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  • Is it possible to have an enum field in a class persisted with OrmLite?

    - by htf
    Hello. I'm trying to persist the following class with OrmLite: public class Field { @DatabaseField(id = true) public String name; @DatabaseField(canBeNull = false) public FieldType type; public Field() { } } The FieldType is a public enum. The field, corresponding to the type is string in SQLite (is doesn't support enums). When I try to use it, I get the following exception: INFO [main] (SingleConnectionDataSource.java:244) - Established shared JDBC Connection: org.sqlite.Conn@5224ee Exception in thread "main" org.springframework.beans.factory.BeanInitializationException: Initialization of DAO failed; nested exception is java.lang.IllegalArgumentException: Unknown field class class enums.FieldType for field FieldType:name=type,class=class orm.Field at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:51) at orm.FieldDAO.getInstance(FieldDAO.java:17) at orm.Field.fromString(Field.java:23) at orm.Field.main(Field.java:38) Caused by: java.lang.IllegalArgumentException: Unknown field class class enums.FieldType for field FieldType:name=type,class=class orm.Field at com.j256.ormlite.field.FieldType.<init>(FieldType.java:54) at com.j256.ormlite.field.FieldType.createFieldType(FieldType.java:381) at com.j256.ormlite.table.DatabaseTableConfig.fromClass(DatabaseTableConfig.java:82) at com.j256.ormlite.dao.BaseJdbcDao.initDao(BaseJdbcDao.java:116) at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:48) ... 3 more So how do I tell OrmLite, values on the Java side are from an enum?

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  • Should I pass a SqlDataReader by reference or not when passing it out to multiple threads.

    - by deroby
    Hi all, being new to c# I've run into this 'conundrum' when passing around a SqlDataReader between different threads. Without going into too much detail, the idea is to have a main thread fetching data from the database (a large recordset) and then have a helper-task run through this record by record and doing some stuff based upon the contents of this. There is no feedback to the recordset, it simply wades through until no records are left. This works fine, but given the nature of the job at hand it should be possible to have this job spread over different threads (CPUs) to maximize throughput (the order of execution is of no significance). The question then becomes, when I pass this recordset in a SqlDataReader, do I have to use ref or not ? It kind of boils down to the question : if I pass the object around without specifying ref, won't it create new copies in memory and have records processed n times ? Or, don't I risk having the record-position being moved forward while not all fields have been fully read yet ? The latter seems more like a 'data racing' issue and probably is covered by the lock()ing mechanism (or not?). My initial take on the problem was that it doesn't really hurt passing the variable using ref, yet as a colleague put it : "you only need ref when you're doing something wrong" =) Additionally using ref restricts me from applying a Using() construction too which isn't very nice either. I thus create a "basic" project that tackles the same approach but without the ref notation. Tests so far show that it works flawlessly on a Core2Duo (2cpu) using any number of threads, yet I'm still a bit wary... What do you experts think about this ? Use ref or not ? You can find the test-project here as it seems I can't upload it to this question directly ?!? ps: it's just a test-project and I'm new to c#, so please be gentle on me when breaking down the code =P

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  • Is there a better way to write named-pipes in F#?

    - by Niran
    Hi I am new to F#. I am trying to communicate with java from F# using named pipe. The code below works but I am not sure if there is a better way to do this (I know the infinite loop is a bad idea but this is just a proof of concept) if anyone have any idea to improve this code please post your comments. Thanks in advance Niran open System.IO open System.IO.Pipes exception OuterError of string let continueLooping = true while continueLooping do let pipeServer = new NamedPipeServerStream("testpipe", PipeDirection.InOut, 4) printfn "[F#] NamedPipeServerStream thread created." //wait for connection printfn "[F#] Wait for a client to connect" pipeServer.WaitForConnection() printfn "[F#] Client connected." try // Stream for the request. let sr = new StreamReader(pipeServer) // Stream for the response. let sw = new StreamWriter(pipeServer) sw.AutoFlush <- true; // Read request from the stream. let echo = sr.ReadLine(); printfn "[F#] Request message: %s" echo // Write response to the stream. sw.WriteLine("[F#]: " + echo) pipeServer.Disconnect() with | OuterError(str) -> printfn "[F#]ERROR: %s" str printfn "[F#] Client Closing." pipeServer.Close()

