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  • JPanel: both implementing my own paintComponent() and rendering children doesn't work

    - by Paul Marshall
    I'm extending a JPanel to display a game board, and adding a JEditorPane at the bottom to hold some status text. Unfortunately, the game board renders just fine, but the JEditorPane is just a blank gray area until I highlight the text in it, when it will render whatever text is highlighted (but not the rest). If I'm understanding Swing right, it should work, because super.paintComponent(g) should render the other children (i.e., the JEditorPane). Tell me, o great stackoverflow, what bonehead mistake am I making? public GameMap extends JPanel { public GameMap() { JEditorPane statusLines = new JEditorPane("text/plain","Stuff"); this.setLayout(new BoxLayout(this,BoxLayout.PAGE_AXIS)); this.add(new Box.Filler(/*enough room to draw my game board*/)); this.add(statusLines); } public void paintComponent(Graphics g){ super.paintComponent(g); for ( all rows ){ for (all columns){ //paint one tile } } } }

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  • What does these FindBug messages show?

    - by Hans Klock
    Not every description from from http://findbugs.sourceforge.net/bugDescriptions.html is clear to me. Sure, I can study the implementation but if somebody is more experienced then me, some explanation and examples would be great. Do you have some examples for UI_INHERITANCE_UNSAFE_GETRESOURCE when this is getting a problem? In BX_UNBOXED_AND_COERCED_FOR_TERNARY_OPERATOR I don't see the problem either. If one type is "bigger" then the other, for example int and float, then the result is float. If its Integer and Float its the wrapper Float too. That's what I expect. Does the GC_UNRELATED_TYPES really help to find errors? Isn't it the job of the compiler to check, if--taking the given example--Foo can't go into a Collection<String>. Does HE_SIGNATURE_DECLARES_HASHING_OF_UNHASHABLE_CLASS mean something like bla(Foo f){hashtable.put(f);}, where ´Foo´ is not hashable? Does FingBugs "see" the subclasses too? NP_GUARANTEED_DEREF_ON_EXCEPTION_PATH is stronger "wrong" then NP_ALWAYS_NULL_EXCEPTION? Why two error cases and with NP_NULL_ON_SOME_PATH_EXCEPTION even one more? Sounds very similar to me. What is an example of SIO_SUPERFLUOUS_INSTANCEOF? Something like foo(String s){if (s intenceof String) .... This does a null check too, but this is not the test here... NN_NAKED_NOTIFY. I my opinion the description is not clear. A change of the state is not necessary. If I use new Object() to wait and notify on I don't change the object state. Or is state the lock-state? I don't get it. SP_SPIN_ON_FIELD. Can this really happen that a compiler will move this outside from a loop? This doesn't make sense to me because from outside a Thread can always change the values. And if the variable is volatile the JVM can't cache the value. So what's the meaning? That is the difference between STCAL_STATIC_CALENDAR_INSTANCE and STCAL_INVOKE_ON_STATIC_CALENDAR_INSTANCE or STCAL_INVOKE_ON_STATIC_DATE_FORMAT_INSTANCE/STCAL_STATIC_SIMPLE_DATE_FORMAT_INSTANCE? Why is XXXX.class in WL_USING_GETCLASS_RATHER_THAN_CLASS_LITERAL better then getClass()? A getClass() in a superclass called from the subclass will always return the Class object from the subclass which is good I think. What exactly does EQ_UNUSUAL do? It should check that the argument is of the same type of the class itself but it does't? Did you ever had problems with breaks? Is there real value with SF_SWITCH_FALLTHROUGH? Sounds to strong for me. No idea what TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_ALWAYS_SINK and TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_NEVER_SINK could be.

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  • How do I left join tables in unidirectional many-to-one in Hibernate?

    - by jbarz
    I'm piggy-backing off of http://stackoverflow.com/questions/2368195/how-to-join-tables-in-unidirectional-many-to-one-condition. If you have two classes: class A { @Id public Long id; } class B { @Id public Long id; @ManyToOne @JoinColumn(name = "parent_id", referencedColumnName = "id") public A parent; } B - A is a many to one relationship. I understand that I could add a Collection of Bs to A however I do not want that association. So my actual question is, Is there an HQL or Criteria way of creating the SQL query: select * from A left join B on (b.parent_id = a.id) This will retrieve all A records with a Cartesian product of each B record that references A and will include A records that have no B referencing them. If you use: from A a, B b where b.a = a then it is an inner join and you do not receive the A records that do not have a B referencing them. I have not found a good way of doing this without two queries so anything less than that would be great. Thanks.

