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  • OpenGL gluLookAt issues

    - by Chris D
    I am trying to switch my space invaders game to a first person view, i.e. a view of the world from the ship. I am getting a bit confused about what point I should be looking at. I am currently using these parameters in gluLookAt: GL11.glMatrixMode(GL11.GL_MODELVIEW); GL11.glLoadIdentity(); GLU.gluLookAt(ship3dPos.x, ship3dPos.y, ship3dPos.z,400.0f, 600.0f,-50.0f, 0.0f, 1.0f,-0.0f); Where ship3dPos is a Vector3f. I'm not sure what I'm supposed to set parameters 4,5 and 6 to, to get a view of the whole world(window is 800/600). I want to have a view of say 100.0 wide from the ships perspective, with this view moving along the x-axis as the player moves the ship. Thanks

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  • Hibernate is performing unwanted SELECTs on call to saveOrUpdate

    - by digiarnie
    Let's say I have a House entity which maps to many Person entities. I then load an existing House which has 20 occupants. beginTransaction(); House house = houseDao.find(1L); commitTransaction(); Later in the code, I can then add a new Person to the House: ... List<Person> people = house.getPeople(); people.add(new Person("Dilbert")); .... When I make the call: session.saveOrUpdate(house); Hibernate performs 21 queries: 1 to SELECT the House and 20 to SELECT each existing Person in the House. I'm sure it's a small issue on my part, however, what should I do so that I can add a new Person to the house without having such a heavy hit on the database in this situation? This is all done within the same session.

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  • copy child collection to another object

    - by Bogdan
    Hi everyone, I have a one-to-many relationship between Part and Params (a "Part" has many "Params). I'm trying to do something naive like this: Part sourcePart = em.find(Part.class, partIdSource); Part destPart = em.find(Part.class, partIdDest); Collection<Param> paramListSource = sourcePart.getParamList(); destPart.setParamList(paramListSource); Basically I want to copy all the parameters from sourcePart to destPart. Hopefully the persistence provider will automatically set the right foreign keys in the Param table/entity. The above code will obviously not work. Is there any easy way of doing this, or do I have to do create a new collection, then add each Param (creating new Param, setting attributes, etc) ?

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  • FindBugs and CheckForNull on classes vs. interfaces

    - by ndn
    Is there any way to let FindBugs check and warn me if a CheckForNull annotation is present on the implementation of a method in a class, but not on the declaration of the method in the interface? import javax.annotation.CheckForNull; interface Foo { public String getBar(); } class FooImpl implements Foo { @CheckForNull @Override public String getBar() { return null; } } public class FindBugsDemo { public static void main(String[] args) { Foo foo = new FooImpl(); System.out.println(foo.getBar().length()); } } I just discovered a bug in my application due to a missing null check that was not spotted by FindBugs because CheckForNull was only present on FooImpl, but not on Foo, and I don't want to spot all other locations of this problem manually.

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  • Why new String(bytes, enc).getBytes(enc) does not return the original byte array?

    - by Bozho
    I made the following "simulation": byte[] b = new byte[256]; for (int i = 0; i < 256; i ++) { b[i] = (byte) (i - 128); } byte[] transformed = new String(b, "cp1251").getBytes("cp1251"); for (int i = 0; i < b.length; i ++) { if (b[i] != transformed[i]) { System.out.println("Wrong : " + i); } } For cp1251 this outputs only one wrong byte - at position 23. For KOI8-R - all fine. For cp1252 - 4 or 5 differences. What is the reason for this and how can this be overcome? I know it is wrong to represent byte arrays as strings in whatever encoding, but it is a requirement of the protocol of a payment provider, so I don't have a choice. Update: representing it in ISO-8859-1 works, and I'll use it for the byte[] part, and cp1251 for the textual part, so the question remains only out of curiousity

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  • Is it possible to use instanceof when passing objects between Threads?

    - by Risser
    I've run into an issue where instanceof works, and then it doesn't. Going into details is difficult, but I think this might be the problem: Reading this: http://www.theserverside.com/news/thread.tss?thread_id=40229 (search for Thread.currentThread), it seems to imply that, even if the two objects are the same class, if you pass them between threads with different class loaders, instanceof (and isAssignableFrom) might still fail. This certainly would explain the behavior I'm having, but I was wondering if anyone could verify it? (I wish the article linked at the beginning of the discussion was still available, but it doesn't seem like it is.) Thanks, Peter

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  • Is there any point in using a volatile long?

