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  • Java invalid stream header Problem

    - by David zsl
    Hi all, im writen a client-server app, and now i´m facing a problem that I dont know how to solve: This is the client: try { Socket socket = new Socket(ip, port); ObjectOutputStream ooos = new ObjectOutputStream(socket .getOutputStream()); SendMessage message = new SendMessage(); message.numDoc = value.numDoc; message.docFreq = value.docFreq; message.queryTerms = query; message.startIndex = startIndex; message.count = count; message.multiple = false; message.ips = null; message.ports = null; message.value = true; message.docFreq = value.docFreq; message.numDoc = value.numDoc; ooos.writeObject(message); ObjectInputStream ois = new ObjectInputStream(socket .getInputStream()); ComConstants mensajeRecibido; Object mensajeAux; String mensa = null; byte[] by = null; do { mensajeAux = ois.readObject(); if (mensajeAux instanceof ComConstants) { System.out.println("Thread by Thread has Search Results"); String test; ByteArrayOutputStream testo = new ByteArrayOutputStream(); mensajeRecibido = (ComConstants) mensajeAux; byte[] wag; testo.write( mensajeRecibido.fileContent, 0, mensajeRecibido.okBytes); wag = testo.toByteArray(); if (by == null) { by = wag; } else { int size = wag.length; System.arraycopy(wag, 0, by, 0, size); } } else { System.err.println("Mensaje no esperado " + mensajeAux.getClass().getName()); break; } } while (!mensajeRecibido.lastMessage); //ByteArrayInputStream bs = new ByteArrayInputStream(by.toByteArray()); // bytes es el byte[] ByteArrayInputStream bs = new ByteArrayInputStream(by); ObjectInputStream is = new ObjectInputStream(bs); QueryWithResult[] unObjetoSerializable = (QueryWithResult[])is.readObject(); is.close(); //AQUI TOCARIA METER EL QUICKSORT XmlConverter xce = new XmlConverter(unObjetoSerializable, startIndex, count); String serializedd = xce.runConverter(); tempFinal = serializedd; ois.close(); socket.close(); } catch (Exception e) { e.printStackTrace(); } i++; } And this is the sender: try { QueryWithResult[] outputLine; Operations op = new Operations(); boolean enviadoUltimo=false; ComConstants mensaje = new ComConstants(); mensaje.queryTerms = query; outputLine = op.processInput(query, value); //String c = new String(); //c = outputLine.toString(); //StringBuffer swa = sw.getBuffer(); ByteArrayOutputStream bs= new ByteArrayOutputStream(); ObjectOutputStream os = new ObjectOutputStream (bs); os.writeObject(outputLine); os.close(); byte[] mybytearray = bs.toByteArray(); ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(mybytearray); BufferedInputStream bis = new BufferedInputStream(byteArrayInputStream); int readed = bis.read(mensaje.fileContent,0,4000); while (readed > -1) { mensaje.okBytes = readed; if (readed < ComConstants.MAX_LENGTH) { mensaje.lastMessage = true; enviadoUltimo=true; } else mensaje.lastMessage = false; oos.writeObject(mensaje); if (mensaje.lastMessage) break; mensaje = new ComConstants(); mensaje.queryTerms = query; readed = bis.read(mensaje.fileContent); } if (enviadoUltimo==false) { mensaje.lastMessage=true; mensaje.okBytes=0; oos.writeObject(mensaje); } oos.close(); } catch (Exception e) { e.printStackTrace(); } } And this is the error log: Thread by Thread has Search Results java.io.StreamCorruptedException: invalid stream header: 20646520 at java.io.ObjectInputStream.readStreamHeader(Unknown Source) at java.io.ObjectInputStream.<init>(Unknown Source) at org.tockit.comunication.ServerThread.enviaFicheroMultiple(ServerThread.java:747) at org.tockit.comunication.ServerThread.run(ServerThread.java:129) at java.lang.Thread.run(Unknown Source) Where at org.tockit.comunication.ServerThread.enviaFicheroMultiple(ServerThread.java:747) is this line ObjectInputStream is = new ObjectInputStream(bs); on the 1st code just after while (!mensajeRecibido.lastMessage); Any ideas?

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  • Stop the screen saver and hibernation temporarily in VB.Net

    - by Tim Santeford
    I have a very long running syncronization task that cannot be interrupted by the screen saver or aggressive power saving modes. I want to make a single api call to stop power save mode and then restore it once the task is done. The following code is peaced together from various other posts but it has no effect on XP's power management settings. What am I doing wrong? TIA! Private Declare Function SetThreadExecutionState Lib "kernel32" (ByVal esFlags As Long) As Long Public Enum EXECUTION_STATE As Integer ES_CONTINUOUS = &H80000000 ES_DISPLAY_REQUIRED = &H2 ES_SYSTEM_REQUIRED = &H1 ES_AWAYMODE_REQUIRED = &H40 End Enum Public Shared Sub PowerSaveOff() SetThreadExecutionState(EXECUTION_STATE.ES_DISPLAY_REQUIRED Or EXECUTION_STATE.ES_CONTINUOUS) End Sub Public Shared Sub PowerSaveOn() SetThreadExecutionState(EXECUTION_STATE.ES_CONTINUOUS) End Sub Here are the systems screensaver and powermode settings:

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  • Computer crashes on resume from standby almost every time

    - by Los Frijoles
    I am running Ubuntu 12.04 on a Core i5 2500K and ASRock Z68 Pro3-M motherboard (no graphics card, hd is a WD Green 1TB, and cd drive is some cheap lite-on drive). Since installing 12.04, my computer has been freezing after resume, but not every time. When I start to resume, it starts going normally with a blinking cursor on the screen and then sometimes it will continue on to the gnome 3 unlock screen. Most of the time, however, it will blink for a little bit and then the monitor will flip modes and shut off due to no signal. Pressing keys on the keyboard gets no response (num lock light doesn't respond, Ctrl-Alt-F1 fails to drop it into a terminal, Ctrl-Alt-Backspace doesn't work) and so I assume the computer is crashed. The worst part is, the logs look entirely normal. Here is my system log during one of these crashes and my subsequent hard poweroff and restart: Jun 6 21:54:43 kcuzner-desktop udevd[10448]: inotify_add_watch(6, /dev/dm-2, 10) failed: No such file or directory Jun 6 21:54:43 kcuzner-desktop udevd[10448]: inotify_add_watch(6, /dev/dm-2, 10) failed: No such file or directory Jun 6 21:54:43 kcuzner-desktop udevd[10448]: inotify_add_watch(6, /dev/dm-1, 10) failed: No such file or directory Jun 6 21:54:43 kcuzner-desktop udevd[12419]: inotify_add_watch(6, /dev/dm-0, 10) failed: No such file or directory Jun 6 21:54:43 kcuzner-desktop udevd[10448]: inotify_add_watch(6, /dev/dm-0, 10) failed: No such file or directory Jun 6 22:09:01 kcuzner-desktop CRON[9061]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {} 2>/dev/null \; -delete) Jun 6 22:17:01 kcuzner-desktop CRON[22142]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) Jun 6 22:39:01 kcuzner-desktop CRON[26909]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {} 2>/dev/null \; -delete) Jun 6 22:54:21 kcuzner-desktop kernel: [57905.560822] show_signal_msg: 36 callbacks suppressed Jun 6 22:54:21 kcuzner-desktop kernel: [57905.560828] chromium-browse[9139]: segfault at 0 ip 00007f3a78efade0 sp 00007fff7e2d2c18 error 4 in chromium-browser[7f3a76604000+412b000] Jun 6 23:05:43 kcuzner-desktop kernel: [58586.415158] chromium-browse[21025]: segfault at 0 ip 00007f3a78efade0 sp 00007fff7e2d2c18 error 4 in chromium-browser[7f3a76604000+412b000] Jun 6 23:09:01 kcuzner-desktop CRON[13542]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {} 2>/dev/null \; -delete) Jun 6 23:12:43 kcuzner-desktop kernel: [59006.317590] usb 2-1.7: USB disconnect, device number 8 Jun 6 23:12:43 kcuzner-desktop kernel: [59006.319672] sd 7:0:0:0: [sdg] Synchronizing SCSI cache Jun 6 23:12:43 kcuzner-desktop kernel: [59006.319737] sd 7:0:0:0: [sdg] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK Jun 6 23:17:01 kcuzner-desktop CRON[26580]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) Jun 6 23:19:04 kcuzner-desktop acpid: client connected from 29925[0:0] Jun 6 23:19:04 kcuzner-desktop acpid: 1 client rule loaded Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Successfully made thread 30131 of process 30131 (n/a) owned by '104' high priority at nice level -11. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Supervising 1 threads of 1 processes of 1 users. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Successfully made thread 30162 of process 30131 (n/a) owned by '104' RT at priority 5. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Supervising 2 threads of 1 processes of 1 users. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Successfully made thread 30163 of process 30131 (n/a) owned by '104' RT at priority 5. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Supervising 3 threads of 1 processes of 1 users. Jun 6 23:19:07 kcuzner-desktop bluetoothd[1140]: Endpoint registered: sender=:1.239 path=/MediaEndpoint/HFPAG Jun 6 23:19:07 kcuzner-desktop bluetoothd[1140]: Endpoint registered: sender=:1.239 path=/MediaEndpoint/A2DPSource Jun 6 23:19:07 kcuzner-desktop bluetoothd[1140]: Endpoint registered: sender=:1.239 path=/MediaEndpoint/A2DPSink Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Successfully made thread 30166 of process 30166 (n/a) owned by '104' high priority at nice level -11. Jun 6 23:19:07 kcuzner-desktop rtkit-daemon[1835]: Supervising 4 threads of 2 processes of 1 users. Jun 6 23:19:07 kcuzner-desktop pulseaudio[30166]: [pulseaudio] pid.c: Daemon already running. Jun 6 23:19:10 kcuzner-desktop acpid: client 2942[0:0] has disconnected Jun 6 23:19:10 kcuzner-desktop acpid: client 29925[0:0] has disconnected Jun 6 23:19:10 kcuzner-desktop acpid: client connected from 1286[0:0] Jun 6 23:19:10 kcuzner-desktop acpid: 1 client rule loaded Jun 6 23:19:31 kcuzner-desktop bluetoothd[1140]: Endpoint unregistered: sender=:1.239 path=/MediaEndpoint/HFPAG Jun 6 23:19:31 kcuzner-desktop bluetoothd[1140]: Endpoint unregistered: sender=:1.239 path=/MediaEndpoint/A2DPSource Jun 6 23:19:31 kcuzner-desktop bluetoothd[1140]: Endpoint unregistered: sender=:1.239 path=/MediaEndpoint/A2DPSink Jun 6 23:28:12 kcuzner-desktop kernel: imklog 5.8.6, log source = /proc/kmsg started. Jun 6 23:28:12 kcuzner-desktop rsyslogd: [origin software="rsyslogd" swVersion="5.8.6" x-pid="1053" x-info="http://www.rsyslog.com"] start Jun 6 23:28:12 kcuzner-desktop rsyslogd: rsyslogd's groupid changed to 103 Jun 6 23:28:12 kcuzner-desktop rsyslogd: rsyslogd's userid changed to 101 Jun 6 23:28:12 kcuzner-desktop rsyslogd-2039: Could not open output pipe '/dev/xconsole' [try http://www.rsyslog.com/e/2039 ] Jun 6 23:28:12 kcuzner-desktop modem-manager[1070]: <info> Loaded plugin Ericsson MBM Jun 6 23:28:12 kcuzner-desktop modem-manager[1070]: <info> Loaded plugin Sierra Jun 6 23:28:12 kcuzner-desktop modem-manager[1070]: <info> Loaded plugin Generic Jun 6 23:28:12 kcuzner-desktop modem-manager[1070]: <info> Loaded plugin Huawei Jun 6 23:28:12 kcuzner-desktop modem-manager[1070]: <info> Loaded plugin Linktop Jun 6 23:28:12 kcuzner-desktop bluetoothd[1072]: Failed to init gatt_example plugin Jun 6 23:28:12 kcuzner-desktop bluetoothd[1072]: Listening for HCI events on hci0 Jun 6 23:28:12 kcuzner-desktop NetworkManager[1080]: <info> NetworkManager (version 0.9.4.0) is starting... Jun 6 23:28:12 kcuzner-desktop NetworkManager[1080]: <info> Read config file /etc/NetworkManager/NetworkManager.conf Jun 6 23:28:12 kcuzner-desktop NetworkManager[1080]: <info> VPN: loaded org.freedesktop.NetworkManager.pptp Jun 6 23:28:12 kcuzner-desktop NetworkManager[1080]: <info> DNS: loaded plugin dnsmasq Jun 6 23:28:12 kcuzner-desktop kernel: [ 0.000000] Initializing cgroup subsys cpuset Jun 6 23:28:12 kcuzner-desktop kernel: [ 0.000000] Initializing cgroup subsys cpu Sorry it's so huge; the restart happens at 23:28:12 I believe and all I see is that chromium segfaulted a few times. I wouldn't think a segfault from an individual program on the computer would crash it, but could that be the issue?

