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  • ArrayList<String> NullPointerException

    - by Carlucho
    Am trying to solve a labyrinth by DFS, using adj List to represent the vertices and edges of the graph. In total there are 12 nodes (3 rows[A,B,C] * 4 cols[0,..,3]). My program starts by saving all the vertex labels (A0,..C3), so far so good, then checks the adjacent nodes, also no problems, if movement is possible, it proceeds to create the edge, here its where al goes wrong. adjList[i].add(vList[j].label); I used the debugger and found that vList[j].label is not null it contains a correct string (ie. "B1"). The only variables which show null are in adjList[i], which leads me to believe i have implemented it wrongly. this is how i did it. public class GraphList { private ArrayList<String>[] adjList; ... public GraphList(int vertexcount) { adjList = (ArrayList<String>[]) new ArrayList[vertexCount]; ... } ... public void addEdge(int i, int j) { adjList[i].add(vList[j].label); //NULLPOINTEREXCEPTION HERE } ... } I will really appreaciate if anyone can point me on the right track regrading to what its going wrong... Thanks!

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  • Deleting orphans with JPA

    - by homaxto
    I have a one-to-one relation where I use CascadeType.PERSIST. This has over time build up a huge amount of child records that has not been deleted, to such an extend that it is reflected in the performance. Now I wish to add some code that cleans up the database removing all the child records that are not referenced by a parent. At the moment we are talking 400K+ records, at I need to run the code on all customer installations just to be sure they do not run into the same problem. I think the best solution would be to run a named query (because we support two databases) that deletes the necessary records, and this is where I get into problems, because how should I write it in JPQL? The result I want can be defined like the following sql statement, which unfortunaltely does not run on MySQL. DELETE FROM child c1 WHERE c1.pk NOT IN (SELECT DISTINCT p.pk FROM child c2 JOIN parent p ON p.child = c2.pk);

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  • Log4j - Logging to multiple log files based on the project modules

    - by Veera
    Consider this scenario: I have a project with two modules and one common module as below (the package structure): com.mysite.moduleone com.mysite.moduletwo com.mysite.commonmodule In the above, the commonmodule classes can be used by other two modules. The question: I need to configureLog4J such a way that the log messages from moduleone and moduletwo goes to different log file. I can always do this using using category. But the real problem is when I want to log the messages from the commonmodule also. So, when the commonmodule classes are called from moduleone the commonmodule log messages should go to the moduleone log file. If the commonmodule is accesse from moduletwo the commonmodule log messages should go to moduletwo log file. Is it possible to configure Log4J in this fashion? Any comments? PS: I think I made my question clear. If any confusion, leave a comment, wil try to clear it. :)

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  • mockito ArrayList<String> problem...

    - by Sardathrion
    I have a method that I am trying to unit test. This method takes a parameter as an ArrayList and does things with it. The mock I am trying to define is: ArrayList<String> mocked = mock(ArrayList.class); which gives a [unchecked] unchecked conversion" warning. ArrayList<String> mocked = mock(ArrayList<String>.class); gives me an error. Anyone care to enlighten me as to what I am doing wrong?

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  • JFrame the same shape as an Image / Program running in background

    - by Jan Weber
    My question is simple, the solution surely not. I am looking for a way to shape a JFrame the same as an Image it will be displaying. By shape I mean the shape of the pixels that have an alpha != 0. I've already found a working example using a GeneralPath object, but it created ~110000 "nodes" for an Image of about 500*400, so starting the JFrame took more than 2 minutes, which is definitely not the desired effect, the startup should be in under 2 seconds. Thanks for your time.

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  • Why is my GUI unresponsive while a SwingWorker thread runs?

