>: Relay access denied; from=<mrm@website_name.com> to=<[email protected]> proto=ESMTP helo=<[192.168.1.38]> Nov 23 13:26:24 website_name postfix/smtpd[16391]: generic_checks: name=reject_unauth_destination status=2 Nov 23 13:26:24 website_name postfix/smtpd[16391]: > unknown[178.193.xxx.xxx]: 554 5.7.1 <[email protected]>: Relay access denied Nov 23 13:26:24 website_name postfix/smtpd[16391]: smtp_get: EOF What's wrong with this? UPDATE : added to main.cf broken_sasl_auth_clients = yes smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated smtpd_sasl_auth_enable = yes smtpd_sasl_path = private/auth smtpd_sasl_security_options = noanonymous noplaintext smtpd_sasl_tls_security_options = $smtpd_sasl_security_options smtpd_sasl_type = dovecot UPDATE : EHLO EHLO mail.perflux.com 250-perflux.com 250-PIPELINING 250-SIZE 20971520 250-VRFY 250-ETRN 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN

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  • CodePlex Daily Summary for Monday, February 22, 2010

    CodePlex Daily Summary for Monday, February 22, 2010New ProjectsAVDB: System to keep track of orders and the inventory of televisions, DVDs, VCRs etcBooky: Booky is an online Bookmark Management Tool. Gear Up for Lord of the Rings Online (lotro): Windows utility for checking what your LOTRO character currently has equipped and figuring out gear you should get to improve your stats.GotSharp Extensions: GotSharp Extensions is a set of helpful classes and extension methods that can make your coding experience easier and cleaner. Halfwit: A minimalist WPF Twitter client.HOA Starter Kit: A community subdivision website starter kit. First draft.Lua For Irony: Project to define the Lua language using the Irony (http://irony.codeplex.com/) development kit. This work is based heavily on the work done for V...MimeCloud: Scalable .NET Digital Asset & Media Management: MimeCloud is a scalable digital asset library & media management toolset. Founded by Alex Norcliffe and Peter Miller Written by people who have b...Parallel Mandelbrot Set solver: Solving the Mandelbrot set using the Parallel class in .NET 4.0. Showing the resulting image in a WPF application. The solution file requires VS 2010.Pomogad - Pomodoro Windows Gadget: Você usa Pomodoro Technique? Não sabe o que é? Veja aqui http://www.pomodorotechnique.com Agora que você já sabe, que tal usar essa técnica? E p...PostCrap - flyweight .NET AOP post compiler: PostCrap is a flyweight attribute based aspect injection .NET post compiler It is written in C# and uses Mono.Cecil to modify assemblies and injec...Software + Service Reference Demo Kit: MS China Developer and Platform Evangelism team created an End-2-End demo for Software + Service. Yet Another SharePoint Tool: YEAST provides you with a simple to integrate approach to generating SharePoint solution packages as part of a Visual Studio project. Zen Coding Visual Studio Plugin: Zen Coding for Visual Studio is plugin for HTML and CSS hi-speed codingNew Releases.Net MSBuild Google Closure Compiler Task: .Net MSBuild Google Closure Compiler Task 1.1: - Corrected issue with regular expression source file and renamingdotNails: dotNails_0.5.9: NOTE - the latest source code has been moved to google code to take advantage of Mercurial source control - http://code.google.com/p/dotnails/sourc...EasyWFUnit: EasyWFUnit-2.2: Release 2.2 of EasyWFUnit, an extension library to support unit testing of Windows Workflow, includes a revised WinForm GUI Test Builder that utili...Fluent Ribbon Control Suite: Fluent Ribbon Control Suite BETA2 (for .NET 4.0RC): Includes Fluent.dll (with .pdb and .xml) and test application compiled with .NET 4.0 RC.FolderSize: FolderSize.Win32.1.0.3.0: FolderSize.Win32.1.0.3.0 A simple utility intended to be used to scan harddrives for the folders that take most place and display this to the user...Fusion Charts Free for SharePoint: 1.3: Fix release for issue #11833 : Feature Must Be Activated on Root of Web Application.GotSharp Extensions: 1.0: First release, containing only a few extension methods for the System.String and System.IO.Stream classes, and a Range utility class.Jeremy's Experimental Repository: FluentValidation with IoC Sample: Sample code for the blog post Using FluentValidation with an IoC containerMiniTwitter: 1.08: MiniTwitter 1.08 更新内容 修正 自動更新が CodePlex の変更で動いていなかった問題を修正 自動更新に失敗すると落ちるバグを修正 通知領域アイコン右クリックで表示されるメニューが消えないバグを修正 変更 ハッシュタグの抽出条件を変更 API のエンドポイ...MSTS Editors & Tools: Simis Editor v0.3: Simis Editor v0.3 Enabled Edit > Undo and Edit > Redo. Undoing/redoing back to last saved state is identified as saved (no prompt on exit, etc.)....Parallel Mandelbrot Set solver: Alpha 1: First releaseParallelTasks: ParallelTasks 2.0 beta1: ParallelTasks 2.0 is a total re-write of the original version. Featuring improved performance and stability and a more consistent API.Personal Expense Tracker: Personal Expense Tracker v0.1 beta: This is the first beta release. Please provide me with your feedback.PostCrap - flyweight .NET AOP post compiler: PostCrap 1.0 AOP source and binaries: PostCrap 1.0 source and binaries (the unit test project contains sample interceptor attributes for exception handling & logging)Protoforma | Tactica Adversa: Skilful 0.1.3.276: AlphaRawr: Rawr 2.3.10: - More improvements to the default filters - Further improvement on avoiding useless gem swaps from the Optimizer. - Normal/Heroic ICC items shou...Reusable Library: v1.0.2: A collection of reusable abstractions for enterprise application developer.Sem.Sync: 2010-02-21 - Synchronization Manager - Beta: This release is not tested very well, so you should use this version only to evaluate new features. - Changed way of handling source-ids in order ...Survey - web survey & form engine: Survey 1.1.0: Release Survey v. 1.1.0.0 Major changes: - layout & graphics completely overhauled - several technical changes & repairs (e.g. matrix question iss...Yet Another SharePoint Tool: Version 1: Version 1Zeta Resource Editor: Release 2010-02-21: New source code release.Most Popular ProjectsWBFS ManagerRawrAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)Image Resizer Powertoy Clone for WindowsASP.NETDotNetNuke® Community EditionMicrosoft SQL Server Community & SamplesMost Active ProjectsDinnerNow.netRawrBlogEngine.NETNB_Store - Free DotNetNuke Ecommerce Catalog ModuleSharpyjQuery Library for SharePoint Web ServicesSharePoint ContribInfoServicepatterns & practices – Enterprise LibraryPHPExcel