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  • Cant delete more than 200 contacts in HTC HERO

    - by rahul
    I'm working on security application which will copy all contacts to some other database and delete all contacts from phonebook. I'm testing this on android HTC HERO. I'm successful to delete contacts from phonebook and create new contact info database, Till 200 it is working, but after 200 contacts its not working properly. After tht application starts throwing error. There is one Sync with Google Option in MenuSettingData Sync, I think that is creating problem. There is notification that "Too many contacts deleted" n if i click tht there will b a dialog with title "Delete Limit exceeded". Is there anything i can do to stop syncronization or any other ideas by which i can achieve required output? Please Help me on this

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  • Techniques for modeling a dynamic dataflow with Java concurrency API

    - by Maian
    Is there an elegant way to model a dynamic dataflow in Java? By dataflow, I mean there are various types of tasks, and these tasks can be "connected" arbitrarily, such that when a task finishes, successor tasks are executed in parallel using the finished tasks output as input, or when multiple tasks finish, their output is aggregated in a successor task (see flow-based programming). By dynamic, I mean that the type and number of successors tasks when a task finishes depends on the output of that finished task, so for example, task A may spawn task B if it has a certain output, but may spawn task C if has a different output. Another way of putting it is that each task (or set of tasks) is responsible for determining what the next tasks are. Sample dataflow for rendering a webpage: I have as task types: file downloader, HTML/CSS renderer, HTML parser/DOM builder, image renderer, JavaScript parser, JavaScript interpreter. File downloader task for HTML file HTML parser/DOM builder task File downloader task for each embedded file/link If image, image renderer If external JavaScript, JavaScript parser JavaScript interpreter Otherwise, just store in some var/field in HTML parser task JavaScript parser for each embedded script JavaScript interpreter Wait for above tasks to finish, then HTML/CSS renderer (obviously not optimal or perfectly correct, but this is simple) I'm not saying the solution needs to be some comprehensive framework (in fact, the closer to the JDK API, the better), and I absolutely don't want something as heavyweight is say Spring Web Flow or some declarative markup or other DSL. To be more specific, I'm trying to think of a good way to model this in Java with Callables, Executors, ExecutorCompletionServices, and perhaps various synchronizer classes (like Semaphore or CountDownLatch). There are a couple use cases and requirements: Don't make any assumptions on what executor(s) the tasks will run on. In fact, to simplify, just assume there's only one executor. It can be a fixed thread pool executor, so a naive implementation can result in deadlocks (e.g. imagine a task that submits another task and then blocks until that subtask is finished, and now imagine several of these tasks using up all the threads). To simplify, assume that the data is not streamed between tasks (task output-succeeding task input) - the finishing task and succeeding task won't exist together, so the input data to the succeeding task will not be changed by the preceeding task (since it's already done). There are only a couple operations that the dataflow "engine" should be able to handle: A mechanism where a task can queue more tasks A mechanism whereby a successor task is not queued until all the required input tasks are finished A mechanism whereby the main thread (or other threads not managed by the executor) blocks until the flow is finished A mechanism whereby the main thread (or other threads not managed by the executor) blocks until certain tasks have finished Since the dataflow is dynamic (depends on input/state of the task), the activation of these mechanisms should occur within the task code, e.g. the code in a Callable is itself responsible for queueing more Callables. The dataflow "internals" should not be exposed to the tasks (Callables) themselves - only the operations listed above should be available to the task. Note that the type of the data is not necessarily the same for all tasks, e.g. a file download task may accept a File as input but will output a String. If a task throws an uncaught exception (indicating some fatal error requiring all dataflow processing to stop), it must propagate up to the thread that initiated the dataflow as quickly as possible and cancel all tasks (or something fancier like a fatal error handler). Tasks should be launched as soon as possible. This along with the previous requirement should preclude simple Future polling + Thread.sleep(). As a bonus, I would like to dataflow engine itself to perform some action (like logging) every time task is finished or when no has finished in X time since last task has finished. Something like: ExecutorCompletionService<T> ecs; while (hasTasks()) { Future<T> future = ecs.poll(1 minute); some_action_like_logging(); if (future != null) { future.get() ... } ... } Are there straightforward ways to do all this with Java concurrency API? Or if it's going to complex no matter what with what's available in the JDK, is there a lightweight library that satisfies the requirements? I already have a partial solution that fits my particular use case (it cheats in a way, since I'm using two executors, and just so you know, it's not related at all to the web browser example I gave above), but I'd like to see a more general purpose and elegant solution.

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  • Listview selects mutliple items when clicked

    - by xlph
    I'm trying to make a task manager, and I only have one problem. I have a listview that gets inflated. All the elements in the listview are correct. The problem is that when I select an item, the listview will select another item away. I've heard listviews repopulate the list as it scrolls down to save memory. I think this may be some sort of problem. Here is a picture of the problem. If i had more apps loaded, then it would continue to select multiple at once. Here is the code of my adapter and activity and XML associated public class TaskAdapter extends BaseAdapter{ private Context mContext; private List<TaskInfo> mListAppInfo; private PackageManager mPack; public TaskAdapter(Context c, List<TaskInfo> list, PackageManager pack) { mContext = c; mListAppInfo = list; mPack = pack; } @Override public int getCount() { return mListAppInfo.size(); } @Override public Object getItem(int position) { return mListAppInfo.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(final int position, View convertView, ViewGroup parent) { TaskInfo entry = mListAppInfo.get(position); if (convertView == null) { LayoutInflater inflater = LayoutInflater.from(mContext); //System.out.println("Setting LayoutInflater in TaskAdapter " +mContext +" " +R.layout.taskinfo +" " +R.id.tmbox); convertView = inflater.inflate(R.layout.taskinfo,null); } ImageView ivIcon = (ImageView)convertView.findViewById(R.id.tmImage); ivIcon.setImageDrawable(entry.getIcon()); TextView tvName = (TextView)convertView.findViewById(R.id.tmbox); tvName.setText(entry.getName()); convertView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { final CheckBox checkBox = (CheckBox)v.findViewById(R.id.tmbox); if(v.isSelected()) { System.out.println("Listview not selected "); //CK.get(arg2).setChecked(false); checkBox.setChecked(false); v.setSelected(false); } else { System.out.println("Listview selected "); //CK.get(arg2).setChecked(true); checkBox.setChecked(true); v.setSelected(true); } } }); return convertView; public class TaskManager extends Activity implements Runnable { private ProgressDialog pd; private TextView ram; private String s; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.taskpage); setTitleColor(Color.YELLOW); Thread thread = new Thread(this); thread.start(); } @Override public void run() { //System.out.println("In Taskmanager Run() Thread"); final PackageManager pm = getPackageManager(); final ListView box = (ListView) findViewById(R.id.cBoxSpace); final List<TaskInfo> CK = populate(box, pm); runOnUiThread(new Runnable() { @Override public void run() { ram.setText(s); box.setAdapter(new TaskAdapter(TaskManager.this, CK, pm)); //System.out.println("In Taskmanager runnable Run()"); endChecked(CK); } }); handler.sendEmptyMessage(0); } Taskinfo.xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center_horizontal"> <ImageView android:id="@+id/tmImage" android:layout_width="48dp" android:layout_height="48dp" android:scaleType="centerCrop" android:adjustViewBounds="false" android:focusable="false" /> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tmbox" android:lines="2"/> </LinearLayout> Taskpage.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <ListView android:id="@+id/cBoxSpace" android:layout_width="wrap_content" android:layout_height="400dp" android:orientation="vertical"/> <TextView android:id="@+id/RAM" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="18sp" /> <Button android:id="@+id/endButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="End Selected Tasks" /> </LinearLayout> Any ideas for what reason mutliple items are selected with a single click would be GREATLY appreciated. I've been messing around with different implementations and listeners and listadapters but to no avail.

