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• Combining FileStream and MemoryStream to avoid disk accesses/paging while receiving gigabytes of data?

  - by w128

  I'm receiving a file as a stream of byte[] data packets (total size isn't known in advance) that I need to store somewhere before processing it immediately after it's been received (I can't do the processing on the fly). Total received file size can vary from as small as 10 KB to over 4 GB. One option for storing the received data is to use a MemoryStream, i.e. a sequence of MemoryStream.Write(bufferReceived, 0, count) calls to store the received packets. This is very simple, but obviously will result in out of memory exception for large files. An alternative option is to use a FileStream, i.e. FileStream.Write(bufferReceived, 0, count). This way, no out of memory exceptions will occur, but what I'm unsure about is bad performance due to disk writes (which I don't want to occur as long as plenty of memory is still available) - I'd like to avoid disk access as much as possible, but I don't know of a way to control this. I did some testing and most of the time, there seems to be little performance difference between say 10 000 consecutive calls of MemoryStream.Write() vs FileStream.Write(), but a lot seems to depend on buffer size and the total amount of data in question (i.e the number of writes). Obviously, MemoryStream size reallocation is also a factor. Does it make sense to use a combination of MemoryStream and FileStream, i.e. write to memory stream by default, but once the total amount of data received is over e.g. 500 MB, write it to FileStream; then, read in chunks from both streams for processing the received data (first process 500 MB from the MemoryStream, dispose it, then read from FileStream)? Another solution is to use a custom memory stream implementation that doesn't require continuous address space for internal array allocation (i.e. a linked list of memory streams); this way, at least on 64-bit environments, out of memory exceptions should no longer be an issue. Con: extra work, more room for mistakes. So how do FileStream vs MemoryStream read/writes behave in terms of disk access and memory caching, i.e. data size/performance balance. I would expect that as long as enough RAM is available, FileStream would internally read/write from memory (cache) anyway, and virtual memory would take care of the rest. But I don't know how often FileStream will explicitly access a disk when being written to. Any help would be appreciated.

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• Race condition for thread startup

  - by Ozzah

  A similar question was asked here, but the answers generally all seem to relate to the lambda notation. I get a similar result without the lambda so I thought I'd ask for some clarification: Say I have something like this: for (int i = 0; i < 5; i++) (new Thread(new ThreadStart(delegate() { Console.WriteLine("Thread " + i); }))).Start(); One would expect the following output: Thread 0 Thread 1 Thread 2 Thread 3 Thread 4 Now I realise that the threads aren't started in any particular order, so let's just assume that the above lines can come out in any order. But that is not what happens. What instead happens: Thread 3 Thread 4 Thread 4 Thread 4 Thread 4 or something similar, which leads me to believe that rather than passing the value if i, it is passing the reference. (Which is weird, since an int is a value type). Doing something like this: for (int i = 0; i < 5; i++) (new Thread(new ThreadStart(delegate() { int j = i; Console.WriteLine("Thread " + j); }))).Start(); does not help either, even though we have made a copy of i. I am assuming the reason is that it hasn't made a copy of i in time. Doing something like this: for (int i = 0; i < 5; i++) { (new Thread(new ThreadStart(delegate() { Console.WriteLine("Thread " + i); }))).Start(); Thread.Sleep(50); } seems to fix the problem, however it is extremely undesirable as we're wasting 50ms on each iteration, not to mention the fact that if the computer is heavily loaded then maybe 50ms may not be enough. Here is a sample with my current, specific problem: Thread t = new Thread(new ThreadStart(delgate() { threadLogic(param1, param2, param3, param4); })); t.Start(); param1 = param2 = param3 = param4 = null; with: void threadLogic(object param1, object param2, object param3, object param4) { // Do some stuff here... } I want threadLogic() to run in its own thread, however the above code gives a null reference exception. I assume this is because the values are set to null before the thread has had a chance to start. Again, putting a Thread.Sleep(100) works, but it is an awful solution from every aspect. What do you guys recommend for this particular type of race condition?

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• getting Cannot identify image file when trying to create thumbnail in django

  - by Mo J. Mughrabi

  Am trying to create a thumbnail in django, am trying to build a custom class specifically to be used for generating thumbnails. As following from StringIO import StringIO from PIL import Image class Thumbnail(object): source = '' size = (50, 50) output = '' def __init__(self): pass @staticmethod def load(src): self = Thumbnail() self.source = src return self def generate(self, size=(50, 50)): if not isinstance(size, tuple): raise Exception('Thumbnail class: The size parameter must be an instance of a tuple.') self.size = size # resize properties box = self.size factor = 1 fit = True image = Image.open(self.source) # Convert to RGB if necessary if image.mode not in ('L', 'RGB'): image = image.convert('RGB') while image.size[0]/factor > 2*box[0] and image.size[1]*2/factor > 2*box[1]: factor *=2 if factor > 1: image.thumbnail((image.size[0]/factor, image.size[1]/factor), Image.NEAREST) #calculate the cropping box and get the cropped part if fit: x1 = y1 = 0 x2, y2 = image.size wRatio = 1.0 * x2/box[0] hRatio = 1.0 * y2/box[1] if hRatio > wRatio: y1 = int(y2/2-box[1]*wRatio/2) y2 = int(y2/2+box[1]*wRatio/2) else: x1 = int(x2/2-box[0]*hRatio/2) x2 = int(x2/2+box[0]*hRatio/2) image = image.crop((x1,y1,x2,y2)) #Resize the image with best quality algorithm ANTI-ALIAS image.thumbnail(box, Image.ANTIALIAS) # save image to memory temp_handle = StringIO() image.save(temp_handle, 'png') temp_handle.seek(0) self.output = temp_handle return self def get_output(self): return self.output.read() the purpose of the class is so i can use it inside different locations to generate thumbnails on the fly. The class works perfectly, I've tested it directly under a view.. I've implemented the thumbnail class inside the save method of the forms to resize the original images on saving. in my design, I have two fields for thumbnails. I was able to generate one thumbnail, if I try to generate two it crashes and I've been stuck for hours not sure whats the problem. Here is my model class Image(models.Model): article = models.ForeignKey(Article) title = models.CharField(max_length=100, null=True, blank=True) src = models.ImageField(upload_to='publication/image/') r128 = models.ImageField(upload_to='publication/image/128/', blank=True, null=True) r200 = models.ImageField(upload_to='publication/image/200/', blank=True, null=True) uploaded_at = models.DateTimeField(auto_now=True) Here is my forms class ImageForm(models.ModelForm): """ """ class Meta: model = Image fields = ('src',) def save(self, commit=True): instance = super(ImageForm, self).save(commit=True) file = Thumbnail.load(instance.src) instance.r128 = SimpleUploadedFile( instance.src.name, file.generate((128, 128)).get_output(), content_type='image/png' ) instance.r200 = SimpleUploadedFile( instance.src.name, file.generate((200, 200)).get_output(), content_type='image/png' ) if commit: instance.save() return instance the strange part is, when i remove the line which contains instance.r200 in the form save. It works fine, and it does the thumbnail and stores it successfully. Once I add the second thumbnail it fails.. Any ideas what am doing wrong here? Thanks Update: I tried earlier doing the following but I still got the same error class ImageForm(models.ModelForm): """ """ class Meta: model = Image fields = ('src',) def save(self, commit=True): instance = super(ImageForm, self).save(commit=True) instance.r128 = SimpleUploadedFile( instance.src.name, Thumbnail.load(instance.src).generate((128, 128)).get_output(), content_type='image/png' ) instance.r200 = SimpleUploadedFile( instance.src.name, Thumbnail.load(instance.src).generate((200, 200)).get_output(), content_type='image/png' ) if commit: instance.save() return instance