    - by Adamski
    I occasionally use a volatile instance variable in cases where I have two threads reading from / writing to it and don't want the overhead (or potential deadlock risk) of taking out a lock; for example a timer thread periodically updating an int ID that is exposed as a getter on some class: public class MyClass { private volatile int id; public MyClass() { ScheduledExecutorService execService = Executors.newScheduledThreadPool(1); execService.scheduleAtFixedRate(new Runnable() { public void run() { ++id; } }, 0L, 30L, TimeUnit.SECONDS); } public int getId() { return id; } } My question: Given that the JLS only guarantees that 32-bit reads will be atomic is there any point in ever using a volatile long? (i.e. 64-bit). Caveat: Please do not reply saying that using volatile over synchronized is a case of pre-optimisation; I am well aware of how / when to use synchronized but there are cases where volatile is preferable. For example, when defining a Spring bean for use in a single-threaded application I tend to favour volatile instance variables, as there is no guarantee that the Spring context will initialise each bean's properties in the main thread.

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  • Maven2 junit timeout annotation doesn't work

    - by roesslerj
    We have a bunch of tests in a maven2 project and build with cruisecontrol. However the build regularly hangs, because the annotation of the test with a timeout @Test(timeout = 5000) is ignored. I tried and run maven locally, reproducing the fact, that the timeout is ignored. Is there a way to activate the timeout for the tests again? I currently use a work arround in setting a timeout in cruisecontrol. However this simply means that the whole build is chancelled, and not just the tests that should fail. Remark: It seems in maven 1 there was a property to activate the junit timeout which is missing in maven 2.

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  • Draw Circle on the Map once the application gets loaded

    - by TechGeeky
    Background:- In my application what is happening currently- Whenever I am opening the application, In the top half of the android screen, it draws a Map and in the bottom half of the android screen it show's a list view. And then as soon as the location gets changed, it draw's a Circle with the current location as the center of the circle and show's an image at the current location(center of circle). Everything is working fine till here- Problem Statement:- What I want is when the user opens my application, circle should get draw immediately on the Google Map (this is currently not happening, it draw's circle only on the location changed), without waiting for the location to get changed and without any image on the center of circle and then if the location get's changed, take the current location as the center of circle and draw the circle with an image at the center of circle. And this is my below code which fulfills the scenario that I mentioned in my Background- How can I make this code to work the way I wanted to? hope I am clear enough in my question. Any suggestions will be appreciated. @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mapView = (MapView) findViewById(R.id.mapView); listView = (ListView) findViewById(R.id.mylist); locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); locationListener = new GPSLocationListener(mapView); locationManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 35000, 10, locationListener); mapView.setStreetView(true); mapView.setBuiltInZoomControls(true); mapController = mapView.getController(); mapController.setZoom(14); } Location Update class where I am sending the request to Overlay to draw the circle private class GPSLocationListener implements LocationListener { MapOverlay mapOverlay; public GPSLocationListener(MapView mapView) { } @Override public void onLocationChanged(Location location) { if (location != null) { GeoPoint point = new GeoPoint( (int) (location.getLatitude() * 1E6), (int) (location.getLongitude() * 1E6)); mapController.animateTo(point); mapController.setZoom(15); if (mapOverlay == null) { mapOverlay = new MapOverlay(this,android.R.drawable.star_on); List<Overlay> listOfOverlays = mapView.getOverlays(); listOfOverlays.add(mapOverlay); } mapOverlay.setPointToDraw(point); mapView.invalidate(); } } @Override public void onProviderDisabled(String provider) { } @Override public void onProviderEnabled(String provider) { } @Override public void onStatusChanged(String provider, int status, Bundle extras) { } } Class in which circle is getting drawn. class MapOverlay extends Overlay { private GeoPoint pointToDraw; int[] imageNames=new int[6]; private Point mScreenPoints; private Bitmap mBitmap; private Paint mCirclePaint; public MapOverlay(GPSLocationListener gpsLocationListener, int currentUser) { imageNames[0]=currentUser; mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG); mCirclePaint.setColor(0x30000000); mCirclePaint.setStyle(Style.FILL_AND_STROKE); mBitmap = BitmapFactory.decodeResource(getResources(),imageNames[0]); mScreenPoints = new Point(); } public void setPointToDraw(GeoPoint point) { pointToDraw = point; } public GeoPoint getPointToDraw() { return pointToDraw; } @Override public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { super.draw(canvas, mapView, shadow); if (pointToDraw == null) { return true; } mScreenPoints = mapView.getProjection().toPixels(pointToDraw, mScreenPoints); int totalCircle=5; int radius=40; int centerimagesize=35; for (int i = 1; i <= totalCircle; i ++) { canvas.drawCircle(mScreenPoints.x,mScreenPoints.y, i*radius, mCirclePaint); } canvas.drawBitmap(mBitmap, (mScreenPoints.x-(centerimagesize/2)),(mScreenPoints.y-(centerimagesize/2)), null); super.draw(canvas,mapView,shadow); return true; } }

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  • OSGi bundle imports packages from non-bundle jars: create bundles for them?

