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  • Getting Frequency Components with FFT

    - by ruhig brauner
    so I was able to solv my last problem but i stubmled upon the next already. So I want to make a simple spectrogram but in oder to do so I want to understand how FFT-libaries work and what they actually calculate and return. (FFT and Signal Processing is the number 1 topic I will get into as soon as I have time but right now, I only have time for some programming exercises in the evening. ;) ) Here I just summarized the most important parts: int framesPerSecond; int samplesPerSecond; int samplesPerCycle; // right now i want to refresh the spectogram every DoubleFFT_1D fft; WAVReader audioIn; double audioL[], audioR[]; double fftL[], fftR[]; ..... framesPerSecond = 30; audioIn= new WAVReader("Strobe.wav"); int samplesPerSecond = (int)audioIn.GetSampleRate(); samplesPerCycle = (int)(audioIn.GetSampleRate()/framesPerSecond); audioL = new double[samplesPerCycle*2]; audioR = new double[samplesPerCycle*2]; fftL = new double[samplesPerCycle]; fftR = new double[samplesPerCycle]; for(int i = 0; i < samplesPerCycle; i++) { // don't even know why,... fftL[i] = 0; fftR[i] = 0; } fft = new DoubleFFT_1D(samplesPerCycle); ..... for(int i = 0; i < samplesPerCycle; i++) { audioIn.GetStereoSamples(temp); audioL[i]=temp[0]; audioR[i]=temp[1]; } fft.realForwardFull(audioL); //still stereo fft.realForwardFull(audioR); System.out.println("Check"); for(int i = 0; i < samplesPerCycle; i++) { //storing the magnitude in the fftL/R arrays fftL[i] = Math.sqrt(audioL[2*i]*audioL[2*i] + audioL[2*i+1]*audioL[2*i+1]); fftR[i] = Math.sqrt(audioR[2*i]*audioR[2*i] + audioR[2*i+1]*audioR[2*i+1]); } So the question is, if I want to know, what frequencys are in the sampled signal, how do I calculate them? (When I want to print the fftL / fftR arrays, I get some exponential formes at both ends of the array.) Thx :)

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  • JPA 2.0 Provider Hibernate Spring MVC 3.0

    - by user558019
    Dear All i have very strange problem we are using jpa 2.0 with hibernate and spring 3.0 mvc annotations based Database generated through JPA DDL is true and MySQL as Database; i will provide some refference classes and then my porblem. public abstract class Common implements serializable{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", updatable = false) private Long id; @ManyToOne @JoinColumn private Address address; //with all getter and setters //as well equal and hashCode } public class Parent extends Common{ private String name; @OneToMany(cascade = {CascadeType.MERGE,CascadeType.PERSIST}, mappedBy = "parent") private List<Child> child; //setters and rest of class } public class child extends Common{ //some properties with getter/setters } public class Address implements Serializable{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", updatable = false) private Long id; private String street; //rest of class with get/setter } as in code you can see that parents and child classes extends Common class so both have address property and id , the problem occurs when change the address refference in parent class it reflect same change in all child objects in list and if change address refference in child class then on merge it will change address refference of parent as well i am not able to figure out is it is problem of jpa or hibernate or spring thanks in advance

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  • How to deploy to Tomcat from NetBeans?

    - by deamon
    I've added Tomcat in the "Tools Servers" menu and as you can see it appears in the list of servers: But when I try to run my project, I cannot select Tomcat! The drop-down with servers is empty. I tried it with NetBeans 6.8 and 6.9 Beta. Any idea?

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  • Should filters write to the response during or after filtering?

    - by Mark
    I have a filter which processes generated HTML and rewrites certain elements. For example, it adds class attributes to some anchors. Finally, it writes the processed HTML to the response (a subclass of HttpServletResponseWrapper). Naturally, this means that the processed HTML is a different length after it has passed through the filter. I can see two ways of approaching this. One is to iterate over the HTML, using a StringBuilder to build up the processed HTML, and write the processed HTML to the response once all filtering is complete. The other is to iterate over the HTML but to write it to the response as soon as each element has been processed. Which is the better way for this operation, or is there another option which would be preferable? I am looking to minimise temporary memory usage primarily.

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  • What is the event dispatching thread?

    - by Roman
    I know what "thread" means and if I understand the event dispatching thread (EDT) as "just a thread", it explains a lot but, apparently, it does not explain everything. I do not understand what is special about this thread. For example I do not understand why we should start a GUI in a the EDT? Why the "main" thread is bed for GUI? Well, if we just do not want to occupy the main thread why we cannot start GUI just in "another thread" why it should be some "special" thread called EDT? Then I do not understand why we cannot start the EDT like any other thread? Why we should use some special tool (called invokeLater). And why GUI, unlike any other thread, does not start immediately. We should wait until it is ready to accept our job. Is it because EDT can, potentially execute several task simultaneously? If you decide to answer this question, could you pleas use a really simple terminology because otherwise, I am afraid, I will not be able to understand the answer.

