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  • Problem when scaling game screen in Libgdx

    - by Nicolas Martel
    Currently, I'm able to scale the screen by applying this bit of code onto an OrthographicCamera Camera.setToOrtho(true, Gdx.graphics.getWidth() / 2, Gdx.graphics.getHeight() / 2); But something quite strange is happening with this solution, take a look at this picture of my game below Seems fine right? But upon further investigation, many components are rendered off by one pixels, and the tiles all are. Take a closer look I circled a couple of the errors. Note that the shadow of the warrior I circled appears fine for the other warriors. Also keep in mind that everything is rendered at pixel-perfect precision when I disable the scaling. I actually thought of a possible source for the problem as I'm writing this but I decided to still post this because I would assume somebody else might run into the same issue.

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  • Naming your unit tests

    - by kerry
    When you create a test for your class, what kind of naming convention do you use for the tests? How thorough are your tests? I have lately switched from the conventional camel case test names to lower case letters with underscores. I have found this increases the readability and causes me to write better tests. A simple utility class: public class ArrayUtils { public static T[] gimmeASlice(T[] anArray, Integer start, Integer end) { // implementation (feeling lazy today) } } I have seen some people who would write a test like this: public class ArrayUtilsTest { @Test public void testGimmeASliceMethod() { // do some tests } } A more thorough and readable test would be: public class ArrayUtilsTest { @Test public void gimmeASlice_returns_appropriate_slice() { // ... } @Test public void gimmeASlice_throws_NullPointerException_when_passed_null() { // ... } @Test public void gimmeASlice_returns_end_of_array_when_slice_is_partly_out_of_bounds() { // ... } @Test public void gimmeASlice_returns_empty_array_when_slice_is_completely_out_of_bounds() { // ... } } Looking at this test, you have no doubt what the method is supposed to do. And, when one fails, you will know exactly what the issue is.

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  • libgdx draw issue and animation

    - by johnny-b
    it seems as though i cannot get the draw method to work??? it seems as though the bullet.draw(batcher) does not work and i cannot understand why as the bullet is a sprite. i have made a Sprite[] and added them as animation. could that be it? i tried batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY(), bullet.getOriginX() / 2, bullet.getOriginY() / 2, bullet.getWidth(), bullet.getHeight(), 1, 1, bullet.getRotation()); but that dont work, the only way it draws is this batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY()); below is the code. // this is in a Asset Class texture = new Texture(Gdx.files.internal("SpriteN1.png")); texture.setFilter(TextureFilter.Nearest, TextureFilter.Nearest); bullet1 = new Sprite(texture, 380, 350, 45, 20); bullet1.flip(false, true); bullet2 = new Sprite(texture, 425, 350, 45, 20); bullet2.flip(false, true); Sprite[] bullets = { bullet1, bullet2 }; bulletAnimation = new Animation(0.06f, bullets); bulletAnimation.setPlayMode(Animation.PlayMode.LOOP); // this is the GameRender class public class GameRender() { private Bullet bullet; private Ball ball; public GameRenderer(GameWorld world) { myWorld = world; cam = new OrthographicCamera(); cam.setToOrtho(true, 480, 320); batcher = new SpriteBatch(); // Attach batcher to camera batcher.setProjectionMatrix(cam.combined); shapeRenderer = new ShapeRenderer(); shapeRenderer.setProjectionMatrix(cam.combined); // Call helper methods to initialize instance variables initGameObjects(); initAssets(); } private void initGameObjects() { ball = GameWorld.getBall(); bullet = myWorld.getBullet(); scroller = myWorld.getScroller(); } private void initAssets() { ballAnimation = AssetLoader.ballAnimation; bulletAnimation = AssetLoader.bulletAnimation; } public void render(float runTime) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT); batcher.begin(); // Disable transparency // This is good for performance when drawing images that do not require // transparency. batcher.disableBlending(); // The ball needs transparency, so we enable that again. batcher.enableBlending(); batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight()); batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY()); // End SpriteBatch batcher.end(); } } // this is the gameworld class public class GameWorld { public static Ball ball; private Bullet bullet; private ScrollHandler scroller; public GameWorld() { ball = new Ball(480, 273, 32, 32); bullet = new Bullet(10, 10); scroller = new ScrollHandler(0); } public void update(float delta) { ball.update(delta); bullet.update(delta); scroller.update(delta); } public static Ball getBall() { return ball; } public ScrollHandler getScroller() { return scroller; } public Bullet getBullet() { return bullet; } } is there anyway so make the sprite work?