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  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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  • parallel_for_each from amp.h – part 1

    - by Daniel Moth
    This posts assumes that you've read my other C++ AMP posts on index<N> and extent<N>, as well as about the restrict modifier. It also assumes you are familiar with C++ lambdas (if not, follow my links to C++ documentation). Basic structure and parameters Now we are ready for part 1 of the description of the new overload for the concurrency::parallel_for_each function. The basic new parallel_for_each method signature returns void and accepts two parameters: a grid<N> (think of it as an alias to extent) a restrict(direct3d) lambda, whose signature is such that it returns void and accepts an index of the same rank as the grid So it looks something like this (with generous returns for more palatable formatting) assuming we are dealing with a 2-dimensional space: // some_code_A parallel_for_each( g, // g is of type grid<2> [ ](index<2> idx) restrict(direct3d) { // kernel code } ); // some_code_B The parallel_for_each will execute the body of the lambda (which must have the restrict modifier), on the GPU. We also call the lambda body the "kernel". The kernel will be executed multiple times, once per scheduled GPU thread. The only difference in each execution is the value of the index object (aka as the GPU thread ID in this context) that gets passed to your kernel code. The number of GPU threads (and the values of each index) is determined by the grid object you pass, as described next. You know that grid is simply a wrapper on extent. In this context, one way to think about it is that the extent generates a number of index objects. So for the example above, if your grid was setup by some_code_A as follows: extent<2> e(2,3); grid<2> g(e); ...then given that: e.size()==6, e[0]==2, and e[1]=3 ...the six index<2> objects it generates (and hence the values that your lambda would receive) are:    (0,0) (1,0) (0,1) (1,1) (0,2) (1,2) So what the above means is that the lambda body with the algorithm that you wrote will get executed 6 times and the index<2> object you receive each time will have one of the values just listed above (of course, each one will only appear once, the order is indeterminate, and they are likely to call your code at the same exact time). Obviously, in real GPU programming, you'd typically be scheduling thousands if not millions of threads, not just 6. If you've been following along you should be thinking: "that is all fine and makes sense, but what can I do in the kernel since I passed nothing else meaningful to it, and it is not returning any values out to me?" Passing data in and out It is a good question, and in data parallel algorithms indeed you typically want to pass some data in, perform some operation, and then typically return some results out. The way you pass data into the kernel, is by capturing variables in the lambda (again, if you are not familiar with them, follow the links about C++ lambdas), and the way you use data after the kernel is done executing is simply by using those same variables. In the example above, the lambda was written in a fairly useless way with an empty capture list: [ ](index<2> idx) restrict(direct3d), where the empty square brackets means that no variables were captured. If instead I write it like this [&](index<2> idx) restrict(direct3d), then all variables in the some_code_A region are made available to the lambda by reference, but as soon as I try to use any of those variables in the lambda, I will receive a compiler error. This has to do with one of the direct3d restrictions, where only one type can be capture by reference: objects of the new concurrency::array class that I'll introduce in the next post (suffice for now to think of it as a container of data). If I write the lambda line like this [=](index<2> idx) restrict(direct3d), all variables in the some_code_A region are made available to the lambda by value. This works for some types (e.g. an integer), but not for all, as per the restrictions for direct3d. In particular, no useful data classes work except for one new type we introduce with C++ AMP: objects of the new concurrency::array_view class, that I'll introduce in the post after next. Also note that if you capture some variable by value, you could use it as input to your algorithm, but you wouldn’t be able to observe changes to it after the parallel_for_each call (e.g. in some_code_B region since it was passed by value) – the exception to this rule is the array_view since (as we'll see in a future post) it is a wrapper for data, not a container. Finally, for completeness, you can write your lambda, e.g. like this [av, &ar](index<2> idx) restrict(direct3d) where av is a variable of type array_view and ar is a variable of type array - the point being you can be very specific about what variables you capture and how. So it looks like from a large data perspective you can only capture array and array_view objects in the lambda (that is how you pass data to your kernel) and then use the many threads that call your code (each with a unique index) to perform some operation. You can also capture some limited types by value, as input only. When the last thread completes execution of your lambda, the data in the array_view or array are ready to be used in the some_code_B region. We'll talk more about all this in future posts… (a)synchronous Please note that the parallel_for_each executes as if synchronous to the calling code, but in reality, it is asynchronous. I.e. once the parallel_for_each call is made and the kernel has been passed to the runtime, the some_code_B region continues to execute immediately by the CPU thread, while in parallel the kernel is executed by the GPU threads. However, if you try to access the (array or array_view) data that you captured in the lambda in the some_code_B region, your code will block until the results become available. Hence the correct statement: the parallel_for_each is as-if synchronous in terms of visible side-effects, but asynchronous in reality.   That's all for now, we'll revisit the parallel_for_each description, once we introduce properly array and array_view – coming next. Comments about this post by Daniel Moth welcome at the original blog.

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  • Hibernate Lazy init exception in spring scheduled job

    - by Noam Nevo
    I have a spring scheduled job (@Scheduled) that sends emails from my system according to a list of recipients in the DB. This method is annotated with the @Scheduled annotation and it invokes a method from another interface, the method in the interface is annotated with the @Transactional annotation. Now, when i invoke the scheduled method manually, it works perfectly. But when the method is invoked by spring scheduler i get the LazyInitFailed exception in the method implementing the said interface. What am I doing wrong? code: The scheduled method: @Component public class ScheduledReportsSender { public static final int MAX_RETIRES = 3; public static final long HALF_HOUR = 1000 * 60 * 30; @Autowired IScheduledReportDAO scheduledReportDAO; @Autowired IDataService dataService; @Autowired IErrorService errorService; @Scheduled(cron = "0 0 3 ? * *") // every day at 2:10AM public void runDailyReports() { // get all daily reports List<ScheduledReport> scheduledReports = scheduledReportDAO.getDaily(); sendScheduledReports(scheduledReports); } private void sendScheduledReports(List<ScheduledReport> scheduledReports) { if(scheduledReports.size()<1) { return; } //check if data flow ended its process by checking the report_last_updated table in dwh int reportTimeId = scheduledReportDAO.getReportTimeId(); String todayTimeId = DateUtils.getTimeid(DateUtils.getTodayDate()); int yesterdayTimeId = Integer.parseInt(DateUtils.addDaysSafe(todayTimeId, -1)); int counter = 0; //wait for time id to update from the daily flow while (reportTimeId != yesterdayTimeId && counter < MAX_RETIRES) { errorService.logException("Daily report sender, data not ready. Will try again in one hour.", null, null, null); try { Thread.sleep(HALF_HOUR); } catch (InterruptedException ignore) {} reportTimeId = scheduledReportDAO.getReportTimeId(); counter++; } if (counter == MAX_RETIRES) { MarketplaceServiceException mse = new MarketplaceServiceException(); mse.setMessage("Data flow not done for today, reports are not sent."); throw mse; } // get updated timeid updateTimeId(); for (ScheduledReport scheduledReport : scheduledReports) { dataService.generateScheduledReport(scheduledReport); } } } The Invoked interface: public interface IDataService { @Transactional public void generateScheduledReport(ScheduledReport scheduledReport); } The implementation (up to the line of the exception): @Service public class DataService implements IDataService { public void generateScheduledReport(ScheduledReport scheduledReport) { // if no recipients or no export type - return if(scheduledReport.getRecipients()==null || scheduledReport.getRecipients().size()==0 || scheduledReport.getExportType() == null) { return; } } } Stack trace: ERROR: 2012-09-01 03:30:00,365 [Scheduler-15] LazyInitializationException.<init>(42) | failed to lazily initialize a collection of role: com.x.model.scheduledReports.ScheduledReport.recipients, no session or session was closed org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.x.model.scheduledReports.ScheduledReport.recipients, no session or session was closed at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383) at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375) at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:122) at org.hibernate.collection.PersistentBag.size(PersistentBag.java:248) at com.x.service.DataService.generateScheduledReport(DataService.java:219) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy208.generateScheduledReport(Unknown Source) at com.x.scheduledJobs.ScheduledReportsSender.sendScheduledReports(ScheduledReportsSender.java:85) at com.x.scheduledJobs.ScheduledReportsSender.runDailyReports(ScheduledReportsSender.java:38) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273) at org.springframework.scheduling.support.MethodInvokingRunnable.run(MethodInvokingRunnable.java:65) at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:51) at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:81) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:165) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:636) ERROR: 2012-09-01 03:30:00,366 [Scheduler-15] MethodInvokingRunnable.run(68) | Invocation of method 'runDailyReports' on target class [class com.x.scheduledJobs.ScheduledReportsSender] failed org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.x.model.scheduledReports.ScheduledReport.recipients, no session or session was closed at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383) at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375) at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:122) at org.hibernate.collection.PersistentBag.size(PersistentBag.java:248) at com.x.service.DataService.generateScheduledReport(DataService.java:219) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy208.generateScheduledReport(Unknown Source) at com.x.scheduledJobs.ScheduledReportsSender.sendScheduledReports(ScheduledReportsSender.java:85) at com.x.scheduledJobs.ScheduledReportsSender.runDailyReports(ScheduledReportsSender.java:38) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273) at org.springframework.scheduling.support.MethodInvokingRunnable.run(MethodInvokingRunnable.java:65) at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:51) at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:81) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:165) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:636)

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  • How should I delete a child object from within a parent's slot? Possibly boost::asio specific.