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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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  • Element to string in HTMLDocument

    - by kalpesh
    i have a Element object its a HTMLDocument object and i want to string value of this element. i want this result Christina Toth, Pharm. D. ======================= plz see below code. public static void main(String args[]) throws Exception { InputStream is = Nullsoft.getInputStream(); InputStreamReader isr = new InputStreamReader(is); BufferedReader br = new BufferedReader(isr); HTMLEditorKit htmlKit = new HTMLEditorKit(); HTMLDocument htmlDoc = (HTMLDocument) htmlKit.createDefaultDocument(); HTMLEditorKit.Parser parser = new ParserDelegator(); HTMLEditorKit.ParserCallback callback = htmlDoc.getReader(0); parser.parse(br, callback, true); // Parse ElementIterator iterator = new ElementIterator(htmlDoc); Element element; while ((element = iterator.next()) != null) { AttributeSet attributes = element.getAttributes(); Object name = attributes.getAttribute(StyleConstants.NameAttribute); if ((name instanceof HTML.Tag) && ((name == HTML.Tag.DIV) || (name == HTML.Tag.H2) || (name == HTML.Tag.H3))) { StringBuffer text = new StringBuffer(); int count = element.getElementCount(); for (int i = 0; i < count; i++) { Element child = element.getElement(i); AttributeSet childAttributes = child.getAttributes(); // if (childAttributes.getAttribute(StyleConstants.NameAttribute) == HTML.Tag.CONTENT) { int startOffset = child.getStartOffset(); int endOffset = child.getEndOffset(); int length = endOffset - startOffset; text.append(htmlDoc.getText(startOffset, length)); } } System.out.println(name + ": " + text.toString()); } } System.exit(0); } public static InputStream getInputStream() { String text = "<html>\n" + "<head>\n" + "<title>pg_0001</title>\n" + "\n" + "<style type=\"text/css\">\n" + ".ft3{font-style:normal;font-weight:bold;font-size:11px;font-family:Helvetica;color:#000000;}\n" + "</style>\n" + "</head>\n" + "<body vlink=\"#FFFFFF\" link=\"#FFFFFF\" bgcolor=\"#ffffff\">\n" + "\n" + "\n" + "<div style=\"position:absolute;top:597;left:252\"><nobr><span class=\"ft3\">Christina Toth, Pharm. D.</span></nobr></div>\n" + "\n" + "\n" + "</body>\n" + "</html>"; InputStream is = null; try { is = new ByteArrayInputStream(text.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } return is; }

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  • Logic for controll concurrent in block/method

    - by Hlex
    1)My environment is web application, I develop servlet to receive request. A) In some block/method i want to control concurrent to not greater than 5 B) if there are 5 request in that block , the new coming must wait up to 60 second then throws error C) if there are sleep/waiting request more then 30, the 31th request will be throwed an error How I do this? 2)(Optional Question) from above I have to distribute control logic to all clustered host. I plan to use hazelcast to share the control logic (e.g. current counter) I see they provide BlockingQueue & ExectorService but I have no idea how to use in my case. Please recommend if you have idea.

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  • Counting viable sublist lengths from an array.

    - by Ben B.
    This is for a genetic algorithm fitness function, so it is important I can do this as efficiently as possible, as it will be repeated over and over. Lets say there is a function foo(int[] array) that returns true if the array is a "good" array and false if the array is a "bad" array. What makes it good or bad does not matter here. Given the full array [1,6,8,9,5,11,45,16,9], lets say that subarray [1,6,8] is a "good" array and [9,5,11,45] is a "good" array. Furthermore [5,11,45,16,9] is a "good" array, and also the longest "good" subarray. Notice that while [9,5,11,45] is a "good" array, and [5,11,45,16,9] is a "good" array, [9,5,11,45,16,9] is a "bad" array. We wants the length counts of all "good" arrays, but not subarrays of "good" arrays. Furthermore, as described above, a "good" array might begin in the middle of another "good" array, but the combination of the two might be a "bad" array.

