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  • Can someone explain the (reasons for the) implications of colum vs row major in multiplication/concatenation?

    - by sebf
    I am trying to learn how to construct view and projection matrices, and keep reaching difficulties in my implementation owing to my confusion about the two standards for matrices. I know how to multiply a matrix, and I can see that transposing before multiplication would completely change the result, hence the need to multiply in a different order. What I don't understand though is whats meant by only 'notational convention' - from the articles here and here the authors appear to assert that it makes no difference to how the matrix is stored, or transferred to the GPU, but on the second page that matrix is clearly not equivalent to how it would be laid out in memory for row-major; and if I look at a populated matrix in my program I see the translation components occupying the 4th, 8th and 12th elements. Given that: "post-multiplying with column-major matrices produces the same result as pre-multiplying with row-major matrices. " Why in the following snippet of code: Matrix4 r = t3 * t2 * t1; Matrix4 r2 = t1.Transpose() * t2.Transpose() * t3.Transpose(); Does r != r2 and why does pos3 != pos for: Vector4 pos = wvpM * new Vector4(0f, 15f, 15f, 1); Vector4 pos3 = wvpM.Transpose() * new Vector4(0f, 15f, 15f, 1); Does the multiplication process change depending on whether the matrices are row or column major, or is it just the order (for an equivalent effect?) One thing that isn't helping this become any clearer, is that when provided to DirectX, my column major WVP matrix is used successfully to transform vertices with the HLSL call: mul(vector,matrix) which should result in the vector being treated as row-major, so how can the column major matrix provided by my math library work?

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  • Predictive firing (in a tile-based game)

    - by n00bster
    I have a (turn-based) tile-based game, in which you can shoot at entities. You can move around with mouse and keyboard, it's all tile-based, except that bullets move "freely". I've got it all working just fine except that when I move, and the creatures shoot towards the player, they shoot towards the previous tiles.. resulting in ugly looking "miss hits" or lag. I think I need to implement some kind of predictive firing based on the bullet speed and the distance, but I don't quite know how to implement such a thing... Here's a simplified snip of my firing code. class Weapon { public void fire(int x, int y) { ... ... ... Creature owner = getOwner(); Tile targetTile = Zone.getTileAt(x, y); float dist = Vector.distance(owner.getCenterPosition(), targetTile.getCenterPosition()); Bullet b = new Bullet(); b.setPosition(owner.getCenterPosition()); // Take dist into account in the duration to get constant speed regardless of distance float duration = dist / 600f; // Moves the bullet to the centre of the target tile in the given amount of time (in seconds) b.moveTo(targetTile.getCenterPosition(), duration); // This is what I'm after // Vector v = predict the position // b.moveTo(v, duration); Zone.add(bullet); // Now the bullet gets "ticked" and moveTo will be implemented } } Movement of creatures is as simple as setting the position variable. If you need more information, just ask.

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  • What is the best way to store a table in C++

    - by Topo
    I'm programming a decision tree in C++ using a slightly modified version of the C4.5 algorithm. Each node represents an attribute or a column of your data set and it has a children per possible value of the attribute. My problem is how to store the training data set having in mind that I have to use a subset for each node so I need a quick way to only select a subset of rows and columns. The main goal is to do it in the most memory and time efficient possible (in that order of priority). The best way I have thought of is to have an array of arrays (or std::vector), or something like that, and for each node have a list (array, vector, etc) or something with the column,line(probably a tuple) pairs that are valid for that node. I now there should be a better way to do this, any suggestions? UPDATE: What I need is something like this: In the beginning I have this data: Paris 4 5.0 True New York 7 1.3 True Tokio 2 9.1 False Paris 9 6.8 True Tokio 0 8.4 False But for the second node I just need this data: Paris 4 5.0 New York 7 1.3 Paris 9 6.8 And for the third node: Tokio 2 9.1 Tokio 0 8.4 But with a table of millions of records with up to hundreds of columns. What I have in mind is keep all the data in a matrix, and then for each node keep the info of the current columns and rows. Something like this: Paris 4 5.0 True New York 7 1.3 True Tokio 2 9.1 False Paris 9 6.8 True Tokio 0 8.4 False Node 2: columns = [0,1,2] rows = [0,1,3] Node 3: columns = [0,1,2] rows = [2,4] This way on the worst case scenario I just have to waste size_of(int) * (number_of_columns + number_of_rows) * node That is a lot less than having an independent data matrix for each node.