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  • how should I design Objects around this business requirement?

    - by brainydexter
    This is the business requirement: " A Holiday Package (e.g. New York NY Holiday Package) can be offered in different ways based on the Origin city: From New Delhi to NY From Bombay to NY NY itself ( Land package ) (Bold implies default selection) a. and b. User can fly from either New Delhi or Bombay to NY. c. NY is a Land package, where a user can reach NY by himself and is a standalone holidayPackage. " Let's say I have a class that represents HolidayPackage, Destination (aka City). public class HolidayPackage{ Destination holidayCity; ArrayList<BaseHolidayPackageVariant> variants; BaseHolidayPackageVariant defaultVariant; } public abstract class BaseHolidayPackageVariant { private Integer variantId; private HolidayPackage holidayPackage; private String holidayPackageType; } public class LandHolidayPackageVariant extends BaseHolidayPackageVariant{ } public class FlightHolidayPackageVariant extends BaseHolidayPackageVariant{ private Destination originCity; } What data structure/objects should I design to support: options a default within those options Sidenote: A HolidayPackage can also be offered in different ways based on Hotel selections. I'd like to follow a design which I can leverage to support that use case in the future. This is the backend design I have in mind.

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  • OpenGL ES 2 jittery camera movement

    - by user16547
    First of all, I am aware that there's no camera in OpenGL (ES 2), but from my understanding proper manipulation of the projection matrix can simulate the concept of a camera. What I'm trying to do is make my camera follow my character. My game is 2D, btw. I think the principle is the following (take Super Mario Bros or Doodle Jump as reference - actually I'm trying to replicate the mechanics of the latter): when the caracter goes beyond the center of the screen (in the positive axis/direction), update the camera to be centred on the character. Else keep the camera still. I did accomplish that, however the camera movement is noticeably jittery and I ran out of ideas how to make it smoother. First of all, my game loop (following this article): private int TICKS_PER_SECOND = 30; private int SKIP_TICKS = 1000 / TICKS_PER_SECOND; private int MAX_FRAMESKIP = 5; @Override public void run() { loops = 0; if(firstLoop) { nextGameTick = SystemClock.elapsedRealtime(); firstLoop = false; } while(SystemClock.elapsedRealtime() > nextGameTick && loops < MAX_FRAMESKIP) { step(); nextGameTick += SKIP_TICKS; loops++; } interpolation = ( SystemClock.elapsedRealtime() + SKIP_TICKS - nextGameTick ) / (float)SKIP_TICKS; draw(); } And the following code deals with moving the camera. I was unsure whether to place it in step() or draw(), but it doesn't make a difference to my problem at the moment, as I tried both and neither seemed to fix it. center just represents the y coordinate of the centre of the screen at any time. Initially it is 0. The camera object is my own custom "camera" which basically is a class that just manipulates the view and projection matrices. if(character.getVerticalSpeed() >= 0) { //only update camera if going up float[] projectionMatrix = camera.getProjectionMatrix(); if( character.getY() > center) { center += character.getVerticalSpeed(); cameraBottom = center + camera.getBottom(); cameraTop = center + camera.getTop(); Matrix.orthoM(projectionMatrix, 0, camera.getLeft(), camera.getRight(), center + camera.getBottom(), center + camera.getTop(), camera.getNear(), camera.getFar()); } } Any thought about what I should try or what I am doing wrong? Update 1: I think I updated every value you can see on screen to check whether the jittery movement is affected by that, but nothing changed, so something must be fundamentally flawed with my approach/calculations.

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  • How to fire a bullet in a specific direction?

    - by Mike
    I am developing an Android game. I have problem with bullet firing. It's a space ship that has to fire bullets but right now it's firing in a random direction. I have to fire a bullet to the enemy from the only one point on the nose of the ship. Right now the bullets fire sometimes from the tailpart or other. So that's a problem. How do I give a bullet direction and how to fire it from only the head of my space ship?

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  • What is a software prototype?