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  • Why a new instance uses logger from old instances?

    - by Roman
    I generate 2 instances in this way: gameManager manager1 = new CTManager(owner,players1,"en"); manager1.start(); gameManager manager2 = new CTManager(owner,players2,"en"); manager2.start(); The start() method of the gameManager looks like that: void start() { game.start(); } When I create the game instance I create a loger: log = Logger.getLogger("TestLog"); (log is a public field of the class in which the game belongs). In the game.start() I run many processes and give them a reference to the corresponding log. So, I expect that manager1 and manager2 will write to different files. But manager2 writes to its own file and to the log file of the manager1. Why can it happen?

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  • servlet ArrayList and HashMap problem witch result

    - by nonameplum
    Hi, I have that code List<Map<String, Object>> data = new ArrayList<Map<String, Object>>(); Map<String, Object> item = new HashMap<String, Object>(); data.clear(); item.clear(); int i = 0; while (i < 5){    item.put("id", i);    i++;    out.println("id: " + item.get("id"));    out.println("--------------------------");    data.add(item); } for(i=0 ; i<5 ; i++){    out.println("print data[" + i + "]" + data.get(i)); } Result of that is: id: 0 -------------------------- id: 1 -------------------------- id: 2 -------------------------- id: 3 -------------------------- id: 4 -------------------------- print data[0]{id=4} print data[1]{id=4} print data[2]{id=4} print data[3]{id=4} print data[4]{id=4} Why only last element is stored?

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  • value from resource bundle as pattern in formatDate

    - by binary_runner
    I want to read pattern for JST formatDate also from resource bundle but this naive approach does not working, what I'm doing wrong ? in com/company/MyPortlet.properties is this key: company.date.format = yyyy-MM-dd HH:mm:ss In page I have: <fmt:setBundle basename="com.company.MyPortlet"/> <fmt:formatDate value="${date}" pattern="${company.date.format}" />

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  • Controlling race condition at startup.

    - by Will Hartung
    I have some code that I want to have some one time initialisation performed. But this code doesn't have a definite lifecycle, so my logic can be potentially invoked by multiple threads before my initialisation is done. So, I want to basically ensure that my logic code "waits" until initialisation is done. This is my first cut. public class MyClass { private static final AtomicBoolean initialised = new AtomicBoolean(false); public void initialise() { synchronized(initialised) { initStuff(); initialised.getAndSet(true); initialised.notifyAll(); } } public void doStuff() { synchronized(initialised) { if (!initialised.get()) { try { initialised.wait(); } catch (InterruptedException ex) { throw new RuntimeException("Uh oh!", ex); } } } doOtherStuff(); } } I basically want to make sure this is going to do what I think it's going to do -- block doStuff until the initialised is true, and that I'm not missing a race condition where doStuff might get stuck on a Object.wait() that will never arrive. Edit: I have no control over the threads. And I want to be able to control when all of the initialisation is done, which is why doStuff() can't call initialise(). I used an AtomicBoolean as it was a combination of a value holder, and an object I could synchronize. I could have also simply had a "public static final Object lock = new Object();" and a simple boolean flag. AtomicBoolean conveniently gave me both. A Boolean can not be modified. The CountDownLatch is exactly what I was looking for. I also considered using a Sempahore with 0 permits. But the CountDownLatch is perfect for just this task.

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  • What is the easiest straightforward way of telling which version performs better?

    - by Peter Perhác
    I have an application, which I have re-factored so that I believe it is now faster. One can't possibly feel the difference, but in theory, the application should run faster. Normally I would not care, but as this is part of my project for my master's degree, I would like to support my claim that the re-factoring did not only lead to improved design and 'higher quality', but also an increase in performance of the application (a small toy-thing - a train set simulation). I have toyed with the latest VisualVM thing today for about four hours but I couldn't get anything helpful out of it. There isn't (or I haven't found it) a way to simply compare the profiling results taken from the two versions (pre- and post- refactoring). What would be the easiest, the most straightforward way of simply telling the slower from the faster version of the application. The difference of the two must have had an impact on the performance. Thank you.

