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  • JButtons re-enable themselves after being disabled

    - by Anarchist
    I have an array of JButtons which form a keypad interface. After six numbers are entered I want to disable the keypad so that no further numbers can be entered by the user. I have written the code and the buttons do disable until the mouse hovers above any of them, then the buttons seem to re-enable themselves and run actionEvents added to them. The full code is available here. Possible things that I think are wrong. There is some sort of MouseListener which is ignoring when I set button.setEnabled(false); I haven't separated attributes from the buildGUI(); correctly, I only did this anyway so that the inner class could access them. Possibly something to do with the gridLayout as disabling the buttons seems to work for my services JPanel buttons.

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  • Singletons vs. Application Context in Android?

    - by mschonaker
    Recalling this post enumerating several problems of using singletons and having seen several examples of Android applications using singleton pattern, I wonder if it's a good idea to use Singletons instead of single instances shared through global application state (subclassing android.os.Application and obtaining it through context.getApplication()). What advantages/drawbacks would have both mechanisms? To be honest, I expect the same answer in this post http://stackoverflow.com/questions/2709071/singleton-pattern-with-web-application-not-a-good-idea but applied to Android. Am I correct? What's different in DalvikVM otherwise? EDIT: I would like to have opinions on several aspects involved: Synchronization Reusability Testing Thanks in advance.

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  • Whats wrong with this method?

    - by David
    Here's the method: public static String CPUcolor () { System.out.println ("What color am I?") ; String s = getIns() ; System.out.println ("are you sure I'm "+s+"? (Y/N)") ; String a = getIns() ; while (!((a.equals ("y")) || (a.equals ("Y")) || (a.equals ("n")) || (a.equals ("N")))) { System.out.println ("try again") ; a = getIns () ; } if (a.equals ("n") || a.equals("N")) {CPUcolor() ;} System.out.println ("I am "+s) ; return s ; } here is a possible output of this method (y's and n's are user inputs): What color am I? red are you sure I'm red? (Y/N) N What color am I? blue are you sure I'm blue? (Y/N) N What color am I? Yellow are you sure I'm Yellow? (Y/N) y I am Yellow I am blue I am red Why is it that the line's "I am blue" and "I am Blue" printed? Why are they printed in reverse order with red, the first entered, printed last?

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  • Can I override spring beans instatiated with component scanning?

    - by Pablojim
    If I use component scanning in Spring 2.5 but then also define a controller in xml. Do I get two instances of this bean in my application context? If so which instance will be called for its related RequestMappings? <bean id="myController" class="domain.MyController"> <property name="filters"> <list> <ref local="filter1"/> <ref local="filter2"/> </list> </property> </bean>

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  • How do I detect the colillison of components?

    - by Coupon22
    How do I detect the collision of components, specifically JLabels (or ImageIcons?)?I have tried this: add(test1); test1.setLocation(x, y); add(test2); test1.setLocation(x1, y1); validate(); if(intersects(test1, test2)) { ehealth-=50; } public boolean intersects(JLabel testa, JLabel testb) { boolean b3 = false; if(testa.contains(testb.getX(), testb.getY())) { b3 = true; } return b3; } When I run this, it does nothing! I used to use rectangle, but it didn't go well with me. I was thinking about an image with a border (using paint.net) and moving an imageicon, but I don't know how to get the x of an imageicon or detect collision. I don't know how to detect collision of a label or increase the location either. I have searched for collision detection with components/ImageIcons, but nothing has came up. I have also searched for getting the x of ImageIcons.

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  • Do "if" statements affect in the time complexity analysis?

    - by FranXh
    According to my analysis, the running time of this algorithm should be N2, because each of the loops goes once through all the elements. I am not sure whether the presence of the if statement changes the time complexity? for(int i=0; i<N; i++){ for(int j=1; j<N; j++){ System.out.println("Yayyyy"); if(i<=j){ System.out.println("Yayyy not"); } } }

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  • Thread sleep and thread join.