    - by Stack Stock
    I understand this site is for programmers, and i have to ask specific coding question. I am doing a software engineering degree and i have been asked to reference at-least 7 books in my definition of prototyping. The best place to ask is here because most of you have probably read books on this and would be able to recommend books to me. I dont mind buying them from Amazon so if you could some books for me that define prototyping or a prototype i would really appreciate it.

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  • Sending Graphics to the C drive [on hold]

    - by CodeOfGenius
    I'm trying to create image files on the users' desktop. Let's say i have a picture of an orange in my eclipse workspace in the resource folder. When somebody downloads the project, I want to take that image of an orange and put it in a folder called fruit on their desktop. Whenever i export my game it can't read the images anymore which is wierd so I prefer to try this method. Just like minecraft has its' stuff in %Appdata%, I want to put a folder with my images the game uses on the desktop. There isn't any errors, I'm just asking how do i do this.

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  • Multiple enemy array in LibGDX

    - by johnny-b
    I am trying to make a multiple enemy array, where every 30 secods a new bullet comes from a random point. And if the bullet is clicked it should disapear and a pop like an explosion should appear. And if the bullet hits the ball then the ball pops. so the bullet should change to a different sprite or texture. same with the ball pop. But all that happens is the bullet if touched pops and nothing else happens. And if modified then the bullet keeps flashing as the update is way too much. I have added COMMENTS in the code to explain more on the issues. below is the code. if more code is needed i will provide. Thank you public class GameRenderer { private GameWorld myWorld; private OrthographicCamera cam; private ShapeRenderer shapeRenderer; private SpriteBatch batcher; // Game Objects private Ball ball; private ScrollHandler scroller; private Background background; private Bullet bullet1; private BulletPop bPop; private Array<Bullet> bullets; // This is for the delay of the bullet coming one by one every 30 seconds. /** The time of the last shot fired, we set it to the current time in nano when the object is first created */ double lastShot = TimeUtils.nanoTime(); /** Convert 30 seconds into nano seconds, so 30,000 milli = 30 seconds */ double shotFreq = TimeUtils.millisToNanos(30000); // Game Assets private TextureRegion bg, bPop; private Animation bulletAnimation, ballAnimation; private Animation ballPopAnimation; public GameRenderer(GameWorld world) { myWorld = world; cam = new OrthographicCamera(); cam.setToOrtho(true, 480, 320); batcher = new SpriteBatch(); // Attach batcher to camera batcher.setProjectionMatrix(cam.combined); shapeRenderer = new ShapeRenderer(); shapeRenderer.setProjectionMatrix(cam.combined); // This is suppose to produce 10 bullets at random places on the background. bullets = new Array<Bullet>(); Bullet bullet = null; float bulletX = 00.0f; float bulletY = 00.0f; for (int i = 0; i < 10; i++) { bulletX = MathUtils.random(-10, 10); bulletY = MathUtils.random(-10, 10); bullet = new Bullet(bulletX, bulletY); AssetLoader.bullet1.flip(true, false); AssetLoader.bullet2.flip(true, false); bullets.add(bullet); } // Call helper methods to initialize instance variables initGameObjects(); initAssets(); } private void initGameObjects() { ball = GameWorld.getBall(); bullet1 = myWorld.getBullet1(); bPop = myWorld.getBulletPop(); scroller = myWorld.getScroller(); } private void initAssets() { bg = AssetLoader.bg; ballAnimation = AssetLoader.ballAnimation; bullet1Animation = AssetLoader.bullet1Animation; ballPopAnimation = AssetLoader.ballPopAnimation; } // This is to take the bullet away when clicked or touched. public void onClick() { for (int i = 0; i < bullets.size; i++) { if (bullets.get(i).getBounds().contains(0, 0)) bullets.removeIndex(i); } } private void drawBackground() { batcher.draw(bg1, background.getX(), background.getY(), background.getWidth(), backgroundMove.getHeight()); } public void render(float runTime) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT); batcher.begin(); // Disable transparency // This is good for performance when drawing images that do not require // transparency. batcher.disableBlending(); drawBackground(); batcher.enableBlending(); // when the bullet hits the ball, it should be disposed or taken away and a ball pop sprite/texture should be put in its place if (bullet1.collides(ball)) { // draws the bPop texture but the bullet does not go just keeps going around, and the bPop texture goes. batcher.draw(AssetLoader.bPop, 195, 273); } batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight()); // this is where i am trying to make the bullets come one by one, and if removed via the onClick() then bPop animation // should play but does not??? if(TimeUtils.nanoTime() - lastShot > shotFreq){ // Create your stuff for (int i = 0; i < bullets.size; i++) { bullets.get(i); batcher.draw(AssetLoader.bullet1Animation.getKeyFrame(runTime), bullet1.getX(), bullet1.getY(), bullet1.getOriginX(), bullet1.getOriginY(), bullet1.getWidth(), bullet1.getHeight(), 1.0f, 1.0f, bullet1.getRotation()); if (bullets.removeValue(bullet1, false)) { batcher.draw(AssetLoader.ballPopAnimation.getKeyFrame(runTime), bPop1.getX(), bPop1.getY(), bPop1.getWidth(), bPop1.getHeight()); } } /* Very important to set the last shot to now, or it will mess up and go full auto */ lastShot = TimeUtils.nanoTime(); } // End SpriteBatch batcher.end(); } } Thank you