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  • CodePlex Daily Summary for Friday, February 19, 2010

    CodePlex Daily Summary for Friday, February 19, 2010New ProjectsApplication Management Library: Application Management makes your application life easier. It will automatic do memory management, handle and log unhandled exceptions, profiling y...Audio Service - Play Wave Files From Windows Service: This is a windows service that Check a registry key, when the key is updated with a new wave file path the service plays the wave file.Aviamodels: 3d drawing AviamodelsControl of payment proofs program for Greek citizens: This is a program that is used for Greek citizens who want to keep track of their payment proofs.Cover Creator: Cover Creator gives you the possibility to create and print CD covers. Content of CD is taken from http://www.freedb.org/ or can be added/modyfied ...DevBoard: DevBoard is a webbased scrum tool that helps developers/team get a clear overview of the project progress. It's developed in C# and silverlight.Flex AdventureWorks: The is mostly a skunk-works application to help me get acclimated to CodePlex. The long term goal is to integrate a Flex UI with the AdventureWor...GRE Wordlist: An intuitive and customizable word list for GRE aspirants. Developed in Java using a word list similar to Barron's.Indexer: A desktop file Index and Search tool which allows you to choose a list of folders to index, and then search on later. It is based on Lucene.net an...Project Management Office (PMO) for SharePoint: Sample web part for the Code Mastery event in Boston, February 11, 2010.Restart SQL Audit Policy and Job: Resolve SQL 2008 Audit Network Connectivity Issue.Rounded Corners / DIV Container: The RoundedDiv round corners container is a skin-able, CSS compliant UI control. Select which corners should be rounded, collapse and expand the c...Silverlight Google Search Application: The Silverlight Google Search Application uses Google Search API and behaves like Internet Search Application with option to preview desired page i...Weather Forecast Control: MyWeather forecast control pulls up to date weather forecast information from The Weather Channel for your website.New ReleasesApplication Management Library: ApplicationManagement v1.0: First ReleaseAudio Service - Play Wave Files From Windows Service: Audio Service v1.0: This is a working version of the Audio Service. Please use as you need to.AutoMapper: 1.0.1 for Silverlight 3.0 Alpha: AutoMapper for Silverlight 3.0. Features not supported: IDataReader mapping IListSource mapping All other features are supported.Buzz Dot Net: Buzz Dot Net v.1.10219: Buzz Dot Net Library (Parser & Objects) + WPF Example (using MVVM & Threading)Canvas VSDOC Intellisense: V 1.0.0.0a: This release contains two JavaScript files: canvas-utils.js (can be referenced in both runtime and development environment) canvas-vsdoc.js (must ...Control of payment proofs program for Greek citizens: Payment Proofs: source codeCourier: Beta 2: Added Rx Framework support and re-factored how message registration and un-registration works Blog post explaining the updates and re-factoring c...Cover Creator: Initial release: This is initial stable release. For now only in Polish language.Employee Scheduler: Employee Scheduler 2.2: Small Bug found. Small total hour calculation bug. See http://employeescheduler.codeplex.com/WorkItem/View.aspx?WorkItemId=6059 Extract the files...EnhSim: Release v1.9.7.1: Release v1.9.7.1Implemented Dislodged Foreign Object trinket Whispering Fanged Skull now also procs off Flame shock dots You can toggle bloodlust o...Extend SmallBasic: Teaching Extensions v.007: added SimpleSquareTest added Tortoise.Approve() for virtual proctor how to use