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• JAXB doesn't unmarshal list of interfaces

  - by Joker_vD

  It seems JAXB can't read what it writes. Consider the following code: interface IFoo { void jump(); } @XmlRootElement class Bar implements IFoo { @XmlElement public String y; public Bar() { y = ""; } public Bar(String y) { this.y = y; } @Override public void jump() { System.out.println(y); } } @XmlRootElement class Baz implements IFoo { @XmlElement public int x; public Baz() { x = 0; } public Baz(int x) { this.x = x; } @Override public void jump() { System.out.println(x); } } @XmlRootElement public class Holder { private List<IFoo> things; public Holder() { things = new ArrayList<>(); } @XmlElementWrapper @XmlAnyElement public List<IFoo> getThings() { return things; } public void addThing(IFoo thing) { things.add(thing); } } // ... try { JAXBContext context = JAXBContext.newInstance(Holder.class, Bar.class, Baz.class); Holder holder = new Holder(); holder.addThing(new Bar("1")); holder.addThing(new Baz(2)); holder.addThing(new Baz(3)); for (IFoo thing : holder.getThings()) { thing.jump(); } StringWriter s = new StringWriter(); context.createMarshaller().marshal(holder, s); String data = s.toString(); System.out.println(data); StringReader t = new StringReader(data); Holder holder2 = (Holder)context.createUnmarshaller().unmarshal(t); for (IFoo thing : holder2.getThings()) { thing.jump(); } } catch (Exception e) { System.err.println(e.getMessage()); } It's a simplified example, of course. The point is that I have to store two very differently implemented classes, Bar and Baz, in one collection. Well, I observed that they have pretty similar public interface, so I created an interface IFoo and made them two to implement it. Now, I want to have tools to save and load this collection to/from XML. Unfortunately, this code doesn't quite work: the collection is saved, but then it cannot be loaded! The intended output is 1 2 3 some xml 1 2 3 But unfortunately, the actual output is 1 2 3 some xml com.sun.org.apache.xerces.internal.dom.ElementNSImpl cannot be cast to testapplication1.IFoo Apparently, I need to use the annotations in a different way? Or to give up on JAXB and look for something else? I, well, can write "XMLNode toXML()" method for all classes I wan't to (de)marshal, but...

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• Minutia on Objective-C Categories and Extensions.

  - by Matt Wilding

  I learned something new while trying to figure out why my readwrite property declared in a private Category wasn't generating a setter. It was because my Category was named: // .m @interface MyClass (private) @property (readwrite, copy) NSArray* myProperty; @end Changing it to: // .m @interface MyClass () @property (readwrite, copy) NSArray* myProperty; @end and my setter is synthesized. I now know that Class Extension is not just another name for an anonymous Category. Leaving a Category unnamed causes it to morph into a different beast: one that now gives compile-time method implementation enforcement and allows you to add ivars. I now understand the general philosophies underlying each of these: Categories are generally used to add methods to any class at runtime, and Class Extensions are generally used to enforce private API implementation and add ivars. I accept this. But there are trifles that confuse me. First, at a hight level: Why differentiate like this? These concepts seem like similar ideas that can't decide if they are the same, or different concepts. If they are the same, I would expect the exact same things to be possible using a Category with no name as is with a named Category (which they are not). If they are different, (which they are) I would expect a greater syntactical disparity between the two. It seems odd to say, "Oh, by the way, to implement a Class Extension, just write a Category, but leave out the name. It magically changes." Second, on the topic of compile time enforcement: If you can't add properties in a named Category, why does doing so convince the compiler that you did just that? To clarify, I'll illustrate with my example. I can declare a readonly property in the header file: // .h @interface MyClass : NSObject @property (readonly, copy) NSString* myString; @end Now, I want to head over to the implementation file and give myself private readwrite access to the property. If I do it correctly: // .m @interface MyClass () @property (readonly, copy) NSString* myString; @end I get a warning when I don't synthesize, and when I do, I can set the property and everything is peachy. But, frustratingly, if I happen to be slightly misguided about the difference between Category and Class Extension and I try: // .m @interface MyClass (private) @property (readonly, copy) NSString* myString; @end The compiler is completely pacified into thinking that the property is readwrite. I get no warning, and not even the nice compile error "Object cannot be set - either readonly property or no setter found" upon setting myString that I would had I not declared the readwrite property in the Category. I just get the "Does not respond to selector" exception at runtime. If adding ivars and properties is not supported by (named) Categories, is it too much to ask that the compiler play by the same rules? Am I missing some grand design philosophy?