    - by Dhruv Gairola
    hi guys, if i put a thread to sleep in a loop, netbeans gives me a caution saying Invoking Thread.sleep in loop can cause performance problems. However, if i were to replace the sleep with join, no such caution is given. Both versions compile and work fine tho. My code is below (check the last few lines for "Thread.sleep() vs t.join()"). public class Test{ //Display a message, preceded by the name of the current thread static void threadMessage(String message) { String threadName = Thread.currentThread().getName(); System.out.format("%s: %s%n", threadName, message); } private static class MessageLoop implements Runnable { public void run() { String importantInfo[] = { "Mares eat oats", "Does eat oats", "Little lambs eat ivy", "A kid will eat ivy too" }; try { for (int i = 0; i < importantInfo.length; i++) { //Pause for 4 seconds Thread.sleep(4000); //Print a message threadMessage(importantInfo[i]); } } catch (InterruptedException e) { threadMessage("I wasn't done!"); } } } public static void main(String args[]) throws InterruptedException { //Delay, in milliseconds before we interrupt MessageLoop //thread (default one hour). long patience = 1000 * 60 * 60; //If command line argument present, gives patience in seconds. if (args.length > 0) { try { patience = Long.parseLong(args[0]) * 1000; } catch (NumberFormatException e) { System.err.println("Argument must be an integer."); System.exit(1); } } threadMessage("Starting MessageLoop thread"); long startTime = System.currentTimeMillis(); Thread t = new Thread(new MessageLoop()); t.start(); threadMessage("Waiting for MessageLoop thread to finish"); //loop until MessageLoop thread exits while (t.isAlive()) { threadMessage("Still waiting..."); //Wait maximum of 1 second for MessageLoop thread to //finish. /*******LOOK HERE**********************/ Thread.sleep(1000);//issues caution unlike t.join(1000) /**************************************/ if (((System.currentTimeMillis() - startTime) > patience) && t.isAlive()) { threadMessage("Tired of waiting!"); t.interrupt(); //Shouldn't be long now -- wait indefinitely t.join(); } } threadMessage("Finally!"); } } As i understand it, join waits for the other thread to complete, but in this case, arent both sleep and join doing the same thing? Then why does netbeans throw the caution?

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  • why Observable snapshot observer vector

    - by han14466
    In Observable's notifyObservers method, why does the coder use arrLocal = obs.toArray();? Why does not coder iterate vector directly? Thanks public void notifyObservers(Object arg) { Object[] arrLocal; synchronized (this) { /* We don't want the Observer doing callbacks into * arbitrary code while holding its own Monitor. * The code where we extract each Observable from * the Vector and store the state of the Observer * needs synchronization, but notifying observers * does not (should not). The worst result of any * potential race-condition here is that: * 1) a newly-added Observer will miss a * notification in progress * 2) a recently unregistered Observer will be * wrongly notified when it doesn't care */ if (!changed) return; arrLocal = obs.toArray(); clearChanged(); } for (int i = arrLocal.length-1; i>=0; i--) ((Observer)arrLocal[i]).update(this, arg); }

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  • Has anyone tried the "objectify" library for Google App Engine?

    - by Spines
    I was using JDO for my google app engine project but got fed up with the additional 5 seconds it adds to my cold start time. I was planning on just writing stuff directly to the database with the low level datastore api, but then I came accross the objectify project ( http://code.google.com/p/objectify-appengine/ ). Apparently its a super light wrapper above the low level api. Does anyone have experiences with this library that they could share?

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  • What is the most efficient way to list all of the files in a directory (including sub-directories)?

    - by prometheus
    I am writing a servlet which will examine a directory on the server (external to the web container), and recursively search for certain files (by certain files, I mean files that are of a certain extension as well as a certain naming convention). Once these files are found, the servlet responds with a long list of all of the found files (including the full path to the files). My problem is that there are so many files and directories that my servlet goes extremely slow. I was wondering if there was a best practice or existing servlet for this type of problem? Would it be more efficient to simply compile the entire list of files and do the filtering via js/jquery on the client side?