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  • NullPointerException on Activity Testing Tutorial

    - by Bendik
    Hello, I am currently trying the activity testing tutorial (Found here), and have a problem. It seems that whenever I try to call something inside the UIThread, I get a java.lang.NullPointerException. public void testSpinnerUI() { mActivity.runOnUiThread( new Runnable() { public void run() { mSpinner.requestFocus(); } }); } This gives me: Incomplete: java.lang.NullPointerException and nothing else. I have tried this on two different samples now, with the same result. I tried with a try/catch clause around the mSpinner.requestFocus() call, and it seems that mSpinner is null inside the thread. I have set it properly up with the setUp() function found in the same sample, and a quick assertNotNull( mSpinner ) shows me that mSpinner is in fact not null after the setUp() function. What can be the cause of this? EDIT; ok, some more testing has been done. It seems that the application that is being tested resets between each test. This essentially makes me have to reinstantiate all variables between each test. Is this normal?

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  • PHP strtotime without leap-years

    - by Christian Sciberras
    With regards to this thread, I've developed a partial solution: function strtosecs($time,$now=null){ static $LEAPDIFF=86400; $time=strtotime($time,$now); return $time-((date('Y',$time)-1968)/4*$LEAPDIFF); } The function is supposed to get the number of seconds given a string without checking leap-years. It does this calculating the number of leap-years 1970 [(year-1986)/4], multiplying it by the difference in seconds between a leap-year and a normal year (which in the end, it's just the number of seconds in a day). Finally, I simply remove all those excess leap-year seconds from the calculated time. Here's some examples of the inputs/outputs: // test code echo strtosecs('+20 years',0).'=>'.(strtosecs('+20 years',0)/31536000); echo strtosecs('+1 years',0).'=>'.(strtosecs('+1 years',0)/31536000); // test output 630676800 => 19.998630136986 31471200 => 0.99794520547945 You will probably ask why am I doing a division on the output? It's to test it out; 31536000 is the number of seconds in a year, so that 19.99... should be 20 and 0.99... should be a 1. Sure, I could round it all and get "correct" answer, but I'm worried about the inaccuracies.

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  • Multi-Part HTTP Request through xcode

    - by devsri
    Hello Everyone, i want to upload image,video and audio files to a server. I have read this thread on the similar topic but wasn't able to understand completely the flow of the code. It would be great if you can suggest me some sample code or tutorial to start with. I am using the following code to connect without any media to the server [UIApplication sharedApplication].networkActivityIndicatorVisible = YES; NSString *url =[[NSString alloc]initWithFormat:@"%@",[NetworkConstants getURL]]; NSURL *theURL =[NSURL URLWithString:url]; [url release]; NSMutableURLRequest *theRequest =[NSMutableURLRequest requestWithURL:theURL cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:0.0f]; [theRequest setHTTPMethod:@"POST"]; NSString *theBodyString = [NSString stringWithFormat:@"json1=%@&userID=%@",jsonObject,[GlobalConstants getUID]]; NSData *theBodyData = [theBodyString dataUsingEncoding:NSUTF8StringEncoding]; [theRequest setHTTPBody:theBodyData]; NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; if (conn) { NSLog(@"Successful in sending sync"); } else { NSLog(@"Failed Connection in sending sync"); } [conn release]; It would be really convenient for me if anything could be done editing this part of code. Any form of help would be highly appreciated. Thanks in advance!!

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  • Cross-platform general purpose C++ RPC library

    - by iUm
    Here's the task: Imagine, we have an applications and a plug-in for it (dynamic library). Interface between the application and the plug-in is completely defined. Now I need to run the application and the plug-in on different computers. I wrote a stub for the plug-in on a computer where the real applications is running. And the application loads it and calls its functions like if it were a native plug-in. On the other computer there's a stub instead of the real application, which loads the native plug-in. Now I need to organize RPCs between my stubs over the network, regardless the very transport. Usually, it's not difficult. But there're some restrictions: Application-plug-in interaction can be reenterable (e.g. application calls f1() from plug-in, in f1() plug-in calls g1() from application, in g1() application calls f2() from plug-in and so on...) Any such reenteration should be executed exactly by the same thread, which started the sequence Where can I find a cross-platform C++ RPC library with such features?

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  • CreateThread() fails on 64 bit Windows, works on 32 bit Windows. Why?