    - by kaliatech
    I have written a network server class that maintains a std::set of network clients. The network clients emit a signal to the network server on disconnect (via boost::bind). When a network client disconnects, the client instance needs to be removed from the Set and eventually deleted. I would think this is a common pattern, but I am having problems that might, or might not, be specific to ASIO. I've tried to trim down to just the relevant code: /** NetworkServer.hpp **/ class NetworkServices : private boost::noncopyable { public: NetworkServices(void); ~NetworkServices(void); private: void run(); void onNetworkClientEvent(NetworkClientEvent&); private: std::set<boost::shared_ptr<const NetworkClient>> clients; }; /** NetworkClient.cpp **/ void NetworkServices::run() { running = true; boost::asio::io_service::work work(io_service); //keeps service running even if no operations // This creates just one thread for the boost::asio async network services boost::thread iot(boost::bind(&NetworkServices::run_io_service, this)); while (running) { boost::system::error_code err; try { tcp::socket* socket = new tcp::socket(io_service); acceptor->accept(*socket, err); if (!err) { NetworkClient* networkClient = new NetworkClient(io_service, boost::shared_ptr<tcp::socket>(socket)); networkClient->networkClientEventSignal.connect(boost::bind(&NetworkServices::onNetworkClientEvent, this, _1)); clients.insert(boost::shared_ptr<NetworkClient>(networkClient)); networkClient->init(); //kicks off 1st asynch_read call } } // etc... } } void NetworkServices::onNetworkClientEvent(NetworkClientEvent& evt) { switch(evt.getType()) { case NetworkClientEvent::CLIENT_ERROR : { boost::shared_ptr<const NetworkClient> clientPtr = evt.getClient().getSharedPtr(); // ------ THIS IS THE MAGIC LINE ----- // If I keep this, the io_service hangs. If I comment it out, // everything works fine (but I never delete the disconnected NetworkClient). // If actually deleted the client here I might expect problems because it is the caller // of this method via boost::signal and bind. However, The clientPtr is a shared ptr, and a // reference is being kept in the client itself while signaling, so // I would the object is not going to be deleted from the heap here. That seems to be the case. // Never-the-less, this line makes all the difference, most likely because it controls whether or not the NetworkClient ever gets deleted. clients.erase(clientPtr); //I should probably put this socket clean-up in NetworkClient destructor. Regardless by doing this, // I would expect the ASIO socket stuff to be adequately cleaned-up after this. tcp::socket& socket = clientPtr->getSocket(); try { socket.shutdown(boost::asio::socket_base::shutdown_both); socket.close(); } catch(...) { CommServerContext::error("Error while shutting down and closing socket."); } break; } default : { break; } } } /** NetworkClient.hpp **/ class NetworkClient : public boost::enable_shared_from_this<NetworkClient>, Client { NetworkClient(boost::asio::io_service& io_service, boost::shared_ptr<tcp::socket> socket); virtual ~NetworkClient(void); inline boost::shared_ptr<const NetworkClient> getSharedPtr() const { return shared_from_this(); }; boost::signal <void (NetworkClientEvent&)> networkClientEventSignal; void onAsyncReadHeader(const boost::system::error_code& error, size_t bytes_transferred); }; /** NetworkClient.cpp - onAsyncReadHeader method called from io_service.run() thread as result of an async_read operation. Error condition usually result of an unexpected client disconnect.**/ void NetworkClient::onAsyncReadHeader( const boost::system::error_code& error, size_t bytes_transferred) { if (error) { //Make sure this instance doesn't get deleted from parent/slot deferencing //Alternatively, somehow schedule for future delete? boost::shared_ptr<const NetworkClient> clientPtr = getSharedPtr(); //Signal to service that this client is disconnecting NetworkClientEvent evt(*this, NetworkClientEvent::CLIENT_ERROR); networkClientEventSignal(evt); networkClientEventSignal.disconnect_all_slots(); return; } I believe it's not safe to delete the client from within the slot handler because the function return would be ... undefined? (Interestingly, it doesn't seem to blow up on me though.) So I've used boost:shared_ptr along with shared_from_this to make sure the client doesn't get deleted until all slots have been signaled. It doesn't seem to really matter though. I believe this question is not specific to ASIO, but the problem manifests in a peculiar way when using ASIO. I have one thread executing io_service.run(). All ASIO read/write operations are performed asynchronously. Everything works fine with multiple clients connecting/disconnecting UNLESS I delete my client object from the Set per the code above. If I delete my client object, the io_service seemingly deadlocks internally and no further asynchronous operations are performed unless I start another thread. I have try/catches around the io_service.run() call and have not been able to detect any errors. Questions: Are there best practices for deleting child objects, that are also signal emitters, from within parent slots? Any ideas as to why the io_service is hanging when I delete my network client object?

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  • Entity Framework 6: Alpha2 Now Available

    - by ScottGu
    The Entity Framework team recently announced the 2nd alpha release of EF6.   The alpha 2 package is available for download from NuGet. Since this is a pre-release package make sure to select “Include Prereleases” in the NuGet package manager, or execute the following from the package manager console to install it: PM> Install-Package EntityFramework -Pre This week’s alpha release includes a bunch of great improvements in the following areas: Async language support is now available for queries and updates when running on .NET 4.5. Custom conventions now provide the ability to override the default conventions that Code First uses for mapping types, properties, etc. to your database. Multi-tenant migrations allow the same database to be used by multiple contexts with full Code First Migrations support for independently evolving the model backing each context. Using Enumerable.Contains in a LINQ query is now handled much more efficiently by EF and the SQL Server provider resulting greatly improved performance. All features of EF6 (except async) are available on both .NET 4 and .NET 4.5. This includes support for enums and spatial types and the performance improvements that were previously only available when using .NET 4.5. Start-up time for many large models has been dramatically improved thanks to improved view generation performance. Below are some additional details about a few of the improvements above: Async Support .NET 4.5 introduced the Task-Based Asynchronous Pattern that uses the async and await keywords to help make writing asynchronous code easier. EF 6 now supports this pattern. This is great for ASP.NET applications as database calls made through EF can now be processed asynchronously – avoiding any blocking of worker threads. This can increase scalability on the server by allowing more requests to be processed while waiting for the database to respond. The following code shows an MVC controller that is querying a database for a list of location entities:     public class HomeController : Controller     {         LocationContext db = new LocationContext();           public async Task<ActionResult> Index()         {             var locations = await db.Locations.ToListAsync();               return View(locations);         }     } Notice above the call to the new ToListAsync method with the await keyword. When the web server reaches this code it initiates the database request, but rather than blocking while waiting for the results to come back, the thread that is processing the request returns to the thread pool, allowing ASP.NET to process another incoming request with the same thread. In other words, a thread is only consumed when there is actual processing work to do, allowing the web server to handle more concurrent requests with the same resources. A more detailed walkthrough covering async in EF is available with additional information and examples. Also a walkthrough is available showing how to use async in an ASP.NET MVC application. Custom Conventions When working with EF Code First, the default behavior is to map .NET classes to tables using a set of conventions baked into EF. For example, Code First will detect properties that end with “ID” and configure them automatically as primary keys. However, sometimes you cannot or do not want to follow those conventions and would rather provide your own. For example, maybe your primary key properties all end in “Key” instead of “Id”. Custom conventions allow the default conventions to be overridden or new conventions to be added so that Code First can map by convention using whatever rules make sense for your project. The following code demonstrates using custom conventions to set the precision of all decimals to 5. As with other Code First configuration, this code is placed in the OnModelCreating method which is overridden on your derived DbContext class:         protected override void OnModelCreating(DbModelBuilder modelBuilder)         {             modelBuilder.Properties<decimal>()                 .Configure(x => x.HasPrecision(5));           } But what if there are a couple of places where a decimal property should have a different precision? Just as with all the existing Code First conventions, this new convention can be overridden for a particular property simply by explicitly configuring that property using either the fluent API or a data annotation. A more detailed description of custom code first conventions is available here. Community Involvement I blogged a while ago about EF being released under an open source license.  Since then a number of community members have made contributions and these are included in EF6 alpha 2. Two examples of community contributions are: AlirezaHaghshenas contributed a change that increases the startup performance of EF for larger models by improving the performance of view generation. The change means that it is less often necessary to use of pre-generated views. UnaiZorrilla contributed the first community feature to EF: the ability to load all Code First configuration classes in an assembly with a single method call like the following: protected override void OnModelCreating(DbModelBuilder modelBuilder) {        modelBuilder.Configurations            .AddFromAssembly(typeof(LocationContext).Assembly); } This code will find and load all the classes that inherit from EntityTypeConfiguration<T> or ComplexTypeConfiguration<T> in the assembly where LocationContext is defined. This reduces the amount of coupling between the context and Code First configuration classes, and is also a very convenient shortcut for large models. Other upcoming features coming in EF 6 Lots of information about the development of EF6 can be found on the EF CodePlex site, including a roadmap showing the other features that are planned for EF6. One of of the nice upcoming features is connection resiliency, which will automate the process of retying database operations on transient failures common in cloud environments and with databases such as the Windows Azure SQL Database. Another often requested feature that will be included in EF6 is the ability to map stored procedures to query and update operations on entities when using Code First. Summary EF6 is the first open source release of Entity Framework being developed in CodePlex. The alpha 2 preview release of EF6 is now available on NuGet, and contains some really great features for you to try. The EF team are always looking for feedback from developers - especially on the new features such as custom Code First conventions and async support. To provide feedback you can post a comment on the EF6 alpha 2 announcement post, start a discussion or file a bug on the CodePlex site. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • connecting clients to server with emulator on different computers

