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  • null pointer exception on list.add

    - by Eric
    I've been working on this one error for a few hours so I thought I'd pick the brains of some pros. I am getting a null pointer exception at the modelData.add(i, es) method. I know from debugging that es isn't null. I'm really confused, thanks. public class EventTableModel extends AbstractTableModel { //private int rowCount = 0; protected List<EventSeat> modelData; private static final int COLUMN_COUNT = 3; private Event e; Event j = GUIpos.m; int i = 1; public EventTableModel(Event e) { this.e = e; try { System.out.println(modelData); for (EventSeat es : e.getEventSeats()) { modelData.add(i, es); i++; } } catch (DataException ex) { Logger.getLogger(EventTableModel.class.getName()).log(Level.SEVERE, null, ex); } }

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  • I want a function to return a type of the subclass its invoked from

    - by Jay
    I want to have a function defined in a superclass that returns a value of the type of the subclass that is used to invoke the function. That is, say I have class A with a function plugh. Then I create subclasses B and C that extend A. I want B.plugh to return a B and C.plugh to return a C. Yes, they could return an A, but then the caller would have to either cast it to the right subtype, which is a pain when used a lot, or declare the receiving variable to be of the supertype, which loses type safety. So I was trying to do this with generics, writing something like this: class A<T extends A> { private T foo; public T getFoo() { return foo; } } class B extends A<B> { public void calcFoo() { foo=... whatever ... } } class C extends A<C> { public void calcFoo() { foo=... whatever ... } } This appears to work but it looks pretty ugly. For one thing, I get warnings on "class A". The compiler says that A is generic and I should specify the type. I guess it wants me to say "class A". But what would I put in for x? I think I could get stuck in an infinite loop here. It seems weird to write "class B extends A", but this causes no complaints, so maybe that's just fine. Is this the right way to do it? Is there a better way?

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  • How do I change the build's SDK version in Xcode?

    - by Kavon Farvardin
    I'm using Xcode 2.5 on Mac 10.4.11 PPC. javac -version returns 1.5.x yet when I imported my source code and tried to build it in Xcode, I get errors all over because generics, annotations, and for-each loops are not supported in -source 1.3. I thought I found the setting to change the source version in Xcode in the above but it doesn't work. Any ideas?

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  • Best way to reuse a Runnable

    - by Gandalf
    I have a class that implements Runnable and am currently using an Executor as my thread pool to run tasks (indexing documents into Lucene). executor.execute(new LuceneDocIndexer(doc, writer)); My issue is that my Runnable class creates many Lucene Field objects and I would rather reuse them then create new ones every call. What's the best way to reuse these objects (Field objects are not thread safe so I cannot simple make them static) - should I create my own ThreadFactory? I notice that after a while the program starts to degrade drastically and the only thing I can think of is it's GC overhead. I am currently trying to profile the project to be sure this is even an issue - but for now lets just assume it is.

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  • How to use ASTRewrite split one field declaration into two?

    - by user307598
    For example: private long p, q, g, h; I want to split this field declaration as: private long p; private long q, g, h; How can I use ASTRewrite to do it? I tried to use ASTNode copyFd = rewriter.createCopyTarget(fd) to copy the field declaration, modify it, then add to field declaration list, but my modification on copyFd is not seen. It's just the same to fd. Why? Anybody can help?

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  • what's the difference between DEFAULT_SIZE and PREFERRED_SIZE?

    - by CD1
    hi, I'm using Swing GroupLayout and I'm confused about the values GroupLayout.DEFAULT_SIZE and GroupLayout.PREFERRED_SIZE. I never know when to use each one of them in methods like GroupLayout.addComponent(Component, int, int, int). suppose I have this code: GroupLayout l = ...; l.setHorizontalGroup(l.createSequentialGroup() .addComponent(tf1) .addComponent(tf2)); l.setVerticalGroup(l.createParallelGroup() .addComponent(tf1) .addComponent(tf2)); there are two JTextFields on a single line laid out with GroupLayout (one sequential group horizontally and one parallel group vertically). if I resize the window now, both components get the available space (50% each). but I want only the first text field to grow/shrink horizontally and only the second text field to grow/shrink vertically. what values of min, pref and max should I use to accomplish that? I know I can just try it and see what combination works but I'd like to know the reasoning behind this problem.

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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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  • Does it mean JVM Suspended?

    - by Joe.wang
    When my application run . I got a message says : Ping: Timed out waiting for signal from JVM. The JVM was launched with debug options so this may be because the JVM is currently suspended by a debugger. Any future timeouts during this JVM invocation will be silently ignored. What does that mean? It seems it will block any web request from outside? because when I upload a file to it, it failed. help me .

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  • Using an unencoded key vs a real Key, benefits?

    - by user246114
    Hi, I am reading the docs for Key generation in app engine. I'm not sure what effect using a simple String key has over a real Key. For example, when my users sign up, they must supply a unique username: class User { /** Key type = unencoded string. */ @PrimaryKey private String name; } now if I understand the docs correctly, I should still be able to generate named keys and entity groups using this, right?: // Find an instance of this entity: User user = pm.findObjectById(User.class, "myusername"); // Create a new obj and put it in same entity group: Key key = new KeyFactory.Builder( User.class.getSimpleName(), "myusername") .addChild(Goat.class.getSimpleName(), "baa").getKey(); Goat goat = new Goat(); goat.setKey(key); pm.makePersistent(goat); the Goat instance should now be in the same entity group as that User, right? I mean there's no problem with leaving the User's primary key as just the raw String? Is there a performance benefit to using a Key though? Should I update to: class User { /** Key type = unencoded string. */ @PrimaryKey private Key key; } // Generate like: Key key = KeyFactory.createKey( User.class.getSimpleName(), "myusername"); user.setKey(key); it's almost the same thing, I'd still just be generating the Key using the unique username anyway, Thanks

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  • Invisible JFrame/JTable how much faster ?

