println - Page 68 - Developer IT

How is Object[] cloneable

- by java_geek

Object[] o = new Object[]{}; System.out.println(o instanceof Cloneable); This gives true as o/p. I could not understand why?

CPU/JVM/JBoss 7 slows down over time

I'm experiencing performance slow down on JBoss 7.1.1 Final. I wrote simple program that demostrates this behavior. I generate an array of 100,000 of random integers and run bubble sort on it. @Model public class PerformanceTest { public void proceed() { long now = System.currentTimeMillis(); int[] arr = new int[100000]; for(int i = 0; i < arr.length; i++) { arr[i] = (int) (Math.random() * 200000); } long now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to generate array"); now = System.currentTimeMillis(); bubbleSort(arr); now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to bubblesort array"); } public void bubbleSort(int[] arr) { boolean swapped = true; int j = 0; int tmp; while (swapped) { swapped = false; j++; for (int i = 0; i < arr.length - j; i++) { if (arr[i] > arr[i + 1]) { tmp = arr[i]; arr[i] = arr[i + 1]; arr[i + 1] = tmp; swapped = true; } } } } } Just after I start the server, it takes approximately 22 seconds to run this code. After few days of JBoss 7.1.1. running, it takes 330 sec to run this code. In both cases, I launch the code when the CPU utilization is very low (say, 1%). Any ideas why? I run the server with following arguments: -Xms1280m -Xmx2048m -XX:MaxPermSize=2048m -Djava.net.preferIPv4Stack=true -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true -Duser.timezone=UTC -Djboss.server.default.config=standalone-full.xml -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n I'm running it on Linux 2.6.32-279.11.1.el6.x86_64 with java version "1.7.0_07". It's within J2EE applicaiton. I use CDI so I have a button on JSF page that will call method "proceed" on @RequestScoped component PerformanceTest. I deploy this as separate war file and even if I undeploy other applications, it doesn't change the performance. It's a virtual machine that is sharing CPUs with another machine but that one doesn't consume anything. Here's yet another observation: when the server is after fresh start and I run the bubble sort, It utilizes 100% of one processor core. It never switches to another core or drops utilization below 95%. However after some time the server is running and I'm experiencing the performance problems, the method above is utilizing CPU core usually 100%, however I just found out from htop that this task is being switched very often to other cores. That is, at the beginning it's running on core #1, after say 2 seconds it's running on #5 then after say 2 seconds #8 etc. Furthermore, the utilization is not kept at 100% at the core but sometimes drops to 80% or even lower. For the server after fresh start, even though If I simulate a load, it never switches the task to another core.

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Infinite loop during A* algorithm

- by Tashu

The A* algorithm is used by enemies to have a path to the goal. It's working but when sometimes I placed a tower in a grid (randomly) it produces a stack overflow error. The A* algorithm would iterate the enemy and find its path and pass the list to the enemy's path. I added debug logs and the list that I'm getting it looks like it would arrive from start cell to goal cell. Here's the log - 06-19 19:26:41.982: DEBUG/findEnemyPath, enemy X:Y(4281): X2.8256836:Y3.5 06-19 19:26:41.990: DEBUG/findEnemyPath, grid X:Y(4281): X3:Y2 06-19 19:26:41.990: DEBUG/START CELL ID:(4281): 38 06-19 19:26:41.990: DEBUG/GOAL CELL ID:(4281): 47 06-19 19:26:41.990: DEBUG/Best : 38(4281): passThrough:0.0 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Best : 39(4281): passThrough:8.875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Best : 40(4281): passThrough:7.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 40 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 40 06-19 19:26:41.990: DEBUG/Best : 52(4281): passThrough:8.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 52 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 52 06-19 19:26:41.990: DEBUG/Best : 53(4281): passThrough:7.96875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 53 06-19 19:26:41.990: DEBUG/Best : 28(4281): passThrough:8.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 28 06-19 19:26:41.990: DEBUG/Best : 65(4281): passThrough:8.984375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 65 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 65 06-19 19:26:41.990: DEBUG/Best : 66(4281): passThrough:7.9921875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 66 06-19 19:26:42.000: DEBUG/Best : 78(4281): passThrough:8.99609375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 78 06-19 19:26:42.000: DEBUG/Best : 79(4281): passThrough:7.998046875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 79 06-19 19:26:42.000: DEBUG/Best : 80(4281): passThrough:6.9990234375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 80 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 80 06-19 19:26:42.000: DEBUG/Best : 81(4281): passThrough:5.99951171875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 81 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 81 06-19 19:26:42.000: DEBUG/Best : 82(4281): passThrough:4.999755859375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 82 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 82 06-19 19:26:42.000: DEBUG/Best : 83(4281): passThrough:3.9998779296875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 83 06-19 19:26:42.000: DEBUG/Best : 71(4281): passThrough:2.99993896484375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 71 06-19 19:26:42.000: DEBUG/Best : 59(4281): passThrough:1.99951171875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Best : 47(4281): passThrough:0.99951171875 Then, the goal cell would be iterating its parent till start cell to break off the loop. private void populateBestList(Cell cell, List<Cell> bestList) { bestList.add(cell); if (cell.parent.start == false) { Log.d("ID:", ""+cell.id); Log.d("ParentID:", ""+cell.parent.id); populateBestList(cell.parent, bestList); } return; } The log with error above would show like this - 06-19 19:26:42.010: DEBUG/ID:(4281): 47 06-19 19:26:42.010: DEBUG/ParentID:(4281): 59 06-19 19:26:42.010: DEBUG/ID:(4281): 59 06-19 19:26:42.010: DEBUG/ParentID:(4281): 71 06-19 19:26:42.010: DEBUG/ID:(4281): 71 06-19 19:26:42.010: DEBUG/ParentID:(4281): 59 06-19 19:26:42.010: DEBUG/ID:(4281): 59 06-19 19:26:42.010: DEBUG/ParentID:(4281): 71 06-19 19:26:42.010: DEBUG/ID:(4281): 71 71 and 59 would switch over and goes on. I thought the grid is the issue due to the fact that enemies are using the single grid so I make the parent, start, and goal clear before starting the A* algorithm for an enemy. for(int i = 0; i < GRID_HEIGHT; i++) { for(int j = 0; j < GRID_WIDTH; j++) { grid[i][j].parent = null; grid[i][j].start = false; grid[i][j].goal = false; } } That didn't work. I thought it might be something related to this code, but not sure if I'm on right track - neighbor.parent = best; openList.remove(neighbor); closedList.remove(neighbor); openList.add(0, neighbor); Here's the code of the A* algorithm - private List<Cell> findEnemyPath(Enemy enemy) { for(int i = 0; i < GRID_HEIGHT; i++) { for(int j = 0; j < GRID_WIDTH; j++) { grid[i][j].parent = null; grid[i][j].start = false; grid[i][j].goal = false; } } List<Cell> openList = new ArrayList<Cell>(); List<Cell> closedList = new ArrayList<Cell>(); List<Cell> bestList = new ArrayList<Cell>(); int width = (int)Math.floor(enemy.position.x); int height = (int)Math.floor(enemy.position.y); width = (width < 0) ? 0 : width; height = (height < 0) ? 0 : height; Log.d("findEnemyPath, enemy X:Y", "X"+enemy.position.x+":"+"Y"+enemy.position.y); Log.d("findEnemyPath, grid X:Y", "X"+height+":"+"Y"+width); Cell start = grid[height][width]; Cell goal = grid[ENEMY_GOAL_HEIGHT][ENEMY_GOAL_WIDTH]; if(start.id != goal.id) { Log.d("START CELL ID: ", ""+start.id); Log.d("GOAL CELL ID: ", ""+goal.id); //Log.d("findEnemyPath, grid X:Y", "X"+start.position.x+":"+"Y"+start.position.y); start.start = true; goal.goal = true; openList.add(start); while(openList.size() > 0) { Cell best = findBestPassThrough(openList, goal); //Log.d("ID:", ""+best.id); openList.remove(best); closedList.add(best); if (best.goal) { System.out.println("Found Goal"); System.out.println(bestList.size()); populateBestList(goal, bestList); /* for(Cell cell : bestList) { Log.d("ID:", ""+cell.id); Log.d("ParentID:", ""+cell.parent.id); } */ Collections.reverse(bestList); Cell exit = new Cell(13.5f, 3.5f, 1, 1); exit.isExit = true; bestList.add(exit); //Log.d("PathList", "Enemy ID : " + enemy.id); return bestList; } else { List<Cell> neighbors = getNeighbors(best); for (Cell neighbor : neighbors) { if(neighbor.isTower) { continue; } if (openList.contains(neighbor)) { Cell tmpCell = new Cell(neighbor.position.x, neighbor.position.y, 1, 1); tmpCell.parent = best; if (tmpCell.getPassThrough(goal) >= neighbor.getPassThrough(goal)) { continue; } } if (closedList.contains(neighbor)) { Cell tmpCell = new Cell(neighbor.position.x, neighbor.position.y, 1, 1); tmpCell.parent = best; if (tmpCell.getPassThrough(goal) >= neighbor.getPassThrough(goal)) { continue; } } Log.d("Neighbor's Parent: ", ""+best.id); neighbor.parent = best; openList.remove(neighbor); closedList.remove(neighbor); openList.add(0, neighbor); } } } } Log.d("Cannot find a path", ""); return null; }

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How-to tell the ViewCriteria a user chose in an af:query component