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• X264 encoding using Opencv

  - by user573193

  I am working with a high resolution camera: 4008x2672. I a writing a simple program which grabs frame from the camera and sends the frame to a avi file. For working with such a high resolution, I found only x264 codec that could do the trick (Suggestions welcome). I am using opencv for most of the image handling stuff. As mentioned in this post http://doom10.org/index.php?topic=1019.0 , I modified the AVCodecContext members as per ffmpeg presets for libx264 (Had to do this to avoid broken ffmpeg defaults settings error). This is output I am getting when I try to run the program [libx264 @ 0x992d040]non-strictly-monotonic PTS 1294846981.526675 1 0 //Timestamp camera_no frame_no 1294846981.621101 1 1 1294846981.715521 1 2 1294846981.809939 1 3 1294846981.904360 1 4 1294846981.998782 1 5 1294846982.093203 1 6 Last message repeated 7 times [avi @ 0x992beb0]st:0 error, non monotone timestamps -614891469123651720 = -614891469123651720 OpenCV Error: Unspecified error (Error while writing video frame) in icv_av_write_frame_FFMPEG, file /home/ajoshi/ext/OpenCV-2.2.0/modules/highgui/src/cap_ffmpeg.cpp, line 1034 terminate called after throwing an instance of 'cv::Exception' what(): /home/ajoshi/ext/OpenCV-2.2.0/modules/highgui/src/cap_ffmpeg.cpp:1034: error: (-2) Error while writing video frame in function icv_av_write_frame_FFMPEG Aborted Modifications to the AVCodecContext are: if(codec_id == CODEC_ID_H264) { //fprintf(stderr, "Trying to parse a preset file for libx264\n"); //Setting Values manually from medium preset c-me_method = 7; c-qcompress=0.6; c-qmin = 10; c-qmax = 51; c-max_qdiff = 4; c-i_quant_factor=0.71; c-max_b_frames=3; c-b_frame_strategy = 1; c-me_range = 16; c-me_subpel_quality=7; c-coder_type = 1; c-scenechange_threshold=40; c-partitions = X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8; c-flags = CODEC_FLAG_LOOP_FILTER; c-flags2 = CODEC_FLAG2_BPYRAMID | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_WPRED | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP; c-keyint_min = 25; c-refs = 3; c-trellis=1; c-directpred = 1; c-weighted_p_pred=2; } I am probably not setting the dts and pts values which I believed ffmpeg should be setting it for me. Any sugggestions welcome. Thanks in advance

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• Help me with this java program

  - by aser

  The question : Input file: customer’s account number, account balance at beginning of month, transaction type (withdrawal, deposit, interest), transaction amount Output: account number, beginning balance, ending balance, total interest paid, total amount deposited, number of deposits, total amount withdrawn, number of withdrawals package sentinel; import java.io.*; import java.util.*; public class Ex7 { /** * @param args the command line arguments */ public static void main(String[] args) throws FileNotFoundException { int AccountNum; double BeginningBalance; double TransactionAmount; int TransactionType; double AmountDeposited=0; int NumberOfDeposits=0; double InterestPaid=0.0; double AmountWithdrawn=0.0; int NumberOfWithdrawals=0; boolean found= false; Scanner inFile = new Scanner(new FileReader("Account.in")); PrintWriter outFile = new PrintWriter("Account.out"); AccountNum = inFile.nextInt(); BeginningBalance= inFile.nextDouble(); while (inFile.hasNext()) { TransactionAmount=inFile.nextDouble(); TransactionType=inFile.nextInt(); outFile.printf("Account Number: %d%n", AccountNum); outFile.printf("Beginning Balance: $%.2f %n",BeginningBalance); outFile.printf("Ending Balance: $%.2f %n",BeginningBalance); outFile.println(); switch (TransactionType) { case '1': // case 1 if we have a Deposite BeginningBalance = BeginningBalance + TransactionAmount; AmountDeposited = AmountDeposited + TransactionAmount; NumberOfDeposits++; outFile.printf("Amount Deposited: $%.2f %n",AmountDeposited); outFile.printf("Number of Deposits: %d%n",NumberOfDeposits); outFile.println(); break; case '2':// case 2 if we have an Interest BeginningBalance = BeginningBalance + TransactionAmount; InterestPaid = InterestPaid + TransactionAmount; outFile.printf("Interest Paid: $%.2f %n",InterestPaid); outFile.println(); break; case '3':// case 3 if we have a Withdraw BeginningBalance = BeginningBalance - TransactionAmount; AmountWithdrawn = AmountWithdrawn + TransactionAmount; NumberOfWithdrawals++; outFile.printf("Amount Withdrawn: $%.2f %n",AmountWithdrawn); outFile.printf("Number of Withdrawals: %d%n",NumberOfWithdrawals); outFile.println(); break; default: System.out.println("Invalid transaction Tybe: " + TransactionType + TransactionAmount); } } inFile.close(); outFile.close(); } } But is gives me this : Exception in thread "main" java.util.InputMismatchException at java.util.Scanner.throwFor(Scanner.java:840) at java.util.Scanner.next(Scanner.java:1461) at java.util.Scanner.nextInt(Scanner.java:2091) at java.util.Scanner.nextInt(Scanner.java:2050) at sentinel.Ex7.main(Ex7.java:36) Java Result: 1

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• calling startActivity() inside of a instance method - causing a NullPointerException

  - by Cole

  Heya - I'm trying to call startActivity() from a class that extends AsyncTask in the onPostExecute(). Here's the flow: Class that extends AsyncTask: protected void onPostExecute() { Login login = new Login(); login.pushCreateNewOrChooseExistingFormActivity(); } Class that extends Activity: public void pushCreateNewOrChooseExistingFormActivity() { // start the CreateNewOrChooseExistingForm Activity Intent intent = new Intent(Intent.ACTION_VIEW); **ERROR_HERE*** intent.setClassName(this, CreateNewOrChooseExistingForm.class.getName()); startActivity(intent); } And I get this error… every time: 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): FATAL EXCEPTION: main 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): java.lang.NullPointerException 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:120) 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): at android.content.ComponentName.(ComponentName.java:62) 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): at android.content.Intent.setClassName(Intent.java:4850) 03-17 16:04:29.579: ERROR/AndroidRuntime(1503): at com.att.AppName.Login.pushCreateNewOrChooseExistingFormActivity(Login.java:47) For iOS developers - I'm just trying to push a new view controller on to a navigational controller's stack a la pushViewController:animated:. Which apparently - is hard to do on this platform. Any ideas? Thanks in advance! UPDATE - FIXED: per @Falmarri advice, i managed to resolve this issue. first of all, i'm no longer calling Login login = new Login(); to create a new login object. bad. bad. bad. no cookie. instead, when preparing to call .execute(), this tutorial suggests passing the applicationContext to the class the executes the AsyncTask, for my purposes, as shown below: CallWebServiceTask task = new CallWebServiceTask(); // pass the login object to the task task.applicationContext = login; // execute the task in the background, passing the required params task.execute(login); now, in onPostExecute(), i can get to my Login objects methods like so: ((Login) applicationContext).pushCreateNewOrChooseExistingFormActivity(); ((Login) applicationContext).showLoginFailedAlert(result.get("httpResponseCode").toString()); ... hope this helps someone else out there! especially iOS developers transistioning over to Android...

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• when get pagecontent from URL the connect alway return nopermistion ?