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  • Rotating a sprite to touch

    - by user1691659
    I know this has been asked before and Ive looked through peoples questions and answers all over the internet and I just cant get it to work. Im sure its down to my inexperience. Ive got an arrow attached to a sprite, this sprite appears when touched but I want the arrow to point where the sprite will launch. I have had the arrow moving but it was very erratic and not pointing as it should. Its not moving at the moment but this is what I have. - (void)update:(ccTime)delta { arrow.rotation = dialRotation; } -(void) ccTouchMoved:(UITouch*)touch withEvent:(UIEvent *)event { pt1 = [self convertTouchToNodeSpace:touch]; CGPoint firstVector = ccpSub(pt, arrow.position); CGFloat firstRotateAngle = -ccpToAngle(firstVector); CGFloat previousTouch = CC_RADIANS_TO_DEGREES(firstRotateAngle); CGPoint vector = ccpSub(pt1, arrow.position); CGFloat rotateAngle = -ccpToAngle(vector); CGFloat currentTouch = CC_RADIANS_TO_DEGREES(rotateAngle); dialRotation += currentTouch - previousTouch; } I have got pt from ccTouchBegan the same way as pt1 Thanks

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  • soapfault: Couldn't create SOAP message

    - by polarw
    11-23 16:19:30.085: SoapFault - faultcode: 'S:Client' faultstring: 'Couldn't create SOAP message due to exception: Unable to create StAX reader or writer' faultactor: 'null' detail: null 11-23 16:19:30.085: at org.ksoap2.serialization.SoapSerializationEnvelope.parseBody(SoapSerializationEnvelope.java:121) 11-23 16:19:30.085: at org.ksoap2.SoapEnvelope.parse(SoapEnvelope.java:137) 11-23 16:19:30.085: at org.ksoap2.transport.Transport.parseResponse(Transport.java:63) 11-23 16:19:30.085: at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:104) 11-23 16:19:30.085: at com.mobilebox.webservice.CommonWSClient.callWS(CommonWSClient.java:247) 11-23 16:19:30.085: at com.mobilebox.webservice.CommonWSClient.access$1(CommonWSClient.java:217) 11-23 16:19:30.085: at com.mobilebox.webservice.CommonWSClient$WSHandle.run(CommonWSClient.java:201) 11-23 16:19:30.085: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 11-23 16:19:30.085: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 11-23 16:19:30.085: at java.lang.Thread.run(Thread.java:1019) My Android application use Soap webservice client to call remote method. Sometimes, it will return the excepion as above. When I call it with SoapUI, it never occours.

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  • c# Network Programming - HTTPWebRequest Scraping

    - by masterguru
    Hi, I am building a web scraping application. It should scrape a complex web site with concurrent HttpWebRequests from a single host to a single target web server. The application should run on Windows server 2008. One single HttpWebRequest for data could take from 1 minute to 4 minutes to complete (because of long running db operations) I should have at least 100 parallel requests to the target web server, but i have noticed that when i use more then 2-3 long-running requests i have big performance issues (request timeouts/hanging). How many concurrent requests can i have in this scenario from a single host to a single target web server? can i use Thread Pools in the application to run parallel HttpWebRequests to the server? will i have any issues with the default outbound HTTP connection/requests limits? what about Request timeouts when i reach outbound connection limits? what would be the best setup for my scenario? Any help would be appreciated. Thanks

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  • TFS Load Testing Web Tests

    - by durilai
    I am configuring a load test and am curious/confused on settings. I am testing an intranet website, that is expected to have 6000 concurrent users. My employer had some previous consultant tell them that the load test users does not matter and that we need to worry about requests/second. They have previously determined that those 6000 users would generate 30 rps, while I feel that is not correct we need to show that we can exceed that number. The previous load test was set for only 200 users and the results showed that it did exceed the 200 rps. They were happy with the results, but that is not how I understand this. My question is, if we need to support 6000 concurrent users should I just set my users to 6000 and run, or is the rps an adequate piece of data to rely on? Any help is appreciated. Thanks