    - by chacko
    I have a swing app. with a jframe with lots of internal frames containing large JTable. Those jtables get updated continuously so there is lots of repainting going on. in some circumstances I can simply keep the JFrame invisible. (frame.setVisible(false)) I was wondering if anybody knows if I will gain something in terms of performance (something considerable or not) such as 50% gain or you would only get 2% gain... and maybe some sort of explaination on what to expect. thanks

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  • Update rich:dataTable binding on Ajax selectionchange

    - by MilkJug
    I want to find the current selection of the data table whenever a selection changes. I can update other items using: <a4j:ajax render=":tmp,:tmp2" event="selectionchange"> But I cannot find the current selection - I think the major issue is that the UIExtendedDataTable backing does not get updated on the Ajax request. Is there a way to update the current selection on a selectionchange (Using RichFaces 4)?

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  • @Unique doesn't have any effect in DataNucleus w/ NeoDatis

    - by David Parks
    Using JDO / DataNucleus / NeoDatis datastore I added @Unique to a field of a persistable object, however I am allowed to create multiple objects which violate the unique constraint. The docs for DataNucleus/NeoDatis suggest that Unique fields are supported. @PersistenceCapable public class User { @Persistent @Unique private String username; //... } If I add multiple objects to the DB with the same username there's no problem doing so. :(

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  • How to inspect JSP request URL for String

    - by IAmYourFaja
    I have the following processor.jsp file: <% response.sendRedirect("http://buzz.example.com"); %> I want to change it so that it inspects the HTTP request URL for the presence of the word "fizz" and, if it exists, redirect the user to http://fizz.example.org instead. So something like: <% String reqUrl = request.getURL().toLowerCase(); String token = null; if(reqUrl.contains("fizz")) { token = "fizz"; } else { token = "buzz"; } String respUrl = "http://%%%TOKEN%%%.example.com".replace("%%%TOKEN%%%", token); response.sendRedirect(respUrl); %> However this doesn't work. Any ideas on what I should be using instead of request, or if I'm doing anything else wrong?

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  • Move and rename file in android

    - by Andre Fróes
    I am trying to copy a file to another folder in the android, but so far, i got no success. I manage to do so with a selected image and when taking a photo, but not with files. I've read and tried several solutions passed by the community (searched over the forum and the internet), but none of it was able to solve my problem when copying. First things first. I added the permissions to my manifest: <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> after that, before copying a file, i print its filepath and the directory file path: 06-10 11:11:11.700: I/System.out(1442): /mimetype/storage/sdcard/Misc/Javascript erros for Submit and Plan buttons in IE.doc 06-10 11:11:11.710: I/System.out(1442): /storage/sdcard/mywfm/checklist-files both exists: to copy the file to the expected folder I used the FileUtils: try { FileUtils.copyFile(selectedFile, dir); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } The problem is: I get no exception and the file isn't there. I tried this solution either: How to move/rename file from internal app storage to external storage on Android? same thing, no exception, but no file either.

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  • hibernate restrictions.in with and, how to use?

    - by cometta
    I have table like below id, employee_no, survey_no, name 1 test 1 test_name 2 test2 1 test_name2 3 test3 1 test_name3 4 test4 2 test_name4 how to query with Restriction.in by combining below AND into one IN statement? IN[ (if(survey_no==1) && employee_no== 'test') , (if(survey_no==1) && employee_no== 'test2') , ... ]

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  • how can i refresh table content without refreshing all the page

    - by gin
    i have a table and the content of it is all from data base ,which is a rows of student names and a columns of questions, and with this table an instructor can track the students progress of solving question on real time, so what i want is to update the only the table , without refreshing the whole page, which causes starting at the beginning of the page so it would distract the instructor,, any suggestion

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  • Why does this compile?

    - by akf
    I was taken aback earlier today when debugging some code to find that something like the following does not throw a compile-time exception: public Test () { HashMap map = (HashMap) getList(); } private List getList(){ return new ArrayList(); } As you can imagine, a ClassCastException is thrown at runtime, but can someone explain why the casting of a List to a HashMap is considered legal at compile time?

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  • need to clean malformed tags using regular expression

    - by Brian
    Looking to find the appropriate regular expression for the following conditions: I need to clean certain tags within free flowing text. For example, within the text I have two important tags: <2004:04:12 and . Unfortunately some of tags have missing "<" or "" delimiter. For example, some are as follows: 1) <2004:04:12 , I need this to be <2004:04:12> 2) 2004:04:12>, I need this to be <2004:04:12> 3) <John Doe , I need this to be <John Doe> I attempted to use the following for situation 1: String regex = "<\\d{4}-\\d{2}-\\d{2}\\w*{2}[^>]"; String output = content.replaceAll(regex,"$0>"); This did find all instances of "<2004:04:12" and the result was "<2004:04:12 ". However, I need to eliminate the space prior to the ending tag. Not sure this is the best way. Any suggestions. Thanks

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  • A file is being http posted, how can I reference the parameter by index?

    - by Blankman
    An XML file is being posted to a url that my spring mvc is responding to. In .NET, I could do this: request.Form[0] request.Form["abc"] or request.QueryString[0] request.QueryString["some_key"] Now with spring/servlets it seems I can only do this: request.getParameter("some_key") or get all the names or values. When someone is posting a file to a url, using http post, won't this be just a single request parameter then? Can I get the parameter using index with servlets?

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