  - by tiendv

  I have a methor to return pagecontent of link but when it run, alway return "Do not perrmisson ", plesea check it here is code to return string pagecontent public static String getPageContent(String targetURL) throws Exception { Hashtable contentHash = new Hashtable(); URL url; URLConnection conn; // The data streams used to read from and write to the URL connection. DataOutputStream out; DataInputStream in; // String returned as the result . String returnString = ""; // Create the URL object and make a connection to it. url = new URL(targetURL); conn = url.openConnection(); // check out permission of acess URL if (conn.getPermission() != null) { returnString = "Do not Permission access URL "; } else { // Set connection parameters. We need to perform input and output, // so set both as true. conn.setDoInput(true); conn.setDoOutput(true); // Disable use of caches. conn.setUseCaches(false); // Set the content type we are POSTing. We impersonate it as // encoded form data conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); // get the output stream . out = new DataOutputStream(conn.getOutputStream()); String content = ""; // Create a single String value pairs for all the keys // in the Hashtable passed to us. Enumeration e = contentHash.keys(); boolean first = true; while (e.hasMoreElements()) { // For each key and value pair in the hashtable Object key = e.nextElement(); Object value = contentHash.get(key); // If this is not the first key-value pair in the hashtable, // concantenate an "&" sign to the constructed String if (!first) content += "&"; // append to a single string. Encode the value portion content += (String) key + "=" + URLEncoder.encode((String) value); first = false; } // Write out the bytes of the content string to the stream. out.writeBytes(content); out.flush(); out.close(); // check if can't read from URL // Read input from the input stream. in = new DataInputStream(conn.getInputStream()); String str; while (null != ((str = in.readLine()))) { returnString += str + "\n"; } in.close(); } // return the string that was read. return returnString; }

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• Why isn't my File.Move() working?

  - by yeahumok

  I'm not sure what exactly i'm doing wrong here...but i noticed that my File.Move() isn't renaming any files. Also, does anybody know how in my 2nd loop, i'd be able to populate my .txt file with a list of the path AND sanitized file name? using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Text.RegularExpressions; namespace ConsoleApplication2 { class Program { static void Main(string[] args) { //recurse through files. Let user press 'ok' to move onto next step string[] files = Directory.GetFiles(@"C:\Documents and Settings\jane.doe\Desktop\~Test Folder for [SharePoint] %testing", "*.*", SearchOption.AllDirectories); foreach (string file in files) { Console.Write(file + "\r\n"); } Console.WriteLine("Press any key to continue..."); Console.ReadKey(true); //End section //Regex -- find invalid chars string pattern = " *[\\~#%&*{}/<>?|\"-]+ *"; string replacement = " "; Regex regEx = new Regex(pattern); string[] fileDrive = Directory.GetFiles(@"C:\Documents and Settings\jane.doe\Desktop\~Test Folder for [SharePoint] %testing", "*.*", SearchOption.AllDirectories); List<string> filePath = new List<string>(); //clean out file -- remove the path name so file name only shows string result; foreach(string fileNames in fileDrive) { result = Path.GetFileName(fileNames); filePath.Add(result); } StreamWriter sw = new StreamWriter(@"C:\Documents and Settings\jane.doe\Desktop\~Test Folder for [SharePoint] %testing\File_Renames.txt"); //Sanitize and remove invalid chars foreach(string Files2 in filePath) { try { string sanitized = regEx.Replace(Files2, replacement); sw.Write(sanitized + "\r\n"); System.IO.File.Move(Files2, sanitized); System.IO.File.Delete(Files2); } catch (Exception ex) { Console.Write(ex); } } sw.Close(); } } } I'm VERY new to C# and trying to write an app that recurses through a specific drive, finds invalid characters (as specified in the RegEx pattern), removes them from the filename and then write a .txt file that has the path name and the corrected filename. Any ideas?

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• Why does DebugActiveProcessStop crash my debugging app?

  - by SparkyNZ

  I have a debugging program which I've written to attach to a process and create a crash dump file. That part works fine. The problem I have is that when the debugger program terminates, so does the program that it was debugging. I did some Googling and found the DebugActiveProcessStop() API call. This didn't show up in my older MSDN documentation as it was only introduced in Windows XP so I've tried loading it dynamicall from Kernel32.dll at runtime. Now my problem is that my debugger program crashes as soon as the _DebugActiveProcessStop() call is made. Can somebody please tell me what I'm doing wrong? typedef BOOL (*DEBUGACTIVEPROCESSSTOP)(DWORD); DEBUGACTIVEPROCESSSTOP _DebugActiveProcessStop; HMODULE hK32 = LoadLibrary( "kernel32.dll" ); if( hK32 ) _DebugActiveProcessStop = (DEBUGACTIVEPROCESSSTOP) GetProcAddress( hK32,"DebugActiveProcessStop" ); else { printf( "Can't load Kernel32.dll\n" ); return; } if( ! _DebugActiveProcessStop ) { printf( "Can't find DebugActiveProcessStop\n" ); return; } ... void DebugLoop( void ) { DEBUG_EVENT de; while( 1 ) { WaitForDebugEvent( &de, INFINITE ); switch( de.dwDebugEventCode ) { case CREATE_PROCESS_DEBUG_EVENT: hProcess = de.u.CreateProcessInfo.hProcess; break; case EXCEPTION_DEBUG_EVENT: // PDS: I want a crash dump immediately! dwProcessId = de.dwProcessId; dwThreadId = de.dwThreadId; WriteCrashDump( &de.u.Exception ); return; case CREATE_THREAD_DEBUG_EVENT: case OUTPUT_DEBUG_STRING_EVENT: case EXIT_THREAD_DEBUG_EVENT: case EXIT_PROCESS_DEBUG_EVENT : case LOAD_DLL_DEBUG_EVENT: case UNLOAD_DLL_DEBUG_EVENT: case RIP_EVENT: default: break; } ContinueDebugEvent( de.dwProcessId, de.dwThreadId, DBG_CONTINUE ); } } ... void main( void ) { ... BOOL bo = DebugActiveProcess( dwProcessId ); if( bo == 0 ) printf( "DebugActiveProcess failed, GetLastError: %u \n",GetLastError() ); hProcess = OpenProcess( PROCESS_ALL_ACCESS, TRUE, dwProcessId ); if( hProcess == NULL ) printf( "OpenProcess failed, GetLastError: %u \n",GetLastError() ); DebugLoop(); _DebugActiveProcessStop( dwProcessId ); CloseHandle( hProcess ); }

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• Look over my C# SQLite Query, what am I doing wrong?