    - by Stephen Kellett
    Operating System: Windows XP 64 bit, SP2. I have an unusual problem. I am porting some code from 32 bit to 64 bit. The 32 bit code works just fine. But when I call CreateThread() for the 64 bit version the call fails. I have three places where this fails. 2 call CreateThread(). 1 calls beginthreadex() which calls CreateThread(). All three calls fail with error code 0x3E6, "Invalid access to memory location". The problem is all the input parameters are correct. HANDLE h; DWORD threadID; h = CreateThread(0, // default security 0, // default stack size myThreadFunc, // valid function to call myParam, // my param 0, // no flags, start thread immediately &threadID); All three calls to CreateThread() are made from a DLL I've injected into the target program at the start of the program execution (this is before the program has got to the start of main()/WinMain()). If I call CreateThread() from the target program (same params) via say a menu, it works. Same parameters etc. Bizarre. If I pass NULL instead of &threadID, it still fails. If I pass NULL as myParam, it still fails. I'm not calling CreateThread from inside DllMain(), so that isn't the problem. I'm confused and searching on Google etc hasn't shown any relevant answers. If anyone has seen this before or has any ideas, please let me know. Thanks for reading.

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  • OpenMP: Get total number of running threads

    - by Konrad Rudolph
    I need to know the total number of threads that my application has spawned via OpenMP. Unfortunately, the omp_get_num_threads() function does not work here since it only yields the number of threads in the current team. However, my code runs recursively (divide and conquer, basically) and I want to spawn new threads as long as there are still idle processors, but no more. Is there a way to get around the limitations of omp_get_num_threads and get the total number of running threads? If more detail is required, consider the following pseudo-code that models my workflow quite closely: function divide_and_conquer(Job job, int total_num_threads): if job.is_leaf(): # Recurrence base case. job.process() return left, right = job.divide() current_num_threads = omp_get_num_threads() if current_num_threads < total_num_threads: # (1) #pragma omp parallel num_threads(2) #pragma omp section divide_and_conquer(left, total_num_threads) #pragma omp section divide_and_conquer(right, total_num_threads) else: divide_and_conquer(left, total_num_threads) divide_and_conquer(right, total_num_threads) job = merge(left, right) If I call this code with a total_num_threads value of 4, the conditional annotated with (1) will always evaluate to true (because each thread team will contain at most two threads) and thus the code will always spawn two new threads, no matter how many threads are already running at a higher level. I am searching for a platform-independent way of determining the total number of threads that are currently running in my application.

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  • Error Reading Image

    - by javawarrior
    When I tried to open a simple smile.png image using package com.java3d.java3d.graphics; import java.awt.Color; import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public class Texture { public static Render floor = loadBitMap("smile.png"); public Texture(){} public static Render loadBitMap(String fileName) { try { BufferedImage image = ImageIO.read(Thread.currentThread().getContextClassLoader().getResource(fileName)); System.out.print(image==null); int width = image.getWidth(); System.out.println(width); int height = image.getHeight(); System.out.println(height); System.out.println(image.getRGB(4, 4)); Render result = new Render(width, height); image.getRGB(0, 0, width, height, result.pixels, 0, width); return result; } catch (Exception e) { System.out.println("CRASH!"); throw new RuntimeException(e); } } } it returns every pixel as -1; what could be causing this problem? Here is the image:

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  • How can i mock or test my deferred execution functionality?

    - by cottsak
    I have what could be seen as a bizarre hybrid of IQueryable<T> and IList<T> collections of domain objects passed up my application stack. I'm trying to maintain as much of the 'late querying' or 'lazy loading' as possible. I do this in two ways: By using a LinqToSql data layer and passing IQueryable<T>s through by repositories and to my app layer. Then after my app layer passing IList<T>s but where certain elements in the object/aggregate graph are 'chained' with delegates so as to defer their loading. Sometimes even the delegate contents rely on IQueryable<T> sources and the DataContext are injected. This works for me so far. What is blindingly difficult is proving that this design actually works. Ie. If i defeat the 'lazy' part somewhere and my execution happens early then the whole thing is a waste of time. I'd like to be able to TDD this somehow. I don't know a lot about delegates or thread safety as it applies to delegates acting on the same source. I'd like to be able to mock the DataContext and somehow trace both methods of deferring (IQueryable<T>'s SQL and the delegates) the loading so that i can have tests that prove that both functions are working at different levels/layers of the app/stack. As it's crucial that the deferring works for the design to be of any value, i'd like to see tests fail when i break the design at a given level (separate from the live implementation). Is this possible?