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  • Draw a position from a 2d Array on respected canvas location

    - by Anon
    Background: I have two 2d arrays. Each index within each 2d array represents a tile which is drawn on a square canvas suitable for 8 x 8 tiles. The first 2d array represents the ground tiles and is looped and drawn on the canvas using the following code: //Draw the map from the land 2d array map = new Canvas(mainFrame, 20, 260, 281, 281); for(int i=0; i < world.length; i++){ for(int j=0; j < world[i].length; j++){ for(int x=0; x < 280; x=x+35){ for(int y=0; y < 280; y=y+35){ Point p = new Point(x,y); map.add(new RectangleObject(p,35,35,Colour.green)); } } } } This creates a grid of green tiles 8 x 8 across as intended. The second 2d array represents the position on the ground. This 2d array has everyone of its indexes as null apart from one which is comprised of a Person class. Problem I am unsure of how I can draw the position on the grid. I was thinking of a similar loop, so it draws over the previous 2d array another set of 64 tiles. Only this time they are all transparent but the one tile which isn't null. In other words, the tile where Person is located. I wanted to use a search throughout the loop using a comparative if statement along the lines of if(!(world[] == null)){ map.add(new RectangleObject(p,35,35,Colour.red));} However my knowledge is limited and I am confused on how to implement it.

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  • Native functions throw UnsatisfiedLinkError in custom view, despite working in main activity

    - by Mark Ingram
    For some reason I can only call native functions from my main activity and not any custom views that I've created. Here is an example file (I followed a tutorial, but renamed the classes http://mindtherobot.com/blog/452/android-beginners-ndk-setup-step-by-step/) See the usage of the native function "getNewString". package com.example.native; import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.os.Bundle; import android.view.View; public class NativeTestActivity extends Activity { static { System.loadLibrary("nativeTest"); } private native String getNewString(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.setContentView(new BitmapView(this)); String hello = getNewString(); // This line works fine new AlertDialog.Builder(this).setMessage(hello).show(); } } class BitmapView extends View { static { System.loadLibrary("nativeTest"); } private native String getNewString(); public BitmapView(Context context) { super(context); String hello = getNewString(); // This line throws the UnsatisfiedLinkError new AlertDialog.Builder(this.getContext()).setMessage(hello).show(); } } How can I call native functions in my custom views? I've built the application as an Android 2.2 app. I'm running the application on my HTC Desire. I have the latest SDK (9) and latest NDK (r5).

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  • Efficient representation of Hierarchies in Hibernate.

    - by Alison G
    I'm having some trouble representing an object hierarchy in Hibernate. I've searched around, and haven't managed to find any examples doing this or similar - you have my apologies if this is a common question. I have two types which I'd like to persist using Hibernate: Groups and Items. * Groups are identified uniquely by a combination of their name and their parent. * The groups are arranged in a number of trees, such that every Group has zero or one parent Group. * Each Item can be a member of zero or more Groups. Ideally, I'd like a bi-directional relationship allowing me to get: * all Groups that an Item is a member of * all Items that are a member of a particular Group or its descendants. I also need to be able to traverse the Group tree from the top in order to display it on the UI. The basic object structure would ideally look like this: class Group { ... /** @return all items in this group and its descendants */ Set<Item> getAllItems() { ... } /** @return all direct children of this group */ Set<Group> getChildren() { ... } ... } class Item { ... /** @return all groups that this Item is a direct member of */ Set<Group> getGroups() { ... } ... } Originally, I had just made a simple bi-directional many-to-many relationship between Items and Groups, such that fetching all items in a group hierarchy required recursion down the tree, and fetching groups for an Item was a simple getter, i.e.: class Group { ... private Set<Item> items; private Set<Group> children; ... /** @return all items in this group and its descendants */ Set<Item> getAllItems() { Set<Item> allItems = new HashSet<Item>(); allItems.addAll(this.items); for(Group child : this.getChildren()) { allItems.addAll(child.getAllItems()); } return allItems; } /** @return all direct children of this group */ Set<Group> getChildren() { return this.children; } ... } class Item { ... private Set<Group> groups; /** @return all groups that this Item is a direct member of */ Set<Group> getGroups() { return this.groups; } ... } However, this resulted in multiple database requests to fetch the Items in a Group with many descendants, or for retrieving the entire Group tree to display in the UI. This seems very inefficient, especially with deeper, larger group trees. Is there a better or standard way of representing this relationship in Hibernate? Am I doing anything obviously wrong or stupid? My only other thought so far was this: Replace the group's id, parent and name fields with a unique "path" String which specifies the whole ancestry of a group, e.g.: /rootGroup /rootGroup/aChild /rootGroup/aChild/aGrandChild The join table between Groups and Items would then contain group_path and item_id. This immediately solves the two issues I was suffering previously: 1. The entire group hierarchy can be fetched from the database in a single query and reconstructed in-memory. 2. To retrieve all Items in a group or its descendants, we can select from group_item where group_path='N' or group_path like 'N/%' However, this seems to defeat the point of using Hibernate. All thoughts welcome!