virtual proctor: change the path in the proctor.txt file (located i...FolderSize: FolderSize.Win32.1.0.1.0: FolderSize.Win32.1.0.1.0 A simple utility intended to be used to scan harddrives for the folders that take most place and display this to the user...GLB Virtual Player Builder: v0.4.0 Beta: Allows for user to import and use archetypes for building players. The archetypes are contained in the file "archetypes.xml". This file is editab...Google Map WebPart from SharePoint List: GMap Stable Release: GMap Stable ReleaseHenge3D Physics Library for XNA: Henge3D Source (2010-02 R2): Fixed a build error related to an assembly attribute in XBOX 360 builds. Tweaked the controls in the sample when targeting the 360. Reduced the...Indexer: Beta Release 1: Just the initial/rough cut.NukeCS: NukeCS 5.2.3 Source Code: update version to 5.2.3ODOS: ODOS STABLE 1.5.0: Thank you for your patience while we develop this version. Not that much has been added, though. Just doing some sub-conscious stuff to make life...PoshBoard: PoshBoard 3.0 Beta 1: Welcome to the first beta release of PoshBoard 3.0 ! IMPORTANT WARNING : this release is absolutly not feature complete and is error-prone. Okay, ...Restart SQL Audit Policy and Job: Restart SQL 2008 Audit Policy and Job: This folder contains three pieces of source code: Server Audit Status (Started).xml - Import this on-schedule policy into your server's Policy-Ba...SAL- Self Artificial Learning: Artificial Learning 2AQV Working Proof Of Concept: This is the Simulation proof of concept version that comes after the 1aq version. AQ stands for Anwering Questions.SharePoint 2010 Word Automation: SP 2010 Word Automation - Workflow Actions 1.1: This release includes two new custom workflow activities for SharePoint designer Convert Folder Convert Library More information about these new...SharePoint Outlook Connector: Version 1.0.1.1: Exception Logging has been improved.Sharpy: Sharpy 1.2 Alpha: This is the third Sharpy release. A change has been made to allow overriding the master page from the controller. The release contains the single ...Silverlight Google Search Application: SL Google Search App Alpha: This is just a first alpha version of the application, as it looks like when I uploaded it to CodePlex. The application works, requires Silverlight...Starter Kit Mytrip.Mvc.Entity: Mytrip.Mvc.Entity 1.0 RC: EF Membership UserManager FileManager Localization Captcha ClientValidation Theme CrossBrowser VS 2010 RC MVC 2 RC db MSSQL2008thinktecture WSCF.blue: WSCF.blue V1 Update (1.0.6): This release is an update for WSCF.blue V1. Below are the bug fixes made since the V1.0.5 release: The data contract type filter was not including...TS3QueryLib.Net: TS3QueryLib.Net Version 0.18.13.0: Changelog Added overloads to all methods of QueryRunenr class handling permission tasks to allow passing of permission name instead of permissionid...Umbraco CMS: Umbraco 4.1 Beta 2: This is the second beta of Umbraco 4.1. Umbraco 4.1 is more advanced than ever, yet faster, lighter and simpler to use than ever. We, on behalf of...VCC: Latest build, v2.1.30218.0: Automatic drop of latest buildZack's Fiasco - Code Generated DAL: v1.2.4: Enhancements: SQL Server CRUD Stored Procedures added option for USE <db> added option to create or not create INSERT sprocs added option to cr...Most Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)Image Resizer Powertoy Clone for WindowsASP.NETMicrosoft SQL Server Community & SamplesDotNetNuke® Community EditionMost Active ProjectsRawrSharpyDinnerNow.netBlogEngine.NETjQuery Library for SharePoint Web ServicesNB_Store - Free DotNetNuke Ecommerce Catalog Modulepatterns & practices – Enterprise LibraryPHPExcelFacebook Developer ToolkitFluent Ribbon Control Suite