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  • BackgroundWorker

    - by vdh_ant
    Hi guys I'm working on some code that calls a service. This service call could fail and if it does I want the system to try again until it works or too much time has passed. I am wondering where I am going wrong as the following code doesn't seem to be working correctly... It randomly only does one to four loops... protected virtual void ProcessAsync(object data, int count) { var worker = new BackgroundWorker(); worker.DoWork += (sender, e) => { throw new InvalidOperationException("oh shiznit!"); }; worker.RunWorkerCompleted += (sender, e) => { //If an error occurs we need to tell the data about it if (e.Error != null) { count++; System.Threading.Thread.Sleep(count * 5000); if (count <= 10) { if (count % 5 == 0) this.Logger.Fatal("LOAD ERROR - The system can't load any data", e.Error); else this.Logger.Error("LOAD ERROR - The system can't load any data", e.Error); this.ProcessAsync(data, count); } } }; worker.RunWorkerAsync(); } Cheers Anthony

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  • Java Applet - ArrayIndexOutOfBoundsException (pt 2)

    - by Dan
    Hi there, I fixed my previous problem. But now when on my tile map... if I try to go 9 tiles to the RIGHT, and on trying to get to the 9th tile.... I will get this error: Exception in thread "AWT-EventQueue-1" java.lang.ArrayIndexOutOfBoundsException: 8 at tileGen.blocked(tileGen.java:125) at tileGen.keyPressed(tileGen.java:58) at java.awt.Component.processKeyEvent(Component.java:6221) at java.awt.Component.processEvent(Component.java:6040) at java.awt.Container.processEvent(Container.java:2041) at java.awt.Component.dispatchEventImpl(Component.java:4630) at java.awt.Container.dispatchEventImpl(Container.java:2099) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1850) at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:712) at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:990) at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:855) at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:676) at java.awt.Component.dispatchEventImpl(Component.java:4502) at java.awt.Container.dispatchEventImpl(Container.java:2099) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.EventQueue.dispatchEvent(EventQueue.java:599) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122) Here is code: http://www.so.pastebin.com/hYkpQf13 I have tried many solutions, all of which have failed. Maybe someone here can I help me? Thank you.

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  • Atomic operations on several transactionless external systems

    - by simendsjo
    Say you have an application connecting 3 different external systems. You need to update something in all 3. In case of a failure, you need to roll back the operations. This is not a hard thing to implement, but say operation 3 fails, and when rolling back, the rollback for operation 1 fails! Now the first external system is in an invalid state... I'm thinking a possible solution is to shut down the application and forcing a manual fix of the external system, but then again... It might already have used this information (and perhaps that's why it failed), or we might not have sufficient access. Or it might not even be a good way to rollback the action! Are there some good ways of handling such cases? EDIT: Some application details.. It's a multi user web application. Most of the work is done with scheduled jobs (through Quartz.Net), so most operations is run in it's own thread. Some user actions should trigger jobs that update several systems though. The external systems are somewhat unstable. I Was thinking of changing the application to use the Command and Unit Of Work pattern

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  • JRuby app throws exception in Spring

    - by mat3001
    I am trying to run a JRuby app in Spring. I use Eclipse to run it. But it doesn't compile. Does anybody know what's going on here? Exception in thread "Launcher:/oflaDemo" [INFO] [Launcher:/oflaDemo] org.springframework.beans.factory.support.DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@4a009ab0: defining beans [placeholderConfig,web.context,web.scope,web.handler,demoService.service]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@f5d8d75 [INFO] [Launcher:/installer] org.red5.server.service.Installer - Installer service created org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'web.scope' defined in ServletContext resource [/WEB-INF/red5-web.xml]: Initialization of bean failed; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert property value of type [org.springframework.scripting.jruby.JRubyScriptFactory] to required type [org.red5.server.api.IScopeHandler] for property 'handler'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [org.springframework.scripting.jruby.JRubyScriptFactory] to required type [org.red5.server.api.IScopeHandler] for property 'handler': no matching editors or conversion strategy found at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:480) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409) at java.security.AccessController.doPrivileged(Native Method) I don't have a lot of experience with Spring, so I would really appreciate hits. If you're familiar with red5 - yes it's the oflademo app supplied by red5.