    - by prolink007
    I am writing an application that communicates using sockets. I have a server running on one android emulator on a computer, then i have 2 other clients running on android emulators on 2 other computers. I am trying to get the 2 clients to connect to the server. This works when i run the server and clients on the same computer, but when i attempt to do this on the same wifi network and on separate computers it gives me the following error. The client and server code is posted below. A lot is stripped out just to show the important stuff. Also, after the server starts i telnet into the server and run these commands redir add tcp:5000:6000 (i have also tried without doing the redir but it still says the same thing). Then i start the clients and get the error. Thanks for the help! Both the 5000 port and 6000 port are open on my router. And i have windows firewall disabled on the computer hosting the server. 11-27 18:54:02.274: W/ActivityManager(60): Activity idle timeout for HistoryRecord{44cf0a30 school.cpe434.ClassAidClient/school.cpe434.ClassAid.ClassAidClient4Activity} 11-27 18:57:02.424: W/System.err(205): java.net.SocketException: The operation timed out 11-27 18:57:02.454: W/System.err(205): at org.apache.harmony.luni.platform.OSNetworkSystem.connectSocketImpl(Native Method) 11-27 18:57:02.454: W/System.err(205): at org.apache.harmony.luni.platform.OSNetworkSystem.connect(OSNetworkSystem.java:114) 11-27 18:57:02.465: W/System.err(205): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:245) 11-27 18:57:02.465: W/System.err(205): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:220) 11-27 18:57:02.465: W/System.err(205): at java.net.Socket.startupSocket(Socket.java:780) 11-27 18:57:02.465: W/System.err(205): at java.net.Socket.<init>(Socket.java:314) 11-27 18:57:02.465: W/System.err(205): at school.cpe434.ClassAid.ClassAidClient4Activity.onCreate(ClassAidClient4Activity.java:102) 11-27 18:57:02.474: W/System.err(205): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 11-27 18:57:02.474: W/System.err(205): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) 11-27 18:57:02.474: W/System.err(205): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) 11-27 18:57:02.474: W/System.err(205): at android.app.ActivityThread.access$2200(ActivityThread.java:119) 11-27 18:57:02.474: W/System.err(205): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) 11-27 18:57:02.474: W/System.err(205): at android.os.Handler.dispatchMessage(Handler.java:99) 11-27 18:57:02.474: W/System.err(205): at android.os.Looper.loop(Looper.java:123) 11-27 18:57:02.486: W/System.err(205): at android.app.ActivityThread.main(ActivityThread.java:4363) 11-27 18:57:02.486: W/System.err(205): at java.lang.reflect.Method.invokeNative(Native Method) 11-27 18:57:02.486: W/System.err(205): at java.lang.reflect.Method.invoke(Method.java:521) 11-27 18:57:02.486: W/System.err(205): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 11-27 18:57:02.486: W/System.err(205): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 11-27 18:57:02.486: W/System.err(205): at dalvik.system.NativeStart.main(Native Method) The server code public class ClassAidServer4Activity extends Activity { ServerSocket ss = null; String mClientMsg = ""; String mClientExtraMsg = ""; Thread myCommsThread = null; public static final int SERVERPORT = 6000; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); TextView tv = (TextView) findViewById(R.id.textView1); tv.setText("Nothing from client yet"); this.myCommsThread = new Thread(new CommsThread()); this.myCommsThread.start(); } class CommsThread implements Runnable { public void run() { // Socket s = null; try { ss = new ServerSocket(SERVERPORT ); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } while(true) { try { Socket socket = ss.accept(); connectedDeviceCount++; Thread lThread = new Thread(new ListeningThread(socket)); lThread.start(); } catch (IOException e) { e.printStackTrace(); } } } } class ListeningThread implements Runnable { private Socket s = null; public ListeningThread(Socket socket) { // TODO Auto-generated constructor stub this.s = socket; } @Override public void run() { // TODO Auto-generated method stub while (!Thread.currentThread().isInterrupted()) { Message m = new Message(); // m.what = QUESTION_ID; try { if (s == null) s = ss.accept(); BufferedReader input = new BufferedReader( new InputStreamReader(s.getInputStream())); String st = null; st = input.readLine(); String[] temp = parseReadMessage(st); mClientMsg = temp[1]; if(temp.length > 2) { mClientExtraMsg = temp[2]; } m.what = Integer.parseInt(temp[0]); myUpdateHandler.sendMessage(m); } catch (IOException e) { e.printStackTrace(); } } } } } The client code public class ClassAidClient4Activity extends Activity { //telnet localhost 5554 //redir add tcp:5000:6000 private Socket socket; private String serverIpAddress = "192.168.1.102"; private static final int REDIRECTED_SERVERPORT = 5000; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); try { InetAddress serverAddr = InetAddress.getByName(serverIpAddress); socket = new Socket(serverAddr, REDIRECTED_SERVERPORT); } catch (UnknownHostException e1) { mQuestionAdapter.add("UnknownHostException"); e1.printStackTrace(); } catch (IOException e1) { mQuestionAdapter.add("IOException"); e1.printStackTrace(); } } }

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  • TStringList and TThread that does not free all of its memory

    - by VanillaH
    Version used: Delphi 7. I'm working on a program that does a simple for loop on a Virtual ListView. The data is stored in the following record: type TList=record Item:Integer; SubItem1:String; SubItem2:String; end; Item is the index. SubItem1 the status of the operations (success or not). SubItem2 the path to the file. The for loop loads each file, does a few operations and then, save it. The operations take place in a TStringList. Files are about 2mb each. Now, if I do the operations on the main form, it works perfectly. Multi-threaded, there is a huge memory problem. Somehow, the TStringList doesn't seem to be freed completely. After 3-4k files, I get an EOutofMemory exception. Sometimes, the software is stuck to 500-600mb, sometimes not. In any case, the TStringList always return an EOutofMemory exception and no file can be loaded anymore. On computers with more memory, it takes longer to get the exception. The same thing happens with other components. For instance, if I use THTTPSend from Synapse, well, after a while, the software cannot create any new threads because the memory consumption is too high. It's around 500-600mb while it should be, max, 100mb. On the main form, everything works fine. I guess the mistake is on my side. Maybe I don't understand threads enough. I tried to free everything on the Destroy event. I tried FreeAndNil procedure. I tried with only one thread at a time. I tried freeing the thread manually (no FreeOnTerminate...) No luck. So here is the thread code. It's only the basic idea; not the full code with all the operations. If I remove the LoadFile prodecure, everything works good. A thread is created for each file, according to a thread pool. unit OperationsFiles; interface uses Classes, SysUtils, Windows; type TOperationFile = class(TThread) private Position : Integer; TPath, StatusMessage: String; FileStringList: TStringList; procedure UpdateStatus; procedure LoadFile; protected procedure Execute; override; public constructor Create(Path: String; LNumber: Integer); end; implementation uses Form1; procedure TOperationFile.LoadFile; begin try FileStringList.LoadFromFile(TPath); // Operations... StatusMessage := 'Success'; except on E : Exception do StatusMessage := E.ClassName; end; end; constructor TOperationFile.Create(Path : String; LNumber: Integer); begin inherited Create(False); TPath := Path; Position := LNumber; FreeOnTerminate := True; end; procedure TOperationFile.UpdateStatus; begin FileList[Position].SubItem1 := StatusMessage; Form1.ListView4.UpdateItems(Position,Position); end; procedure TOperationFile.Execute; begin FileStringList:= TStringList.Create; LoadFile; Synchronize(UpdateStatus); FileStringList.Free; end; end. What could be the problem? I thought at one point that, maybe, too many threads are created. If a user loads 1 million files, well, ultimately, 1 million threads is going to be created -- although, only 50 threads are created and running at the same time. Thanks for your input.

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  • SQL SERVER – Reducing CXPACKET Wait Stats for High Transactional Database

    - by pinaldave
    While engaging in a performance tuning consultation for a client, a situation occurred where they were facing a lot of CXPACKET Waits Stats. The client asked me if I could help them reduce this huge number of wait stats. I usually receive this kind of request from other client as well, but the important thing to understand is whether this question has any merits or benefits, or not. Before we continue the resolution, let us understand what CXPACKET Wait Stats are. The official definition suggests that CXPACKET Wait Stats occurs when trying to synchronize the query processor exchange iterator. You may consider lowering the degree of parallelism if a conflict concerning this wait type develops into a problem. (from BOL) In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Note that CXPACKET Wait is done by completed thread and not the one which are unfinished. “Note that not all the CXPACKET wait types are bad. You might experience a case when it totally makes sense. There might also be cases when this is also unavoidable. If you remove this particular wait type for any query, then that query may run slower because the parallel operations are disabled for the query.” Now let us see what the best practices to reduce the CXPACKET Wait Stats are. The suggestions, with which you will find that if you search online through the browser, would play a major role as and might be asked about their jobs In addition, might tell you that you should set ‘maximum degree of parallelism’ to 1. I do agree with these suggestions, too; however, I think this is not the final resolutions. As soon as you set your entire query to run on single CPU, you will get a very bad performance from the queries which are actually performing okay when using parallelism. The best suggestion to this is that you set ‘the maximum degree of parallelism’ to a lower number or 1 (be very careful with this – it can create more problems) but tune the queries which can be benefited from multiple CPU’s. You can use query hint OPTION (MAXDOP 0) to run the server to use parallelism. Here is the two-quick script which helps to resolve these issues: Change MAXDOP at Server Level EXEC sys.sp_configure N'max degree of parallelism', N'1' GO RECONFIGURE WITH OVERRIDE GO Run Query with all the CPU (using parallelism) USE AdventureWorks GO SELECT * FROM Sales.SalesOrderDetail ORDER BY ProductID OPTION (MAXDOP 0) GO Below is the blog post which will help you to find all the parallel query in your server. SQL SERVER – Find Queries using Parallelism from Cached Plan Please note running Queries in single CPU may worsen your performance and it is not recommended at all. Infect this can be very bad advise. I strongly suggest that you identify the queries which are offending and tune them instead of following any other suggestions. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, SQLAuthority News, T SQL, Technology

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  • Parallelism in .NET – Part 19, TaskContinuationOptions

    - by Reed
    My introduction to Task continuations demonstrates continuations on the Task class.  In addition, I’ve shown how continuations allow handling of multiple tasks in a clean, concise manner.  Continuations can also be used to handle exceptional situations using a clean, simple syntax. In addition to standard Task continuations , the Task class provides some options for filtering continuations automatically.  This is handled via the TaskContinationOptions enumeration, which provides hints to the TaskScheduler that it should only continue based on the operation of the antecedent task. This is especially useful when dealing with exceptions.  For example, we can extend the sample from our earlier continuation discussion to include support for handling exceptions thrown by the Factorize method: // Get a copy of the UI-thread task scheduler up front to use later var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Start our task var factorize = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); // When we succeed, report the results to the UI factorize.ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), CancellationToken.None, TaskContinuationOptions.NotOnFaulted, uiScheduler); // When we have an exception, report it factorize.ContinueWith(task => textBox1.Text = string.Format("Error: {0}", task.Exception.Message), CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, uiScheduler); .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; } The above code works by using a combination of features.  First, we schedule our task, the same way as in the previous example.  However, in this case, we use a different overload of Task.ContinueWith which allows us to specify both a specific TaskScheduler (in order to have your continuation run on the UI’s synchronization context) as well as a TaskContinuationOption.  In the first continuation, we tell the continuation that we only want it to run when there was not an exception by specifying TaskContinuationOptions.NotOnFaulted.  When our factorize task completes successfully, this continuation will automatically run on the UI thread, and provide the appropriate feedback. However, if the factorize task has an exception – for example, if the Factorize method throws an exception due to an improper input value, the second continuation will run.  This occurs due to the specification of TaskContinuationOptions.OnlyOnFaulted in the options.  In this case, we’ll report the error received to the user. We can use TaskContinuationOptions to filter our continuations by whether or not an exception occurred and whether or not a task was cancelled.  This allows us to handle many situations, and is especially useful when trying to maintain a valid application state without ever blocking the user interface.  The same concepts can be extended even further, and allow you to chain together many tasks based on the success of the previous ones.  Continuations can even be used to create a state machine with full error handling, all without blocking the user interface thread.