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  • Ubuntu 12.04 version of Netbeans doesn't have the JavaFX plugin

    - by aliasbody
    I just want to know why does Netbeans 7.0.1 from the official Ubuntu 12.04 doesn't have all the plugins (in especial the JavaFX plugin) on it while the official Netbeans from the website (even the version with the less plugin), has it by default ? And how can we change that ? Because I love Ubuntu (even if it is extremly slow on my Asus 1215N (it is the only OS that is slow on it, but that's not very important), but I am trying to use it only with the software provided by the Original repositories without having to download manually or even use any PPA. Thanks in Advance

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  • GWT (Google Web Toolkit) Designer not working on Ubuntu 12.10

    - by Marian Lux
    The GWT Desinger is not working on Ubuntu 12.10. It worked on Ubuntu 12.04. I installed the Eclipse Plugin as described on the GWT Homepate If I want to open the Design-View (for an xml-GWT-File), Eclipse crashes (prompt closing of the application). I found this two workarounds for which are for 12.04 (but on 12.04 i did not need this to get it working - it worked out of the box for me). I tried them on my 12.10 Ubuntu but they are not working. But I have to say that I can't find the "Use WebKit for rendering GWT UI (if available)"-Flag. What can I do to get the GWT Designer working? I tested it successfully again on a 12.04 Ubuntu VMware image. If I don't get a solution, I have to downgrade my Ubuntu to 12.04 again.

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  • Is it time to deprecate synchronized, wait and notify?

    - by OldCurmudgeon
    Is there a single scenario (other than compatibility with ancient JVMs) where using synchronized is preferable to using a Lock? Can anyone justify using wait or notify over the newer systems? Is there any algorithm that must use one of them in its implementation? I see a previous questions that touched on this matter but I would like to take this a little further and actually deprecate them. There are far too many traps and pitfalls and caveats with them that have been ironed out with the new facilities. I just feel it may soon be time to mark them obsolete.

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  • 2D Side scroller collision detection

    - by Shanon Simmonds
    I am trying to do some collision detection between objects and tiles, but the tiles do not have there own x and y position, they are just rendered to the x and y position given, there is an array of integers which has the ids of the tiles to use(which are given from an image and all the different colors are assigned different tiles) int x0 = camera.x / 16; int y0 = camera.y / 16; int x1 = (camera.x + screen.width) / 16; int y1 = (camera.y + screen.height) / 16; for(int y = y0; y < y1; y++) { if(y < 0 || y >= height) continue; // height is the height of the level for(int x = x0; x < x1; x++) { if(x < 0 || x >= width) continue; // width is the width of the level getTile(x, y).render(screen, x * 16, y * 16); } } I tried using the levels getTile method to see if the tile that the object was going to advance to, to see if it was a certain tile, but, it seems to only work in some directions. Any ideas on what I'm doing wrong and fixes would be greatly appreciated. What's wrong is that it doesn't collide properly in every direction and also this is how I tested for a collision in the objects class if(!level.getTile((x + xa) / 16, (y + ya) / 16).isSolid()) { x += xa; y += ya; } EDIT: xa and ya represent the direction as well as the movement, if xa is negative it means the object is moving left, if its positive it is moving right, and same with ya except negative for up, positive for down.