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  • Maven + AspectJ - all steps to configure it

    - by Alice
    I have a problem with applying aspects to my maven project. Probably I am missing something, so I've made a list of steps. Could you please check if it is correct? Let say in projectA is an aspect class and in projectB classes, which should be changed by aspects. Create maven project ProjectA with AspectJ class add Aspectj plugin and dependency Add ProjectA as a dependency to projectB pom.xml Add to projectB pom.xml plugin " <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</artifactId> <version>1.4</version> <executions> <execution> <goals> <goal>compile</goal> <goal>test-compile</goal> </goals> </execution> </executions> <configuration> <source>${maven.compiler.source}</source> <target>${maven.compiler.target}</target> <aspectLibraries> <aspectLibrary> <groupId>ProjectA</groupId> <artifactId>ProjectA</artifactId> </aspectLibrary> </aspectLibraries> </configuration> </plugin> Add aspectj dependency After all these steps my problem is, that during compilation I get: [WARNING] advice defined in AspectE has not been applied [Xlint:adviceDidNotMatch] And then when I run my program: Exception in thread "FeatureExcutionThread" java.lang.NoClassDefFoundError: AspectE

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  • @selector and return value

    - by user320926
    The idea it's very easy, i have an http download class, this class must support the http authentication but it's basically a background thread so i would like to avoid to prompt directly to the screen, i would like to use a delegate method to require from outside of the class, like a viewController. But i don't know if is possible or if i have to use a different syntax. This class use this delegate protocol: //Updater.h @protocol Updater <NSObject> -(NSDictionary *)authRequired; @optional -(void)statusUpdate:(NSString *)newStatus; -(void)downloadProgress:(int)percentage; @end @interface Updater : NSThread { ... } This is the call to the delegate method: //Updater.m // This check always fails :( if ([self.delegate respondsToSelector:@selector(authRequired:)]) { auth = [delegate authRequired]; } This is the implementation of the delegate method //rootViewController.m -(NSDictionary *)authRequired; { // TODO: some kind of popup or modal view NSMutableDictionary *ret=[[NSMutableDictionary alloc] init]; [ret setObject:@"utente" forKey:@"user"]; [ret setObject:@"password" forKey:@"pass"]; return ret; }

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  • Insert or Update using Oracle and PL/SQL

    - by Shane
    I have a PL/SQL function that performs an update/insert on an Oracle database that maintains a target total and returns the difference between the existing value and the new value. Here is the code I have so far: FUNCTION calcTargetTotal(accountId varchar2, newTotal numeric ) RETURN number is oldTotal numeric(20,6); difference numeric(20,6); begin difference := 0; begin select value into oldTotal from target_total WHERE account_id = accountId for update of value; if (oldTotal != newTotal) then update target_total set value = newTotal WHERE account_id = accountId difference := newTotal - oldTotal; end if; exception when NO_DATA_FOUND then begin difference := newTotal; insert into target_total ( account_id, value ) values ( accountId, newTotal ); -- sometimes a race condition occurs and this stmt fails -- in those cases try to update again exception when DUP_VAL_ON_INDEX then begin difference := 0; select value into oldTotal from target_total WHERE account_id = accountId for update of value; if (oldTotal != newTotal) then update target_total set value = newTotal WHERE account_id = accountId difference := newTotal - oldTotal; end if; end; end; end; return difference end calcTargetTotal; This works as expected in unit tests with multiple threads never failing. However when loaded on a live system we have seen this fail with a stack trace looking like this: ORA-01403: no data found ORA-00001: unique constraint () violated ORA-01403: no data found The line numbers (which I have removed since they are meaningless out of context) verify that the first update fails due to no data, the insert fail due to uniqueness, and the 2nd update is failing with no data, which should be impossible. From what I have read on other thread a MERGE statement is also not atomic and could suffer similar problems. Does anyone have any ideas how to prevent this from occurring?