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  • Silverlight Cream for January 26, 2011 -- #1036

    - by Dave Campbell
    In this all-submittal Issue: XamlNinja, Kevin Dockx, Steve Wortham, Andrea Boschin, Mick Norman, Colin Eberhardt, and Rudi Grobler(-2-, -3-, -4-, -5-). Above the Fold: Silverlight: "Getting an invalid cross-thread exception in Silverlight?" Kevin Dockx WP7: "WP7 Contrib – the last messenger" XamlNinja ISO: "How many files are too many files for isolated storage?" Mick Norman Shoutouts: Telerik announced a free WP7 Webinars series that you probably don't want to miss: Join Us for the Special Free Windows Phone 7 Webinars Series. Guest lecturers - Shawn Wildermuth and Mark Arteaga From SilverlightCream.com: WP7 Contrib – the last messenger XamlNinja has a great post up extending Laurent's IMessenger to deal with a tricky issue of trying to fire a message from one VM to another even if the 2nd VM isn't alive yet... oh, and this is in WP7Contrib, so go grab it! Getting an invalid cross-thread exception in Silverlight? Kevin Dockx has a solution to a problem we've all had... the 'invalid cross-thread exception' ... and the solution is even for those of us trying to do this in a VM... cool and easy solution, Kevin! Mastering Storyboards One Mistake at a Time Steve Wortham is back with a tutorial with a great title :) ... check out the progression from one success to another in this picture/title viewer ... don't miss the very end where he has the control rolled up into a CaptionedImageHyperlink, and a link to download it! Windows Phone 7 - Part #2: Your First Application Andrea Boschin has part 2 of his SilverlightShow WP7 series up. Lots of good intro material here on the manifest file and app.xaml ... he even gets into the ApplicationBar, phone orientation, and the Metro theme. How many files are too many files for isolated storage? Mick Norman alerted me to his blog early this morning, and this is his latest post... interesting tests of how many files are too many for ISO on your WP7... and I have to admit... he's stuffing a boatload of them out there in these tests! ... great info Mick! and thanks for the links. A Navigator Control For Visiblox Time Series Charts Colin Eberhardt's latest post is about creating an interactive navigator for large time series datasets in Visiblox charts.... check the images at the top of the post, and it'll be obvious :) ... very cool stuff. MVVM Frameworks with WP7 support Rudi Grobler has been very busy and if you check the dates, these posts are all in a day or two! This first highlights two contenders for MVVM on WP7: Caliburn and MVVMLight... both well-supported... quick intro to each followed by good links out to the author's sites Reading barcodes from your WP7 device Rudi Grobler also has a cool post up on reading barcodes with your WP7... he's using the ZXing Barcode Scanning Library, and makes quick work of the job. Taking Sterling for a Test-Drive Rudi Grobler has a quick intro to Sterlink, Jeremy Likness' ISO database for Silverlight up... quickly taking care of writing and reading back data. SQLite on WP7 After his discussion of Sterling, Rudi Grobler is now demonstrating the use of SQLite that has been ported to WP7. Check out his demo code... looks pretty easy to use. Hacking the WP7 Camera (The basics) Rudi Grobler's latest post is on getting direct access to the camera on WP7... be sure to do all the downloads and check out the external links he has. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • SQL SERVER – CXPACKET – Parallelism – Advanced Solution – Wait Type – Day 7 of 28

    - by pinaldave
    Earlier we discussed about the what is the common solution to solve the issue with CXPACKET wait time. Today I am going to talk about few of the other suggestions which can help to reduce the CXPACKET wait. If you are going to suggest that I should focus on MAXDOP and COST THRESHOLD – I totally agree. I have covered them in details in yesterday’s blog post. Today we are going to discuss few other way CXPACKET can be reduced. Potential Reasons: If data is heavily skewed, there are chances that query optimizer may estimate the correct amount of the data leading to assign fewer thread to query. This can easily lead to uneven workload on threads and may create CXPAKCET wait. While retrieving the data one of the thread face IO, Memory or CPU bottleneck and have to wait to get those resources to execute its tasks, may create CXPACKET wait as well. Data which is retrieved is on different speed IO Subsystem. (This is not common and hardly possible but there are chances). Higher fragmentations in some area of the table can lead less data per page. This may lead to CXPACKET wait. As I said the reasons here mentioned are not the major cause of the CXPACKET wait but any kind of scenario can create the probable wait time. Best Practices to Reduce CXPACKET wait: Refer earlier article regarding MAXDOP and Cost Threshold. De-fragmentation of Index can help as more data can be obtained per page. (Assuming close to 100 fill-factor) If data is on multiple files which are on multiple similar speed physical drive, the CXPACKET wait may reduce. Keep the statistics updated, as this will give better estimate to query optimizer when assigning threads and dividing the data among available threads. Updating statistics can significantly improve the strength of the query optimizer to render proper execution plan. This may overall affect the parallelism process in positive way. Bad Practice: In one of the recent consultancy project, when I was called in I noticed that one of the ‘experienced’ DBA noticed higher CXPACKET wait and to reduce them, he has increased the worker threads. The reality was increasing worker thread has lead to many other issues. With more number of the threads, more amount of memory was used leading memory pressure. As there were more threads CPU scheduler faced higher ‘Context Switching’ leading further degrading performance. When I explained all these to ‘experienced’ DBA he suggested that now we should reduce the number of threads. Not really! Lower number of the threads may create heavy stalling for parallel queries. I suggest NOT to touch the setting of number of the threads when dealing with CXPACKET wait. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and I no way claim it to be accurate. I suggest reading book on-line for further clarification. All the discussion of Wait Stats over here is generic and it varies by system to system. You are recommended to test this on development server before implementing to production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • about the JOGL 2 problem

    - by Chuchinyi
    Please some help me about the JOGL 2 problem(Sorry for previous error format). I complied JOGL2Template.java ok. but execut it with following error. D:\java\java\jogl>javac JOGL2Template.java <== compile ok D:\java\java\jogl>java JOGL2Template <== execute error Exception in thread "main" java.lang.ExceptionInInitializerError at javax.media.opengl.GLProfile.<clinit>(GLProfile.java:1176) at JOGL2Template.<init>(JOGL2Template.java:24) at JOGL2Template.main(JOGL2Template.java:57) Caused by: java.lang.SecurityException: no certificate for gluegen-rt.dll in D:\ java\lib\gluegen-rt-natives-windows-i586.jar at com.jogamp.common.util.JarUtil.validateCertificate(JarUtil.java:350) at com.jogamp.common.util.JarUtil.validateCertificates(JarUtil.java:324) at com.jogamp.common.util.cache.TempJarCache.validateCertificates(TempJa rCache.java:328) at com.jogamp.common.util.cache.TempJarCache.bootstrapNativeLib(TempJarC ache.java:283) at com.jogamp.common.os.Platform$3.run(Platform.java:308) at java.security.AccessController.doPrivileged(Native Method) at com.jogamp.common.os.Platform.loadGlueGenRTImpl(Platform.java:298) at com.jogamp.common.os.Platform.<clinit>(Platform.java:207) ... 3 more there is JOGL2Template.java source code: import java.awt.Dimension; import java.awt.Frame; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.media.opengl.GLAutoDrawable; import javax.media.opengl.GLCapabilities; import javax.media.opengl.GLEventListener; import javax.media.opengl.GLProfile; import javax.media.opengl.awt.GLCanvas; import com.jogamp.opengl.util.FPSAnimator; import javax.swing.JFrame; /* * JOGL 2.0 Program Template For AWT applications */ public class JOGL2Template extends JFrame implements GLEventListener { private static final int CANVAS_WIDTH = 640; // Width of the drawable private static final int CANVAS_HEIGHT = 480; // Height of the drawable private static final int FPS = 60; // Animator's target frames per second // Constructor to create profile, caps, drawable, animator, and initialize Frame public JOGL2Template() { // Get the default OpenGL profile that best reflect your running platform. GLProfile glp = GLProfile.getDefault(); // Specifies a set of OpenGL capabilities, based on your profile. GLCapabilities caps = new GLCapabilities(glp); // Allocate a GLDrawable, based on your OpenGL capabilities. GLCanvas canvas = new GLCanvas(caps); canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT)); canvas.addGLEventListener(this); // Create a animator that drives canvas' display() at 60 fps. final FPSAnimator animator = new FPSAnimator(canvas, FPS); addWindowListener(new WindowAdapter() { // For the close button @Override public void windowClosing(WindowEvent e) { // Use a dedicate thread to run the stop() to ensure that the // animator stops before program exits. new Thread() { @Override public void run() { animator.stop(); System.exit(0); } }.start(); } }); add(canvas); pack(); setTitle("OpenGL 2 Test"); setVisible(true); animator.start(); // Start the animator } public static void main(String[] args) { new JOGL2Template(); } @Override public void init(GLAutoDrawable drawable) { // Your OpenGL codes to perform one-time initialization tasks // such as setting up of lights and display lists. } @Override public void display(GLAutoDrawable drawable) { // Your OpenGL graphic rendering codes for each refresh. } @Override public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) { // Your OpenGL codes to set up the view port, projection mode and view volume. } @Override public void dispose(GLAutoDrawable drawable) { // Hardly used. } }

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  • What packages do I need to compile .tex documents using XeLaTeX?