  - by CODe

  I'm writing a WinForms database application using SQLite and C#. I have a sqlite query that is failing, and I'm unsure as to where I'm going wrong, as I've tried everything I could think of. public DataTable searchSubs(String businessName, String contactName) { string SQL = null; if ((businessName != null && businessName != "") && (contactName != null && contactName != "")) { // provided business name and contact name for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE BusinessName LIKE %@BusinessName% AND Contact LIKE %@ContactName%"; } else if ((businessName != null && businessName != "") && (contactName == null || contactName == "")) { // provided business name only for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE BusinessName LIKE %@BusinessName%"; } else if ((businessName == null || businessName == "") && (contactName != null && contactName != "")) { // provided contact name only for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE Contact LIKE %@ContactName%"; } else if ((businessName == null || businessName == "") && (contactName == null || contactName == "")) { // provided no search information SQL = "SELECT * FROM SUBCONTRACTOR"; } SQLiteCommand cmd = new SQLiteCommand(SQL); cmd.Parameters.AddWithValue("@BusinessName", businessName); cmd.Parameters.AddWithValue("@ContactName", contactName); cmd.Connection = connection; SQLiteDataAdapter da = new SQLiteDataAdapter(cmd); DataSet ds = new DataSet(); try { da.Fill(ds); DataTable dt = ds.Tables[0]; return dt; } catch (Exception e) { MessageBox.Show(e.ToString()); return null; } finally { cmd.Dispose(); connection.Close(); } } I continually get an error saying that it is failing near the %'s. That's all fine and dandy, but I guess I'm structuring it wrong, but I don't know where! I tried adding apostrophes around the "like" variables, like this: SQL = "SELECT * FROM SUBCONTRACTOR WHERE Contact LIKE '%@ContactName%'"; and quite honestly, that is all I can think of. Anyone have any ideas?

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• Two collections and a for loop. (Urgent help needed) Checking an object variable against an inputted

  - by Elliott

  Hi there, I'm relatively new to java, I'm certain the error is trivial. But can't for the life of me spot it. I have an end of term exam on monday and currently trying to get to grips with past papers! Anyway heregoes, in another method (ALGO_1) I search over elements of and check the value H_NAME equals a value entered in the main. When I attempt to run the code I get a null pointer exception, also upon trying to print (with System.out.println etc) the H_NAME value after each for loop in the snippet I also get a null statement returned to me. I am fairly certain that the collection is simply not storing the data gathered up by the Scanner. But then again when I check the collection size with size() it is about the right size. Either way I'm pretty lost and would appreciate the help. Main questions I guess to ask are: from the readBackground method is the data.add in the wrong place? is the snippet simply structured wrongly? oh and another point when I use System.out.println to check the Background object values name, starttime, increment etc they print out fine. Thanks in advance.(PS im guessing the formatting is terrible, apologies.) snippet of code: for(Hydro hd: hydros){ System.out.println(hd.H_NAME); for(Background back : backgs){ System.out.println(back.H_NAME); if(back.H_NAME.equals(hydroName)){ //get error here public static Collection<Background> readBackground(String url) throws IOException { URL u = new URL(url); InputStream is = u.openStream(); InputStreamReader isr = new InputStreamReader(is); BufferedReader b = new BufferedReader(isr); String line =""; Vector<Background> data = new Vector<Background>(); while((line = b.readLine())!= null){ Scanner s = new Scanner(line); String name = s.next(); double starttime = Double.parseDouble(s.next()); double increment = Double.parseDouble(s.next()); double sum = 0; double p = 0; double nterms = 0; while((s.hasNextDouble())){ p = Double.parseDouble(s.next()); nterms++; sum += p; } double pbmean = sum/nterms; Background SAMP = new Background(name, starttime, increment, pbmean); data.add(SAMP); } return data; } Edit/Delete Message

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• CultureManager issue

  - by Serge

  I have a bug I don't understand. While the following works fine: Resources.Classes.AFieldFormula.DirectFieldFormula this one throws an exception: new ResourceManager(typeof(Resources.Classes.AFieldFormula)).GetString("DirectFieldFormula"); Could not find any resources appropriate for the specified culture or the neutral culture. Make sure \"Resources.Classes.AFieldFormula.resources\" was correctly embedded or linked into assembly \"MygLogWeb\" at compile time, or that all the satellite assemblies required are loadable and fully signed. How comes? Resource designer.cs file: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.18408 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace Resources.Classes { using System; /// <summary> /// A strongly-typed resource class, for looking up localized strings, etc. /// </summary> // This class was auto-generated by the StronglyTypedResourceBuilder // class via a tool like ResGen or Visual Studio. // To add or remove a member, edit your .ResX file then rerun ResGen // with the /str option, or rebuild your VS project. [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")] [global::System.Diagnostics.DebuggerNonUserCodeAttribute()] [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()] public class AFieldFormula { private static global::System.Resources.ResourceManager resourceMan; private static global::System.Globalization.CultureInfo resourceCulture; [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] internal AFieldFormula() { } /// <summary> /// Returns the cached ResourceManager instance used by this class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Resources.ResourceManager ResourceManager { get { if (object.ReferenceEquals(resourceMan, null)) { global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("MygLogWeb.Classes.AFieldFormula", typeof(AFieldFormula).Assembly); resourceMan = temp; } return resourceMan; } } /// <summary> /// Overrides the current thread's CurrentUICulture property for all /// resource lookups using this strongly typed resource class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Globalization.CultureInfo Culture { get { return resourceCulture; } set { resourceCulture = value; } } /// <summary> /// Looks up a localized string similar to Direct field. /// </summary> public static string DirectFieldFormula { get { return ResourceManager.GetString("DirectFieldFormula", resourceCulture); } } } }

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• JPanels, JFrames, and Windows, Oh my!

  - by Jonathan

  Simply stated, I am trying to make a game I am working on full-screen. I have the following code I am trying to use: GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); GraphicsDevice gs = ge.getDefaultScreenDevice(); if(!gs.isFullScreenSupported()) { System.out.println("full-screen not supported"); } Frame frame = new Frame(gs.getDefaultConfiguration()); Window win = new Window(frame); try { // Enter full-screen mode gs.setFullScreenWindow(win); win.validate(); } Problem with this is that I am working within a class that extends JPanel, and while I have a variable of type Frame, I have none of type Window within the class. My understanding of JPanel is that it is a Window of sorts, but I cannot pass 'this' into gs.setFullScreenWindow(Window win)... How should I go about doing this? Is there any easy way of calling that, or a similar method, using a JPanel? Is there a way I can get something of type Window from my JPanel? - EDIT: The following method changes the state of JFrame and is called every 10ms: public void paintScreen() { Graphics g; try{ g = this.getGraphics(); //get Panel's graphic context if(g == null) { frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setExtendedState(frame.getExtendedState()|JFrame.MAXIMIZED_BOTH); frame.add(this); frame.pack(); frame.setResizable(false); frame.setTitle("Game Window"); frame.setVisible(true); } if((g != null) && (dbImage != null)) { g.drawImage(dbImage, 0, 0, null); } Toolkit.getDefaultToolkit().sync(); //sync the display on some systems g.dispose(); } catch (Exception e) { if(blockError) { blockError = false; } else { System.out.println("Graphics context error: " + e); } } } I anticipate that there may be a few redundancies or unnecessary calls after the if(g==null) statement (all the frame.somethingOrOther()s), any cleanup advice would be appreciated... Also, the block error is what it seems. I am ignoring an error. The error only occurs once, and this works fine when setup to ignore the first instance of the error... For anyone interested I can post additional info there if anyone wants to see if that block can be removed, but i'm not concerned... I might look into it later.