- by frank.nimphius

Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The af:query component defines a search form for application users to enter search conditions for a selected View Criteria. A View Criteria is a named where clauses that you can create declaratively on the ADF Business Component View Object. A default View Criteria that allows users to search in all attributes exists by default and exposed in the Data Controls panel. To create an ADF Faces search form, expand the View Object node that contains the View Criteria definition in the Data Controls panel. Drag the View Criteria that should be displayed as the default criteria onto the page and choose Query in the opened context menu. One of the options within the Query option is to create an ADF Query Panel with Table, which displays the result set in a table view, which can have additional column filters defined. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} To intercept the user query for modification, or just to know about the selected View Criteria, you override the QueryListener property on the af:query component of the af:table component. Overriding the QueryListener on the table makes sense if the table allows users to further filter the result set using column filters.To override the default QueryListener, copy the existing string referencing the binding layer to the clipboard and then select Edit from the field context menu (press the arrow icon to open it) to selecte or create a new managed bean and method to handle the query event. The code below is from a managed bean with custom query listener handlers defined for the af:query component and the af:table component. The default listener entry copied to the clipboard was "#{bindings.ImplicitViewCriteriaQuery.processQuery}" public void onQueryList(QueryEvent queryEvent) { // The generated QueryListener replaced by this method //#{bindings.ImplicitViewCriteriaQuery.processQuery} QueryDescriptor qdes = queryEvent.getDescriptor(); //print or log selected View Criteria System.out.println("NAME "+qdes.getName()); //call default Query Event invokeQueryEventMethodExpression(" #{bindings.ImplicitViewCriteriaQuery.processQuery}",queryEvent); } public void onQueryTable(QueryEvent queryEvent) { // The generated QueryListener replaced by this method //#{bindings.ImplicitViewCriteriaQuery.processQuery} QueryDescriptor qdes = queryEvent.getDescriptor(); //print or log selected View Criteria System.out.println("NAME "+qdes.getName()); invokeQueryEventMethodExpression( "#{bindings.ImplicitViewCriteriaQuery.processQuery}",queryEvent); } private void invokeQueryEventMethodExpression( String expression, QueryEvent queryEvent){ FacesContext fctx = FacesContext.getCurrentInstance(); ELContext elctx = fctx.getELContext(); ExpressionFactory efactory fctx.getApplication().getExpressionFactory(); MethodExpression me = efactory.createMethodExpression(elctx,expression, Object.class, new Class[]{QueryEvent.class}); me.invoke(elctx, new Object[]{queryEvent}); } Of course, this code also can be used as a starting point for other query manipulations and also works with saved custom criterias. To read more about the af:query component, see: http://download.oracle.com/docs/cd/E15523_01/apirefs.1111/e12419/tagdoc/af_query.html

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Client side code snipets

- by raghu.yadav

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3D picking lwjgl

- by Wirde

I have written some code to preform 3D picking that for some reason dosn't work entirely correct! (Im using LWJGL just so you know.) I posted this at stackoverflow at first but after researching some more in to my problem i found this neat site and tought that you guys might be more qualified to answer this question. This is how the code looks like: if(Mouse.getEventButton() == 1) { if (!Mouse.getEventButtonState()) { Camera.get().generateViewMatrix(); float screenSpaceX = ((Mouse.getX()/800f/2f)-1.0f)*Camera.get().getAspectRatio(); float screenSpaceY = 1.0f-(2*((600-Mouse.getY())/600f)); float displacementRate = (float)Math.tan(Camera.get().getFovy()/2); screenSpaceX *= displacementRate; screenSpaceY *= displacementRate; Vector4f cameraSpaceNear = new Vector4f((float) (screenSpaceX * Camera.get().getNear()), (float) (screenSpaceY * Camera.get().getNear()), (float) (-Camera.get().getNear()), 1); Vector4f cameraSpaceFar = new Vector4f((float) (screenSpaceX * Camera.get().getFar()), (float) (screenSpaceY * Camera.get().getFar()), (float) (-Camera.get().getFar()), 1); Matrix4f tmpView = new Matrix4f(); Camera.get().getViewMatrix().transpose(tmpView); Matrix4f invertedViewMatrix = (Matrix4f)tmpView.invert(); Vector4f worldSpaceNear = new Vector4f(); Matrix4f.transform(invertedViewMatrix, cameraSpaceNear, worldSpaceNear); Vector4f worldSpaceFar = new Vector4f(); Matrix4f.transform(invertedViewMatrix, cameraSpaceFar, worldSpaceFar); Vector3f rayPosition = new Vector3f(worldSpaceNear.x, worldSpaceNear.y, worldSpaceNear.z); Vector3f rayDirection = new Vector3f(worldSpaceFar.x - worldSpaceNear.x, worldSpaceFar.y - worldSpaceNear.y, worldSpaceFar.z - worldSpaceNear.z); rayDirection.normalise(); Ray clickRay = new Ray(rayPosition, rayDirection); Vector tMin = new Vector(), tMax = new Vector(), tempPoint; float largestEnteringValue, smallestExitingValue, temp, closestEnteringValue = Camera.get().getFar()+0.1f; Drawable closestDrawableHit = null; for(Drawable d : this.worldModel.getDrawableThings()) { // Calcualte AABB for each object... needs to be moved later... firstVertex = true; for(Surface surface : d.getSurfaces()) { for(Vertex v : surface.getVertices()) { worldPosition.x = (v.x+d.getPosition().x)*d.getScale().x; worldPosition.y = (v.y+d.getPosition().y)*d.getScale().y; worldPosition.z = (v.z+d.getPosition().z)*d.getScale().z; worldPosition = worldPosition.rotate(d.getRotation()); if (firstVertex) { maxX = worldPosition.x; maxY = worldPosition.y; maxZ = worldPosition.z; minX = worldPosition.x; minY = worldPosition.y; minZ = worldPosition.z; firstVertex = false; } else { if (worldPosition.x > maxX) { maxX = worldPosition.x; } if (worldPosition.x < minX) { minX = worldPosition.x; } if (worldPosition.y > maxY) { maxY = worldPosition.y; } if (worldPosition.y < minY) { minY = worldPosition.y; } if (worldPosition.z > maxZ) { maxZ = worldPosition.z; } if (worldPosition.z < minZ) { minZ = worldPosition.z; } } } } // ray/slabs intersection test... // clickRay.getOrigin().x + clickRay.getDirection().x * f = minX // clickRay.getOrigin().x - minX = -clickRay.getDirection().x * f // clickRay.getOrigin().x/-clickRay.getDirection().x - minX/-clickRay.getDirection().x = f // -clickRay.getOrigin().x/clickRay.getDirection().x + minX/clickRay.getDirection().x = f largestEnteringValue = -clickRay.getOrigin().x/clickRay.getDirection().x + minX/clickRay.getDirection().x; temp = -clickRay.getOrigin().y/clickRay.getDirection().y + minY/clickRay.getDirection().y; if(largestEnteringValue < temp) { largestEnteringValue = temp; } temp = -clickRay.getOrigin().z/clickRay.getDirection().z + minZ/clickRay.getDirection().z; if(largestEnteringValue < temp) { largestEnteringValue = temp; } smallestExitingValue = -clickRay.getOrigin().x/clickRay.getDirection().x + maxX/clickRay.getDirection().x; temp = -clickRay.getOrigin().y/clickRay.getDirection().y + maxY/clickRay.getDirection().y; if(smallestExitingValue > temp) { smallestExitingValue = temp; } temp = -clickRay.getOrigin().z/clickRay.getDirection().z + maxZ/clickRay.getDirection().z; if(smallestExitingValue < temp) { smallestExitingValue = temp; } if(largestEnteringValue > smallestExitingValue) { //System.out.println("Miss!"); } else { if (largestEnteringValue < closestEnteringValue) { closestEnteringValue = largestEnteringValue; closestDrawableHit = d; } } } if(closestDrawableHit != null) { System.out.println("Hit at: (" + clickRay.setDistance(closestEnteringValue).x + ", " + clickRay.getCurrentPosition().y + ", " + clickRay.getCurrentPosition().z); this.worldModel.removeDrawableThing(closestDrawableHit); } } } I just don't understand what's wrong, the ray are shooting and i do hit stuff that gets removed but the result of the ray are verry strange it sometimes removes the thing im clicking at, sometimes it removes things thats not even close to what im clicking at, and sometimes it removes nothing at all. Edit: Okay so i have continued searching for errors and by debugging the ray (by painting smal dots where it travles) i can now se that there is something oviously wrong with the ray that im sending out... it has its origin near the world center (nearer or further away depending on where on the screen im clicking) and always shots to the same position no matter where I direct my camera... My initial toughts is that there might be some error in the way i calculate my viewMatrix (since it's not possible to get the viewmatrix from the gluLookAt method in lwjgl; I have to build it my self and I guess thats where the problem is at)... Edit2: This is how i calculate it currently: private double[][] viewMatrixDouble = {{0,0,0,0}, {0,0,0,0}, {0,0,0,0}, {0,0,0,1}}; public Vector getCameraDirectionVector() { Vector actualEye = this.getActualEyePosition(); return new Vector(lookAt.x-actualEye.x, lookAt.y-actualEye.y, lookAt.z-actualEye.z); } public Vector getActualEyePosition() { return eye.rotate(this.getRotation()); } public void generateViewMatrix() { Vector cameraDirectionVector = getCameraDirectionVector().normalize(); Vector side = Vector.cross(cameraDirectionVector, this.upVector).normalize(); Vector up = Vector.cross(side, cameraDirectionVector); viewMatrixDouble[0][0] = side.x; viewMatrixDouble[0][1] = up.x; viewMatrixDouble[0][2] = -cameraDirectionVector.x; viewMatrixDouble[1][0] = side.y; viewMatrixDouble[1][1] = up.y; viewMatrixDouble[1][2] = -cameraDirectionVector.y; viewMatrixDouble[2][0] = side.z; viewMatrixDouble[2][1] = up.z; viewMatrixDouble[2][2] = -cameraDirectionVector.z; /* Vector actualEyePosition = this.getActualEyePosition(); Vector zaxis = new Vector(this.lookAt.x - actualEyePosition.x, this.lookAt.y - actualEyePosition.y, this.lookAt.z - actualEyePosition.z).normalize(); Vector xaxis = Vector.cross(upVector, zaxis).normalize(); Vector yaxis = Vector.cross(zaxis, xaxis); viewMatrixDouble[0][0] = xaxis.x; viewMatrixDouble[0][1] = yaxis.x; viewMatrixDouble[0][2] = zaxis.x; viewMatrixDouble[1][0] = xaxis.y; viewMatrixDouble[1][1] = yaxis.y; viewMatrixDouble[1][2] = zaxis.y; viewMatrixDouble[2][0] = xaxis.z; viewMatrixDouble[2][1] = yaxis.z; viewMatrixDouble[2][2] = zaxis.z; viewMatrixDouble[3][0] = -Vector.dot(xaxis, actualEyePosition); viewMatrixDouble[3][1] =-Vector.dot(yaxis, actualEyePosition); viewMatrixDouble[3][2] = -Vector.dot(zaxis, actualEyePosition); */ viewMatrix = new Matrix4f(); viewMatrix.load(getViewMatrixAsFloatBuffer()); } Would be verry greatfull if anyone could verify if this is wrong or right, and if it's wrong; supply me with the right way of doing it... I have read alot of threads and documentations about this but i can't seam to wrapp my head around it... Edit3: Okay with the help of Byte56 (thanks alot for the help) i have now concluded that it's not the viewMatrix that is the problem... I still get the same messedup result; anyone that think that they can find the error in my code, i certenly can't, have bean working on this for 3 days now :(