    - by Starchy
    Hello, I have a SwingWorker thread with an IOBound task which is totally locking up the interface while it runs. Swapping out the normal workload for a counter loop has the same result. The SwingWorker looks basically like this: public class BackupWorker extends SwingWorker<String, String> { private static String uname = null; private static String pass = null; private static String filename = null; static String status = null; BackupWorker (String uname, String pass, String filename) { this.uname = uname; this.pass = pass; this.filename = filename; } @Override protected String doInBackground() throws Exception { BackupObject bak = newBackupObject(uname,pass,filename); return "Done!"; } } The code that kicks it off lives in a class that extends JFrame: public void actionPerformed(ActionEvent event) { String cmd = event.getActionCommand(); if (BACKUP.equals(cmd)) { SwingUtilities.invokeLater(new Runnable() { public void run() { final StatusFrame statusFrame = new StatusFrame(); statusFrame.setVisible(true); SwingUtilities.invokeLater(new Runnable() { public void run () { statusFrame.beginBackup(uname,pass,filename); } }); } }); } } Here's the interesting part of StatusFrame: public void beginBackup(final String uname, final String pass, final String filename) { worker = new BackupWorker(uname, pass, filename); worker.execute(); try { System.out.println(worker.get()); } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } } } So far as I can see, everything "long-running" is handled by the worker, and everything that touches the GUI on the EDT. Have I tangled things up somewhere, or am I expecting too much of SwingWorker?

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  • Catching constraint violations in JPA 2.0.

    - by Dennetik
    Consider the following entity class, used with, for example, EclipseLink 2.0.2 - where the link attribute is not the primary key, but unique nontheless. @Entity public class Profile { @Id private Long id; @Column(unique = true) private String link; // Some more attributes and getter and setter methods } When I insert records with a duplicate value for the link attribute, EclipseLink does not throw a EntityExistsException, but throws a DatabaseException, with the message explaining that the unique constraint was violated. This doesn't seem very usefull, as there would not be a simple, database independent, way to catch this exception. What would be the advised way to deal with this? A few things that I have considered are: Checking the error code on the DatabaseException - I fear that this error code, though, is the native error code for the database; Checking the existence of a Profile with the specific value for link beforehand - this obviously would result in an enormous amount of superfluous queries.

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  • How to use pom.xml/Maven to initialize a local thoughtsite (App Engine sample) project in Eclipse?

    - by ovr
    This sample app ("thoughtsite") for App Engine contains a pom.xml in its trunk: http://code.google.com/p/thoughtsite/source/browse/#svn/trunk But I don't know what command to run in Maven to set up the project locally. (The README doesn't mention anything about Maven.) I tried to just import the project code directly into Eclipse but it doesn't look like it's in an appropriate format for a direct import. So I assume I need to do something with Maven to get it set up correctly. I haven't really used Maven before so I'm not sure what command I would need to run to set everything up. The pom.xml seems like it downloads a bunch of dependencies for the project like the Spring jar files which I don't see anywhere else in the svn repository.

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  • Generate Javadoc for interfaces only?

    - by ipkiss
    Hi, I am finding a way to write a script that I can generate javadoc for my program's Interfaces only (not for public classes). I have tried Eclipse built-in tool and even JAutodoc tool but have not been successful yet. Does anyone have some ideas, please? Thanks.

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  • Strategy for locale sensitive sort with pagination

    - by Thom Birkeland
    Hi, I work on an application that is deployed on the web. Part of the app is search functions where the result is presented in a sorted list. The application targets users in several countries using different locales (= sorting rules). I need to find a solution for sorting correctly for all users. I currently sort with ORDER BY in my SQL query, so the sorting is done according to the locale (or LC_LOCATE) set for the database. These rules are incorrect for those users with a locale different than the one set for the database. Also, to further complicate the issue, I use pagination in the application, so when I query the database I ask for rows 1 - 15, 16 - 30, etc. depending on the page I need. However, since the sorting is wrong, each page contains entries that are incorrectly sorted. In a worst case scenario, the entire result set for a given page could be out of order, depending on the locale/sorting rules of the current user. If I were to sort in (server side) code, I need to retrieve all rows from the database and then sort. This results in a tremendous performance hit given the amount of data. Thus I would like to avoid this. Does anyone have a strategy (or even technical solution) for attacking this problem that will result in correctly sorted lists without having to take the performance hit of loading all data? Tech details: The database is PostgreSQL 8.3, the application an EJB3 app using EJB QL for data query, running on JBoss 4.5.