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• NSFetchedResultsChangeUpdate crashes when called on a searched tableview

  - by Zachary Fisher

  So I nearly have this thing figured out, but I am stumbling over the NSFetchedResultsChangeUpdate when I update my managedObjectContext from a detail view that was entered after searching the table. I have a tableview generated from a core data set. I can enter a detail view from this table and make changes without any issue. I can also search the table and make changes MOST of the time without any issues. However, on certain objects, I get an "Exception was caught during Core Data change processing". I tracked this down to the NSFetchedResultsChangeUpdate. I'm using the following code: case NSFetchedResultsChangeUpdate: if (searchTermForSegue) { NSLog(@"index info:%@.....",theIndexPath); NSLog(@"crashing at the next line"); [self fetchedResultsController:self.searchFetchedResultsController configureCell:[tableView cellForRowAtIndexPath:theIndexPath] atIndexPath:theIndexPath]; break; } else { [self fetchedResultsController:controller configureCell:[tableView cellForRowAtIndexPath:theIndexPath] atIndexPath:theIndexPath]; } break; When the table is not being searched, it runs the else method and that works 100% of the time. When the table is being searched, it runs the if (searchTermForSegue) and that works most of the time, but not always. I logged theIndexPath and discovered the following: When it works, theIndexPath is correctly reporting the objects indexPat, when it fails, the wrong theIndexPath has been called. For example, if I do a search that narrows the tableView to 3 sections, 2 items in first, 1 in second, 1 in third, I get the following nslog: On first object: index info:<NSIndexPath 0xb0634d0> 2 indexes [0, 0]..... on second object: index info:<NSIndexPath 0xb063e70> 2 indexes [0, 1]..... on third object: index info:<NSIndexPath 0xb042880> 2 indexes [1, 0]..... but on the last object: index info:<NSIndexPath 0x9665790> 2 indexes [2, 17]..... it should be calling [2, 0] Note that I am simply updating these objects, not deleting them or adding new ones. Any thoughts would be appreciated!

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• Why do I get a WCF timeout even though my service call and callback are successful?

  - by KallDrexx

  I'm playing around with hooking up an in-game console to a WCF interface, so an external application can send console commands and receive console output. To accomplish this I created the following service contracts: public interface IConsoleNetworkCallbacks { [OperationContract(IsOneWay = true)] void NewOutput(IEnumerable<string> text, string category); } [ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IConsoleNetworkCallbacks))] public interface IConsoleInterface { [OperationContract] void ProcessInput(string input); [OperationContract] void ChangeCategory(string category); } On the server I implemented it with: public class ConsoleNetworkInterface : IConsoleInterface, IDisposable { public ConsoleNetworkInterface() { ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler); } public void Dispose() { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); } public void ProcessInput(string input) { ConsoleManager.Instance.ProcessInput(input); } public void ChangeCategory(string category) { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler, category); } protected void OutputHandler(IEnumerable<string> text, string category) { var callbacks = OperationContext.Current.GetCallbackChannel<IConsoleNetworkCallbacks>(); callbacks.NewOutput(text, category); } } On the client I implemented the callback with: public class Callbacks : IConsoleNetworkCallbacks { public void NewOutput(IEnumerable<string> text, string category) { MessageBox.Show(string.Format("{0} lines received for '{1}' category", text.Count(), category)); } } Finally, I establish the service host with the following class: public class ConsoleServiceHost : IDisposable { protected ServiceHost _host; public ConsoleServiceHost() { _host = new ServiceHost(typeof(ConsoleNetworkInterface), new Uri[] { new Uri("net.pipe://localhost") }); _host.AddServiceEndpoint(typeof(IConsoleInterface), new NetNamedPipeBinding(), "FrbConsolePipe"); _host.Open(); } public void Dispose() { _host.Close(); } } and use the following code on my client to establish the connection: protected Callbacks _callbacks; protected IConsoleInterface _proxy; protected void ConnectToConsoleServer() { _callbacks = new Callbacks(); var factory = new DuplexChannelFactory<IConsoleInterface>(_callbacks, new NetNamedPipeBinding(), new EndpointAddress("net.pipe://localhost/FrbConsolePipe")); _proxy = factory.CreateChannel(); _proxy.ProcessInput("Connected"); } So what happens is that my ConnectToConsoleServer() is called and then it gets all the way to _proxy.ProcessInput("Connected");. In my game (on the server) I immediately see the output caused by the ProcessInput call, but the client is still stalled on the _proxy.ProcessInput() call. After a minute my client gets a JIT TimeoutException however at the same time my MessageBox message appears. So obviously not only is my command being sent immediately, my callback is being correctly called. So why am I getting a timeout exception? Note: Even removing the MessageBox call, I still have this issue, so it's not an issue of the GUI blocking the callback response.