    - by maria
    Hi I'm aware of the existence of similar threads on this forum. But any of replies mach to my problem. I'm using Ubuntu 10.4 and I hadn't problems with fonts till I've decided to use XeLaTeX instead of LaTeX (cf http://tex.stackexchange.com/questions/12347/typesetting-a-document-using-arabic-script/12358#12358). The problem is that I'm not able to compile any .tex document using XeLaTeX, as well as properly display XeLaTeX documentation. As I've learn thanks to mentioned thread, XeLaTeX uses the fonts availables in general in the system. I was trying yo read fontspec documentation, but it opens in pdf with a lot of white gaps and terminal output (quite long) consist mostly of errors. This are just few lines of it: Error: Missing language pack for 'Adobe-Japan1' mapping Error: Unknown font tag 'F5.1' Error (24124): No font in show Error: Unknown font tag 'F5.1' I was trying to compile simple XeLaTeX file: \documentclass{article} \usepackage{fontspec} \setmainfont{Linux Libertine O} \begin{document} Hello World! \end{document} without succes. This is terminal output of compilation: This is XeTeX, Version 3.1415926-2.2-0.9995.2 (TeX Live 2009/Debian) restricted \write18 enabled. entering extended mode (./ex.tex LaTeX2e <2009/09/24> Babel <v3.8l> and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, polish, loaded. (/usr/share/texmf-texlive/tex/latex/base/article.cls Document Class: article 2007/10/19 v1.4h Standard LaTeX document class (/usr/share/texmf-texlive/tex/latex/base/size10.clo)) (/usr/share/texmf-texlive/tex/xelatex/fontspec/fontspec.sty (/usr/share/texmf-texlive/tex/generic/ifxetex/ifxetex.sty) (/usr/share/texmf-texlive/tex/latex/tools/calc.sty) (/usr/share/texmf-texlive/tex/latex/xkeyval/xkeyval.sty (/usr/share/texmf-texlive/tex/generic/xkeyval/xkeyval.tex (/usr/share/texmf-texlive/tex/generic/xkeyval/keyval.tex))) (/usr/share/texmf-texlive/tex/latex/base/fontenc.sty (/usr/share/texmf-texlive/tex/xelatex/euenc/eu1enc.def) (/usr/share/texmf-texlive/tex/xelatex/euenc/eu1lmr.fd)) fontspec.cfg loaded. (/usr/share/texmf-texlive/tex/xelatex/fontspec/fontspec.cfg))kpathsea: Invalid fontname `Linux Libertine O', contains ' ' ! Font \zf@basefont="Linux Libertine O" at 10.0pt not loadable: Metric (TFM) fi le or installed font not found. \zf@fontspec ...ntname \zf@suffix " at \f@size pt \unless \ifzf@icu \zf@set@... l.3 \setmainfont{Linux Libertine O} ? I can't find Linux Libertine O. Searching for otf- by aptitude gives as result: maria@maria-laptop:/etc/fonts$ aptitude search otf p emdebian-rootfs - emdebian root filesystem support p libotf-bin - A Library for handling OpenType Font - utilities p libotf-dev - A Library for handling OpenType Font - development i libotf0 - A Library for handling OpenType Font - runtime p libotf0-dbg - The libotf libraries and debugging symbols p libpam-dotfile - A PAM module which allows users to have more than one password p livecd-rootfs - construction script for the livecd rootfs p makebootfat - Utility to create a bootable FAT filesystem p otf-ipaexfont - Japanese OpenType font, IPAexFont (IPAexGothic/Mincho) p otf-ipaexfont-gothic - Japanese OpenType font, IPAexFont (IPAexGothic) p otf-ipaexfont-mincho - Japanese OpenType font, IPAexFont (IPAexMincho) p otf-ipafont - Japanese OpenType font set, IPAfont p otf-ipafont-gothic - Japanese OpenType font set, IPA Gothic font p otf-ipafont-mincho - Japanese OpenType font set, IPA Mincho font p otf-stix - the Scientific and Technical Information eXchange fonts p otf-thai-tlwg - Thai fonts in OpenType format p otf-yozvox-yozfont - Japanese proportional Handwriting OpenType font p otf2bdf - generate BDF bitmap fonts from OpenType outline fonts p robotfindskitten - Zen Simulation of robot finding kitten So font in question is not just uninstalled, but not available, if I'm not wrong. Does it mean that I lack some repositoires? I was trying also to apply solution from the thread How do I reinstall default fonts?, but the result is: maria@maria-laptop:~$ sudo apt-get install msttcorefonts [sudo] password for maria: Reading package lists... Done Building dependency tree Reading state information... Done Note, selecting ttf-mscorefonts-installer instead of msttcorefonts ttf-mscorefonts-installer is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. maria@maria-laptop:~$ It seems that is not a usual problem for use of XeLaTeX; nobody in the mentioned thread suggested instalation of anything else than TeX Live. Thanks in advance

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  • Critical Threads Optimization

    - by Rafael Vanoni
    Background One of the more common issues we've been seeing in the field is the growing difficulty in optimizing performance of multi-threaded applications. A good portion of this difficulty is due to the increasing complexity of modern processors that present various degrees of sharing relationships between hardware components. Take any current CMT processor and you'll find any number of CPUs sharing execution pipelines, floating point units, caches, etc. Consequently, applying the traditional recipe of one software thread for each CPU will have varying degrees of success, according to the layout of the underlying hardware. On top of this increasing complexity we've also seen processors with features that aim at dynamically resourcing software threads according to their utilization. Intel's Turbo Boost allows processors to increase their operating frequency if there is enough thermal headroom available and the processor isn't fully utilized. More recently, the SPARC T4 processor introduced dynamic threading, allowing each core to dynamically allocate more resources to its active CPUs. Both cases are in essence recognizing that current processors will be running a wide mix of workloads, some will be designed for throughput, others for low latency. The hardware is providing mechanisms to dynamically resource threads according to their runtime behavior. We're very aware of these challenges in Solaris, and have been working to provide the best out of box performance while providing mechanisms to further optimize applications when necessary. The Critical Threads Optimzation was introduced in Solaris 10 8/11 and Solaris 11 as one such mechanism that allows customers to both address issues caused by contention over shared hardware resources and explicitly take advantage of features such as T4's dynamic threading. What it is The basic idea is to allow performance critical threads to execute with more exclusive access to hardware resources. For example, when deploying an application that implements a producer/consumer model, it'll likely be advantageous to give the producer more exclusive access to the hardware instead of having it competing for resources with all the consumers. In the case of a T4 based system, we may want to have a producer running by itself on a single core and create one consumer for each of the remaining CPUs. With the Critical Threads Optimization we're extending the semantics of scheduling priorities (which thread should run first) to include priority over shared resources (which thread should have more "space"). Now the scheduler will not only run higher priority threads first: it will also provide them with more exclusive access to hardware resources if they are available. How does it work ? Using the previous example in Solaris 11, all you'd have to do would be to place the producer in the Fixed Priority (FX) scheduling class at priority 60, or in the Real Time (RT) class at any priority and Solaris will try to give it more "hardware space". On both Solaris 10 8/11 and Solaris 11 this can be achieved through the existing priocntl(1,2) and priocntlset(2) interfaces. If your application already assigns these priorities to performance critical threads, there's no additional step you need to take. One important aspect of this optimization is that it requires some level of idleness in the system, either as a result of sizing the application before hand or through periods of transient idleness during runtime. If the system is fully committed, the scheduler will put all the available CPUs to work.Best practices If you're an application developer, we encourage you to look into assigning the right priorities for the different threads in your application. Solaris provides different scheduling classes (Time Share, Interactive, Fair Share, Fixed Priority and Real Time) that offer different policies and behaviors. It is not always simple to figure out which set of threads are critical to the performance of a workload, and it may not always be feasible to take advantage of this optimization, but we believe that this can be correctly (and safely) done during development. Overall, the out of box performance in Solaris should meet your workload's requirements. If you are looking into that extra bit of performance, then the Critical Threads Optimization may be what you're looking for.

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  • JOGL2 test compiles, but doesn't execute - help?

    - by Chuchinyi
    I have a problem with JOGL2. My JOGL2Template.java compiles fine, but executing it results in the following error: D:\java\java\jogl>javac JOGL2Template.java <== compile ok D:\java\java\jogl>java JOGL2Template <== execute error Exception in thread "main" java.lang.ExceptionInInitializerError at javax.media.opengl.GLProfile.<clinit>(GLProfile.java:1176) at JOGL2Template.<init>(JOGL2Template.java:24) at JOGL2Template.main(JOGL2Template.java:57) Caused by: java.lang.SecurityException: no certificate for gluegen-rt.dll in D:\ java\lib\gluegen-rt-natives-windows-i586.jar at com.jogamp.common.util.JarUtil.validateCertificate(JarUtil.java:350) at com.jogamp.common.util.JarUtil.validateCertificates(JarUtil.java:324) at com.jogamp.common.util.cache.TempJarCache.validateCertificates(TempJa rCache.java:328) at com.jogamp.common.util.cache.TempJarCache.bootstrapNativeLib(TempJarC ache.java:283) at com.jogamp.common.os.Platform$3.run(Platform.java:308) at java.security.AccessController.doPrivileged(Native Method) at com.jogamp.common.os.Platform.loadGlueGenRTImpl(Platform.java:298) at com.jogamp.common.os.Platform.<clinit>(Platform.java:207) ... 3 more Here is the JOGL2Template.java source code: import java.awt.Dimension; import java.awt.Frame; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.media.opengl.GLAutoDrawable; import javax.media.opengl.GLCapabilities; import javax.media.opengl.GLEventListener; import javax.media.opengl.GLProfile; import javax.media.opengl.awt.GLCanvas; import com.jogamp.opengl.util.FPSAnimator; import javax.swing.JFrame; /* * JOGL 2.0 Program Template For AWT applications */ public class JOGL2Template extends JFrame implements GLEventListener { private static final int CANVAS_WIDTH = 640; // Width of the drawable private static final int CANVAS_HEIGHT = 480; // Height of the drawable private static final int FPS = 60; // Animator's target frames per second // Constructor to create profile, caps, drawable, animator, and initialize Frame public JOGL2Template() { // Get the default OpenGL profile that best reflect your running platform. GLProfile glp = GLProfile.getDefault(); // Specifies a set of OpenGL capabilities, based on your profile. GLCapabilities caps = new GLCapabilities(glp); // Allocate a GLDrawable, based on your OpenGL capabilities. GLCanvas canvas = new GLCanvas(caps); canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT)); canvas.addGLEventListener(this); // Create a animator that drives canvas' display() at 60 fps. final FPSAnimator animator = new FPSAnimator(canvas, FPS); addWindowListener(new WindowAdapter() { // For the close button @Override public void windowClosing(WindowEvent e) { // Use a dedicate thread to run the stop() to ensure that the // animator stops before program exits. new Thread() { @Override public void run() { animator.stop(); System.exit(0); } }.start(); } }); add(canvas); pack(); setTitle("OpenGL 2 Test"); setVisible(true); animator.start(); // Start the animator } public static void main(String[] args) { new JOGL2Template(); } @Override public void init(GLAutoDrawable drawable) { // Your OpenGL codes to perform one-time initialization tasks // such as setting up of lights and display lists. } @Override public void display(GLAutoDrawable drawable) { // Your OpenGL graphic rendering codes for each refresh. } @Override public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) { // Your OpenGL codes to set up the view port, projection mode and view volume. } @Override public void dispose(GLAutoDrawable drawable) { // Hardly used. } } Any ideas what might be the cause of these errors?