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Turning on collision crashes game

- by MomentumGaming

I am getting a null pointer excecption to both my sprite and level. I am working on my mob class, and when I try to move him and the move function is called, the game crashes after checking collision with a null pointer excecption. Taking out the one line that actually checks if the tile located in front of it fixes the problem. Also, if i keep collision ON but don't move the position of the mob (the spider) the game works fine. I will have collision, and the spider appears on the screen, only problem is, getting it to move causes this nasty error that i just can't fix. true Exception in thread "Display" java.lang.NullPointerException at com.apcompsci.game.entity.mob.Mob.collision(Mob.java:67) at com.apcompsci.game.entity.mob.Mob.move(Mob.java:38) at com.apcompsci.game.entity.mob.spider.update(spider.java:58) at com.apcompsci.game.level.Level.update(Level.java:55) at com.apcompsci.game.Game.update(Game.java:128) at com.apcompsci.game.Game.run(Game.java:106) at java.lang.Thread.run(Unknown Source) Here is my renderMob mehtod: public void renderMob(int xp,int yp,Sprite sprite,int flip) { xp -= xOffset; yp-=yOffset; for(int y = 0; y<32; y++) { int ya = y + yp; int ys = y; if(flip == 2||flip == 3)ys = 31-y; for(int x = 0; x<32; x++) { int xa = x + xp; int xs = x; if(flip == 1||flip == 3)xs = 31-x; if(xa < -32 || xa >=width || ya<0||ya>=height) break; if(xa<0) xa =0; int col = sprite.pixels[xs+ys*32]; if(col!= 0x000000) pixels[xa+ya*width] = col; } } } My spider class which determines the sprite and where I control movement, also rendering the spider onto the screen, when I increment ya to move the sprite, I get the crash, but without ya++, it runs flawlessly with a spider sprite on screen: package com.apcompsci.game.entity.mob; import com.apcompsci.game.entity.mob.Mob.Direction; import com.apcompsci.game.graphics.Screen; import com.apcompsci.game.graphics.Sprite; import com.apcompsci.game.level.Level; public class spider extends Mob{ Direction dir; private Sprite sprite; private boolean walking; public spider(int x, int y) { this.x = x <<4; this.y = y <<4; sprite = sprite.spider_forward; } public void update() { int xa = 0, ya = 0; ya++; if(ya<0) { sprite = sprite.spider_forward; dir = Direction.UP; } if(ya>0) { sprite = sprite.spider_back; dir = Direction.DOWN; } if(xa<0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa>0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa!= 0 || ya!= 0) { System.out.println("true"); move(xa,ya); walking = true; } else{ walking = false; } } public void render(Screen screen) { screen.renderMob(x, y, sprite, 0); } } This is th mob class that contains the move() method that is called in the spider class above. This move method calls the collision method. tile and sprite comes up null in the debugger: package com.apcompsci.game.entity.mob; import java.util.ArrayList; import java.util.List; import com.apcompsci.game.entity.Entity; import com.apcompsci.game.entity.projectile.DemiGodProjectile; import com.apcompsci.game.entity.projectile.Projectile; import com.apcompsci.game.graphics.Sprite; public class Mob extends Entity{ protected Sprite sprite; protected boolean moving = false; protected enum Direction { UP,DOWN,LEFT,RIGHT } protected Direction dir; public void move(int xa,int ya) { if(xa != 0 && ya != 0) { move(xa,0); move(0,ya); return; } if(xa>0) dir = Direction.RIGHT; if(xa<0) dir = Direction.LEFT; if(ya>0)dir = Direction.DOWN; if(ya<0)dir = Direction.UP; if(!collision(xa,ya)){ x+= xa; y+=ya; } } public void update() { } public void shoot(int x, int y, double dir) { //dir = Math.toDegrees(dir); Projectile p = new DemiGodProjectile(x, y,dir); level.addProjectile(p); } public boolean collision(int xa,int ya) { boolean solid = false; for(int c = 0; c<4; c++) { int xt = ((x+xa) + c % 2 * 14 - 8 )/16; int yt = ((y+ya) + c / 2 * 12 +3 )/16; if(level.getTile(xt, yt).solid()) solid = true; } return solid; } public void render() { } } Finally, here is the method in which i call the add() method for the spider to add it to the level: protected void loadLevel(String path) { try{ BufferedImage image = ImageIO.read(SpawnLevel.class.getResource(path)); int w = width =image.getWidth(); int h = height = image.getHeight(); tiles = new int[w*h]; image.getRGB(0, 0, w,h, tiles,0, w); } catch(IOException e){ e.printStackTrace(); System.out.println("Exception! Could not load level file!"); } add(new spider(20,45)); } I don't think i need to include the level class but just in case, I have provided a gistHub link for better context. It contains all of the full classes listed above , plus my entity class and maybe another. Thanks for the help if you decide to do so, much appreciated! Also, please tell me if i'm in the wrong section of stackeoverflow, i figured that since this is the gamign section that it belonged but debugging code normally goes into the general section.

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Super constructor must be a first statement in Java constructor [closed]

- by Val

I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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Problem with my whiteboard application

- by swift

I have to develop a whiteboard application in which both the local user and the remote user should be able to draw simultaneously, is this possible? If possible then any logic? I have already developed a code but in which i am not able to do this, when the remote user starts drawing the shape which i am drawing is being replaced by his shape and co-ordinates. This problem is only when both draw simultaneously. any idea guys? Here is my code class Paper extends JPanel implements MouseListener,MouseMotionListener,ActionListener { static BufferedImage image; int bpressed; Color color; Point start; Point end; Point mp; Button elipse=new Button("elipse"); Button rectangle=new Button("rect"); Button line=new Button("line"); Button empty=new Button(""); JButton save=new JButton("Save"); JButton erase=new JButton("Erase"); String selected; int ex,ey;//eraser DatagramSocket dataSocket; JButton button = new JButton("test"); Client client; Point p=new Point(); int w,h; public Paper(DatagramSocket dataSocket) { this.dataSocket=dataSocket; client=new Client(dataSocket); System.out.println("paper"); setBackground(Color.white); addMouseListener(this); addMouseMotionListener(this); color = Color.black; setBorder(BorderFactory.createLineBorder(Color.black)); //save.setPreferredSize(new Dimension(100,20)); save.setMaximumSize(new Dimension(75,27)); erase.setMaximumSize(new Dimension(75,27)); } public void paintComponent(Graphics g) { try { g.drawImage(image, 0, 0, this); Graphics2D g2 = (Graphics2D)g; g2.setPaint(Color.black); if(selected==("elipse")) g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y)); else if(selected==("rect")) g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("line")) g2.drawLine(start.x,start.y,end.x,end.y); } catch(Exception e) {} } //Function to draw the shape on image public void draw() { Graphics2D g2 = image.createGraphics(); g2.setPaint(color); if(selected=="line") g2.drawLine(start.x, start.y, end.x, end.y); if(selected=="elipse") g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y)); if(selected=="rect") g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); repaint(); g2.dispose(); start=null; } //To add the point to the board which is broadcasted by the server public synchronized void addPoint(Point ps,String varname,String shape,String event) { try { if(end==null) end = new Point(); if(start==null) start = new Point(); if(shape.equals("elipse")) selected="elipse"; else if(shape.equals("line")) selected="line"; else if(shape.equals("rect")) selected="rect"; else if(shape.equals("erase")) { selected="erase"; erase(); } if(end!=null && start!=null) { if(varname.equals("end")) end=ps; if(varname.equals("mp")) mp=ps; if(varname.equals("start")) start=ps; if(event.equals("drag")) repaint(); else if(event.equals("release")) draw(); } } catch(Exception e) { e.printStackTrace(); } } //To set the size of the image public void setWidth(int x,int y) { System.out.println("("+x+","+y+")"); w=x; h=y; image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = image.createGraphics(); g2.setPaint(Color.white); g2.fillRect(0,0,w,h); g2.dispose(); } //Function which provides the erase functionality public void erase() { Graphics2D pic=(Graphics2D) image.getGraphics(); pic.setPaint(Color.white); pic.fillRect(start.x, start.y, 10, 10); } //Function to add buttons into the panel, calling this function returns a panel public JPanel addButtons() { JPanel buttonpanel=new JPanel(); JPanel row1=new JPanel(); JPanel row2=new JPanel(); JPanel row3=new JPanel(); JPanel row4=new JPanel(); buttonpanel.setPreferredSize(new Dimension(80,80)); //buttonpanel.setMinimumSize(new Dimension(150,150)); row1.setLayout(new BoxLayout(row1,BoxLayout.X_AXIS)); row1.setPreferredSize(new Dimension(150,150)); row2.setLayout(new BoxLayout(row2,BoxLayout.X_AXIS)); row3.setLayout(new BoxLayout(row3,BoxLayout.X_AXIS)); row4.setLayout(new BoxLayout(row4,BoxLayout.X_AXIS)); buttonpanel.setLayout(new BoxLayout(buttonpanel,BoxLayout.Y_AXIS)); elipse.addActionListener(this); rectangle.addActionListener(this); line.addActionListener( this); save.addActionListener( this); erase.addActionListener( this); buttonpanel.add(Box.createRigidArea(new Dimension(10,10))); row1.add(elipse); row1.add(Box.createRigidArea(new Dimension(5,0))); row1.add(rectangle); buttonpanel.add(row1); buttonpanel.add(Box.createRigidArea(new Dimension(10,10))); row2.add(line); row2.add(Box.createRigidArea(new Dimension(5,0))); row2.add(empty); buttonpanel.add(row2); buttonpanel.add(Box.createRigidArea(new Dimension(10,10))); row3.add(save); buttonpanel.add(row3); buttonpanel.add(Box.createRigidArea(new Dimension(10,10))); row4.add(erase); buttonpanel.add(row4); return buttonpanel; } //To save the image drawn public void save() { try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos); JFileChooser fc = new JFileChooser(); fc.showSaveDialog(this); encoder.encode(image); byte[] jpgData = bos.toByteArray(); FileOutputStream fos = new FileOutputStream(fc.getSelectedFile()+".jpeg"); fos.write(jpgData); fos.close(); //add replce confirmation here } catch (IOException e) { System.out.println(e); } } public void mouseClicked(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseEntered(MouseEvent arg0) { } public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } public void mousePressed(MouseEvent e) { if(selected=="line"||selected=="erase") { start=e.getPoint(); client.broadcast(start,"start", selected,"press"); } else if(selected=="elipse"||selected=="rect") { mp = e.getPoint(); client.broadcast(mp,"mp", selected,"press"); } } public void mouseReleased(MouseEvent e) { if(start!=null) { if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"release"); } else if(selected=="elipse"||selected=="rect") { end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(end,"end", selected,"release"); } draw(); } //start=null; } public void mouseDragged(MouseEvent e) { if(end==null) end = new Point(); if(start==null) start = new Point(); if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"drag"); } else if(selected=="erase") { start=e.getPoint(); erase(); client.broadcast(start,"start", selected,"drag"); } else if(selected=="elipse"||selected=="rect") { start.x = Math.min(mp.x,e.getX()); start.y = Math.min(mp.y,e.getY()); end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(start,"start", selected,"drag"); client.broadcast(end,"end", selected,"drag"); } repaint(); } @Override public void mouseMoved(MouseEvent arg0) { // TODO Auto-generated method stub } public void actionPerformed(ActionEvent e) { if(e.getSource()==elipse) selected="elipse"; if(e.getSource()==line) selected="line"; if(e.getSource()==rectangle) selected="rect"; if(e.getSource()==save) save(); if(e.getSource()==erase) { selected="erase"; erase(); } } } class Button extends JButton { String name; public Button(String name) { this.name=name; Dimension buttonSize = new Dimension(35,35); setMaximumSize(buttonSize); } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //g2.setStroke(new BasicStroke(1.2f)); if (name == "line") g.drawLine(5,5,30,30); if (name == "elipse") g.drawOval(5,7,25,20); if (name== "rect") g.drawRect(5,5,25,23); } }