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  • Safe to pass objects to C functions when working in JNI Invocation API?

    - by bubbadoughball
    I am coding up something using the JNI Invocation API. A C program starts up a JVM and makes calls into it. The JNIenv pointer is global to the C file. I have numerous C functions which need to perform the same operation on a given class of jobject. So I wrote helper functions which take a jobject and process it, returning the needed data (a C data type...for example, an int status value). Is it safe to write C helper functions and pass jobjects to them as arguments? i.e. (a simple example - designed to illustrate the question): int getStatusValue(jobject jStatus) { return (*jenv)->CallIntMethod(jenv,jStatus,statusMethod); } int function1() { int status; jobject aObj = (*jenv)->NewObject (jenv, aDefinedClass, aDefinedCtor); jobject j = (*jenv)->CallObjectMethod (jenv, aObj, aDefinedObjGetMethod) status = getStatusValue(j); (*jenv)->DeleteLocalRef(jenv,aObj); (*jenv)->DeleteLocalRef(jenv,j); return status; } Thanks.

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  • Using a Session Scoped Bean

    - by jboyd
    The following code is returning null: private MyAppUser getMyAppUser(HttpSession session) { MyAppUser myAppUser = (MyAppUser) session.getAttribute("myAppUserManager"); return myAppUser; } Despite the fact that I have the following in my context: <bean id="myAppUserManager" class="com.myapp.profile.MyAppUser" scope="session"/> This doesn't make any sense to me, the "myAppUser" bean is a bean that absolutely can never be null, and I need to be able to reference it from controllers, I don't need it in services or repositories, just controllers, but it doesn't seem to be getting stored in the session, the use case is extremely simple, but I haven't been able to get to the bottom of what's wrong, or come up with a good workaround

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  • Use continue or Checked Exceptions when checking and processing objects

    - by Johan Pelgrim
    I'm processing, let's say a list of "Document" objects. Before I record the processing of the document successful I first want to check a couple of things. Let's say, the file referring to the document should be present and something in the document should be present. Just two simple checks for the example but think about 8 more checks before I have successfully processed my document. What would have your preference? for (Document document : List<Document> documents) { if (!fileIsPresent(document)) { doSomethingWithThisResult("File is not present"); continue; } if (!isSomethingInTheDocumentPresent(document)) { doSomethingWithThisResult("Something is not in the document"); continue; } doSomethingWithTheSucces(); } Or for (Document document : List<Document> documents) { try { fileIsPresent(document); isSomethingInTheDocumentPresent(document); doSomethingWithTheSucces(); } catch (ProcessingException e) { doSomethingWithTheExceptionalCase(e.getMessage()); } } public boolean fileIsPresent(Document document) throws ProcessingException { ... throw new ProcessingException("File is not present"); } public boolean isSomethingInTheDocumentPresent(Document document) throws ProcessingException { ... throw new ProcessingException("Something is not in the document"); } What is more readable. What is best? Is there even a better approach of doing this (maybe using a design pattern of some sort)? As far as readability goes my preference currently is the Exception variant... What is yours?

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  • Getting a nicely formatted timestamp without lots of overhead?