    - by John Simmons
    I am new to OSGi, and am using Equinox. I have done several searches and can find no answer to this. The discussion at OSGI - handling 3rd party JARs required by a bundle helps somewhat, but does not fully answer my question. I have obtained a jar file, rabbitmq-client.jar, that is already packaged as an OSGi bundle (with Bundle-Name and other such properties in its MANIFEST.MF), that I would like to install as a bundle. This jar imports packages org.apache.commons.io and org.apache.commons.io.input from commons-io-1.2.jar. The RabbitMQ client 2.7.1 distribution also includes commons-cli-1.1.jar, so I presume that it is required as well. I examined the manifests of these commons jars and found that they do not appear to be packaged as bundles. That is, their manifests have none of the standard bundle properties. My specific question is: if I install rabbitmq-client.jar as a bundle, what is the proper way to get access to the packages that it needs to import from the commons jars? There are only three alternatives that I can think of, without rebuilding rabbitmq-client.jar. The packages from the commons jars are already included in the Equinox global classpath, and rabbitmq-client.jar will get them automatically from there. I must make another bundle with the two commons jars, export the needed packages, and install that bundle in Equinox. I must put these two commons jars in the global classpath when I start Equinox, and they will be available to rabbitmq-client.jar from there. I have read that one normally does not use the global classpath in an OSGi container. I am not clear on whether items from the global classpath are even available when building individual bundle classpaths. However, I note that rabbitmq-client.jar also imports other packages such as javax.net, which I presume come from the global classpath. Or is there some other bundle that exports them? Thanks for any assistance!

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  • Problem with ModelAndView and ModelMap in AnnotationController, Springframework

    - by saltfactory
    I have a question that is a point difference between ModelAndView and ModelMap. I want to maintain modelAndView when requestMethod is "GET" and requestMethod is "POST". My modelAndView saved others. So I made modelAndView return type to "GET", "POST" methods. But, Request lost commandObject, form:errors..., if request return showForm on "POST" because request validation failed. example) private ModelAndView modelAndView; public ControllerTest{ this.modelAndView = new ModelAndView(); } @RequestMapping(method = RequestMethod.GET) public ModelAndView showForm(ModelMap model) { EntityObject entityObject = new EntityObject(); CommandObject commandObject = new CommandObject(); commandObject.setEntityObject(entityObject); model.addAttribute("commandObject", commandObject); this.modelAndView.addObject("id", "GET"); this.modelAndView.setViewName("registerForm"); return this.modelAndView; } @RequestMapping(method = RequestMethod.POST) public ModelAndView submit(@ModelAttribute("commandObject") CommandObject commandObject, BindingResult result, SessionStatus status) { this.commandValidator.validate(commandObject, result); if (result.hasErrors()) { this.modelAndView.addObject("id", "POST"); this.modelAndView.setViewName("registerForm"); return this.modelAndView; } else { this.modelAndView.addObject("id", "after POST"); this.modelAndView.setViewName("success"); } status.setComplete(); return this.modelAndView; }

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  • How do I redirect to the current page in Servlet Filter?

    - by JeffJak
    I have a page say: /myapp/test.jsp?queryString=Y. The filter needs to redirect to current page. It should go to /myapp/test.jsp (without the query string). The below seems to bring it to to the context root: /myapp. I am running in WAS6.1. public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpReq = (HttpServletRequest) req; HttpServletResponse httpResp = (HttpServletResponse) resp; { boolean blnNeedToRedirect = true; if (blnNeedToRedirect) { httpResp.sendRedirect("."); return; } chain.doFilter(req, resp); }

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  • Benefits of arrays

    - by Vitalii Fedorenko
    As I see it, the advantages of List over array are pretty obvious: Generics provide more precise typing: List<Integer>, List<? extends Number>, List<? super Integer>. List interface has a bunch useful methods: addAll, remove etc. While for arrays all standard operations except get/set must be performed in a procedure manner by passing it to a static method. Collections offer different implementations like ArrayList, LinkedList, unmodifieable and synchronized lists, which can be hidden under common List interface. OOB length control. As disadvantages I can only mention absence of syntactic sugar and runtime type check. At the same time supporting of both structures requires frequent using of asList and toArray methods, which makes code less readable. So I am curious if there are any important benefits of using arrays that I miss.