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  • Apache HttpClient 4.0. Weird behavior.

    - by Mikhail T
    Hello. I'm using Apache HttpClient 4.0 for my web crawler. The behavior i found strange is: i'm trying to get page via HTTP GET method and getting response about 404 HTTP error. But if i try to get that page using browser it's done successfully. Details: 1. I upload multipart form to server this way: HttpPost httpPost = new HttpPost("http://[host here]/in.php"); MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE); entity.addPart("method", new StringBody("post")); entity.addPart("key", new StringBody("223fwe0923fjf23")); FileBody fileBody = new FileBody(new File("photo.jpg"), "image/jpeg"); entity.addPart("file", fileBody); httpPost.setEntity(entity); HttpResponse response = httpClient.execute(httpPost); HttpEntity result = response.getEntity(); String responseString = ""; if (result != null) { InputStream inputStream = result.getContent(); byte[] buffer = new byte[1024]; while(inputStream.read(buffer) > 0) responseString += new String(buffer); result.consumeContent(); } Uppload succefully ends. I'm getting some results from web server: HttpGet httpGet = new HttpGet("http://[host here]/res.php?key="+myKey+"&action=get&id="+id); HttpResponse response = httpClient.execute(httpGet); HttpEntity entity = response.getEntity(); I'm getting ClientProtocolException while execute method run. I was debugging this situation with log4j. Server answers "404 Not Found". But my browser loads me that page with no problem. Can anybody help me? Thank you.

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  • richfaces keepAlive not working

    - by Jurgen H
    I have a mediaOutput tag which, in its createContent attribute, requires the backing bean to be in a certain state. A list of values, which is filled in an init method, must be available. I therefore added a keepAlive tag for the whole backing bean. I now indeed see the backingBean in stead of some (richfaces) proxy bean, but the filled list is null again. How to make this possible? I checked that the init method was called and that the list is filled in in the init method. <a4j:keepAlive beanName="myBean" /> <a4j:mediaOutput createContent="#{myBean.writeChart}" ... /> The backing bean public class MyBean implements Serializable { public List list; public void init(ActionEvent event) { // call some resource to fill the list list = service.getItems(); } public void writeChart(final OutputStream out, final Object data) throws IOException { // list is null } // getters & setters }

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  • Google App Engine - What causes cold start latency time to be high, even though my CPU usage is rela

    - by Spines
    I've optimized my code to use only lightweight libraries. I'm even using the low level datastore rather than JDO. And my cold start CPU usage has dropped from about 5 seconds to about 1.5 seconds. However, the time it takes to respond is often about 4.5 seconds, though it varies a lot. Here are some lines from my logs: 03-19 09:16PM 57.368 /donothing 200 4506ms 1516cpu_ms 0kb Mozilla/5.0 03-19 09:22PM 54.884 /donothing 200 4452ms 1477cpu_ms 0kb Mozilla/5.0 What is the app engine doing for those extra 3 seconds that apparently isn't using any CPU?

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  • Checked equivalent to IllegalArgumentException?

    - by jv1975oid
    I have a method that takes an enum as a parameter and returns some information dependent on that parameter. However, that enum contains some values which should not be handled, and should raise an error condition. Currently the method throws an IllegalArgumentException but I would like this to be a checked exception to force callers to catch it (and return gracefully, logging an error). Is there something suitable or should I create my own Exception subclass? I'm open to other patterns as well. A reasonable reaction would be that all values of the enum should be handled, but that isn't the case. When a new value is added to the enum, I want to make sure that this method does the right thing - alerting a human is preferable to using some default return value in this case. Thanks for any advice.