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JAVA image transfer problem

- by user579098

Hi, I have a school assignment, to send a jpg image,split it into groups of 100 bytes, corrupt it, use a CRC check to locate the errors and re-transmit until it eventually is built back into its original form. It's practically ready, however when I check out the new images, they appear with errors.. I would really appreciate if someone could look at my code below and maybe locate this logical mistake as I can't understand what the problem is because everything looks ok :S For the file with all the data needed including photos and error patterns one could download it from this link:http://rapidshare.com/#!download|932tl2|443122762|Data.zip|739 Thanks in advance, Stefan p.s dont forget to change the paths in the code for the image and error files package networks; import java.io.*; // for file reader import java.util.zip.CRC32; // CRC32 IEEE (Ethernet) public class Main { /** * Reads a whole file into an array of bytes. * @param file The file in question. * @return Array of bytes containing file data. * @throws IOException Message contains why it failed. */ public static byte[] readFileArray(File file) throws IOException { InputStream is = new FileInputStream(file); byte[] data=new byte[(int)file.length()]; is.read(data); is.close(); return data; } /** * Writes (or overwrites if exists) a file with data from an array of bytes. * @param file The file in question. * @param data Array of bytes containing the new file data. * @throws IOException Message contains why it failed. */ public static void writeFileArray(File file, byte[] data) throws IOException { OutputStream os = new FileOutputStream(file,false); os.write(data); os.close(); } /** * Converts a long value to an array of bytes. * @param data The target variable. * @return Byte array conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static byte[] toByta(long data) { return new byte[] { (byte)((data >> 56) & 0xff), (byte)((data >> 48) & 0xff), (byte)((data >> 40) & 0xff), (byte)((data >> 32) & 0xff), (byte)((data >> 24) & 0xff), (byte)((data >> 16) & 0xff), (byte)((data >> 8) & 0xff), (byte)((data >> 0) & 0xff), }; } /** * Converts a an array of bytes to long value. * @param data The target variable. * @return Long value conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static long toLong(byte[] data) { if (data == null || data.length != 8) return 0x0; return (long)( // (Below) convert to longs before shift because digits // are lost with ints beyond the 32-bit limit (long)(0xff & data[0]) << 56 | (long)(0xff & data[1]) << 48 | (long)(0xff & data[2]) << 40 | (long)(0xff & data[3]) << 32 | (long)(0xff & data[4]) << 24 | (long)(0xff & data[5]) << 16 | (long)(0xff & data[6]) << 8 | (long)(0xff & data[7]) << 0 ); } public static byte[] nextNoise(){ byte[] result=new byte[100]; // copy a frame's worth of data (or remaining data if it is less than frame length) int read=Math.min(err_data.length-err_pstn, 100); System.arraycopy(err_data, err_pstn, result, 0, read); // if read data is less than frame length, reset position and add remaining data if(read<100){ err_pstn=100-read; System.arraycopy(err_data, 0, result, read, err_pstn); }else // otherwise, increase position err_pstn+=100; // return noise segment return result; } /** * Given some original data, it is purposefully corrupted according to a * second data array (which is read from a file). In pseudocode: * corrupt = original xor corruptor * @param data The original data. * @return The new (corrupted) data. */ public static byte[] corruptData(byte[] data){ // get the next noise sequence byte[] noise = nextNoise(); // finally, xor data with noise and return result for(int i=0; i<100; i++)data[i]^=noise[i]; return data; } /** * Given an array of data, a packet is created. In pseudocode: * frame = corrupt(data) + crc(data) * @param data The original frame data. * @return The resulting frame data. */ public static byte[] buildFrame(byte[] data){ // pack = [data]+crc32([data]) byte[] hash = new byte[8]; // calculate crc32 of data and copy it to byte array CRC32 crc = new CRC32(); crc.update(data); hash=toByta(crc.getValue()); // create a byte array holding the final packet byte[] pack = new byte[data.length+hash.length]; // create the corrupted data byte[] crpt = new byte[data.length]; crpt = corruptData(data); // copy corrupted data into pack System.arraycopy(crpt, 0, pack, 0, crpt.length); // copy hash into pack System.arraycopy(hash, 0, pack, data.length, hash.length); // return pack return pack; } /** * Verifies frame contents. * @param frame The frame data (data+crc32). * @return True if frame is valid, false otherwise. */ public static boolean verifyFrame(byte[] frame){ // allocate hash and data variables byte[] hash=new byte[8]; byte[] data=new byte[frame.length-hash.length]; // read frame into hash and data variables System.arraycopy(frame, frame.length-hash.length, hash, 0, hash.length); System.arraycopy(frame, 0, data, 0, frame.length-hash.length); // get crc32 of data CRC32 crc = new CRC32(); crc.update(data); // compare crc32 of data with crc32 of frame return crc.getValue()==toLong(hash); } /** * Transfers a file through a channel in frames and reconstructs it into a new file. * @param jpg_file File name of target file to transfer. * @param err_file The channel noise file used to simulate corruption. * @param out_file The name of the newly-created file. * @throws IOException */ public static void transferFile(String jpg_file, String err_file, String out_file) throws IOException { // read file data into global variables jpg_data = readFileArray(new File(jpg_file)); err_data = readFileArray(new File(err_file)); err_pstn = 0; // variable that will hold the final (transfered) data byte[] out_data = new byte[jpg_data.length]; // holds the current frame data byte[] frame_orig = new byte[100]; byte[] frame_sent = new byte[100]; // send file in chunks (frames) of 100 bytes for(int i=0; i<Math.ceil(jpg_data.length/100); i++){ // copy jpg data into frame and init first-time switch System.arraycopy(jpg_data, i*100, frame_orig, 0, 100); boolean not_first=false; System.out.print("Packet #"+i+": "); // repeat getting same frame until frame crc matches with frame content do { if(not_first)System.out.print("F"); frame_sent=buildFrame(frame_orig); not_first=true; }while(!verifyFrame(frame_sent)); // usually, you'd constrain this by time to prevent infinite loops (in // case the channel is so wacked up it doesn't get a single packet right) // copy frame to image file System.out.println("S"); System.arraycopy(frame_sent, 0, out_data, i*100, 100); } System.out.println("\nDone."); writeFileArray(new File(out_file),out_data); } // global variables for file data and pointer public static byte[] jpg_data; public static byte[] err_data; public static int err_pstn=0; public static void main(String[] args) throws IOException { // list of jpg files String[] jpg_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo1.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo2.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo3.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo4.jpg" }; // list of error patterns String[] err_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 1.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 2.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 3.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 4.DAT" }; // loop through all jpg/channel combinations and run tests for(int x=0; x<jpg_file.length; x++){ for(int y=0; y<err_file.length; y++){ System.out.println("Transfering photo"+(x+1)+".jpg using Pattern "+(y+1)+"..."); transferFile(jpg_file[x],err_file[y],jpg_file[x].replace("photo","CH#"+y+"_photo")); } } } }

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Web Sockets: Browser won't receive the message, complains about it not starting with 0x00 (byte)