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  • Java ThreadPoolExecutor getting stuck while using ArrayBlockingQueue

    - by Ravi Rao
    Hi, I'm working on some application and using ThreadPoolExecutor for handling various tasks. ThreadPoolExecutor is getting stuck after some duration. To simulate this in a simpler environment, I've written a simple code where I'm able to simulate the issue. import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.RejectedExecutionHandler; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; public class MyThreadPoolExecutor { private int poolSize = 10; private int maxPoolSize = 50; private long keepAliveTime = 10; private ThreadPoolExecutor threadPool = null; private final ArrayBlockingQueue&lt;Runnable&gt; queue = new ArrayBlockingQueue&lt;Runnable&gt;( 100000); public MyThreadPoolExecutor() { threadPool = new ThreadPoolExecutor(poolSize, maxPoolSize, keepAliveTime, TimeUnit.SECONDS, queue); threadPool.setRejectedExecutionHandler(new RejectedExecutionHandler() { @Override public void rejectedExecution(Runnable runnable, ThreadPoolExecutor threadPoolExecutor) { System.out .println(&quot;Execution rejected. Please try restarting the application.&quot;); } }); } public void runTask(Runnable task) { threadPool.execute(task); } public void shutDown() { threadPool.shutdownNow(); } public ThreadPoolExecutor getThreadPool() { return threadPool; } public void setThreadPool(ThreadPoolExecutor threadPool) { this.threadPool = threadPool; } public static void main(String[] args) { MyThreadPoolExecutor mtpe = new MyThreadPoolExecutor(); for (int i = 0; i &lt; 1000; i++) { final int j = i; mtpe.runTask(new Runnable() { @Override public void run() { System.out.println(j); } }); } } } Try executing this code a few times. It normally print outs the number on console and when all threads end, it exists. But at times, it finished all task and then is not getting terminated. The thread dump is as follows: MyThreadPoolExecutor [Java Application] MyThreadPoolExecutor at localhost:2619 (Suspended) Daemon System Thread [Attach Listener] (Suspended) Daemon System Thread [Signal Dispatcher] (Suspended) Daemon System Thread [Finalizer] (Suspended) Object.wait(long) line: not available [native method] ReferenceQueue&lt;T&gt;.remove(long) line: not available ReferenceQueue&lt;T&gt;.remove() line: not available Finalizer$FinalizerThread.run() line: not available Daemon System Thread [Reference Handler] (Suspended) Object.wait(long) line: not available [native method] Reference$Lock(Object).wait() line: 485 Reference$ReferenceHandler.run() line: not available Thread [pool-1-thread-1] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-2] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-3] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-4] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-6] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-8] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-5] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-10] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-9] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [pool-1-thread-7] (Suspended) Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: not available AbstractQueuedSynchronizer$ConditionObject.await() line: not available ArrayBlockingQueue&lt;E&gt;.take() line: not available ThreadPoolExecutor.getTask() line: not available ThreadPoolExecutor$Worker.run() line: not available Thread.run() line: not available Thread [DestroyJavaVM] (Suspended) C:\Program Files\Java\jre1.6.0_07\bin\javaw.exe (Jun 17, 2010 10:42:33 AM) In my actual application,ThreadPoolExecutor threads go in this state and then it stops responding. Regards, Ravi Rao

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  • atomic writes to ehcache

    - by Jacques René Mesrine
    Context I am storing a java.util.List inside ehcache. Key(String) --> List<UserDetail> The ordered List contains a Top 10 ranking of my most active users. Problem Concurrent 3rd party clients might be requesting for this list. I have a requirement to be as current as possible with regards to the ranking. Thus if the ranking is changed due the activities of users, the ordered List in the cache must not be left stale for very long. Once I've recalculated a new List, I want to replace the one in cache immediately. Consider a busy scenario whereby multiple concurrent clients are requesting for the ranking; how can I replace the cache item in an fashion such that: Clients can continue to pull a possibly stale snapshot. They should never get a null value. There will only be 1 server thread that writes to the cache.