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• BlackBerry OS 7.1 secured TLS connection is closed after very short time

  - by MrVincenzo

  To make a long story short: Same client-server configuration, same network topology, same device (Bold 9900) - works perfectly well on OS 7.0 but doesn't work as expected on OS 7.1 and the secured tls connection is being closed by the server after a very short time. My application opens a secured tls connection to a server. The connection is kept alive by a application layer keep-alive mechanism and remains open until the client closes it. Attached is a simplified version of the actual code that opens connection and reads from the socket. The code works perfectly on OS 5.0-7.0 but doesn't work as expected on OS 7.1. When running on OS 7.1, the blocking read() returns with -1 (end of the stream has been reached) after very short time (10-45 seconds). For OS 5.0-7.0 the call to read() remains blocking until next data arrives and the connection is never closed by the server. Connection connection = Connector.open(connectionString); connInputStream = connection.openInputStream(); while (true) { try { retVal = connInputStream.read(); if (-1 == retVal) { break; // end of stream has been reached } } catch (Exception e ) { // do error handling } // data read from stream is handled here } UPDATE 1: Apparently, the problem appears only when I use secured tls connection (either using mobile network or WiFi) on OS 7.1. Everything works as expected when opening a non secured connection on OS 7.1. For tls on mobile networks I use the following connection string: connectionString = "tls://someipaddress:443;deviceside=false;ConnectionType=mds-public;EndToEndDesired"; For tls on Wifi I use the following connection string: connectionString = "tls://someipaddress:443;deviceside=true;interface=wifi;EndToEndRequired" UPDATE 2: The connection is never idle. I am constantly receiving and sending data on it. The issue appears both when using mobile connection and WiFi. The issue appears both on real OS 7.1 devices and simulators. I am starting to suspect that it is somehow related either to the connection string I am using or to the tls handshake. UPDATE 3: According to Wireshark's captures that I made with the OS 7.1 simulator, the secured tls connection is being closed by the server (client receives FIN). For the moment I don't have the server's private key therefore I unable to debug the tls handshake.

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• Conceptual inheritance implementation

  - by TheSENDER

  Hi there, I'm writing a spatial data structure and I have a doubt about what's the best NODE implementation. According to my design I have an abstract node entity and three classes which inherit from it: EMPTYNODE, FULLNODE, INTERNALNODE. The first one has no particular data. The second one has 1 reference to a generic element. The third one has 2 references to other nodes. I have found several ways to implement this situation (that I have already coded) but I can't decide what's the best. The first solution that I have found is to use a single class Node that potentially performs all the operation in this way: private static class Node { private Elem elem = null; private Node left = null, right = null; public Elem getElem() { assert isFull(); return elem; } public boolean isEmpty() { return elem == null && left == null; } public boolean isFull() { return elem != null; } public boolean isInternal() { return elem == null && left != null; } } The second solution is to write an explicit division by classes where every class offers only its methods. Obviously in this way we are obliged to perform several casts to the node objects. private static abstract class Node { public abstract boolean isEmpty(); public abstract boolean isFull(); public abstract boolean isInternal(); } private static class FullNode extends Node{ private ITriangle elem; @Override public boolean isEmpty() { return false; } @Override public final boolean isFull() { return true; } @Override public final boolean isInternal() { return false; } public Elem getElem() { return elem; } } The third one solution is to use the inheritance allowing every classes to offer all the methods, but the object type should by check by "isEmpty()" and similar methods. In case of wrong call we'll throw an exception. private static abstract class Node { public abstract boolean isEmpty(); public abstract boolean isFull(); public abstract boolean isInternal(); public abstract Elem getElem(); } private static class Empty extends Node{ @Override public boolean isEmpty() { return true; } @Override public final boolean isFull() { return false; } @Override public final boolean isInternal() { return false; } @Override public Elem getElem() { throw new AssertionError(); } } What do you think about these three solutions? Which one would you use? Any other ideas? Thanks for your help. Every idea will be appreciated.

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• Assign value to HTML textbox from JSP

  - by prakash_d22

  Hello I am creating a web page to add some information about given product.I need to enter id,name,description and image as information.I need the id to be auto generated.I am using jsp and database as access.I am fetching the count(*)+1 value from database and assigning to my html text box but its showing as null.can i get some help? Code: <body> <%@page import="java.sql.*"%> <%! String no; %> <% try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con = DriverManager.getConnection("jdbc:odbc:pd"); ResultSet rs = null; Statement st = con.createStatement(); String sql = ("select count(*)+1 from products"); st.executeUpdate(sql); while (rs.next()) { no=rs.getString("count(*)+1"); } rs.close(); st.close(); con.close(); } catch(Exception e){} %> <Form name='Form1' action="productcode.jsp" method="post"> <table width="1024" border="0"> <tr> <td width="10">&nbsp;</td> <td width="126">Add Product: </td> <td width="277">&nbsp;</td> <td width="583">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>Product Id:</td> <td><label> <input type="text" name="id" value="<%= no%>"/> </label></td> <td>&nbsp;</td> .... and so on

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• Programmatically triggering events in Javascript for IE using jQuery

  - by Dan Herbert

  When an Event is triggered by a user in IE, it is set to the window.event object. The only way to see what triggered the event is by accessing the window.event object (as far as I know) This causes a problem in ASP.NET validators if an event is triggered programmatically, like when triggering an event through jQuery. In this case, the window.event object stores the last user-triggered event. When the onchange event is fired programmatically for a text box that has an ASP.NET validator attached to it, the validation breaks because it is looking at the element that fired last event, which is not the element the validator is for. Does anyone know a way around this? It seems like a problem that is solvable, but from looking online, most people just find ways to ignore the problem instead of solving it. To explain what I'm doing specifically: I'm using a jQuery time picker plugin on a text box that also has 2 ASP.NET validators associated with it. When the time is changed, I'm using an update panel to post back to the server to do some things dynamically, so I need the onchange event to fire in order to trigger the postback for that text box. The jQuery time picker operates by creating a hidden unordered list that is made visible when the text box is clicked. When one of the list items is clicked, the "change" event is fired programmatically for the text box through jQuery's change() method. Because the trigger for the event was a list item, IE sees the list item as the source of the event, not the text box, like it should. I'm not too concerned with this ASP.NET validator working as soon as the text box is changed, I just need the "change" event to be processed so my postback event is called for the text box. The problem is that the validator throws an exception in IE which stops any event from being triggered. Firefox (and I assume other browsers) don't have this issue. Only IE due to the different event model. Has anyone encountered this and seen how to fix it? I've found this problem reported several other places, but they offer no solutions: jQuery's forum, with the jQuery UI Datepicker and an ASP.NET Validator ASP.NET forums, bug with ValidatorOnChange() function

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• arrayListOutOfBoundsException... Please Help?