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  • JSF - <h:outputText> making some of words Bold

    - by karansardana
    How can we go about making some of the words in a sentence appear in BOLD for example - I'm trying to put one of the words of a sentence in BOLD i.e. sentence is "please select the amount" amount should be in BOLD, and now, when I use message = "please select the amount " This doesn't work. It simply shows please select the amount . How can I get this to work?

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  • How could I send live video stream to remote server from my phone !!!

    - by poc
    Hello , I have a problem about streaming my video to server in real-time from my phone. that is , let my phone be a IP Camera , and server can watch the live video from my phone I have googled many many solutions, but there is no one can solve my problem. I use MediaRecorder to record . it can save video file in the SD card correctly. then , I refered this page and used some method as followings skt = new Socket(InetAddress.getByName(hostname),port); pfd =ParcelFileDescriptor.fromSocket(skt); mediaRecorder.setOutputFile(pfd.getFileDescriptor()); now it seems I can send the video stream while recording however, I wrote a receiver-side program to receive the video stream from Android , but it doesn't work . is there any error? I can receive file , but I can not open the video file . I guess the problem may caused by file format ? there are outline of my code. in android side Socket skt = new Socket(hostIP,port); ParcelFileDescriptor pfd =ParcelFileDescriptor.fromSocket(skt); .... .... mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); mediaRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT); mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4); mediaRecorder.setOutputFile(pfd.getFileDescriptor()); ..... mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT); mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP); ..... mediaRecorder.start(); in receiver side (my ACER notebook) // anyway , I don't think the file extentions will do any effect File video = new File (strDate+".3gpp"); FileOutputStream fos; try { fos = new FileOutputStream(video); byte[] data = new byte[1024]; int count =-1; while( (count = fin.read(data,0,1024) ) !=-1) { fos.write(data,0,count); fos.flush(); } fos.close(); fin.close(); I confused a long time.... thanks in advance

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  • Changing the direction of a Combo box dropdown in SWT

    - by Kris
    Hi, I'm building an Eclipse plugin in SWT, and I have the following problem: one of my fields is a combo box, and in some cases it may have fairly long items as selection options. My plugin runs on the right side of the screen, so when you go to use the combo-box, the right side of the combo box is cut off. So, my question is: is there any way to change the dropdown's alignment relative to the combo control? It seems to be permanently left-aligned... and I'm pretty sure you can change the direction in Swing (though the only place I've seen it done is in the Substance UI demo. The Combo Box tab has boxes with North, South East, and West flyout directions... for my application, I need something like the West flyout) Note: Setting actual text limits is a last-case-scenario option; it would be quite a bit of guesswork to set the text limit dynamically (since the widget's view can be resized). Here's a picture (sorry, I can only have one link and no images :( ... I need some more rep :p) Left side of the line: Proper width - the view is the wide enough for the combo dropdown to display all the text; you can see the scrollbars on the right side. Right side of the line: Too small - Here, the view has been resized, and the combo dropdown scrollbar (as well as some of the text) is cut off by the right side of the screen. I always have more screen space available to the left (since this is always on the right hand side of the screen), but the combo dropdown always appears to the lower right. Hopefully this is clear enough.