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  • What happens if two COM classes each without a threading model are implemented in one in-proc COM se

    - by sharptooth
    Consider a situation. I have an in-proc COM server that contains two COM classes. Both classes are marked as "no threading model" in the registry - the "ThreadingModel" value is just absent. Both classes read/write the same set of global variable without any synchronization. As far as I know "no threading model" will enforce COM to disallow concurrent access to the same or different instances of the same class by different threads. Will COM prevent concurrent access to instances of the two abovementioned different classes? Do I need synchronization when accessing the global variables from two different COM classes in this situation?

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  • Producer/consumer in Grails?

    - by Mulone
    Hi all, I'm trying to implement a Consumer/Producer app in Grails, after several unsuccessful attempts at implementing concurrent threads. Basically I want to store all the events coming from a clients (through separate AJAX calls) in a single queue and then process such a queue in a linear way as soon as new events are added. This looks like a Producer/Consumer problem: http://en.wikipedia.org/wiki/Producer-consumer_problem How can I implement this in Grails (maybe with a timer or even better by generating an event 'process queue')? Basically I'd like to a have a singleton service waiting for new events in the queue and processing them linearly (even if the queue is loaded by several concurrent processes). Any hints? Cheers!

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  • How to prevent column b containing the same value as any column a in Oracle?

    - by Janek Bogucki
    What is a good way to prevent a table with 2 columns, a and b, from having any record where column b is equal to any value in column a? This would be used for a table of corrections like this, MR -> Mr Prf. -> Prof. MRs -> Mrs I can see how it could be done with a trigger and a subquery assuming no concurrent activity but a more declarative approach would be preferable. This is an example of what should be prevented, Wing Commdr. -> Wing Cdr. Wing Cdr. -> Wing Commander Ideally the solution would work with concurrent inserts and updates.

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  • Push data to flex client

    - by KensoDev
    Howday, I want to push data to flex clients. I am talking about anywhere between 5000-15000 concurrent users, need to get data every time a currency is changed so that means lots of changes for lots of users. I have been looking into WebOrb.net, but the performance seem very poor (100 users concurrent) for a product so pricy (we purchased a license). So, I have to look into alternatives, I know there's fluorineFx but it seems no one is really using it for products and it lacks in examples and documentation. My question is: what products can answer my needs (.net backend) and what are the performance I can expect out of these products? Thanks

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  • spring web application context is not loaded from jar file in WEB-INF/lib when running tomcat in eclipse

