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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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  • Connecting Android app to MySQL database

    - by opuhliyvladyslav
    Can somebody help me with question related with MySQL database using? Yesterday i was making app for getting some text data and sending them to database located on remote server! I was making POST request to database and sent few text fields to one table in database. So MY QUESTION IS: "Can I use MySQL directly (not though POST method )? and how to use it ?" (will be so glad to see url to solutions or examples) P.S. when i was sending data to server i have some errors in database fields when sending russian characters (what type of encoding sending from my app to server????)

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  • Help in setting the setClientInfo with JPA

    - by enrique
    i am trying to set to jpa the new JDBC method which allows the application to be identified with a name it is the setClientInfo() and i could do it using pure JDBC using the lines Properties jdbcProperties = new Properties(); jdbcProperties.put("user", "system"); jdbcProperties.put("password", "sw01"); jdbcProperties.put("v$session.program", "Clients"); Connection connection = DriverManager.getConnection(url,jdbcProperties); However i have new requirements and i need to make it with JPA EclipseLink i have been googling and could not find something substantial on how to set this property out in JPA i guess it is by annotating something but i do not know what, i was trying to setting the persistence unit by putting the following in the persistence unit: <properties> <property name="toplink.ddl-generation" value="create-tables"/> <property name="v$session.program" value="Clients"/> </properties> but no lucky ...does somebody know how to do it or any idea...? thanks in advanced.-

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  • Guice child injector override binding

    - by Roman
    Hi All I am trying to to override a binding in a child injector that was already configured in a base injector. like that : public class PersistenceModule extends Abstract{ @Override protected void configure() { bind(IProductPersistenceHelper.class).to(ProductPersistenceHelper.class); } } then : Injector injector = Guice.createInjector(new PersistenceModule()); injector.createChildInjector(new AbstractModule(){ @Override protected void configure() { bind(IProductPersistenceHelper.class).to(MockProductPersistenceHelper.class); } }) Guice is complaining that it has already a binding for that. Are there any patterns or best practices for that problem ?

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  • Abstract class get parameter from implementing subclass?

    - by soren.qvist
    I'm wondering if there is way to do this without breaking encapsulation, I want the abstract class to rely on parameters defined in the implementing subclass. Like so: public abstract class Parent { private int size; private List<String> someList; public Parent() { size = getSize(); someList = new ArrayList<String>(size); } public abstract int getSize(); } public class Child extends Parent { @Override public int getSize() { return 5; } } Is this ugly? Is there a better way? And perhaps more importantly, is this even a good idea?

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  • why we can't initialize a servlet using constructor itself?

    - by Reddy
    Why do we have to override init() method in Servlets while we can do the initialization in the constructor and have web container call the constructor passing ServletConfig reference to servlet while calling constructor? Ofcourse container has to use reflection for this but container has to use reflection anyway to call a simple no-arg constructor

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  • Building a custom iterator.

    - by Isai
    I am making this class which is a custom Map based off a hash map. I have an add method where if you add an object the object will be the key, and its value will be 1 if the object is not currently in the list. However if you add object that is currently in the list its value will be bumped up by 1. So if I added 10 strings which were all the same, the key would be that string and the value will be 10. I understand in practice when I iterate through the map, there is actually only one object to iterate, however, I am trying to create a inner class that will define an iterator that will iterate the same object however many times its value is. I can do this by simply using for loops to construct an appropriate ArrayList and just create an iterator for that, but that is too inefficient. Is there an easy or more efficient way of doing this?

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  • How can I calculate the age at death?

    - by user521180
    SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy"); if(petDetails.getDateOfDeath() != null){ String formatedDateOfDeath = formatter.format(petDetails.getDateOfDeath()); String formateDateOfBirth = formatter.format(petDetails.getDateOfBirth()); } How can i calculate the age of death from the above. I dont want to use any externallibraries EDIT: please look at what I've got so far.none of the other threads are like mine. most of them are about date from DOB to today and not in the format im using.

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  • SVNKit: How to get the repository url from a local path?

    - by StackedCrooked
    I would like to implement a method that can get the svn revision number from the path where a SVN repository has been checked out. The method declaration would look something like this: long getRevisionNumber(String localPath) { ... } I'm trying to use SVNKit for this, but it seems to require an SVN URL to start with. Is there any way to start with a local path?

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  • Quickest way to clone a GregorianCalendar?

    - by wds
    I'm trying to make a deep copy of an object, including a GregorianCalendar instance. I'm always wary of using clone() and it doesn't seem to have been overridden here, so I'm just doing the copy field by field. Ideally, there'd be a copy constructor, which I could use like so: GregorianCalendar newCalendar = new GregorianCalendar(oldCalendar); Unfortunately I can't find any such functionality in the API and am stuck trying to figure out which fields I need to get an exact copy. So, to make a copy of one of these calendars, how would you do it? Am I missing some simple shortcut here?