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  • Hibernate: fetching multiple bags efficiently

    - by Jens Jansson
    Hi! I'm developing a multilingual application. For this reason many objects have in their name and description fields collections of something I call LocalizedStrings instead of plain strings. Every LocalizedString is basically a pair of a locale and a string localized to that locale. Let's take an example an entity, let's say a book -object. public class Book{ @OneToMany private List<LocalizedString> names; @OneToMany private List<LocalizedString> description; //and so on... } When a user asks for a list of books, it does a query to get all the books, fetches the name and description of every book in the locale the user has selected to run the app in, and displays it back to the user. This works but it is a major performance issue. For the moment hibernate makes one query to fetch all the books, and after that it goes through every single object and asks hibernate for the localized strings for that specific object, resulting in a "n+1 select problem". Fetching a list of 50 entities produces about 6000 rows of sql commands in my server log. I tried making the collections eager but that lead me to the "cannot simultaneously fetch multiple bags"-issue. Then I tried setting the fetch strategy on the collections to subselect, hoping that it would do one query for all books, and after that do one query that fetches all LocalizedStrings for all the books. Subselects didn't work in this case how i would have hoped and it basically just did exactly the same as my first case. I'm starting to run out of ideas on how to optimize this. So in short, what fetching strategy alternatives are there when you are fetching a collection and every element in that collection has one or multiple collections in itself, which has to be fetch simultaneously.

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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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  • hibernate modeling relationships managed through an intermediate table

    - by shikarishambu
    I have a datamodel that has an intermediate table to manage relationships between entities. For example, tables Person and Organization are related through the Relationship table Party (table) - ID Person (table) - ID (references Party.ID) - name Organization (table) -ID (references Party.ID) -name Relationship (table) -ID (PK) -type (references relationshiptype lookup) -fromID (references Party.ID) -ToID (references Party.ID) -fromDate -ToDate Type+fromID+ToID+fromDate+ToDate is guaranteed to be unique. How do I manage this using hibernate? TIA

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  • how to merge two ordered list of objects?

    - by bhavna raghuvanshi
    public class ListMerge { public static void main( String[] args) { Scanner input = new Scanner(System.in); System.out.println ("Input length of arraylist 1:"); int n = input.nextInt(); ArrayList x = new ArrayList(); ArrayList y = new ArrayList(); for (int i = 0; i < n; i++) { System.out.println ("Input x[ " + i +"] :" ); x.add(new Integer(i)); } System.out.println ("Input length of arraylist 2:"); int m = input.nextInt(); for (int i = 0; i < m; i++) { System.out.println ("Input y[ " + i +"] :" ); y.add(new Integer(i)); } List<Integer> all = new ArrayList<Integer>(); all.addAll(x); all.addAll(y); System.out.println(all); } } I did this but its not taking values from user. pls tell me why....

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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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  • What do the external JSF libraries/frameworks add?

    - by kgrad
    I have seen mention of a bunch of external JSF Libraries such as ICEfaces, Richfaces, etc. However, I am unsure as to what these libraries actually add over just using JSF 2.0. Are they just additional components that are pre-built? I know that PrettyFaces adds URL rewriting, and I Believe that ICEFaces/Richfaces add Ajax enabled components? What are some other major component libraries, what are their benefits / why should people use them? Additionally, what does a framework like SEAM add over using straight JSF2 with EJB? Is MYFaces simply a different implementation of JSF?

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  • Digester: Extracting node name for a map<tagname, value>

    - by enguerran
    My question is close to this one: Digester: Extracting node name Even with the answer, I can't find out. Here is my xml file (from smartgwt RestDataSource POST): <data> <isc_OID_14> <attribute1>value1</attribute1> <attribute2>value2</attribute2> </isc_OID_14> </data> I would like to create, with Commons Digester, the following map : {attribute1=value1, attribute2=value2} I already have those lines: digester = new Digester(); digester.addObjectCreate("data", HashMap.class); // some "put" rules matching something like data/* return digester.parse(myFile); I do not know the list nor the name of tags in the <data><sourceId /></data>. isc_OID_14 or attribute1 can be named foobar or id or attribute335...

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  • How to manage user authentication/sessions?

    - by Dan
    What is the best way to manage user authentication/sessions in a web app, ideally in a clustered environment, using Spring Framework/MVC? I thought of creating a login bean that creates a jsession for authenticated users and then using AOP to check for the jsession before each controller method inovcation. If there isn't a better way, what are some possible alternatives? Thanks.

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