- by giggsey

Here is my code: import java.net.*; import java.io.*; import java.util.*; import org.jibble.pircbot.*; public class WebSocket { public static int port = 12345; public static ArrayList<WebSocketClient> clients = new ArrayList<WebSocketClient>(); public static ArrayList<Boolean> handshakes = new ArrayList<Boolean>(); public static ArrayList<String> nicknames = new ArrayList<String>(); public static ArrayList<String> channels = new ArrayList<String>(); public static int indexNum; public static void main(String args[]) { try { ServerSocket ss = new ServerSocket(WebSocket.port); WebSocket.console("Created socket on port " + WebSocket.port); while (true) { Socket s = ss.accept(); WebSocket.console("New Client connecting..."); WebSocket.handshakes.add(WebSocket.indexNum,false); WebSocket.nicknames.add(WebSocket.indexNum,""); WebSocket.channels.add(WebSocket.indexNum,""); WebSocketClient p = new WebSocketClient(s,WebSocket.indexNum); Thread t = new Thread( p); WebSocket.clients.add(WebSocket.indexNum,p); indexNum++; t.start(); } } catch (Exception e) { WebSocket.console("ERROR - " + e.toString()); } } public static void console(String msg) { Date date = new Date(); System.out.println("[" + date.toString() + "] " + msg); } } class WebSocketClient implements Runnable { private Socket s; private int iAm; private String socket_res = ""; private String socket_host = ""; private String socket_origin = ""; protected String nick = ""; protected String ircChan = ""; WebSocketClient(Socket socket, int mynum) { s = socket; iAm = mynum; } public void run() { String client = s.getInetAddress().toString(); WebSocket.console("Connection from " + client); IRCclient irc = new IRCclient(iAm); Thread t = new Thread( irc ); try { Scanner in = new Scanner(s.getInputStream()); PrintWriter out = new PrintWriter(s.getOutputStream(),true); while (true) { if (! in.hasNextLine()) continue; String input = in.nextLine().trim(); if (input.isEmpty()) continue; // Lets work out what's wrong with our input if (input.length() > 3 && input.charAt(0) == 65533) { input = input.substring(2); } WebSocket.console("< " + input); // Lets work out if they authenticate... if (WebSocket.handshakes.get(iAm) == false) { checkForHandShake(input); continue; } // Lets check for NICK: if (input.length() > 6 && input.substring(0,6).equals("NICK: ")) { nick = input.substring(6); Random generator = new Random(); int rand = generator.nextInt(); WebSocket.console("I am known as " + nick); WebSocket.nicknames.set(iAm, "bo-" + nick + rand); } if (input.length() > 9 && input.substring(0,9).equals("CHANNEL: ")) { ircChan = "bo-" + input.substring(9); WebSocket.console("We will be joining " + ircChan); WebSocket.channels.set(iAm, ircChan); } if (! ircChan.isEmpty() && ! nick.isEmpty() && irc.started == false) { irc.chan = ircChan; irc.nick = WebSocket.nicknames.get(iAm); t.start(); continue; } else { irc.msg(input); } } } catch (Exception e) { WebSocket.console(e.toString()); e.printStackTrace(); } t.stop(); WebSocket.channels.remove(iAm); WebSocket.clients.remove(iAm); WebSocket.handshakes.remove(iAm); WebSocket.nicknames.remove(iAm); WebSocket.console("Closing connection from " + client); } private void checkForHandShake(String input) { // Check for HTML5 Socket getHeaders(input); if (! socket_res.isEmpty() && ! socket_host.isEmpty() && ! socket_origin.isEmpty()) { send("HTTP/1.1 101 Web Socket Protocol Handshake\r\n" + "Upgrade: WebSocket\r\n" + "Connection: Upgrade\r\n" + "WebSocket-Origin: " + socket_origin + "\r\n" + "WebSocket-Location: ws://" + socket_host + "/\r\n\r\n",false); WebSocket.handshakes.set(iAm,true); } return; } private void getHeaders(String input) { if (input.length() >= 8 && input.substring(0,8).equals("Origin: ")) { socket_origin = input.substring(8); return; } if (input.length() >= 6 && input.substring(0,6).equals("Host: ")) { socket_host = input.substring(6); return; } if (input.length() >= 7 && input.substring(0,7).equals("Cookie:")) { socket_res = "."; } /*input = input.substring(4); socket_res = input.substring(0,input.indexOf(" HTTP")); input = input.substring(input.indexOf("Host:") + 6); socket_host = input.substring(0,input.indexOf("\r\n")); input = input.substring(input.indexOf("Origin:") + 8); socket_origin = input.substring(0,input.indexOf("\r\n"));*/ return; } protected void send(String msg, boolean newline) { byte c0 = 0x00; byte c255 = (byte) 0xff; try { PrintWriter out = new PrintWriter(s.getOutputStream(),true); WebSocket.console("> " + msg); if (newline == true) msg = msg + "\n"; out.print(msg + c255); out.flush(); } catch (Exception e) { WebSocket.console(e.toString()); } } protected void send(String msg) { try { WebSocket.console(">> " + msg); byte[] message = msg.getBytes(); byte[] newmsg = new byte[message.length + 2]; newmsg[0] = (byte)0x00; for (int i = 1; i <= message.length; i++) { newmsg[i] = message[i - 1]; } newmsg[message.length + 1] = (byte)0xff; // This prints correctly..., apparently... System.out.println(Arrays.toString(newmsg)); OutputStream socketOutputStream = s.getOutputStream(); socketOutputStream.write(newmsg); } catch (Exception e) { WebSocket.console(e.toString()); } } protected void send(String msg, boolean one, boolean two) { try { WebSocket.console(">> " + msg); byte[] message = msg.getBytes(); byte[] newmsg = new byte[message.length+1]; for (int i = 0; i < message.length; i++) { newmsg[i] = message[i]; } newmsg[message.length] = (byte)0xff; // This prints correctly..., apparently... System.out.println(Arrays.toString(newmsg)); OutputStream socketOutputStream = s.getOutputStream(); socketOutputStream.write(newmsg); } catch (Exception e) { e.printStackTrace(); } } } class IRCclient implements Runnable { protected String nick; protected String chan; protected int iAm; boolean started = false; IRCUser irc; IRCclient(int me) { iAm = me; irc = new IRCUser(iAm); } public void run() { WebSocket.console("Connecting to IRC..."); started = true; irc.setNick(nick); irc.setVerbose(false); irc.connectToIRC(chan); } void msg(String input) { irc.sendMessage("#" + chan, input); } } class IRCUser extends PircBot { int iAm; IRCUser(int me) { iAm = me; } public void setNick(String nick) { this.setName(nick); } public void connectToIRC(String chan) { try { this.connect("irc.appliedirc.com"); this.joinChannel("#" + chan); } catch (Exception e) { WebSocket.console(e.toString()); } } public void onMessage(String channel, String sender,String login, String hostname, String message) { // Lets send this message to me WebSocket.clients.get(iAm).send(message); } } Whenever I try to send the message to the browser (via Web Sockets), it complains that it doesn't start with 0x00 (which is a byte). Any ideas? Edit 19/02 - Added the entire code. I know it's real messy and not neat, but I want to get it functioning first. Spend last two days trying to fix.

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Original object is also changed when values of cloned object are changed.

- by fari

I am trying to use clone but the original object is also changed when values of cloned object are changed. As you can see KalaGameState does not use any objects so a shallow copy should work. /** * This class represents the current state of a Kala game, including * which player's turn it is along with the state of the board; i.e. the * numbers of stones in each side pit, and each player's 'kala'). */ public class KalaGameState implements Cloneable { // your code goes here private int turn; private int[] sidePit; private boolean game; public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { // This should never happen throw new InternalError(e.toString()); } } /** * Constructs a new GameState with a specified number of stones in each * player's side pits. * @param startingStones the number of starting stones in each side pit. * @throws InvalidStartingStonesException if startingStones not in the range 1-10. */ public KalaGameState(int startingStones) throws InvalidStartingStonesException { game=true; turn=0; sidePit=new int[14]; for (int i=0; i <= 13 ; i++) { sidePit[i] = startingStones; } sidePit[6] =0; sidePit[13] =0; // your code goes here } /** * Returns the ID of the player whose turn it is. * @return A value of 0 = Player A, 1 = Player B. */ public int getTurn() { return turn; // your code goes here } /** * Returns the current kala for a specified player. * @param playerNum A value of 0 for Player A, 1 for Player B. * @throws IllegalPlayerNumException if the playerNum parameter * is not 0 or 1. */ public int getKala(int playerNum) throws IllegalPlayerNumException { if(playerNum!=0 || playerNum!=1) throw new IllegalPlayerNumException(playerNum); if(playerNum==0) return sidePit[6]; else return sidePit[13]; // your code goes here } /** * Returns the current number of stones in the specified pit for * the player whose turn it is. * @param sidePitNum the side pit being queried in the range 1-6. * @throws IllegalSidePitNumException if the sidePitNum parameter. * is not in the range 1-6. */ public int getNumStones(int sidePitNum) throws IllegalSidePitNumException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); if(turn==0) return sidePit[sidePitNum]; else return sidePit[sidePitNum+6]; // your code goes here } /** * Returns the current number of stones in the specified pit for a specified player. * @param playerNum the player whose kala is sought. (0 = Player A, 1 = Player B). * @param sidePitNum the side pit being queried (in the range 1-6). * @throws IllegalPlayerNumException if the playerNum parameter is not 0 or 1. * @throws IllegalSidePitNumException if the sidePitNum parameter is not in the * range 1-6. */ public int getNumStones(int playerNum, int sidePitNum) throws IllegalPlayerNumException, IllegalSidePitNumException { /*if(playerNum>2) throw new IllegalPlayerNumException(playerNum); if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); */ if(playerNum==0) return sidePit[sidePitNum]; else if(playerNum==1) return sidePit[sidePitNum+7]; else return sidePit[sidePitNum]; } /** * Returns the current score for a specified player - the player's * kala plus the number of stones in each of their side pits. * @param playerNum the player whose kala is sought. (0 = Player A, 1 = Player B). * @throws IllegalPlayerNumException if the playerNum parameter is not 0 or 1. */ public int getScore(int playerNum) throws IllegalPlayerNumException { if(playerNum>1) throw new IllegalPlayerNumException(playerNum); int score=0; if(playerNum==0) { for(int i=0;i<=5;i++) score=score+sidePit[i]; score=score+sidePit[6]; } else { for(int i=7;i<=12;i++) score=score+sidePit[i]; score=score+sidePit[13]; } // your code goes here return score; } private int getSidePitArrayIndex(int sidePitNum) throws IllegalSidePitNumException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); if(turn==0) { return sidePitNum--; } else { return sidePitNum+6; } } public boolean gameOver() { int stone=0; if(turn==0) for(int i=0;i<=5;i++) stone=stone+getNumStones(i); else for(int i=7;i<=12;i++) stone=stone+getNumStones(i-7); if (stone==0) game=false; return game; } /** * Makes a move for the player whose turn it is. * @param sidePitNum the side pit being queried (should be in the range 1-6) * @throws IllegalSidePitNumException if the sidePitNum parameter is not in the range 1-6. * @throws IllegalMoveException if the side pit is empty and has no stones in it. */ public void makeMove(int sidePitNum) throws IllegalSidePitNumException, IllegalMoveException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); /* if(turn==0) { if(sidePit[sidePitNum-1]==0) throw new IllegalMoveException(sidePitNum); } else { if(sidePit[sidePitNum-1+7]==0) throw new IllegalMoveException(sidePitNum); } */ sidePitNum--; int temp=sidePitNum; int pitNum=sidePitNum+1; int stones=getNumStones(turn,sidePitNum); if(turn==0) sidePit[sidePitNum]=0; else { sidePitNum=sidePitNum+7; sidePit[sidePitNum]=0; pitNum=pitNum+7; } while(stones!=0) { if(turn==0) { sidePit[pitNum]=sidePit[pitNum]+1; stones--; pitNum++; if(pitNum==13) pitNum=0; } else { sidePit[pitNum]=sidePit[pitNum]+1; stones--; pitNum++; if(pitNum==6) pitNum=7; else if(pitNum==14) pitNum=0; } } boolean res=anotherTurn(pitNum); if(!res){ capture(pitNum,temp); if(turn==0) turn=1; else turn=0;} } private boolean anotherTurn(int pitNum) {pitNum--; boolean temp=false; if(turn==0) {if(pitNum==6) {turn=0; temp=true; } } else if(pitNum==-1) {turn=1; temp=true; } return temp; } private void capture(int pitNum, int pit) { pitNum--; if(turn==0){ if(sidePit[pitNum]==1 && pitNum<6) { if(pitNum==0) { sidePit[6]=sidePit[6]+sidePit[12]+1; sidePit[12]=0; } else if(pitNum==1) { sidePit[6]=sidePit[6]+sidePit[11]+1; sidePit[11]=0; } else if(pitNum==2) { sidePit[6]=sidePit[6]+sidePit[10]+1; sidePit[10]=0; } else if(pitNum==3) { sidePit[6]=sidePit[6]+sidePit[9]+1; sidePit[9]=0; } else if(pitNum==4) { sidePit[6]=sidePit[6]+sidePit[8]+1; sidePit[8]=0; } else if(pitNum==5) { sidePit[6]=sidePit[6]+sidePit[7]+1; sidePit[7]=0; } sidePit[pitNum]=0; } } if(turn==1) { //pitNum=pitNum; if(sidePit[pitNum]==1 && pit+7>6) { if(pitNum==7) { sidePit[13]=sidePit[13]+sidePit[5]+1; sidePit[7]=0; } else if(pitNum==8) { sidePit[13]=sidePit[13]+sidePit[4]+1; sidePit[4]=0; } else if(pitNum==9) { sidePit[13]=sidePit[13]+sidePit[3]+1; sidePit[3]=0; } else if(pitNum==10) { sidePit[13]=sidePit[13]+sidePit[2]+1; sidePit[2]=0; } else if(pitNum==11) { sidePit[13]=sidePit[13]+sidePit[1]+1; sidePit[1]=0; } else if(pitNum==12) { sidePit[13]=sidePit[13]+sidePit[0]+1; sidePit[0]=0; } sidePit[pitNum]=0; } } } } import java.io.BufferedReader; import java.io.InputStreamReader; public class RandomPlayer extends KalaPlayer{ //KalaGameState state; public int chooseMove(KalaGameState gs) throws NoMoveAvailableException {int[] moves; moves=getMoves(gs); try{ for(int i=0;i<=5;i++) System.out.println(moves[i]); for(int i=0;i<=5;i++) { if(moves[i]==1) { KalaGameState state=(KalaGameState) gs.clone(); state.makeMove(moves[i]); gs.getTurn(); moves[i]=evalValue(state.getScore(0),state.getScore(1)); } } } catch(IllegalMoveException e) { System.out.println(e); //chooseMove(state); } return 10; } private int evalValue(int score0,int score1) { int score=0; //int score0=0; // int score1=0; //getScore(0); //score1=state.getScore(1); //if((state.getTurn())==0) score=score1-score0; //else //score=score1-score0; System.out.println("score: "+score); return score; } public int[] getMoves(KalaGameState gs) { int[] moves=new int[6]; for(int i=1;i<=6;i++) { if(gs.getNumStones(i)!=0) moves[i-1]=1; else moves[i-1]=0; } return moves; } } Can you explain what is going wrong, please?