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  • javac will not compile enum, ( Windows Sun 1.6 --> OpenJDK 1.6)

    - by avgvstvs
    package com.scheduler.process; public class Process { public enum state { NOT_SUBMITTED, SUBMITTED, BLOCKED, READY, RUNNING, COMPLETED } private state currentState; public state getCurrentState() { return currentState; } public void setCurrentState(state currentState) { this.currentState = currentState; } } package com.scheduler.machine; import com.scheduler.process.Process; import com.scheduler.process.Process.state; public class Machine { com.scheduler.process.Process p = new com.scheduler.process.Process(); state s = state.READY; //fails if I don't also explicitly import Process.state p.setCurrentState(s); //says I need a declarator id after 's'... this is wrong. p.setCurrentState(state.READY); } Modified the example to try and direct to the issue. I cannot change the state on this code. Eclipse suggests importing Process.state like I had on my previous example, but this doesn't work either. This allows state s = state.READY but the call to p.setCurrentState(s); fails as does p.setCurrentState(state.READY);

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  • How do I correct feature envy in this case?

    - by RMorrisey
    I have some code that looks like: class Parent { private Intermediate intermediateContainer; public Intermediate getIntermediate(); } class Intermediate { private Child child; public Child getChild() {...} public void intermediateOp(); } class Child { public void something(); public void somethingElse(); } class Client { private Parent parent; public void something() { parent.getIntermediate().getChild().something(); } public void somethingElse() { parent.getIntermediate().getChild().somethingElse(); } public void intermediate() { parent.getIntermediate().intermediateOp(); } } I understand that is an example of the "feature envy" code smell. The question is, what's the best way to fix it? My first instinct is to put the three methods on parent: parent.something(); parent.somethingElse(); parent.intermediateOp(); ...but I feel like this duplicates code, and clutters the API of the Parent class (which is already rather busy). Do I want to store the result of getIntermediate(), and/or getChild(), and keep my own references to these objects?

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  • ActiveMq integration with Spring 2.5

    - by Tony
    I am using ActiveMq 5.32 with Spring 2.5.5. I use pretty generic configuration, as long as I include the jmsTransactionManager in DefaultMessageListenerContainer, Spring throw an error on start up: "Error creating bean with name 'org.springframework.jms.listener.DefaultMessageListenerContainer#0'" Without the transactionManager attribute , this works fine, but when I add 10 messages to the message queue, a transaction exception will occur. Part of my configurations : <bean class="org.springframework.jms.listener.DefaultMessageListenerContainer"> <property name="connectionFactory" ref="connectionFactory" /> <property name="destination" ref="emailDestination" /> <property name="messageListener" ref="emailServiceMDP" /> <property name="transactionManager" ref="jmsTransactionManager" /> </bean> <bean id="jmsTransactionManager" class="org.springframework.jms.connection.JmsTransactionManager"> <property name="connectionFactory" ref="connectionFactory" /> </bean> Does this version of Spring and Activemq has some know issues in integration ? Or do I need additional libs to get jmsTransactionManager to work ?

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  • A member variable's hashCode() value is different

    - by Jacques René Mesrine
    There's a piece of code that looks like this. The problem is that during bootup, 2 initialization takes place. (1) Some method does a reflection on ForumRepository & performs a newInstance() purely to invoke #setCacheEngine. (2) Another method following that invokes #start(). I am noticing that the hashCode of the #cache member variable is different sometimes in some weird scenarios. Since only 1 piece of code invokes #setCacheEngine, how can the hashCode change during runtime (I am assuming that a different instance will have a different hashCode). Is there a bug here somewhere ? public class ForumRepository implements Cacheable { private static CacheEngine cache; private static ForumRepository instance; public void setCacheEngine(CacheEngine engine) { cache = engine; } public synchronized static void start() { instance = new ForumRepository(); } public synchronized static void addForum( ... ) { cache.add( .. ); System.out.println( cache.hashCode() ); // snipped } public synchronized static void getForum( ... ) { ... cache.get( .. ); System.out.println( cache.hashCode() ); // snipped } }

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  • How to send exceptions to exceptionController?