    - by Remy J
    I am experimenting with spring, maven, and eclipse but stumbling on a weird issue. I am running Eclipse Helios SR1 with the STS (Spring tools suite) plugin which includes the Maven plugin also. What i want to achieve is a spring mvc webapp which uses an application context loaded from a local application context xml file, but also from other application contexts in jar files dependencies included in WEB-INF/lib. What i'd ultimately like to do is have my persistence layer separated in its own jar file but containing its own spring context files with persistence specific configuration (e.g a jpa entityManagerFactory for example). So to experiment with loading resources from jar dependencies, i created a simple maven project from eclipse, which defines an applicationContext.xml file in src/main/resources Inside, i define a bean <bean id="mybean" class="org.test.MyClass" /> and create the class in the org.test package I run mvn-install from eclipse, which generates me a jar file containing my class and the applicationContext.xml file: testproj.jar |_META-INF |_org |_test |_MyClass.class |_applicationContext.xml I then create a spring mvc project from the Spring template projects provided by STS. I have configured an instance of Tomcat 7.0.8 , and also an instance of springSource tc Server within eclipse. Deploying the newly created project on both servers works without problem. I then add my previous project as a maven dependency of the mvc project. the jar file is correctly added in the Maven Dependencies of the project. In the web.xml that is generated, i now want to load the applicationContext.xml from the jar file as well as the existing one generated for the project. My web.xml now looks like this: org.springframework.web.context.ContextLoaderListener <!-- Processes application requests --> <servlet> <servlet-name>appServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value> classpath*:applicationContext.xml, /WEB-INF/spring/appServlet/servlet-context.xml </param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>appServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> Also, in my servlet-context.xml, i have the following: <context:component-scan base-package="org.test" /> <context:component-scan base-package="org.remy.mvc" /> to load classes from the jar spring context (org.test) and to load controllers from the mvc app context. I also change one of my controllers in org.remy.mvc to autowire MyClass to verify that loading the context has worked as intended. public class MyController { @Autowired private MyClass myClass; public void setMyClass(MyClass myClass) { this.myClass = myClass; } public MyClass getMyClass() { return myClass; } [...] } Now this is the weird bit: If i deploy the spring mvc web on my tomcat instance inside eclipse (run on server...) I get the following error : org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping#0': Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: org/test/MyClass at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:527) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:580) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:442) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:458) at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:339) at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:306) at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:127) at javax.servlet.GenericServlet.init(GenericServlet.java:160) at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1133) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1087) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:996) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4834) at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5155) at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5150) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.NoClassDefFoundError: org/test/MyClass at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2427) at java.lang.Class.getDeclaredMethods(Class.java:1791) at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:446) at org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping.determineUrlsForHandlerMethods(DefaultAnnotationHandlerMapping.java:172) at org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping.determineUrlsForHandler(DefaultAnnotationHandlerMapping.java:118) at org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping.detectHandlers(AbstractDetectingUrlHandlerMapping.java:79) at org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping.initApplicationContext(AbstractDetectingUrlHandlerMapping.java:58) at org.springframework.context.support.ApplicationObjectSupport.initApplicationContext(ApplicationObjectSupport.java:119) at org.springframework.web.context.support.WebApplicationObjectSupport.initApplicationContext(WebApplicationObjectSupport.java:72) at org.springframework.context.support.ApplicationObjectSupport.setApplicationContext(ApplicationObjectSupport.java:73) at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:106) at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:85) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:394) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1413) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) ... 25 more 20-Feb-2011 10:54:53 org.apache.catalina.core.ApplicationContext log SEVERE: StandardWrapper.Throwable org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping#0': Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: org/test/MyClass If i build the war file (using maven "install" goal), and then deploy that war file in the webapps directory of a standalone tomcat server (7.0.8 as well) it WORKS :-( What am i missing ? Thanks for the help.

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  • Do MyISAM holes get filled in automatically?

    - by NNN
    When you run a delete on a MyISAM table, it leaves a hole in the table until the table is optimized. This affects concurrent inserts. On the default setting, concurrent_inserts only work for tables without holes. However, in the documentation for MyISAM, under the concurrent_insert section it says: Enables concurrent inserts for all MyISAM tables, even those that have holes. For a table with a hole, new rows are inserted at the end of the table if it is in use by another thread. Otherwise, MySQL acquires a normal write lock and inserts the row into the hole. http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_concurrent_insert Does that mean MyISAM automatically fills in holes whenever a new row is insert into the table? Previously I thought the holes would not be fixed until you OPTIMIZE a table.

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  • How/is data shared between fastCGI processes?

    - by Josh the Goods
    I've written a simple perl script that I'm running via fastCGI on Apache. The application loads a set of XML data files which are used to lookup values based upon the the query parameters of an incoming request. As I understand it, if I want to increase the amount of concurrent requests my application can handle I need to allow fastCGI to spawn multiple processes. Will each of these processes have to hold duplicate copies of the XML data in memory? Is there a way to set things up so that I can have one copy of the XML data loaded in memory while increasing the capacity to handle concurrent requests?

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  • java.io.FileNotFoundException for valid URL

    - by Alexei
    Hello. I use library rome.dev.java.net to fetch RSS. Code is URL feedUrl = new URL("http://planet.rubyonrails.ru/xml/rss"); SyndFeedInput input = new SyndFeedInput(); SyndFeed feed = input.build(new XmlReader(feedUrl)); You can check that http://planet.rubyonrails.ru/xml/rss is valid URL and the page is shown in browser. But I get exception from my application java.io.FileNotFoundException: http://planet.rubyonrails.ru/xml/rss at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1311) at com.sun.syndication.io.XmlReader.<init>(XmlReader.java:237) at com.sun.syndication.io.XmlReader.<init>(XmlReader.java:213) at rssdaemonapp.ValidatorThread.run(ValidatorThread.java:32) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619) I don't use any proxy. I get this exception on my PC and on the production server and only for this URL, other URLs are working.