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  • Parallelism in .NET – Part 15, Making Tasks Run: The TaskScheduler

    - by Reed
    In my introduction to the Task class, I specifically made mention that the Task class does not directly provide it’s own execution.  In addition, I made a strong point that the Task class itself is not directly related to threads or multithreading.  Rather, the Task class is used to implement our decomposition of tasks.  Once we’ve implemented our tasks, we need to execute them.  In the Task Parallel Library, the execution of Tasks is handled via an instance of the TaskScheduler class. The TaskScheduler class is an abstract class which provides a single function: it schedules the tasks and executes them within an appropriate context.  This class is the class which actually runs individual Task instances.  The .NET Framework provides two (internal) implementations of the TaskScheduler class. Since a Task, based on our decomposition, should be a self-contained piece of code, parallel execution makes sense when executing tasks.  The default implementation of the TaskScheduler class, and the one most often used, is based on the ThreadPool.  This can be retrieved via the TaskScheduler.Default property, and is, by default, what is used when we just start a Task instance with Task.Start(). Normally, when a Task is started by the default TaskScheduler, the task will be treated as a single work item, and run on a ThreadPool thread.  This pools tasks, and provides Task instances all of the advantages of the ThreadPool, including thread pooling for reduced resource usage, and an upper cap on the number of work items.  In addition, .NET 4 brings us a much improved thread pool, providing work stealing and reduced locking within the thread pool queues.  By using the default TaskScheduler, our Tasks are run asynchronously on the ThreadPool. There is one notable exception to my above statements when using the default TaskScheduler.  If a Task is created with the TaskCreationOptions set to TaskCreationOptions.LongRunning, the default TaskScheduler will generate a new thread for that Task, at least in the current implementation.  This is useful for Tasks which will persist for most of the lifetime of your application, since it prevents your Task from starving the ThreadPool of one of it’s work threads. The Task Parallel Library provides one other implementation of the TaskScheduler class.  In addition to providing a way to schedule tasks on the ThreadPool, the framework allows you to create a TaskScheduler which works within a specified SynchronizationContext.  This scheduler can be retrieved within a thread that provides a valid SynchronizationContext by calling the TaskScheduler.FromCurrentSynchronizationContext() method. This implementation of TaskScheduler is intended for use with user interface development.  Windows Forms and Windows Presentation Foundation both require any access to user interface controls to occur on the same thread that created the control.  For example, if you want to set the text within a Windows Forms TextBox, and you’re working on a background thread, that UI call must be marshaled back onto the UI thread.  The most common way this is handled depends on the framework being used.  In Windows Forms, Control.Invoke or Control.BeginInvoke is most often used.  In WPF, the equivelent calls are Dispatcher.Invoke or Dispatcher.BeginInvoke. As an example, say we’re working on a background thread, and we want to update a TextBlock in our user interface with a status label.  The code would typically look something like: // Within background thread work... string status = GetUpdatedStatus(); Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action( () => { statusLabel.Text = status; })); // Continue on in background method .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This works fine, but forces your method to take a dependency on WPF or Windows Forms.  There is an alternative option, however.  Both Windows Forms and WPF, when initialized, setup a SynchronizationContext in their thread, which is available on the UI thread via the SynchronizationContext.Current property.  This context is used by classes such as BackgroundWorker to marshal calls back onto the UI thread in a framework-agnostic manner. The Task Parallel Library provides the same functionality via the TaskScheduler.FromCurrentSynchronizationContext() method.  When setting up our Tasks, as long as we’re working on the UI thread, we can construct a TaskScheduler via: TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); We then can use this scheduler on any thread to marshal data back onto the UI thread.  For example, our code above can then be rewritten as: string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); // Continue on in background method This is nice since it allows us to write code that isn’t tied to Windows Forms or WPF, but is still fully functional with those technologies.  I’ll discuss even more uses for the SynchronizationContext based TaskScheduler when I demonstrate task continuations, but even without continuations, this is a very useful construct. In addition to the two implementations provided by the Task Parallel Library, it is possible to implement your own TaskScheduler.  The ParallelExtensionsExtras project within the Samples for Parallel Programming provides nine sample TaskScheduler implementations.  These include schedulers which restrict the maximum number of concurrent tasks, run tasks on a single threaded apartment thread, use a new thread per task, and more.

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