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  • Collision checking problem on a Tiled map

    - by nosferat
    I'm working on a pacman styled dungeon crawler, using the free oryx sprites. I've created the map using Tiled, separating the floor, walls and treasure in three different layers. After importing the map in libGDX, it renders fine. I also added the player character, for now it just moves into one direction, the player cannot control it yet. I wanted to add collision and I was planning to do this by checking if the player's new position is on a wall tile. Therefore as you can see in the following code snippet, I get the tile type of the appropriate tile and if it is not zero (since on that layer there is nothing except the wall tile) it is a collision and the player cannot move further: final Vector2 newPos = charController.move(warrior.getX(), warrior.getY()); if(!collided(newPos)) { warrior.setPosition(newPos.x, newPos.y); warrior.flip(charController.flipX(), charController.flipY()); } [..] private boolean collided(Vector2 newPos) { int row = (int) Math.floor((newPos.x / 32)); int col = (int) Math.floor((newPos.y / 32)); int tileType = tiledMap.layers.get(1).tiles[row][col]; if (tileType == 0) { return false; } return true; } The character only moves one tile with this code: If I reduce the col value by two it two more tiles. I think the problem will be around indexing, but I'm totally confused because the zero in the coordinate system of libGDX is in the bottom left corner of the screen, and I don't know the tiles array's indexing is similair or not. The size of the map is 19x21 tiles and looks like the following (the starting position of the player is marked with blue:

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  • initial Class design: access modifiers and no-arg constructors

    - by yas
    Context: Student working through Class design in personal/side project for Summer. I've never written anything implemented by others or had to maintain code. Trying to maximize encapsulation and imagining what would make code easy to maintain. Concept: Tight/Loose Class design where Tight and Loose refer to access modifiers and constructors. Tight: initially, everything, including setters, is private and a no-arg constructor is not provided (only a full constructor). Loose: not Tight Exceptions: the obvious like toString Reasoning: If code, at the very beginning, is tight, then it should be guaranteed that changes, with respect to access/creation, should never damage existing implementations. The loosening of code happens incrementally and must be thought through, justified, and safe (validated). Benefit: Existing implementing code should not break if changes are made later. Cost: Takes more time to create. Since this is my own thinking, I hope to get feedback as to whether I should push to work this way. Good idea or bad idea?

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  • How do I efficiently generate chunks to fill entire screen when my player moves?

    - by Trixmix
    In my game I generate chunks when the player moves. The chunks are all generated on the fly, but currently I just created a simple flat 8X8 floor. What happens is that when he moves to a new chunk the chunk in the direction of the player gets generated and its neighboring chunks. This is not efficient because the generator does not fill the entire screen. I did try to use recursion but its not as fast as I would like it to be. My question is what would be an efficient way of doing so? How does minecraft do so? When I say this I mean just the way it PICKS which chunks to generate and in what order. Not how they generate or how they are saved in regions, just the order/way it generates them. I just want to know what is a good way to load chunks around the player.

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  • How can I write byte[] to socket outputstream and specify the end of file?

    - by Christopher Francisco
    I've googled 2 days straight and I can't find how to do this. I have an open stream between client and server, and client will send a JSON string (encrypted to bytes) to the server each 3 to 5 seconds. How can I write to the Socket OutputStream so that I can read each JSON string in the server. I'm guessing I need to specify some kind of end of file or something, but can't find any info on how to achieve this.

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  • Simple rendering produces minor stutter