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  • How to close a JFrame in the middle of a program

    - by Nick Gibson
    public class JFrameWithPanel extends JFrame implements ActionListener, ItemListener { int packageIndex; double price; double[] prices = {49.99, 39.99, 34.99, 99.99}; DecimalFormat money = new DecimalFormat("$0.00"); JLabel priceLabel = new JLabel("Total Price: "+price); JButton button = new JButton("Check Price"); JComboBox packageChoice = new JComboBox(); JPanel pane = new JPanel(); TextField text = new TextField(5); JButton accept = new JButton("Accept"); JButton decline = new JButton("Decline"); JCheckBox serviceTerms = new JCheckBox("I Agree to the Terms of Service.", false); JTextArea termsOfService = new JTextArea("This is a text area", 5, 10); public JFrameWithPanel() { super("JFrame with Panel"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pane.add(packageChoice); setContentPane(pane); setSize(250,250); setVisible(true); packageChoice.addItem("A+ Certification"); packageChoice.addItem("Network+ Certification "); packageChoice.addItem("Security+ Certifictation"); packageChoice.addItem("CIT Full Test Package"); pane.add(button); button.addActionListener(this); pane.add(text); text.setEditable(false); text.setBackground(Color.WHITE); text.addActionListener(this); pane.add(termsOfService); termsOfService.setEditable(false); termsOfService.setBackground(Color.lightGray); pane.add(serviceTerms); serviceTerms.addItemListener(this); pane.add(accept); accept.addActionListener(this); pane.add(decline); decline.addActionListener(this); } public void actionPerformed(ActionEvent e) { packageIndex = packageChoice.getSelectedIndex(); price = prices[packageIndex]; text.setText("$"+price); Object source = e.getSource(); if(source == accept) { if(serviceTerms.isSelected() == false) { JOptionPane.showMessageDialog(null,"Please accept the terms of service.", "Terms of Service", JOptionPane.ERROR_MESSAGE); } else { JOptionPane.showMessageDialog(null,"Thank you. We will now move on to registering your product."); pane.dispose(); } } else if(source == decline) { System.exit(0); } } public void itemStateChanged(ItemEvent e) { int select = e.getStateChange(); } public static void main(String[] args) { String value1; int constant = 1, invalidNum = 0, answerParse, packNum, packPrice; JOptionPane.showMessageDialog(null,"Hello!"+"\nWelcome to the CIT Test Program."); JOptionPane.showMessageDialog(null,"IT WORKS!"); } }//class How do I get this frame to close so that my JOptionPane Message Dialogs can continue in the program without me exiting the program completely. EDIT: I tried .dispose() but I get this: cannot find symbol symbol : method dispose() location: class javax.swing.JPanel pane.dispose(); ^

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  • Attributes in XML subtree that belong to the parent

    - by Bart van Heukelom
    Say I have this XML <doc:document> <objects> <circle radius="10" doc:colour="red" /> <circle radius="20" doc:colour="blue" /> </objects> </doc:document> And this is how it is parsed (pseudo code): // class DocumentParser public Document parse(Element edoc) { doc = new Document(); doc.objects = ObjectsParser.parse(edoc.getChild("objects")); for ( ...?... ) { doc.objectColours.put(object, colour); } return doc; } ObjectsParser is responsible for parsing the objects bit, but is not and should not be aware of the existence of documents. However, in Document colours are associated with objects by use of a Map. What kind of pattern would you recommend to give the colour settings back to DocumentParser.parse from ObjectsParser.parse so it can associate it with the objects they belong to in a map? The alternative would be something like this: <doc:document> <objects> <circle id="1938" radius="10" /> <circle id="6398" radius="20" /> </objects> <doc:objectViewSettings> <doc:objectViewSetting object="1938" colour="red" /> <doc:objectViewSetting object="6398" colour="blue" /> </doc:objectViewSettings> </doc:document> Ugly!