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  • sending sms to mobile from pc using java [closed]

    - by sjohnfernandas
    hi i need to send sms from pc to mobile phone can u people guide me to achieve? i used the following code to send sms to a mobile from pc but i did not get any output and also not getting any error so guide me and point out the mistakes what i have done. package mobilesms; import java.io.; import java.util.; import javax.comm.*; import java.io.IOException; import java.util.Properties; import java.io.InputStream; import java.io.OutputStream; import java.io.DataInputStream; import java.io.FileInputStream; import java.io.DataOutputStream; import java.io.FileOutputStream; public class ReadSimple implements Runnable, SerialPortEventListener { static CommPortIdentifier portId; static Enumeration portList; OutputStream outputstream; InputStream inputStream; SerialPort serialPort; Thread readThread; public static void main(String[] args) { portList = CommPortIdentifier.getPortIdentifiers(); while (portList.hasMoreElements()) { portId = (CommPortIdentifier) portList.nextElement(); if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) { if (portId.getName().equals("COM1")) { System.out.println("Found port:COM1 "); ReadSimple reader = new ReadSimple(); } } } } public ReadSimple() { try { serialPort = (SerialPort) portId.open("ReadSimpleApp",500); } catch (PortInUseException e) { System.out.println(e); } try { inputStream = serialPort.getInputStream(); OutputStream out=serialPort.getOutputStream(); String line=""; line="AT"+"r\n"; out.write(line.trim().getBytes()); line=""; line="AT+CMGS=7639808583"+"\r\n"; out.write(line.trim().getBytes()); System.out.print(line); line="helloworld"; //line=”ATD 996544325;”+”\r\n”; out.write(line.trim().getBytes()); } catch (IOException e) { serialPort.close(); System.out.println(e); } // catch(InterruptedException E){E.printStackTrace();} try { serialPort.addEventListener(this); } catch (TooManyListenersException e) {System.out.println(e);} serialPort.notifyondataavailable(true); try { serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE); } catch (UnsupportedCommOperationException e) {System.out.println(e);} readThread = new Thread(this); readThread.start(); } public void run() { try { Thread.sleep(200); } catch (InterruptedException e) {System.out.println(e);} } public void serialEvent(SerialPortEvent event) { switch(event.getEventType()) { case SerialPortEvent.BI: case SerialPortEvent.OE: case SerialPortEvent.FE: case SerialPortEvent.PE: case SerialPortEvent.CD: case SerialPortEvent.CTS: case SerialPortEvent.DSR: case SerialPortEvent.RI: case SerialPortEvent.OUTPUT_BUFFER_EMPTY: break; case SerialPortEvent.DATA_AVAILABLE: byte[] readBuffer = new byte[10]; try { while (inputStream.available() 0) { int numBytes = inputStream.read(readBuffer); } System.out.println(new String(readBuffer)); } catch (IOException e) {System.out.println(e);} break; } } }

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  • android client not working [migrated]

    - by Syeda Zunairah
    i have a java client and c# server the server code is static Socket listeningSocket; static Socket socket; static Thread thrReadRequest; static int iPort = 4444; static int iConnectionQueue = 100; static void Main(string[] args) { Console.WriteLine(IPAddress.Parse(getLocalIPAddress()).ToString()); try { listeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); //listeningSocket.Bind(new IPEndPoint(0, iPort)); listeningSocket.Bind(new IPEndPoint(IPAddress.Parse(getLocalIPAddress()), iPort)); listeningSocket.Listen(iConnectionQueue); thrReadRequest = new Thread(new ThreadStart(getRequest)); thrReadRequest.Start(); } catch (Exception e) { Console.WriteLine("Winsock error: " + e.ToString()); //throw; } } static private void getRequest() { int i = 0; while (true) { i++; Console.WriteLine("Outside Try i = {0}", i.ToString()); try { socket = listeningSocket.Accept(); // Receiving //byte[] rcvLenBytes = new byte[4]; //socket.Receive(rcvLenBytes); //int rcvLen = System.BitConverter.ToInt32(rcvLenBytes, 0); //byte[] rcvBytes = new byte[rcvLen]; //socket.Receive(rcvBytes); //String formattedBuffer = System.Text.Encoding.ASCII.GetString(rcvBytes); byte[] buffer = new byte[socket.SendBufferSize]; int iBufferLength = socket.Receive(buffer, 0, buffer.Length, 0); Console.WriteLine("Received {0}", iBufferLength); Array.Resize(ref buffer, iBufferLength); string formattedBuffer = Encoding.ASCII.GetString(buffer); Console.WriteLine("Data received by Client: {0}", formattedBuffer); if (formattedBuffer == "quit") { socket.Close(); listeningSocket.Close(); Environment.Exit(0); } Console.WriteLine("Inside Try i = {0}", i.ToString()); Thread.Sleep(500); } catch (Exception e) { //socket.Close(); Console.WriteLine("Receiving error: " + e.ToString()); Console.ReadKey(); //throw; } finally { socket.Close(); //listeningsocket.close(); } } } static private string getLocalIPAddress() { IPHostEntry host; string localIP = ""; host = Dns.GetHostEntry(Dns.GetHostName()); foreach (IPAddress ip in host.AddressList) { if (ip.AddressFamily == AddressFamily.InterNetwork) { localIP = ip.ToString(); break; } } return localIP; } } and the jave android code is private TCPClient mTcpClient; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final EditText editText = (EditText) findViewById(R.id.edit_message); Button send = (Button)findViewById(R.id.sendbutton); // connect to the server new connectTask().execute(""); send.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String message = editText.getText().toString(); //sends the message to the server if (mTcpClient != null) { mTcpClient.sendMessage(message); } editText.setText(""); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.main, menu); return true; } public class connectTask extends AsyncTask<String,String,TCPClient> { @Override protected TCPClient doInBackground(String... message) { mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() { @Override public void messageReceived(String message) { publishProgress(message); } }); mTcpClient.run(); return null; } @Override protected void onProgressUpdate(String... values) { super.onProgressUpdate(values); } } } when i run the server it gives output of try i=1. can any one tell me what to do next

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  • Displaying wait cursor in while backgroundworker is running

    - by arc1880
    During the start of my windows application, I have to make a call to a web service to retrieve some default data to load onto my application. During the load of the form, I run a backgroundworker to retrieve this data. I want to display the wait cursor until this data is retrieved. How would I do this? I've tried setting the wait cursor before calling the backgroundworker to run. When I report a progress of 100 then I set it back to the default cursor. The wait cursor comes up but when I move the mouse it disappears. Environment: Windows 7 Pro 64-bit VS2010 C# .NET 4.0 Windows Forms EDIT: I am setting the cursor the way Jay Riggs suggested. It only works if I don't move the mouse. **UPDATE: I have created a button click which does the following: When I do the button click and move my mouse, the wait cursor appears regardless if I move my mouse or not. void BtnClick() { Cursor = Cursors.WaitCursor; Thread.Sleep(8000); Cursor = Cursors.Default; } If I do the following: I see the wait cursor and when I move the mouse it disappears inside the form. If I move to my status bar or the menu bar the wait cursor appears. Cursor = Cursors.WaitCursor; if (!backgroundWorker.IsBusy) { backGroundWorker.RunWorkerAsync(); } void backGroundWorkerDoWork(object sender, DoWorkEventArgs e) { Thread.Sleep(8000); } void backGroundWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { Cursor = Cursors.Default; } If I do the following: The wait cursor appears and when I move the mouse it still appears but will sometimes flicker off and on when moving in text fields. if (!backgroundWorker.IsBusy) { backGroundWorker.RunWorkerAsync(); } void backGroundWorkerDoWork(object sender, DoWorkEventArgs e) { UseWaitCursor = true; Thread.Sleep(8000); } void backGroundWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { UseWaitCursor = false; }

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  • NullPointerException when showing JFileChooser

    - by Geo
    I show a JFileChooser with this snippet: public File getDestination() { JFileChooser chooser = new JFileChooser(); chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY); int option = chooser.showSaveDialog(null); if(option == JFileChooser.APPROVE_OPTION) { return chooser.getSelectedFile().getAbsolutePath(); } return new File("."); } Usually, the first time it's showed, it displays & works correctly. The second time, it will always throw this exception: Exception in thread "Basic L&F File Loading Thread" java.lang.NullPointerException at sun.awt.shell.Win32ShellFolder2.pidlsEqual(Unknown Source) at sun.awt.shell.Win32ShellFolder2.equals(Unknown Source) at sun.awt.shell.Win32ShellFolderManager2.isFileSystemRoot(Unknown Source) at sun.awt.shell.ShellFolder.isFileSystemRoot(Unknown Source) at javax.swing.filechooser.FileSystemView.isFileSystemRoot(Unknown Source) at javax.swing.filechooser.WindowsFileSystemView.isTraversable(Unknown Source) at javax.swing.JFileChooser.isTraversable(Unknown Source) at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run0(Unknown Source) at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(Unknown Source) Java -version says: java version "1.6.0_20" Java(TM) SE Runtime Environment (build 1.6.0_20-b02) Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing) And the thread I found here says I should downgrade the Java version. Should I follow their advice, or is there something I could have done wrong?

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