    - by Ben
    For some reason, this game loop renders the movement of a simple rectangle with no stuttering. double currTime; double prevTime = System.nanoTime() / NANO_TO_SEC; double FPSTIMER = System.nanoTime(); double maxTimeDiff = 100.0 / 1000.0; double delta = 1.0 / 60.0; int processes = 0, frames = 0; while(true){ currTime = System.nanoTime() / NANO_TO_SEC; if(currTime - prevTime > maxTimeDiff) prevTime = currTime; if(currTime >= prevTime){ process(); processes++; prevTime += delta; if(currTime < prevTime){ render(); frames++; } } else{ try{ Thread.sleep((long) (1000 * (prevTime - currTime))); } catch(Exception e){} } if(System.nanoTime() - FPSTIMER > 1000000000.0){ System.out.println("Process: " + (1000 / processes) + "ms FPS: " + (1000 / frames) + "ms"); processes = frames = 0; FPSTIMER += 1000000000.0; } } But for this game loop, I get really minor stuttering where the movement does not look smooth. long prevTime = System.currentTimeMillis(); long prevRenderTime = 0; long currRenderTime = 0; long delta = 0; long msPerTick = 1000 / 60; int frames = 0; int ticks = 0; double FPSTIMER = System.currentTimeMillis(); while (true){ long currTime = System.currentTimeMillis(); delta += (currTime - prevTime) / msPerTick; prevTime = currTime; while (delta >= 1){ ticks++; process(); delta -= 1; } prevRenderTime = System.currentTimeMillis(); render(); frames++; currRenderTime = System.currentTimeMillis(); try{ Thread.sleep((long) ((1000 / FPS) - (currRenderTime - prevRenderTime))); } catch(Exception e){} if(System.currentTimeMillis() - FPSTIMER > 1000.0){ System.out.println("Process: " + (1000.0 / ticks) + "ms FPS: " + (1000.0 / frames) + "ms"); ticks = frames = 0; FPSTIMER += 1000.0; } Is there any critical difference that I'm missing here? The one thing I noticed is that if I uncap the fps for the second game loop, the stuttering goes away. It doesn't make sense to me. Also, the second game loop came from Notch's Minicraft code with just my thread sleeping code added in.

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  • Regex to String generation

    - by Mifmif
    Let's say that we have a regex and an index i , if we suppose that the set of string that match our regex are sorted in a lexicographical order, how could we get the i element of this list ? Edit : I added this simple example for more explanation : input : regex="[a-c]{1,2}"; index=4; in this case the ordered list of string that matches this regex contains those elements : a aa ab ac b ba bb bc c ca cb cc output : the 4th element which is ac ps: it's known that the string list that match the regex have infinite element, this doesn't have an impact on the proccess of extracting the element in the given index.

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  • Which VCS is more applicable for our workflow?

    - by Thomas Mancini
    Currently we have code stored on a shared network drive and do not use any kind of VCS. The code stored on our shared network drive is always being backed up. We would like to keep things as close to they are now as possible, while using some kind of VCS software. I am envisioning a centralized workflow with each developer having a local copy of the code on his/her machine. We don't do any branching or working offline. Typically when we spin off a new version we would just copy the current working directory to a new directory. I believe we would continue doing this and just create a repository for the new version. I would rather not get into an argument over which VCS is better, just hoping to get some opinions for which is best suited and most applicable for what we are trying to do.

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  • Movement in RPG

    - by user1264811
    I want to make an RPG game in which I move tile by tile. So when I hit up, the tile row that I am on decreases by one for example. Also, it's supposed to be a slow movement so that I can see the change in tile, i.e. I can see my sprite move from tile to tile. Currently, with the code I have, when I hit a direction on my keyboard, I move several blocks within seconds and by the time I release the button I have already gotten a nullPointerException error because I have left the map. How can I slow down the movement?

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  • I am trying to figure out the best way to understand how to cache domain objects