    - by Brad Hein
    In my app I have a textView which contains real-time messages from my app, as things happen, messages get printed to this text box. Each message is time-stamped with HH:MM:SS. Up to now, I had also been chasing what seemed to be a memory leak, but as it turns out, it's just my time-stamp formatting method (see below), It apparently produces thousands of objects that later get gc'd. For 1-10 messages per second, I was seeing 500k-2MB of garbage collected every second by the GC while this method was in place. After removing it, no more garbage problem (its back to a nice interval of about 30 seconds, and only a few k of junk typically) So I'm looking for a new, more lightweight method for producing a HH:MM:SS timestamp string :) Old code: /** * Returns a string containing the current time stamp. * @return - a string. */ public static String currentTimeStamp() { String ret = ""; Date d = new Date(); SimpleDateFormat timeStampFormatter = new SimpleDateFormat("hh:mm:ss"); ret = timeStampFormatter.format(d); return ret; }

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  • Stub generator utility

    - by Wasim
    Hi all , I'm generating a stub service client for remote web service by the Wireless toolkit Stub Generator utility. I need to add for every class generated to imlement a certain interface . When I do it by hand every time I generate a gain it override my changes. Is there away to customise the stub generator code creating or other way to achieve my task Thanks in advance ...

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  • Add objects to Arraylist inside loop and get a list of them outside loops

    - by AgusDG
    Im already done with a method to do a shot on a board (bidimensional array). THe shot goes from the bottom to the top, and depending of the direction, it do bounces on the walls to get to the top. The thing is that I did the method to represent the trayectory with an 'x'. Now, I want to add the coordinates x and y of each position of the shot (b [x][y]) to and Arraylist of Objects Position. public Position(int row,int col) { this.row = row; this.col = col; } The thing is that the method uses a for loop and inside if loops, and I'll need to create the objects inside, and get them outside. I did that : public static ArrayList<Position> showTrayectory (char [][] b , int shotDirection, char bubble){ int row = 0, col = 0; ArrayList<Position> aListPos = new ArrayList<Position>(); Position positionsOfShot = new Position(row,col); START = ((RIGHT_WALL)/2) + shotDirection; boolean shotRight = false; if(shotDirection < 0) shotRight = false; else if(shotDirection > 0) shotRight = true; for(int y = BOTTOM,x = START ;y >= 0;y--) { if(!isOut(y,x) && !emptyCell(y,x)) break; if(x <= LEFT_WALL) shotRight = true; if(x >= RIGHT_WALL) shotRight = false; if(!isOut(y,x) && shotRight == true) { positionsOfShot = new Position(y,x); aListPos.add(positionsOfShot); b[y][x] = SHOT; ++x; } if(!isOut(y,x) && shotRight == false){ positionsOfShot = new Position(y,x); aListPos.add(positionsOfShot); b[y][x] = SHOT; --x; } } // The nested for loops below are for showing the positions // But I dont need it that way // I must get the trayectory from an ArrayList and print it from there for(int y=0;y < b.length;y++){ System.out.println(); for(int x=0;x < b[y].length;x++){ System.out.print(" "+b [y][x]+" "); } } System.out.println("\nTrayectory of the shot ["+shotDirection+"]"); System.out.println("Next bubble ["+bubble+"]"); for( Position ii : aListPos){ System.out.println("(" + positionsOfShot.getFila() + "," + positionsOfShot.getColumna()+")"); } return aListPos; } The sentence " b[y][x] = SHOT; " is still there, to see the proper trayectory of the shot (its not needed that way), but what I need, is getting the trayectory in an ArrayList, and print the trayectory from there. All that I get is a wrong position, and repeated during the number of positions the shot goes through. I need some help. I suppose the problem is that Im creating and adding Position Objects inside an ArrayList inside loops, but in a wrong way. I will need you to explain me how to do it properly ; ) Thanks in advance. I'll add the output for you see better what is that above haha *************************** y b y b g r b g o y g a a r y o y y r b y g r r o b o y y g b a r y r o a y y o o r r g r - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - - - x - - - - - - - x - - - - - - - x - - - - - - - x - - - Trayectory of the shot [1] Next bubble [y] (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) (5,3) Action?