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  • Recommendations for an in memory database vs thread safe data structures

    - by yx
    TLDR: What are the pros/cons of using an in-memory database vs locks and concurrent data structures? I am currently working on an application that has many (possibly remote) displays that collect live data from multiple data sources and renders them on screen in real time. One of the other developers have suggested the use of an in memory database instead of doing it the standard way our other systems behaves, which is to use concurrent hashmaps, queues, arrays, and other objects to store the graphical objects and handling them safely with locks if necessary. His argument is that the DB will lessen the need to worry about concurrency since it will handle read/write locks automatically, and also the DB will offer an easier way to structure the data into as many tables as we need instead of having create hashmaps of hashmaps of lists, etc and keeping track of it all. I do not have much DB experience myself so I am asking fellow SO users what experiences they have had and what are the pros & cons of inserting the DB into the system?

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  • How can I find file system concurrency issues ?

    - by krosenvold
    I have an application running on Linux, and I find myself wanting windows (!). The problem is that every 1000 times or so I run into concurrency problems that are consistent with concurrent reading/writing of files. I am fairly sure that this behavior would be prohibited by file locking under Windows, but I don't have any sufficiently fast windows box to check. There is simply too much file access (too much data) to expect strace to work reliably - the sheer volume of output is likely to change the problem too. It also happens on different files every time. Ideally I would like to change/reconfigure the linux file system to be more restrictive (as in fail-fast) wrt concurrent access. Are there any tools/settings I can use to achieve this ?

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  • Actors in Scala.net

    - by weijiajun
    I have recently completed some study of erlang, and was intrigued by scala for its feature set and the ease of interpolating with java (and possibly .net) applications. I am finally studying actors and was wondering if there is an actor mechanism that currently works in .net. I have looked at the libararies that come down with sbaz and have found that there is a scala.Concurrent but no scala.actors.Actor. I tried to use the scala.Concurrent.Channel but was unable to use the ! to send messages. I was just wondering if this is something that is currently available and if so how do you go about setting it up.

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  • Android UnknownHost in asyncTask - loading web page

    - by Sneha
    I followed this tutorial for AsyncTask and getting the following error log: 03-23 11:44:42.936: WARN/System.err(315): java.net.UnknownHostException: www.google.co.in 03-23 11:44:42.936: WARN/System.err(315): at java.net.InetAddress.lookupHostByName(InetAddress.java:513) 03-23 11:44:42.936: WARN/System.err(315): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:278) 03-23 11:44:42.936: WARN/System.err(315): at java.net.InetAddress.getAllByName(InetAddress.java:242) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:136) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 03-23 11:44:42.936: WARN/System.err(315): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 03-23 11:44:42.944: WARN/System.err(315): at org.apache.http.impl.client.AbstractHttpC lient.execute(AbstractHttpClient.java:465) 03-23 11:44:42.944: WARN/System.err(315): at com.test.async.AsyncTaskExampleActivity$DownloadWebPageTask.doInBackground (AsyncTaskExampleActivity.java:36) 03-23 11:44:42.944: WARN/System.err(315): at com.test.async.AsyncTaskExampleActivity$DownloadWebPageTask.doInBackground (AsyncTaskExampleActivity.java:1) 03-23 11:44:42.944: WARN/System.err(315): at android.os.AsyncTask$2.call(AsyncTask.java:185) 03-23 11:44:42.944: WARN/System.err(315): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 03-23 11:44:42.944: WARN/System.err(315): at java.util.concurrent.FutureTask.run (FutureTask.java:137) 03-23 11:44:42.944: WARN/System.err(315): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068) 03-23 11:44:42.944: WARN/System.err(315): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561) 03-23 11:44:42.944: WARN/System.err(315): at java.lang.Thread.run(Thread.java:1096) How do i fix it?? My Code: public class AsyncTaskExampleActivity extends Activity { private TextView textView; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); textView = (TextView) findViewById(R.id.TextView01); } private class DownloadWebPageTask extends AsyncTask<String, Void, String> { @Override protected String doInBackground(String... urls) { String response = ""; Log.i("", "in doInBackgroundddddddddd.........."); Log.i("", "in readWebpageeeeeeeeeeeee"); /* * try { InetAddress i = * InetAddress.getByName("http://google.co.in"); } catch * (UnknownHostException e1) { e1.printStackTrace(); } */ for (String url : urls) { Log.i("", "in for looooooop doInBackgroundddddddddd.........."); DefaultHttpClient client = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(url); try { Log .i("", "afetr for looooooop try doInBackgroundddddddddd.........."); HttpResponse execute = client.execute(httpGet); Log .i("", "afetr for looooooop try client ..execute doInBackgroundddddddddd.........."); InputStream content = execute.getEntity().getContent(); BufferedReader buffer = new BufferedReader( new InputStreamReader(content)); String s = ""; while ((s = buffer.readLine()) != null) { response += s; Log .i("", "afetr while looooooop try client ..execute doInBackgroundddddddddd.........."); } } catch (Exception e) { e.printStackTrace(); } } Log .i("", "afetr lasttttttttttttt b4 response doInBackgroundddddddddd.........."); return response; } @Override protected void onPostExecute(String result) { Log.i("", "in onPostExecuteeee.........."); textView.setText(result); } } public void readWebpage(View view) { /* * System.setProperty("http.proxyHost", "10.132.116.10"); * System.setProperty("http.proxyPort", "3128"); */ DownloadWebPageTask task = new DownloadWebPageTask(); task.execute(new String[] { "http://google.co.in" }); Log.i("", "in readWebpageeeeeeeeeeeee after execute.........."); } } main.xml: <Button android:id="@+id/readWebpage" android:layout_width="match_parent" android:layout_height="wrap_content" android:onClick="readWebpage" android:text="Load Webpage"> </Button> <TextView android:id="@+id/TextView01" android:layout_width="match_parent" android:layout_height="match_parent" android:text="Example Text"> </TextView> Manifest: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.test.async" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="8" /> <uses-permission android:name="android.permission.INTERNET"></uses-permission> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".AsyncTaskExampleActivity" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> Thanks Sneha