    - by Brett Ryan
    I've always done this wrong, I'm sure a lot of others have too, hold a reference via a map and write through to DB etc.. I need to do this right, and I just don't know how to go about it. I know how I want my objects to be cached but not sure on how to achieve it. What complicates things is that I need to do this for a legacy system where the DB can change without notice to my application. So in the context of a web application, let's say I have a WidgetService which has several methods: Widget getWidget(); Collection<Widget> getAllWidgets(); Collection<Widget> getWidgetsByCategory(String categoryCode); Collection<Widget> getWidgetsByContainer(Integer parentContainer); Collection<Widget> getWidgetsByStatus(String status); Given this, I could decide to cache by method signature, i.e. getWidgetsByCategory("AA") would have a single cache entry, or I could cache widgets individually, which would be difficult I believe; OR, a call to any method would then first cache ALL widgets with a call to getAllWidgets() but getAllWidgets() would produce caches that match all the keys for the other method invocations. For example, take the following untested theoretical code. Collection<Widget> getAllWidgets() { Entity entity = cache.get("ALL_WIDGETS"); Collection<Widget> res; if (entity == null) { res = loadCache(); } else { res = (Collection<Widget>) entity.getValue(); } return res } Collection<Widget> loadCache() { // Get widgets from underlying DB Collection<Widget> res = db.getAllWidgets(); cache.put("ALL_WIDGETS", res); Map<String, List<Widget>> byCat = new HashMap<>(); for (Widget w : res) { // cache by different types of method calls, i.e. by category if (!byCat.containsKey(widget.getCategory()) { byCat.put(widget.getCategory(), new ArrayList<Widget>); } byCat.get(widget.getCatgory(), widget); } cacheCategories(byCat); return res; } Collection<Widget> getWidgetsByCategory(String categoryCode) { CategoryCacheKey key = new CategoryCacheKey(categoryCode); Entity ent = cache.get(key); if (entity == null) { loadCache(); } ent = cache.get(key); return ent == null ? Collections.emptyList() : (Collection<Widget>)ent.getValue(); } NOTE: I have not worked with a cache manager, the above code illustrates cache as some object that may hold caches by key/value pairs, though it's not modelled on any specific implementation. Using this I have the benefit of being able to cache all objects in the different ways they will be called with only single objects on the heap, whereas if I were to cache the method call invocation via say Spring It would (I believe) cache multiple copies of the objects. I really wish to try and understand the best ways to cache domain objects before I go down the wrong path and make it harder for myself later. I have read the documentation on the Ehcache website and found various articles of interest, but nothing to give a good solid technique. Since I'm working with an ERP system, some DB calls are very complicated, not that the DB is slow, but the business representation of the domain objects makes it very clumsy, coupled with the fact that there are actually 11 different DB's where information can be contained that this application is consolidating in a single view, this makes caching quite important.

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  • WebFX: Running JavaFX as web page

    - by Bruno.Borges
    This weekend I wanted to learn JavaFX, so I decided to code an idea I had a few years ago when I first saw JavaFX Script. So I started coding a web browser that runs HTML with the awesome, HTML5 supported WebView. But this browser also offers one extra feature: it loads FXML files as if they were HTML. So instead of defining your web page with HTML and running with WebKit, you can define a web page with FXML+CSS+JS and run as a JavaFX application. The project is called WebFX and already has a prototype on GitHub. I also uploaded a video on YouTube demonstrating the idea. What do you think about using JavaFX in the future for web pages, instead of HTML?

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  • proper way to creation multiple similiar buttons/panels

    - by JayAvon
    I have the below Code which i tried to do, but it only shows(the minus/plus button) on the last GirdLayout (Intelligence stat): JButton plusButton = new JButton("+"); JButton minusButton = new JButton("-"); statStrengthGridPanel = new JPanel(new GridLayout(1,3)); statStrengthGridPanel.add(minusButton); statStrengthGridPanel.add(new JLabel("10")); statStrengthGridPanel.add(plusButton); statConstitutionGridPanel = new JPanel(new GridLayout(1,3)); statConstitutionGridPanel.add(minusButton); statConstitutionGridPanel.add(new JLabel("10")); statConstitutionGridPanel.add(plusButton); statDexterityGridPanel = new JPanel(new GridLayout(1,3)); statDexterityGridPanel.add(minusButton); statDexterityGridPanel.add(new JLabel("10")); statDexterityGridPanel.add(plusButton); statIntelligenceGridPanel = new JPanel(new GridLayout(1,3)); statIntelligenceGridPanel.add(minusButton); statIntelligenceGridPanel.add(new JLabel("10")); statIntelligenceGridPanel.add(plusButton); I know I can do something like I did for the Panel names(have multiple ones), but I did not want to do that for the Panels in the first place. I am trying to use best practice and not have my code be repetitive. Any suggestions?? The goal is to have 4 stats, to assign points to, with decrement and increment buttons(I decided against sliders). Eventually I will have them have upper and lower limits, decrement the "unused" label, and all of that good stuff, but I just want to not be repetitive. Thanks for any help.

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  • If-else statement comments [closed]

    - by Jin35
    Possible Duplicate: What is a good way to comment if-else-clauses? What is the best way to write comments for if-else statement? There is possible ways: A. //first comment if (condition) { ... } //second comment else { ... } B. if (condition) { //first comment ... } else { //second comment ... } C. if (condition) { //first comment ... } else { //second comment ... } Which one is the best, or there is some better possibilities?

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