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Problem with richfaces ajax datatable + buttons

- by Schyzotrop

Hello i have another problem with RichFaces this is my application and it shows how i want it to work : http://www.screencast.com/users/Schyzotrop/folders/Jing/media/a299dc1e-7a10-440e-8c39-96b1ec6e85a4 this is video of some glitch that i can't solve http://screencast.com/t/MDFiMGMzY the problem is that when i am trying to press any buttons on others than 1st category it won't do anything IF 1st category has less rows than the one i am calling it from from 1st category it works always i am using follwoing code in jsp for collumns : <h:form id="categoryAttributeList"> <rich:panel> <f:facet name="header"> <h:outputText value="Category Attribute List" /> </f:facet> <rich:dataTable id="table" value="#{categoryAttributeBean.allCategoryAttribute}" var="cat" width="100%" rows="10" columnClasses="col1,col2,col2,col3"> <f:facet name="header"> <rich:columnGroup> <h:column>Name</h:column> <h:column>Description</h:column> <h:column>Category</h:column> <h:column>Actions</h:column> </rich:columnGroup> </f:facet> <rich:column filterMethod="#{categoryAttributeFilteringBean.filterNames}"> <f:facet name="header"> <h:inputText value="#{categoryAttributeFilteringBean.filterNameValue}" id="input"> <a4j:support event="onkeyup" reRender="table , ds" ignoreDupResponses="true" requestDelay="700" oncomplete="setCaretToEnd(event);" /> </h:inputText> </f:facet> <h:outputText value="#{cat.name}" /> </rich:column> <rich:column filterMethod="#{categoryAttributeFilteringBean.filterDescriptions}"> <f:facet name="header"> <h:inputText value="#{categoryAttributeFilteringBean.filterDescriptionValue}" id="input2"> <a4j:support event="onkeyup" reRender="table , ds" ignoreDupResponses="true" requestDelay="700" oncomplete="setCaretToEnd(event);" /> </h:inputText> </f:facet> <h:outputText value="#{cat.description}" /> </rich:column> <rich:column filterMethod="#{categoryAttributeFilteringBean.filterCategories}"> <f:facet name="header"> <h:selectOneMenu value="#{categoryAttributeFilteringBean.filterCategoryValue}"> <f:selectItems value="#{categoryAttributeFilteringBean.categories}" /> <a4j:support event="onchange" reRender="table, ds" /> </h:selectOneMenu> </f:facet> <h:outputText value="#{cat.categoryID.name}" /> </rich:column> <h:column> <a4j:commandButton value="Edit" reRender="pnl" action="#{categoryAttributeBean.editCategoryAttributeSetup}"> <a4j:actionparam name="categoryAttributeID" value="#{cat.categoryAttributeID}" assignTo="#{categoryAttributeBean.id}" /> <a4j:actionparam name="state" value="edit" /> <a4j:actionparam name="editId" value="#{cat.categoryAttributeID}" /> </a4j:commandButton> <a4j:commandButton reRender="categoryAttributeList" value="Delete" action="#{categoryAttributeBean.deleteCategoryAttribute}"> <a4j:actionparam name="categoryAttributeID" value="#{cat.categoryAttributeID}" assignTo="#{categoryAttributeBean.id}" /> </a4j:commandButton> </h:column> <f:facet name="footer"> <rich:datascroller id="ds" renderIfSinglePage="false"></rich:datascroller> </f:facet> </rich:dataTable> <rich:panel id="msg"> <h:messages errorStyle="color:red" infoStyle="color:green"></h:messages> </rich:panel> </rich:panel> </h:form> and here is code of my backing bean @EJB private CategoryBeanLocal categoryBean; private CategoryAttribute categoryAttribute = new CategoryAttribute(); private ArrayList<SelectItem> categories = new ArrayList<SelectItem>(); private int id; private int categoryid; // Actions public void newCategoryAttribute() { categoryAttribute.setCategoryID(categoryBean.findCategoryByID(categoryid)); categoryBean.addCategoryAttribute(categoryAttribute); FacesContext.getCurrentInstance().addMessage("newCategoryAttribute", new FacesMessage("CategoryAttribute " + categoryAttribute.getName() + " created.")); this.categoryAttribute = new CategoryAttribute(); } public void editCategoryAttributeSetup() { categoryAttribute = categoryBean.findCategoryAttributeByID(id); } public void editCategoryAttribute() { categoryAttribute.setCategoryID(categoryBean.findCategoryByID(categoryid)); categoryBean.updateCategoryAttribute(categoryAttribute); FacesContext.getCurrentInstance().addMessage("newCategoryAttribute", new FacesMessage("CategoryAttribute " + categoryAttribute.getName() + " edited.")); this.categoryAttribute = new CategoryAttribute(); } public void deleteCategoryAttribute() { categoryAttribute = categoryBean.findCategoryAttributeByID(id); categoryBean.removeCategoryAttribute(categoryAttribute); FacesContext.getCurrentInstance().addMessage("categoryAttributeList", new FacesMessage("CategoryAttribute " + categoryAttribute.getName() + " deleted.")); this.categoryAttribute = new CategoryAttribute(); } // Getters public CategoryAttribute getCategoryAttribute() { return categoryAttribute; } public List<CategoryAttribute> getAllCategoryAttribute() { return categoryBean.findAllCategoryAttributes(); } public ArrayList<SelectItem> getCategories() { categories.clear(); List<Category> allCategory = categoryBean.findAllCategory(); Iterator it = allCategory.iterator(); while (it.hasNext()) { Category cat = (Category) it.next(); SelectItem select = new SelectItem(); select.setLabel(cat.getName()); select.setValue(cat.getCategoryID()); categories.add(select); } return categories; } public int getId() { return id; } public int getCategoryid() { return categoryid; } // Setters public void setCategoryAttribute(CategoryAttribute categoryAttribute) { this.categoryAttribute = categoryAttribute; } public void setId(int id) { this.id = id; } public void setCategoryid(int categoryid) { this.categoryid = categoryid; } and here is filtering bean : @EJB private CategoryBeanLocal categoryBean; private String filterNameValue = ""; private String filterDescriptionValue = ""; private int filterCategoryValue = 0; private ArrayList<SelectItem> categories = new ArrayList<SelectItem>(); public boolean filterNames(Object current) { CategoryAttribute currentName = (CategoryAttribute) current; if (filterNameValue.length() == 0) { return true; } if (currentName.getName().toLowerCase().contains(filterNameValue.toLowerCase())) { return true; } else { System.out.println("name"); return false; } } public boolean filterDescriptions(Object current) { CategoryAttribute currentDescription = (CategoryAttribute) current; if (filterDescriptionValue.length() == 0) { return true; } if (currentDescription.getDescription().toLowerCase().contains(filterDescriptionValue.toLowerCase())) { return true; } else { System.out.println("desc"); return false; } } public boolean filterCategories(Object current) { if (filterCategoryValue == 0) { getCategories(); filterCategoryValue = new Integer(categories.get(0).getValue().toString()); } CategoryAttribute currentCategory = (CategoryAttribute) current; if (currentCategory.getCategoryID().getCategoryID() == filterCategoryValue) { return true; } else { System.out.println(currentCategory.getCategoryID().getCategoryID() + "cate" + filterCategoryValue); return false; } } public ArrayList<SelectItem> getCategories() { categories.clear(); List<Category> allCategory = categoryBean.findAllCategory(); Iterator it = allCategory.iterator(); while (it.hasNext()) { Category cat = (Category) it.next(); SelectItem select = new SelectItem(); select.setLabel(cat.getName()); select.setValue(cat.getCategoryID()); categories.add(select); } return categories; } public String getFilterDescriptionValue() { return filterDescriptionValue; } public String getFilterNameValue() { return filterNameValue; } public int getFilterCategoryValue() { return filterCategoryValue; } public void setFilterDescriptionValue(String filterDescriptionValue) { this.filterDescriptionValue = filterDescriptionValue; } public void setFilterNameValue(String filterNameValue) { this.filterNameValue = filterNameValue; } public void setFilterCategoryValue(int filterCategoryValue) { this.filterCategoryValue = filterCategoryValue; } unfortunetly i can't even imagine what could cause this problem that's why i even made videos to help u understand my problem thanks for help!