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  • Best wrapper for simultaneous API requests?

    - by bluebit
    I am looking for the easiest, simplest way to access web APIs that return either JSON or XML, with concurrent requests. For example, I would like to call the twitter search API and return 5 pages of results at the same time (5 requests). The results should ideally be integrated and returned in one array of hashes. I have about 15 APIs that I will be using, and already have code to access them individually (using simple a NET HTTP request) and parse them, but I need to make these requests concurrent in the easiest way possible. Additionally, any error handling for JSON/XML parsing is a bonus.

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  • MS Access vs SQL Server and others ? Is it worth taking a db server when less than 2 Gb and only 20

    - by asksuperuser
    After my experiment with MSAccess vs MySQL which shows MS Access hugely overperforming Mysql odbc insert by a factor 1000% before I would do the same experiment with SQL Server I searched for some other's people and found this one: http://blog.nkadesign.com/2009/access-vs-sql-server-some-stats-part-1/ which says "As a side note, in this particular test, Access offers much better raw performance than SQL Server. In more complex scenarios it’s very likely that Access’ performance would degrade more than SQL Server, but it’s nice to see that Access isn’t a sloth." So is worth bother with some db server when data is less than 2 Gb and users are about 20 (knowing that MS Access theorically supports up to 255 concurrent users though practically it's around a dozen concurrent users only). Are there any real world studies that really compare MS Access with other db in these specific use case ? Because professionaly speaking I keep hearing people systematically recommend DB server from people who have never used Access just because they think DB Server can only perform better in every case which I used to think myself I confess.

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  • Handling file upload in a non-blocking manner