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  • antlr: Best practice to integrate generated parser into the system

    - by green
    Here is the background, I am trying to create a DSL to allow customer write simple scripts to query into our mongodb based database. I choose antlr to implement the DSL. From my understanding (and pls let me know if it's not correct) there are 2 approaches to integrate antlr generated parser into the system: Embed code into the grammar file so that the generated parser could be used directly to make query to the database and return result in a certain format (e.g. json encoded) Keep the parser purely a parser, after feed the DSL file to it, and construct the query in another class by retrieving the AST from generated parser class So antlrers, which one do you think is the way I as an antlr newbie should go? Can you list the pros and cos of each approach, or you have other way to recommend?

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  • create jar file with images and database

    - by Samurai
    Hi I am using NetBeans IDE and I have my images (what I am using in my project) in a folder named Images. When I am building jar it doesn't take that images. The code I am using to set image is, buttonObj.setIcon(new ImageIcon("\Images\a.jpg") any help please.

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  • JSF getter methods called BEFORE beforePhase fires

    - by Bill Leeper
    I got a recommendation to put all data lookups in the beforePhase for a given page, however, now that I am doing some deeper analysis it appears that some getter methods are being called before the beforePhase is fired. It became very obvious when I added support for a url parameter and I was getting NPEs on objects that are initialized in the beforePhase call. Any thoughts? Something I have set wrong. I have this in my JSP page: <f:view beforePhase="#{someController.beforePhaseSummary}"> That is only the 5th line in the JSP file and is right after the taglibs. Here is the code that is in the beforePhaseSummary method: public void beforePhaseSummary(PhaseEvent event) { logger.debug("Fired Before Phase Summary: " + event.getPhaseId()); if (event.getPhaseId() == PhaseId.RENDER_RESPONSE) { HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest(); if (request.getParameter("application_id") != null) { loadApplication(Long.parseLong(request.getParameter("application_id"))); } /* Do data fetches here */ } } The logging output above indicates that an event is fired. The servlet request is used to capture the url parameters. The data fetches gather data. However, the logging output is below: 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 107 - Getting UnsubmittedCount 2010-04-23 13:44:46,984 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:47,031 [http-8080-4] DEBUG ...SomeController 133 - Fired Before Phase Summary: RENDER_RESPONSE(6) The logs indicate 2 calls to the getPermit method and one to getUnsubmittedCount before the beforePhase is fired.

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  • setCursor on container without it changing cursor of sub components

    - by Mike
    JPanel panel = new JPanel(null); panel.setSize(400, 400); panel.add(new JButton("Test")); panel.setCursor(Cursor.getCursor(Cursor.SOMETHING_SOMETHING_CURSOR)); The panel will have a custom cursor, but I don't want the button to have a custom cursor. I don't want to have to set the cursor of every sub component, because in my application I have many and I don't want to litter the code with setCursor statements. Is there a way, like overriding a method on the JPanel or something? A "contains" method somewhere is used to determine if a cursor needs to be set. Could I fool it into thinking the mouse is not in the container if it's really in a sub component? Any other nifty little trick?

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  • Increasing JRE Memory Usage in Eclipse

    - by gMcizzLe
    I read in another question that you can increase the JRE memory allowance for an app through Window - Preferences in Eclipse, but I can't seem to find anything related to heap memory allocation. Editing -xms/xmx values in eclipse.ini doesn't help since those are for Eclipse itself.

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  • How to see "anti if" movement and its gaol?

    - by Vijay Shanker
    I have a developer for last 3 years, have been using if-else or if-else if statements a lot in my programing habit. And today, I found This link. One obvious sample i put here public void doSomthing(String target, String object){ //validate requests if(target != null && target.trim().length() < 1){ //invalid request; } //further logic } Now, I have seen this sort of check all over the places, libraries. So, I wanted to have a discussion about the worthiness of such a movement. Please let me know your views.

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  • Can anybody explain the code

    - by girinie
    class giri{ public static void main(String args[]) { int x = 17; int y = 013; System.out.println("x+y = " + x+y); } } When I run the program I get the output 1711. Can anybody tell me How do I get 1711

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  • Background image JFrame with content

    - by Petr Safar
    I have a JFrame with BorderLayout, there are panels on all sides (North, East ,...). In the panels there are labels and buttons mostly. Now I want the frame to have a background image, some research told me that i had to change the content pane of my frame. When I try this however, the content gets put in the background and isn't visible. Also, I don't know how to resize the image if the frame is resized. Is there an easy fix for this or will I have to rework most of my code?

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  • Design pattern: Polymorphism for list of objects

    - by ziang
    Suppose I have a class A, and A1, A2 inherits from A. There are 2 functions: List<A1> getListA1(){...} List<A2> getListA2(){...} Now I want to do something similar to both A1 and A2 in another function public void process(List<A>){...} If I want to pass the instance of either ListA1 or ListA2, of course the types doesn't match because the compiler doesn't allow the coercion from List< A1 to List< A. I can't do something like this: List<A1> listA1 = getListA1(); List<A> newList = (List<A>)listA1; //this is not allowed. So what is the best approach to the process()? Is there any way to do it in a universal way rather than write the similar code to both List and List?

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