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Eclipse says "Access Denied" when running javaw and how to fix it?

- by Eduardo de Luna

I'm trying to get Eclipse to compile and run a HelloWorld class but it can't even do that. I have installed Eclipse x86 SDK 4.2.0 together bit with the latest JRE and JDK both in 64 bit as well. I also have the PATH variables set to respond to command prompts. When I try to run the following code: class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!" ) ; } } And it returns the following error: Exception occurred executing command line. Cannot run program "C:\Program Files\Java\jre7\bin\javaw.exe" (in directory "C:\Users\Default\workspace\devs"): CreateProcess error=5, Access is denied. Can you help me fix this? Thanks!

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mysql jdbc got ArrayIndexOutOfBoundsException when database name length = 9

- by Thang Hoang

this code below will throw : Exception in thread "main" java.sql.SQLException: Unable to connect to any hosts due to exception: java.lang.ArrayIndexOutOfBoundsException: 40 mysql 5.1, jdbc driver 5.1.21 if I change connection string to any database have name's lengh != 9, it will pass to print 'connected'. or I create other database as '123456789' it throw same exception. I connect to other database on amazon s3, that have same name length, it throw java.lang.ArrayIndexOutOfBoundsException: 43. this database version is 'mysql Ver 14.14 Distrib 5.5.28, for debian-linux-gnu (i686) using readline 6.2 ' any idea of this weird mysql behavior, thanks public class MysqlConnection { public static void main(String[] args) throws Exception { Connection conn = null; String userName = "root"; String password = "123456"; String url = "jdbc:mysql://localhost:3306/test12345"; Class.forName ("com.mysql.jdbc.Driver").newInstance (); conn = DriverManager.getConnection (url,userName, password); System.out.println ("Connected"); } }

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Linux script to find time difference and send an email if need

- by Gnanam

Hi, I'm not an expert in writing shell scripts but also I'm looking for a very specific solution. OS: CentOS release 5.2 (Final) I've a Java standalone which keeps writing (all System.out.println) to a log file. For some unknown reason, this Java standalone stops working at some point of time in my server and eventually logs writing also stops working. I want to have a script which checks the last modified date & time of the log file with current date & time in the server. If the time difference exceeds more than 5 minutes, I want to send an email immediately to my recipients list. This way I'll come to know when this Java standalone has stopped working. I'll move this script to crontab and make it run for every 1 minute, so that this whole process is automated. Log file location: /usr/local/logs/standalone.log

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Vim: Custom Folding for special doc

- by Matthias Guenther

Here is the code: package localhost import scala.tools.nsc.reporters._ import scala.tools.nsc.util.Position class MyReporter extends Reporter { /** <p> * Give message of an rejected program * </p> */ def info0(pos: Position, msg: String, severity: Severity, force: Boolean) = { severity match { case INFO => case WARNING => case ERROR => println("error on pos: " +pos+" message: "+msg) } } } So I want to to fold /** <p> * Give message of an rejected program * </p> */ to something like: /** */ How is this possible? Thanks for your help.

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Can't execute java files on command prompts when they work perfectly in Eclipse IDE, what to do?

- by Eduardo de Luna

I run the following code in Eclipse IDE: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!" ) ; } } And it renders the expected output. When getting into the command prompt (DOS) already in the directory, I type this javac HelloWorld.java And then this java HelloWorld And the output reads Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld <wrong name:learning/HelloWorld> With a whole lot more errors, learning being the name of my general package. What's wrong? I have installed Eclipse x86 SDK 4.2.0 together bit with the latest JRE and JDK both in 64 bit as well.

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PATH env variable on Mac OS X and/or Eclipse

- by Jason S

When I print out the path in bash, it prints this: /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin When I run System.out.println(System.getenv("PATH")); in Java running under Eclipse, it prints /usr/bin:/bin:/usr/sbin:/sbin How can I figure out why there is this discrepancy? I need to add /usr/local/bin to the PATH and make it available to Java apps under Eclipse. (note: I have made no modifications system paths, so these are the defaults set by the OS or perhaps by one or more of the applications i've installed.)

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How does hadoop decide what its nodes hostnames are?

- by Dan R

Currently the urls generated by the jobtracker & namenode return either hostnames like bubbles.local or just bubbles. These end up not resolving unless the client machine has specified these in their /etc/hosts file. When I run the hostname command on these machines it returns a hostname complete with the domain (E.G bubbles.example.com) Running a small java test on these machines InetAddress addr = InetAddress.getLocalHost(); byte[] ipAddr = addr.getAddress(); String hostname = addr.getHostName(); System.out.println(hostname); Produces output just like the hostname command. Where else could hadoop be grabbing a hostname to use in its jobtracker / namenode UI? This is occurring in clusters with Hadoop 1.0.3 and 1.0.4-SNAPSHOT from early august. The machines are running CentOS release 5.8 (Final). The generated URLs I'm referring to are like this http://example:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=/ or http://example.local:50075/browseDirectory.jsp?namenodeInfoPort=50070&dir=/

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"(401)Authorization Required" when making a web service call using Axis

- by Arun P Johny

Hi, I'm using apache axis to connect to my sugar crm instance. When I'm trying to connect to the instance it is throwing the following exception Exception in thread "main" AxisFault faultCode: {http://xml.apache.org/axis/}HTTP faultSubcode: faultString: (401)Authorization Required faultActor: faultNode: faultDetail: {}:return code: 401 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>401 Authorization Required</title> </head><body> <h1>Authorization Required</h1> <p>This server could not verify that you are authorized to access the document requested. Either you supplied the wrong credentials (e.g., bad password), or your browser doesn't understand how to supply the credentials required.</p> </body></html> {http://xml.apache.org/axis/}HttpErrorCode:401 (401)Authorization Required at org.apache.axis.transport.http.HTTPSender.readFromSocket(HTTPSender.java:744) at org.apache.axis.transport.http.HTTPSender.invoke(HTTPSender.java:144) at org.apache.axis.strategies.InvocationStrategy.visit(InvocationStrategy.java:32) at org.apache.axis.SimpleChain.doVisiting(SimpleChain.java:118) at org.apache.axis.SimpleChain.invoke(SimpleChain.java:83) at org.apache.axis.client.AxisClient.invoke(AxisClient.java:165) at org.apache.axis.client.Call.invokeEngine(Call.java:2784) at org.apache.axis.client.Call.invoke(Call.java:2767) at org.apache.axis.client.Call.invoke(Call.java:2443) at org.apache.axis.client.Call.invoke(Call.java:2366) at org.apache.axis.client.Call.invoke(Call.java:1812) at org.beanizer.sugarcrm.SugarsoapBindingStub.get_server_info(SugarsoapBindingStub.java:1115) at com.greytip.sugarcrm.GreytipCrm.main(GreytipCrm.java:42) This basically says that I do not have the authorization to the resource. The same code is working fine in my testing environment. Sugarsoap service = new SugarsoapLocator(); SugarsoapPortType port = service.getsugarsoapPort(new java.net.URL( SUGAR_CRM_LOCATION + "/soap.php")); System.out.println(port.get_server_info().getVersion()); User_auth userAuth = new User_auth(); userAuth.setUser_name("user_name"); MessageDigest md = MessageDigest.getInstance("MD5"); String password = getHexString(md.digest("password".getBytes())); userAuth.setPassword(password); // userAuth.setVersion("0.1"); Entry_value login = port.login(userAuth, "myAppName", null); String sessionID = login.getId(); Above code is used to connect to the Sugar CRM installation. here line "System.out.println(port.get_server_info().getVersion());" is throwing the exception. One difference I noticed between the test and production environment is when I used the soap url in the browser the production site pops up a 'Authentication Required' popup. When I gives my proxy username and password in this popup, it shows the soap request details. The same is applicable for the login url also. First it will ask for the 'Authentication' then it will take to the sugar crm login page? Is it a server security setting? If it is then how to set this user name and password using java in a web service call. The authentication required popup is same as the one which comes when we try to access the tomcat manager through a browser. Thanks

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Is Multicast broken for Android 2.0.1 (currently on the DROID) or am I missing something?

- by Gubatron

This code works perfectly in Ubuntu, in Windows and MacOSX, it also works fine with a Nexus-One currently running firmware 2.1.1. I start sending and listening multicast datagrams, and all the computers and the Nexus-One will see each other perfectly. Then I run the same code on a Droid (Firmware 2.0.1), and everybody will get the packets sent by the Droid, but the droid will listen only to it's own packets. This is the run() method of a thread that's constantly listening on a Multicast group for incoming packets sent to that group. I'm running my tests on a local network where I have multicast support enabled in the router. My goal is to have devices meet each other as they come on line by broadcasting packages to a multicast group. public void run() { byte[] buffer = new byte[65535]; DatagramPacket dp = new DatagramPacket(buffer, buffer.length); try{ MulticastSocket ms = new MulticastSocket(_port); ms.setNetworkInterface(_ni); //non loopback network interface passed ms.joinGroup(_ia); //the multicast address, currently 224.0.1.16 Log.v(TAG,"Joined Group " + _ia); while (true) { ms.receive(dp); String s = new String(dp.getData(),0,dp.getLength()); Log.v(TAG,"Received Package on "+ _ni.getName() +": " + s); Message m = new Message(); Bundle b = new Bundle(); b.putString("event", "Listener ("+_ni.getName()+"): \"" + s + "\""); m.setData(b); dispatchMessage(m); //send to ui thread } } catch (SocketException se) { System.err.println(se); } catch (IOException ie) { System.err.println(ie); } } Over here, is the code that sends the Multicast Datagram out of every valid network interface available (that's not the loopback interface). public void sendPing() { MulticastSocket ms = null; try { ms = new MulticastSocket(_port); ms.setTimeToLive(TTL_GLOBAL); List<NetworkInterface> interfaces = getMulticastNonLoopbackNetworkInterfaces(); for (NetworkInterface iface : interfaces) { //skip loopback if (iface.getName().equals("lo")) continue; ms.setNetworkInterface(iface); _buffer = ("FW-"+ _name +" PING ("+iface.getName()+":"+iface.getInetAddresses().nextElement()+")").getBytes(); DatagramPacket dp = new DatagramPacket(_buffer, _buffer.length,_ia,_port); ms.send(dp); Log.v(TAG,"Announcer: Sent packet - " + new String(_buffer) + " from " + iface.getDisplayName()); } } catch (IOException e) { e.printStackTrace(); } catch (Exception e2) { e2.printStackTrace(); } } Update (April 2nd 2010) I found a way to have the Droid's network interface to communicate using Multicast! _wifiMulticastLock = ((WifiManager) context.getSystemService(Context.WIFI_SERVICE)).createMulticastLock("multicastLockNameHere"); _wifiMulticastLock.acquire(); Then when you're done... if (_wifiMulticastLock != null && _wifiMulticastLock.isHeld()) _wifiMulticastLock.release(); After I did this, the Droid started sending and receiving UDP Datagrams on a Multicast group. gubatron