    - by ivar
    <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver"> <property name="mappedHandlers"> <set> <ref bean="exceptionController" /> </set> </property> <property name="defaultErrorView" value="tiles/content/error" /> </bean> I'm trying to send exceptions to a controller so I can create a redirect. If I comment out the mappedHandlers part then the error tile is displayed but it is only a tile. The rest of the tiles load normally. I need to make a redirect in the controller so I can show an error page not just an error tile. I can't find enough information or an example how the exception invokes some method in exceptionController.

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  • Viewing directory containing MIME encoded email messages

    - by Mark
    I have an application which generates and sends MIME encoded messages (javax.mail.internet.MimeMessage) through an SMTP server. As part of the development process only, I'd like to be able to view these messages rather than send them (I know the sending works just fine, but there are restrictions on the domains within the dev environment which makes it a little difficult) I thought the easiest way would be to save the text for each message to a directory, then point "an app" at the directory and check them over. So the question is, what would be a good app to use? Is it as simple as configuring Outlook or another email client to do it? Thanks

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  • Designing a chain of states

    - by devoured elysium
    I want to model a kind of FSM(Finite State Machine). I have a sequence of states (let's say, from StateA to StateZ). This sequence is called a Chain and is implemented internally as a List. I will add states by the order I want them to run. My purpose is to be able to make a sequence of actions in my computer (for example, mouse clicks). (I know this has been done a zillion times). So a state is defined as a: boolean Precondition() <- Checks to see if for this state, some condition is true. For example, if I want to click in the Record button of a program, in this method I would check if the program's process is running or not. If it is, go to the next state in the chain list, otherwise, go to what was defined as the fail state (generally is the first state of them all). IState GetNextState() <- Returns the next state to evaluate. If Precondition() was sucessful, it should yield the next state in the chain otherwise it should yield the fail state. Run() Simply checks the Precondition() and sets the internal data so GetNextState() works as expected. So, a naive approach to this would be something like this: Chain chain = new Chain(); //chain.AddState(new State(Precondition, FailState, NextState) <- Method structure chain.AddState(new State(new WinampIsOpenCondition(), null, new <problem here, I want to referr to a state that still wasn't defined!>); The big problem is that I want to make a reference to a State that at this point still wasn't defined. I could circumvent the problem by using strings when refrering to states and using an internal hashtable, but isn't there a clearer alternative? I could just pass only the pre-condition and failure states in the constructor, having the chain just before execution put in each state the correct next state in a public property but that seems kind of awkward.

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  • How can I change jtable height at runtime

    - by wniroshan
    I hava a JFrame with multiple JPanels of similar width aligned one below other. I use one of these JPanels to display a JTable which is the last JPanel of the lot. This JPanel has a JScrollpane as a child component. This is where I try to add my table dynamically. Initial height of this JScrollpane is set to 40. I designed above template using Netbeans 6.8 Now I'm trying to add the table to the JPanel. When a button is pressed below code snippet is called. The class which includes this code extends javax.swing.JFrame class. I am expecting below code would adjust table height according to the row count and display the table. SearchTable = new JTable(RowData, DisplayNames) { @Override public boolean isCellEditable(int rowIndex, int vColIndex) { return false; } }; // if row count is less than 10 then display all the rows without a scroll bar if (SearchTable.getRowCount() < 10) { pnl_tblpanel.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (SearchTable.getRowCount() + 4))); scr_tblholder.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (SearchTable.getRowCount() + 4))); } else {// if row count is more than 10 display first 10 rows and add a scroll bar pnl_tblpanel.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (10 + 2))); scr_tblholder.setAutoscrolls(true); } //pnl_tblpanel.add(scr_tblholder); scr_tblholder.setViewportView(SearchTable); //pnl_tblpanel.repaint(); pnl_tblpanel.validate(); this.validate(); //this.repaint(); pnl_tblpanel.setVisible(true); this.pack(); The table displays, but the table height is not changed according to the row count. It stays its default value. I have been trying many combinations of validate and repaint but nothing worked. (More in desperation) Can anyone shed some light on this Thank you

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  • variables reference value of string

    - by xdevel2000
    How can I get the reference value of a string object? If I hava a class like class T() { } T t = new T(); System.out.println( t); print out T@a3455467 that is the reference value inside t but for string? maybe with method hashCode()??

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