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  • How can I find the jdbc connection timeout of a hibernate session

    - by StevenWilkins
    I currently have a long running thread which uses a hibernate session to perform many updates. We currently have our c3p0 connection timeout set to 20 minutes and it's timing out sometimes because of the number of updates we're performing. The solution I have is to periodically return the connection to the pool via closing the session (we have hibernate configured this way) and get a new one. Upping the timeout is not desirable because the same pool is used for the entire application. The problem is I don't know when to return the connection to the pool because I don't know what the timeout of the connection is. I know what the current setting is in our property file, but that can be changed without my knowledge at any time so it's fragile. Having a counter and returning the connection based on the number of updates I've performed is not ideal but could be my option of last resort. I have a hibernate session, how can I retrieve the connection timeout of the jdbc connection which backs the session? Using the SessionFactory and SessionFactoryImpl classes are perfectly acceptable.

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  • When should EntityManagerFactory instance be created/opened ?

    - by masato-san
    Ok, I read bunch of articles/examples how to write Entity Manager Factory in singleton. One of them easiest for me to understand a bit: http://javanotepad.blogspot.com/2007/05/jpa-entitymanagerfactory-in-web.html I learned that EntityManagerFactory (EMF) should only be created once preferably in application scope. And also make sure to close the EMF once it's used (?) So I wrote EMF helper class for business methods to use: public class EmProvider { private static final String DB_PU = "KogaAlphaPU"; public static final boolean DEBUG = true; private static final EmProvider singleton = new EmProvider(); private EntityManagerFactory emf; private EmProvider() {} public static EmProvider getInstance() { return singleton; } public EntityManagerFactory getEntityManagerFactory() { if(emf == null) { emf = Persistence.createEntityManagerFactory(DB_PU); } if(DEBUG) { System.out.println("factory created on: " + new Date()); } return emf; } public void closeEmf() { if(emf.isOpen() || emf != null) { emf.close(); } emf = null; if(DEBUG) { System.out.println("EMF closed at: " + new Date()); } } }//end class And my method using EmProvider: public String foo() { EntityManager em = null; List<Object[]> out = null; try { em = EmProvider.getInstance().getEntityManagerFactory().createEntityManager(); Query query = em.createNativeQuery(JPQL_JOIN); //just some random query out = query.getResultList(); } catch(Exception e) { //handle error.... } finally { if(em != null) { em.close(); //make sure to close EntityManager } } I made sure to close EntityManager (em) within method level as suggested. But when should EntityManagerFactory be closed then? And why EMF has to be singleton so bad??? I read about concurrency issues but as I am not experienced multi-thread-grammer, I can't really be clear on this idea.

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  • iPhone: Low memory crash...

    - by MacTouch
    Once again I'm hunting memory leaks and other crazy mistakes in my code. :) I have a cache with frequently used files (images, data records etc. with a TTL of about one week and a size limited cache (100MB)). There are sometimes more then 15000 files in a directory. On application exit the cache writes an control file with the current cache size along with other useful information. If the applications crashes for some reason (sh.. happens sometimes) I have in such case to calculate the size of all files on application start to make sure I know the cache size. My app crashes at this point because of low memory and I have no clue why. Memory leak detector does not show any leaks at all. I do not see any too. What's wrong with the code below? Is there any other fast way to calculate the total size of all files within a directory on iPhone? Maybe without to enumerate the whole contents of the directory? The code is executed on the main thread. NSUInteger result = 0; NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSDirectoryEnumerator *dirEnum = [[[NSFileManager defaultManager] enumeratorAtPath:path] retain]; int i = 0; while ([dirEnum nextObject]) { NSDictionary *attributes = [dirEnum fileAttributes]; NSNumber* fileSize = [attributes objectForKey:NSFileSize]; result += [fileSize unsignedIntValue]; if (++i % 500 == 0) { // I tried lower values too [pool drain]; } } [dirEnum release]; dirEnum = nil; [pool release]; pool = nil; Thanks, MacTouch

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  • Loading JNI lib on Mac OS X?

    - by Clinton
    Background So I am attempting to load a jnilib (specifically JOGL) into Java on Mac OS X at runtime. I have been following along the relevant Stack Overflow questions: Maven and the JOGL Library Loading DLL in Java - Eclipse - JNI How to make a jar file that include all jar files The end goal for me is to package platform specific JOGL files into a JAR and unzip them into a temp directory and load them at start-up. I worked my problem back to simply attempting to load JOGL using hard-coded paths: File f = new File("/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/libjogl.jnilib"); System.load(f.toString()); f = new File ("/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/libjogl_awt.jnilib"); System.load(f.toString()); I get the following exception when attempting to use the JOGL API: Exception in thread "main" java.lang.UnsatisfiedLinkError: no jogl in java.library.path But when I specify java.library.path by adding the following JVM option: -Djava.library.path="/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/" Everything works fine. Question Is it possible use System.load (or some other variant) on Mac OS X as a replacement for -Djava.library.path that is invoked at runtime?