  - by Jacob

  This is my class Debugger. Can anyone try and run it and see whens wrong? Ive spent hours on it already. :( public class Debugger { private String codeToDebug = ""; public Debugger(String code) { codeToDebug = code; } /** * This method itterates over a css file and adds all the properties to an arraylist */ public void searchDuplicates() { boolean isInside = false; ArrayList<String> methodStorage = new ArrayList(); int stored = 0; String[] codeArray = codeToDebug.split(""); try { int i = 0; while(i<codeArray.length) { if(codeArray[i].equals("}")) { isInside = false; } if(isInside && !codeArray[i].equals(" ")) { boolean methodFound = false; String method = ""; int c = i; while(!methodFound) { method += codeArray[c]; if(codeArray[c+1].equals(":")) { methodFound = true; } else { c++; } } methodStorage.add(stored, method); System.out.println(methodStorage.get(stored)); stored++; boolean stillInside = true; int skip = i; while(stillInside) { if(codeArray[skip].equals(";")) { stillInside = false; } else { skip++; } } i = skip; } if(codeArray[i].equals("{")) { isInside = true; } i++; } } catch(ArrayIndexOutOfBoundsException ar) { System.out.println("------- array out of bounds exception -------"); } } /** * Takes in String and outputs the number of characters it contains * @param input * @return Number of characters */ public static int countString(String input) { String[] words = input.split(""); int counter = -1; for(int i = 0; i<words.length; i++){ counter++; } return counter; } public static void main(String[] args) { Debugger h = new Debugger("body {margin:;\n}"); h.searchDuplicates(); } }

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• How to write my own global lock / unlock functions for PostgreSQL

  - by rafalmag

  I have postgresql (in perlu) function getTravelTime(integer, timestamp), which tries to select data for specified ID and timestamp. If there are no data or if data is old, it downloads them from external server (downloading time ~300ms). Multiple process use this database and this function. There is an error when two process do not find data and download them and try to do an insert to travel_time table (id and timestamp pair have to be unique). I thought about locks. Locking whole table would block all processes and allow only one to proceed. I need to lock only on id and timestamp. pg_advisory_lock seems to lock only in "current session". But my processes uses their own sessions. I tried to write my own lock/unlock functions. Am I doing it right? I use active waiting, how can I omit this? Maybe there is a way to use pg_advisory_lock() as global lock? My code: CREATE TABLE travel_time_locks ( id_key integer NOT NULL, time_key timestamp without time zone NOT NULL, UNIQUE (id_key, time_key) ); ------------ -- Function: mylock(integer, timestamp) DROP FUNCTION IF EXISTS mylock(integer, timestamp) CASCADE; -- Usage: SELECT mylock(1, '2010-03-28T19:45'); -- function tries to do a global lock similar to pg_advisory_lock(key, key) CREATE OR REPLACE FUNCTION mylock(id_input integer, time_input timestamp) RETURNS void AS $BODY$ DECLARE rows int; BEGIN LOOP BEGIN -- active waiting here !!!! :( INSERT INTO travel_time_locks (id_key, time_key) VALUES (id_input, time_input); EXCEPTION WHEN unique_violation THEN CONTINUE; END; EXIT; END LOOP; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 1; ------------ -- Function: myunlock(integer, timestamp) DROP FUNCTION IF EXISTS myunlock(integer, timestamp) CASCADE; -- Usage: SELECT myunlock(1, '2010-03-28T19:45'); -- function tries to do a global unlock similar to pg_advisory_unlock(key, key) CREATE OR REPLACE FUNCTION myunlock(id_input integer, time_input timestamp) RETURNS integer AS $BODY$ DECLARE BEGIN DELETE FROM ONLY travel_time_locks WHERE id_key=id_input AND time_key=time_input; RETURN 1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 1;

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• Why boost::recursive_mutex is not working as expected?

  - by Kjir

  I have a custom class that uses boost mutexes and locks like this (only relevant parts): template<class T> class FFTBuf { public: FFTBuf(); [...] void lock(); void unlock(); private: T *_dst; int _siglen; int _processed_sums; int _expected_sums; int _assigned_sources; bool _written; boost::recursive_mutex _mut; boost::unique_lock<boost::recursive_mutex> _lock; }; template<class T> FFTBuf<T>::FFTBuf() : _dst(NULL), _siglen(0), _expected_sums(1), _processed_sums(0), _assigned_sources(0), _written(false), _lock(_mut, boost::defer_lock_t()) { } template<class T> void FFTBuf<T>::lock() { std::cerr << "Locking" << std::endl; _lock.lock(); std::cerr << "Locked" << std::endl; } template<class T> void FFTBuf<T>::unlock() { std::cerr << "Unlocking" << std::endl; _lock.unlock(); } If I try to lock more than once the object from the same thread, I get an exception (lock_error): #include "fft_buf.hpp" int main( void ) { FFTBuf<int> b( 256 ); b.lock(); b.lock(); b.unlock(); b.unlock(); return 0; } This is the output: sb@dex $ ./src/test Locking Locked Locking terminate called after throwing an instance of 'boost::lock_error' what(): boost::lock_error zsh: abort ./src/test Why is this happening? Am I understanding some concept incorrectly?

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• Getting huge lags when downloading files via Service

  - by Copa

  I have a Service which receives URLs to download. The Service than downloads these URLs and save them to a file on the SD Card. When I put more than 2 items in the download queue my device is unusable. It nearly freezes. Huge lags and so on. Any idea? Sourcecode: private static boolean downloading = false; private static ArrayList<DownloadItem> downloads = new ArrayList<DownloadItem>(); /** * called once when the service started */ public static void start() { Thread thread = new Thread(new Runnable() { @Override public void run() { while (true) { if (downloads.size() > 0 && !downloading) { downloading = true; DownloadItem item = downloads.get(0); downloadSingleFile(item.getUrl(), item.getFile()); } } } }); thread.start(); } public static void addDownload(DownloadItem item) { downloads.add(item); } private static void downloadSuccessfullFinished() { if (downloads.size() > 0) downloads.get(0).setDownloaded(true); downloadFinished(); } private static void downloadFinished() { // remove the first entry; it has been downloaded if (downloads.size() > 0) downloads.remove(0); downloading = false; } private static void downloadSingleFile(String url, File output) { final int maxBufferSize = 4096; HttpResponse response = null; try { response = new DefaultHttpClient().execute(new HttpGet(url)); if (response != null && response.getStatusLine().getStatusCode() == 200) { // request is ok InputStream is = response.getEntity().getContent(); BufferedInputStream bis = new BufferedInputStream(is); RandomAccessFile raf = new RandomAccessFile(output, "rw"); ByteArrayBuffer baf = new ByteArrayBuffer(maxBufferSize); long current = 0; long i = 0; // read and write 4096 bytes each time while ((current = bis.read()) != -1) { baf.append((byte) current); if (++i == maxBufferSize) { raf.write(baf.toByteArray()); baf = new ByteArrayBuffer(maxBufferSize); i = 0; } } if (i > 0) // write the last bytes to the file raf.write(baf.toByteArray()); baf.clear(); raf.close(); bis.close(); is.close(); // download finished get start next download downloadSuccessfullFinished(); return; } } catch (Exception e) { // not successfully downloaded downloadFinished(); return; } // not successfully downloaded downloadFinished(); return; }

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