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  • Nhibernate fires SQL commands

    - by Chris
    Hi all, when updating an entity A, NHibernate also send an SQL update command for some other entity B. A and B are not related. Just before saving entity A, the parent of entity B is loaded via a SQLQuery. Then, when accessed, B is lazy loaded (part of a collection). If I save entity A an update statement for entity B is generated as well. How can that be, that when saving an entity, another entity loaded before but is not related to the entity saved, is updated as well?! Can I somehow track where the update comes from? Btw. I am using an save event listener. Could it be that this is always triggered for entity loaded, even though they are not saved explicitly? public class EntitySaveEventListener : NHibernate.Event.Default.DefaultSaveEventListener { protected override object PerformSaveOrUpdate(SaveOrUpdateEvent e) { //auditing return base.PerformSaveOrUpdate(e); } } Update (sorry for providing not enough info): I tracked it down a bit. A select stateement on a entity called address is executed (is it lazy loaded by a parent). Then I create a new entity called Request. Right before saving this entity a session flush is called which updates the address, even though I did not call save or update on the address. Address is a collection within Request. <class name="Request" table="Request"> <bag name="addresses" access="field" cascade="all-delete-orphan" where="IsDeleted = 0"> <key column="RequestId"/> <one-to-many class="Address"/> </bag> ... // address is fetched only NHibernate.SQL: 2010-02-17 11:47:21,306 [21] DEBUG NHibernate.SQL [(null)] - SELECT addresses0_.RequestId as ServiceP8_3_, .... // session flushed here // address is updated NHibernate.SQL: 2010-02-17 11:47:34,306 [21] DEBUG NHibernate.SQL [(null)] - Batch commands: command 0:UPDATE Address SET Street = @p0, ..... Would the address be updated automatically when it is manipulated somehow even though it is not explicitly saved via it's parent (cascade)?

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  • Implementing tagging in JDO

    - by Julie Paltrow
    I am implementing a tagging system for a website that uses JDO . I would like to use this method. However I am new to relationships in JDO. To keep it simple, what I have looks like this: @PersistentCapable class Post { @Persistent String title; @Persistent String body; } @PersistentCapable class Tag { @Persistent String name; } What kind of JDO relationships do I need and how to implement them? I want to be able to list all Tags that belong to a Post, and also be able to list all Posts that have a given Tag. So in the end I would like to have something like this: Table: Post Columns: PostID, Title, Body Table: Tag Columns: TagID, name Table: PostTag Columns: PostID, TagID

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  • 500 Worker Threads, what kind of thread pool?

    - by Submerged
    I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } The code that is executing is really simple and basically just this class aThread extends Thread { public void run(){ while(true){ Thread.sleep(ONE_MINUTE); //Lots of computation every minute } } } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful! Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"

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  • Semantic stuff (RDF, OWL) on mobile phones - is it possible?

    - by Brian Schimmel
    I'm thinking about using semantic (web) technogies like RDF and OWL in an application on mobile devices. Currently I'm targeting android, but I'd also be interested in the possibilities on the iPhone and on J2ME. I would like to use a lib instead of implementing everything from scratch. I know that there are some libraries and frameworks like Jena, Redland, Protégé but they don't state on which platforms they are known to work. Having a dynamic object model and parsing from and to XML are must-haves for me. I'd also like to use reasoning, but I've been told it was rather computing-intensive, so that's only a nice-to-have. For all platforms mentioned, the question can be interpreted as Is it possible in theory (especially for J2ME I'm not sure) Are there libs that are known to work on those platforms? Is the performance on a mobile platform good enough for real world usage?

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  • Assigning an @Annotation enum a value

    - by h2g2java
    I created enum Restrictions{ none, enumeration, fractionDigits, length, maxExclusive, maxInclusive, maxLength, minExclusive, minInclusive, minLength, pattern, totalDigits, whiteSpace; public Restrictions setValue(int value){ this.value = value; return this; } public int value; } So that I could happily do something like this, which is perfectly legal syntax. Restrictions r1 = Restrictions.maxLength.setValue(64); The reason being is, I am using enum to restrict the type of restriction that could be used, and be able to assign a value to that restriction. However, my actual motivation is to use that restriction in an @annotation. @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD}) public @interface Presentable { Restrictions[] restrictions() default Restrictions.none; } So that, I intended to do this: @Presentable(restrictions=Restrictions.maxLength.setValue(64)) public String userName; to which, the compiler croaks The value for annotation enum attribute must be an enum constant expression. Is there a way to accomplish what I wish to accomplish

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