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BlackBerry - Facebook extended permissions

- by Max Gontar

Hi! I've just found a great sample of Facebook Connect on Blackberry by Eki Y. Baskoro, The following is a short HOWTO on using Facebook Connect on Blackberry. I created a simple Facade encapsulating the Facebook REST API as well as added 'rough' MVC approach for screen navigation. I have tested on JDE 4.5 using 8320 simulator. This is still work in progress and all work is GPLed. It works great for reading stuff. NB Don't forget to get Facebook App Key and set it in TestBB class. But now I want to post something on my wall. So I've add new method to FacebookFacade class using Stream.publish API: /*** * Publishes message to the stream. * @param message - message that will appear on the facebook stream * @param targetId - The ID of the user, Page, group, or event where * you are publishing the content. */ public void streamPublish(String message, String targetId) { Hashtable arguments = new Hashtable(); arguments.put("method", "stream.publish"); arguments.put("message", message); arguments.put("target_id", targetId); try { JSONObject result = new JSONObject( int new JSONTokener(sendRequest(arguments))); int errorCode = result.getInt("error_code"); if (errorCode != 0) System.out.println("Error Code: "+errorCode); } catch (Exception e) { System.out.println(e); } } /*** * Publishes message on current user wall. * @param message - message that will appear on the facebook stream */ public void postOnTheWall(String message) { String targetId = String.valueOf(getLoggedInUserId()); streamPublish(message, targetId); } This will return Error code 200, "The user hasn't authorized the application to perform this action" First I thought it's related with Facebook - Application Settings - Additional Permissions - Publish recent activity (one line stories) to my wall but even checked, no difference... Then I've found this post explains that issue related with extended permissions. This in turn should be fixed by modifying url a little in LoginScreen class : public LoginScreen(FacebookFacade facebookFacade) { this.facebookFacade = facebookFacade; StringBuffer data = new StringBuffer(); data.append("api_key=" + facebookFacade.getApplicationKey()); data.append("&connect_display=popup"); data.append("&v=1.0"); //revomed //data.append("&next=http://www.facebook.com/connect/login_success.html"); //added data.append("&next=http://www.facebook.com/connect/prompt_permissions.php?" + "api_key="+facebookFacade.getApplicationKey()+"&display=popup&v=1.0"+ "&next=http://www.facebook.com/connect/login_success.html?"+ "xxRESULTTOKENxx&fbconnect=true" + "&ext_perm=read_stream,publish_stream,offline_access"); data.append("&cancel_url=http://www.facebook.com/connect/login_failure.html"); data.append("&fbconnect=true"); data.append("&return_session=true"); (new FetchThread("http://m.facebook.com/login.php?" + data.toString())).start(); } Unfortunately it's not working. Still Error Code 200 in return to stream.publish request... Do you have any suggestions how to resolve this? Thank you!

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Real-time graphing in Java

- by thodinc

I have an application which updates a variable about between 5 to 50 times a second and I am looking for some way of drawing a continuous XY plot of this change in real-time. Though JFreeChart is not recommended for such a high update rate, many users still say that it works for them. I've tried using this demo and modified it to display a random variable, but it seems to use up 100% CPU usage all the time. Even if I ignore that, I do not want to be restricted to JFreeChart's ui class for constructing forms (though I'm not sure what its capabilities are exactly). Would it be possible to integrate it with Java's "forms" and drop-down menus? (as are available in VB) Otherwise, are there any alternatives I could look into? EDIT: I'm new to Swing, so I've put together a code just to test the functionality of JFreeChart with it (while avoiding the use of the ApplicationFrame class of JFree since I'm not sure how that will work with Swing's combo boxes and buttons). Right now, the graph is being updated immediately and CPU usage is high. Would it be possible to buffer the value with new Millisecond() and update it maybe twice a second? Also, can I add other components to the rest of the JFrame without disrupting JFreeChart? How would I do that? frame.getContentPane().add(new Button("Click")) seems to overwrite the graph. package graphtest; import java.util.Random; import javax.swing.JFrame; import org.jfree.chart.ChartFactory; import org.jfree.chart.ChartPanel; import org.jfree.chart.JFreeChart; import org.jfree.chart.axis.ValueAxis; import org.jfree.chart.plot.XYPlot; import org.jfree.data.time.Millisecond; import org.jfree.data.time.TimeSeries; import org.jfree.data.time.TimeSeriesCollection; public class Main { static TimeSeries ts = new TimeSeries("data", Millisecond.class); public static void main(String[] args) throws InterruptedException { gen myGen = new gen(); new Thread(myGen).start(); TimeSeriesCollection dataset = new TimeSeriesCollection(ts); JFreeChart chart = ChartFactory.createTimeSeriesChart( "GraphTest", "Time", "Value", dataset, true, true, false ); final XYPlot plot = chart.getXYPlot(); ValueAxis axis = plot.getDomainAxis(); axis.setAutoRange(true); axis.setFixedAutoRange(60000.0); JFrame frame = new JFrame("GraphTest"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); ChartPanel label = new ChartPanel(chart); frame.getContentPane().add(label); //Suppose I add combo boxes and buttons here later frame.pack(); frame.setVisible(true); } static class gen implements Runnable { private Random randGen = new Random(); public void run() { while(true) { int num = randGen.nextInt(1000); System.out.println(num); ts.addOrUpdate(new Millisecond(), num); try { Thread.sleep(20); } catch (InterruptedException ex) { System.out.println(ex); } } } } }

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Solr WordDelimiterFilter + Lucene Highlighter

- by Lucas

I am trying to get the Highlighter class from Lucene to work properly with tokens coming from Solr's WordDelimiterFilter. It works 90% of the time, but if the matching text contains a ',' such as "1,500" the output is incorrect: Expected: 'test 1,500 this' Observed: 'test 11,500 this' I am not currently sure whether it is Highlighter messing up the recombination or WordDelimiterFilter messing up the tokenization but something is unhappy. Here are the relevant dependencies from my pom: org.apache.lucene lucene-core 2.9.3 jar compile org.apache.lucene lucene-highlighter 2.9.3 jar compile org.apache.solr solr-core 1.4.0 jar compile And here is a simple JUnit test class demonstrating the problem: package test.lucene; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertTrue; import java.io.IOException; import java.io.Reader; import java.util.HashMap; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.TokenStream; import org.apache.lucene.queryParser.ParseException; import org.apache.lucene.queryParser.QueryParser; import org.apache.lucene.search.Query; import org.apache.lucene.search.highlight.Highlighter; import org.apache.lucene.search.highlight.InvalidTokenOffsetsException; import org.apache.lucene.search.highlight.QueryScorer; import org.apache.lucene.search.highlight.SimpleFragmenter; import org.apache.lucene.search.highlight.SimpleHTMLFormatter; import org.apache.lucene.util.Version; import org.apache.solr.analysis.StandardTokenizerFactory; import org.apache.solr.analysis.WordDelimiterFilterFactory; import org.junit.Test; public class HighlighterTester { private static final String PRE_TAG = "<b>"; private static final String POST_TAG = "</b>"; private static String[] highlightField( Query query, String fieldName, String text ) throws IOException, InvalidTokenOffsetsException { SimpleHTMLFormatter formatter = new SimpleHTMLFormatter( PRE_TAG, POST_TAG ); Highlighter highlighter = new Highlighter( formatter, new QueryScorer( query, fieldName ) ); highlighter.setTextFragmenter( new SimpleFragmenter( Integer.MAX_VALUE ) ); return highlighter.getBestFragments( getAnalyzer(), fieldName, text, 10 ); } private static Analyzer getAnalyzer() { return new Analyzer() { @Override public TokenStream tokenStream( String fieldName, Reader reader ) { // Start with a StandardTokenizer TokenStream stream = new StandardTokenizerFactory().create( reader ); // Chain on a WordDelimiterFilter WordDelimiterFilterFactory wordDelimiterFilterFactory = new WordDelimiterFilterFactory(); HashMap<String, String> arguments = new HashMap<String, String>(); arguments.put( "generateWordParts", "1" ); arguments.put( "generateNumberParts", "1" ); arguments.put( "catenateWords", "1" ); arguments.put( "catenateNumbers", "1" ); arguments.put( "catenateAll", "0" ); wordDelimiterFilterFactory.init( arguments ); return wordDelimiterFilterFactory.create( stream ); } }; } @Test public void TestHighlighter() throws ParseException, IOException, InvalidTokenOffsetsException { String fieldName = "text"; String text = "test 1,500 this"; String queryString = "1500"; String expected = "test " + PRE_TAG + "1,500" + POST_TAG + " this"; QueryParser parser = new QueryParser( Version.LUCENE_29, fieldName, getAnalyzer() ); Query q = parser.parse( queryString ); String[] observed = highlightField( q, fieldName, text ); for ( int i = 0; i < observed.length; i++ ) { System.out.println( "\t" + i + ": '" + observed[i] + "'" ); } if ( observed.length > 0 ) { System.out.println( "Expected: '" + expected + "'\n" + "Observed: '" + observed[0] + "'" ); assertEquals( expected, observed[0] ); } else { assertTrue( "No matches found", false ); } } } Anyone have any ideas or suggestions?

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