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  • Large ListView containing images in Android

    - by Marco W.
    For various Android applications, I need large ListViews, i.e. such views with 100-300 entries. All entries must be loaded in bulk when the application is started, as some sorting and processing is necessary and the application cannot know which items to display first, otherwise. So far, I've been loading the images for all items in bulk as well, which are then saved in an ArrayList<CustomType> together with the rest of the data for each entry. But of course, this is not a good practice, as you're very likely to have an OutOfMemoryException then: The references to all images in the ArrayList prevent the garbage collector from working. So the best solution is, obviously, to load only the text data in bulk whereas the images are then loaded as needed, right? The Google Play application does this, for example: You can see that images are loaded as you scroll to them, i.e. they are probably loaded in the adapter's getView() method. But with Google Play, this is a different problem, anyway, as the images must be loaded from the Internet, which is not the case for me. My problem is not that loading the images takes too long, but storing them requires too much memory. So what should I do with the images? Load in getView(), when they are really needed? Would make scrolling sluggish. So calling an AsyncTask then? Or just a normal Thread? Parametrize it? I could save the images that are already loaded into a HashMap<String,Bitmap>, so that they don't need to be loaded again in getView(). But if this is done, you have the memory problem again: The HashMap stores references to all images, so in the end, you could have the OutOfMemoryException again. I know that there are already lots of questions here that discuss "Lazy loading" of images. But they mainly cover the problem of slow loading, not too much memory consumption.

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  • Groovy & Grails Concurrency ( quartz, executor )

    - by Pietro
    What I'm trying to do is to run multiple threads at some starting time. Those threads must stay alive for 90minutes after start. During the 90minutes they execute something after a random sleep time (ex: 5minutes to 15minutes). Here is a pseudo code on how I would implement it. The problem is that doing it in this way the threads run in an unexpected way. How can I implement correctly something like this? Class MyJob { static triggers = { cron name: 'first', cronExpression: "0 30 21 * * FRI" cron name: 'second', cronExpression: "0 30 19 * * FRI" cron name: 'third', cronExpression: "0 30 17 * * FRI" def myService def execute() { switch( between trigger name ) case 'first': model = Model.findByAttribute(...) ... myService.run( model, start_time ) break; ... } } class MyService { def run( model, start_time ) { def end_time = end_time.plusMinutes(90) model.fields.each( field -> Thread.start { executeSomeTasks( field, start_time, end_time ) } ) } def executeSomeTasks( field, start_time, end_time ) { while( start_time < end_time ) { ...do something ... sleep( Random.nextInt( 1000 ) ); } } }

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  • Problem in UITableViewDelegate - RowSelected gives wrong NSIndexPath

    - by vlad259
    I have a UITableViewSource which I have subclassed. I'm overriding GetCell and using my own subclassed cells, like so: public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath) { MarketItem item=_tableItems[indexPath.Section].Items[indexPath.Row]; MarketCell cell=tableView.DequeueReusableCell(_cellIdentifier) as MarketCell; if (cell==null) { cell=new MarketCell(UITableViewCellStyle.Subtitle,_cellIdentifier,item); } // decorate the cell // ... return cell; } This works but when I get events in my UITableViewDelegate, the index path gets me the wrong cell (events like AccessoryButtonTapped, WillSelectRow etc). The Section and Row numbers look correct but when I do a tableView.CellAt(indexPath) I get the wrong cell. (The row and section numbers again look correct.) Things to note: The table is constantly being updated - items arrive in a different thread which are then InvokeOnMainThread'd Although the table is constantly updated, rows and sections are only added - nothing is re-ordered or deleted If I pause the updates when I get a 'WillSelectRow', it doesn't help Most interestingly (but not a shippable solution) if I make a new cell each time rather than doing DequeueReusableCell, it works correctly. I can't help thinking it's a stupid bug of my own making but can't find it. Any help would be most gratefully received!

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