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  • DocumentBuilder.parse() / Parsing Entities

    - by stormin986
    I'm new to parsing XML and am having an issue with entities. (Am doing this on Android, if it makes a difference). Is there a way to have it turn an entity into the character it represents? I have this in the child of an element: "isn&#39;t" (minus quotes). I would prefer it parse it and the end result be a single text node. However, right now this is turned in to TEXT, ENTITY, TEXT. Is there a way to automatically have it parse the entity into text, or a manual way to do it?

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  • @Stateless, @Remote and @Local

    - by Jeff Foster
    In my deployment on JBoss 5.1.0GA with JavaEE-5 I have beans of the general form public interface Foo { void baz (); } @Stateless public class FooBean implements Foo { void baz() { // ... } } I have assumed that this is the same as if I have explicitly annotated the Foo interface with @Local. From seeing a stack trace in the code I think that it is actually using a remote interface, whereas I want all of my beans to be local. Do I need to explicitly annotate interfaces as Local or is there some default? Finding documentation on this is proving challenging so any links to relevant documentation would be greatly appreciated.

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  • Logger.setLevel() doesn't enable logging correctly

    - by ripper234
    Situation: I have this log4j logger: private static final Logger logger = Logger.getLogger(ThisClassName.class); And am trying to set it programatically through: Logger.getLogger(ThisClassName.class).setLevel(Level.DEBUG); Still, DEBUG level prints are swalloed (while INFO prints are printed successfully). Even this bit has no effect: Logger.getRootLogger().setLevel(Level.DEBUG); Calling logger.debug("foo") reaches Category.forcedLog() and ConsoleAppender.doAppend(), and then fails (quits) at: if(!isAsSevereAsThreshold(event.getLevel())) Any idea why this is happening?

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  • Read a file to multiple array byte[]

    - by hankol
    I have an encryption algorithm (AES) that accepts file converted to array byte and encrypt it. Since I am going to process a very big size files, the JVM may go out of memory. I am planing to read the files in multiple array byte. each containing some part of the file. Then I teratively feed the algorithm. Finally merge them to produce encrypted file. So my question is: there any way to read a file part by part to multiple array byte? I thought I can use the following to read the file to array byte: IOUtils.toByteArray(InputStream input). And then split the array into multiple bytes using: Arrays.copyOfRange(). But I am afraid that the first code that reads file to byte will make the JVM to go out of memory. any suggestion please ? thanks

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  • Spring noHandlerFound

    - by Justin
    I am trying to set up my Spring MVC testing environment. But I always get this noHandlerFound error: Aug 21, 2014 4:43:25 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/restful/firstPage] in DispatcherServlet with name 'spring' Aug 21, 2014 4:47:21 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/restful/firstPage2] in DispatcherServlet with name 'spring' Aug 21, 2014 5:10:27 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/restful/index.html] in DispatcherServlet with name 'spring' I already searched for solution, but none can fix my problem. My spring mvc version: 3.1.3.RELEASE This is my web.xml: <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <context-param> <param-name>contextConfigLocation</param-name> <param-value> /WEB-INF/applicationContext.xml </param-value> </context-param> this is my spring-servlet.xml: <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" /> this is my applicationContext.xml: <context:annotation-config /> <context:component-scan base-package="test.spring" /> <mvc:annotation-driven /> <mvc:resources mapping="/index.html" location="/index.html" /> <mvc:view-controller path="/firstPage" /> This is my Controller: package test.spring; .... @Controller @RequestMapping("/") public class FirstController { @RequestMapping(value = "firstPage2", method = RequestMethod.GET) public String showFirstPage(Map<String,Object> model){ return "firstPage"; } } My server is tomcat 7, there is no error and warning when it is deployed. I also tried this with no luck: <mvc:default-servlet-handler/> Before I start Spring MVC, I can access index.html

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  • Creating an instance within the Class itself

    - by didxga
    What's going on when the assignment statement executed at Line 4, does compiler ignore the new operator and keep the foo variable being null or something else happen to handle this awkward moment? public class Foo { // creating an instance before its constructor has been invoked, suppose the "initializing" // gets printed in constructor as a result of the next line, of course it will not print it private Foo foo = new Foo();//Line 4 public Foo() { System.out.println("initializing"); } }

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  • Swing: Programmatically select a text

    - by HH
    Hey everyone, I have a very simple Swing GUI with just a JTetxtArea. I am trying to programmatically select a part of text using: textArea.select(startSelection,endSelection); This work. However as soon as I add some other components to the GUI I do not see selection anymore frame.getContentPane().add(button); frame.getContentPane().add(textArea); textArea.select(startSelection,endSelection); I suspect that during layouting the gui, some event causes the text to be deselected. Am I right? And could anybody suggest a solution? My goal is to have a program which displays a text, and allows the user to input start and end selection position, and a selection appears between these two position. Thank you.

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