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  • JCombobox containing enum values inside a table

    - by Edan
    Hello, I have a class containing Enum with values. (names) In other class I would like to enter inside a table a cell type of JCombobox that will use these enums values. my problem is to combain between string values and the enum. for example the enum class: enum item_Type {entree, main_Meal, Dessert, Drink} for example the table class: setTitle("Add new item" ); setSize(300, 80); setBackground( Color.gray ); // Create a panel to hold all other components topPanel = new JPanel(); topPanel.setLayout( new BorderLayout() ); getContentPane().add( topPanel ); //new JComboBox(item_Type.values()); JComboBox aaa = new JComboBox(); aaa = new JComboBox(item_Type.values()); TableColumn sportColumn = table.getColumnModel().getColumn(2); // Create columns names String columnNames[] = {"Item Description", "Item Type", "Item Price"}; // Create some data String dataValues[][] = {{ "0", aaa, "0" }}; // Create a new table instance table = new JTable( dataValues, columnNames ); // Add the table to a scrolling pane scrollPane = new JScrollPane( table ); topPanel.add( scrollPane, BorderLayout.CENTER ); I know that at the dataValues array I cant use aaa (the enum jcombobox). How can I do that? thanks in advance.

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  • Is it possible to prevent out-of-order execution by using single volatile

    - by Yan Cheng CHEOK
    By referring article, it is using a pair of volatile to prevent out-of-order execution. I was wondering, is it possible to prevent it using single volatile? void fun_by_thread_1() { this.isNuclearFactory = true; this.factory = new NuclearFactory(); } void fun_by_thread_2() { Factory _factory = this.factory; if (this.isNuclearFactory) { // Do not operate nuclear factory!!! return; } // If out-of-order execution happens, _factory might // be NuclearFactory instance. _factory.operate(); } Factory factory = new FoodFactory(); volatile boolean isNuclearFactory = false; The reason I ask, is because I have a single guard flag (similar to isNuclearFactory flag), to guard against multiple variables (similar to many Factory). I do not wish to mark all the Factory as volatile. Or, shall I fall into the following solution? void fun_by_thread_1() { try { writer.lock(); this.isNuclearFactory = true; this.factory = new NuclearFactory(); } finally { writer.unlock(); } } void fun_by_thread_2() { try { reader.lock(); Factory _factory = this.factory; if (this.isNuclearFactory) { // Do not operate nuclear factory!!! return; } } finally { reader.unlock(); } _factory.operate(); } Factory factory = new FoodFactory(); boolean isNuclearFactory = false; P/S: I know instanceof. Factory is just an example to demonstrate of out-of-order problem.

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  • Bulding an multi-platform SWT application using Ant

    - by Mridang Agarwalla
    I'm writing an SWT application which can be used on Windows (32/64 bit) and Mac OSX (32/64 bit). Apart from the JRE I rely on the SWT library found here. I can find four versions of the SWT library depending upon my target platforms (as mentioned above). When building my application, how can I compile using the correct SWT Jar? If possible, I'd like to try and avoid hard-coding the Jar version, platform and architecture. The SWT Jars are named like this: swt-win32-x86_64.jar swt-win32-x86_32.jar swt-macosx-x86_32.jar swt-macosx-x86_64.jar (My project will be an open source project. I'd like people to be able to download the source and build it and therefore I've thought of including all the four versions of the SWT Jars in the source distribution. I hope this is the correct approach of publishing code relying on third-part libraries.) Thanks everyone.

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  • how to add hindi language support to struts webapplication.

    - by Vipin Nemade
    Hi, I am creating Web application using the struts 1.2. On which I have to add the Hindi language support to my Web application.I have created the Application_hi.properties file in which I have key equal to Hindi word. But it is giving the error like "some character cannot be map using ISO-8859-1 character encoding". thanks in advance................

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  • Hierarchical data table for JSF2 and RichFaces

    - by Iravanchi
    I'm using RichFaces on my JSF2 application, and I need a way to have something like a tree-column or tree-table. As far as I know, there's no support for such thing in RichFaces. Something's mentioned for RichFaces 4.0, but the priority of this in their plan isn't promising at all, and I don't think that it's going to be included in 4.0. I know there's a tree table available in IceFaces, but I'd rather not add another library to avoid conflicts and learning curve and ... So, I'm looking for the simplest way that I can achieve the same results with minimum efforts, maybe using sub-tables in RichFaces? Any ideas would be appreciated.

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