    - by Kaliyug Antagonist
    The background thread is here Just to make objective clear - the user will upload a large file and must be redirected immediately to another page for proceeding different operations. But the file being large, will take time to be read from the controller's InputStream. So I unwillingly decided to fork a new Thread to handle this I/O. The code is as follows : The controller servlet /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub System.out.println("In Controller.doPost(...)"); TempModel tempModel = new TempModel(); tempModel.uploadSegYFile(request, response); System.out.println("Forwarding to Accepted.jsp"); /*try { Thread.sleep(1000 * 60); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }*/ request.getRequestDispatcher("/jsp/Accepted.jsp").forward(request, response); } The model class package com.model; import java.io.IOException; import java.util.concurrent.ExecutionException; import java.util.concurrent.Future; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.utils.ProcessUtils; public class TempModel { public void uploadSegYFile(HttpServletRequest request, HttpServletResponse response) { // TODO Auto-generated method stub System.out.println("In TempModel.uploadSegYFile(...)"); /* * Trigger the upload/processing code in a thread, return immediately * and notify when the thread completes */ try { FileUploaderRunnable fileUploadRunnable = new FileUploaderRunnable( request.getInputStream()); /* * Future<FileUploaderRunnable> future = ProcessUtils.submitTask( * fileUploadRunnable, fileUploadRunnable); * * FileUploaderRunnable processed = future.get(); * * System.out.println("Is file uploaded : " + * processed.isFileUploaded()); */ Thread uploadThread = new Thread(fileUploadRunnable); uploadThread.start(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } /* * catch (InterruptedException e) { // TODO Auto-generated catch block * e.printStackTrace(); } catch (ExecutionException e) { // TODO * Auto-generated catch block e.printStackTrace(); } */ System.out.println("Returning from TempModel.uploadSegYFile(...)"); } } The Runnable package com.model; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.nio.ByteBuffer; import java.nio.channels.Channels; import java.nio.channels.ReadableByteChannel; public class FileUploaderRunnable implements Runnable { private boolean isFileUploaded = false; private InputStream inputStream = null; public FileUploaderRunnable(InputStream inputStream) { // TODO Auto-generated constructor stub this.inputStream = inputStream; } public void run() { // TODO Auto-generated method stub /* Read from InputStream. If success, set isFileUploaded = true */ System.out.println("Starting upload in a thread"); File outputFile = new File("D:/06c01_output.seg");/* * This will be changed * later */ FileOutputStream fos; ReadableByteChannel readable = Channels.newChannel(inputStream); ByteBuffer buffer = ByteBuffer.allocate(1000000); try { fos = new FileOutputStream(outputFile); while (readable.read(buffer) != -1) { fos.write(buffer.array()); buffer.clear(); } fos.flush(); fos.close(); readable.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("File upload thread completed"); } public boolean isFileUploaded() { return isFileUploaded; } } My queries/doubts : Spawning threads manually from the Servlet makes sense to me logically but scares me coding wise - the container isn't aware of these threads after all(I think so!) The current code is giving an Exception which is quite obvious - the stream is inaccessible as the doPost(...) method returns before the run() method completes : In Controller.doPost(...) In TempModel.uploadSegYFile(...) Returning from TempModel.uploadSegYFile(...) Forwarding to Accepted.jsp Starting upload in a thread Exception in thread "Thread-4" java.lang.NullPointerException at org.apache.coyote.http11.InternalInputBuffer.fill(InternalInputBuffer.java:512) at org.apache.coyote.http11.InternalInputBuffer.fill(InternalInputBuffer.java:497) at org.apache.coyote.http11.InternalInputBuffer$InputStreamInputBuffer.doRead(InternalInputBuffer.java:559) at org.apache.coyote.http11.AbstractInputBuffer.doRead(AbstractInputBuffer.java:324) at org.apache.coyote.Request.doRead(Request.java:422) at org.apache.catalina.connector.InputBuffer.realReadBytes(InputBuffer.java:287) at org.apache.tomcat.util.buf.ByteChunk.substract(ByteChunk.java:407) at org.apache.catalina.connector.InputBuffer.read(InputBuffer.java:310) at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:202) at java.nio.channels.Channels$ReadableByteChannelImpl.read(Unknown Source) at com.model.FileUploaderRunnable.run(FileUploaderRunnable.java:39) at java.lang.Thread.run(Unknown Source) Keeping in mind the point 1., does the use of Executor framework help me in anyway ? package com.utils; import java.util.concurrent.Future; import java.util.concurrent.ScheduledThreadPoolExecutor; public final class ProcessUtils { /* Ensure that no more than 2 uploads,processing req. are allowed */ private static final ScheduledThreadPoolExecutor threadPoolExec = new ScheduledThreadPoolExecutor( 2); public static <T> Future<T> submitTask(Runnable task, T result) { return threadPoolExec.submit(task, result); } } So how should I ensure that the user doesn't block and the stream remains accessible so that the (uploaded)file can be read from it?

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