Search Results

Search found 32961 results on 1319 pages for 'java'.

Page 472/1319 | < Previous Page | 468 469 470 471 472 473 474 475 476 477 478 479  | Next Page >

• Should I implement an interface directly or have the superclass do it?

  - by c_maker

  Is there a difference between public class A extends AbstractB implements C {...} versus... public class A extends AbstractB {...} AbstractB implements C {...} I understand that in both cases, class A will end up conforming to the interface. In the second case, AbstractB can provide implementation for interface methods in C. Is that the only difference? If I do NOT want to provide an implementation for any of the interface methods in AbstractB, which style should I be using? Does using one or the other have some hidden 'documentation' purpose?

  Read the article

• How to dynamically override a method in an object

  - by Ace Takwas

  If this is possible, how can I change what a method does after I might have created an instance of that class and wish to keep the reference to that object but override a public method in it's class' definition? Here's my code: package time_applet; public class TimerGroup implements Runnable{ private Timer hour, min, sec; private Thread hourThread, minThread, secThread; public TimerGroup(){ hour = new HourTimer(); min = new MinuteTimer(); sec = new SecondTimer(); } public void run(){ hourThread.start(); minThread.start(); secThread.start(); } /*Please pay close attention to this method*/ private Timer activateHourTimer(int start_time){ hour = new HourTimer(start_time){ public void run(){ while (true){ if(min.changed)//min.getTime() == 0) changeTime(); } } }; hourThread = new Thread(hour); return hour; } private Timer activateMinuteTimer(int start_time){ min = new MinuteTimer(start_time){ public void run(){ while (true){ if(sec.changed)//sec.getTime() == 0) changeTime(); } } }; minThread = new Thread(min); return min; } private Timer activateSecondTimer(int start_time){ sec = new SecondTimer(start_time); secThread = new Thread(sec); return sec; } public Timer addTimer(Timer timer){ if (timer instanceof HourTimer){ hour = timer; return activateHourTimer(timer.getTime()); } else if (timer instanceof MinuteTimer){ min = timer; return activateMinuteTimer(timer.getTime()); } else{ sec = timer; return activateSecondTimer(timer.getTime()); } } } So for example in the method activateHourTimer(), I would like to override the run() method of the hour object without having to create a new object. How do I go about that?

  Read the article

• Best Practice: What can be the hashCode() method implementation if custom field used in equals() method are null?

  - by goodspeed

  What is the best practice to return a value for hashCode() method if custom field used in equals are null ? I have a situation, where equals() override is implemented using custom fields. Usually it it is better to override hashCode() also using that custom fields used in equals(). But if all the custom fields used in equals() are null, then what would be the best implementation for hashCode()? Example: class Person { private String firstName; private String lastName; public String getFirstName() { return firstName; } public String getLastName() { return lastName; } @Override public boolean equals(Object object) { boolean result = false; if (object == null || object.getClass() != getClass()) { result = false; } else { Person person = (Person) object; if (this.firstName == person.getFirstName() && this.lastName == tiger.getLastName()) { result = true; } } return result; } @Override public int hashCode() { int hash = 3; if(this.firstName == null || this.lastName == null) { // <b>What is the best practice here, </b> // <b>is return super.hashCode() better ?</b> } hash = 7 * hash + this.firstName.hashCode(); hash = 7 * hash + this.lastName.hashCode(); return hash; } } is it required to check for null in hashCode() ? If yes, what should be returned if custom values are null ?

  Read the article

• Handling commands or events that wait for an action to be completed afterwards

  - by virulent

  Say you have two events: Action1 and Action2. When you receive Action1, you want to store some arbitrary data to be used the next time Action2 rolls around. Optimally, Action1 is normally a command however it can also be other events. The idea is still the same. The current way I am implementing this is by storing state and then simply checking when Action2 is called if that specific state is there. This is obviously a bit messy and leads to a lot of redundant code. Here is an example of how I am doing that, in pseudocode form (and broken down quite a bit, obviously): void onAction1(event) { Player = event.getPlayer() Player.addState("my_action_to_do") } void onAction2(event) { Player = event.getPlayer() if not Player.hasState("my_action_to_do") { return } // Do something } When doing this for a lot of other actions it gets somewhat ugly and I wanted to know if there is something I can do to improve upon it. I was thinking of something like this, which wouldn't require passing data around, but is this also not the right direction? void onAction1(event) { Player = event.getPlayer() Player.onAction2(new Runnable() { public void run() { // Do something } }) } If one wanted to take it even further, could you not simply do this? void onPlayerEnter(event) { // When they join the server Player = event.getPlayer() Player.onAction1(new Runnable() { public void run() { // Now wait for action 2 Player.onAction2(new Runnable() { // Do something }) } }, true) // TRUE would be to repeat the event, // not remove it after it is called. } Any input would be wonderful.

  Read the article

• Pattern for loading and handling resources

  - by Enoon

  Many times there is the need to load external resources into the program, may they be graphics, audio samples or text strings. Is there a patten for handling the loading and the handling of such resources? For example: should I have a class that loads all the data and then call it everytime I need the data? As in: GraphicsHandler.instance().loadAllData() ...//and then later: draw(x,y, GraphicsHandler.instance().getData(WATER_IMAGE)) //or maybe draw(x,y, GraphicsHandler.instance().WATER_IMAGE) Or should I assign each resource to the class where it belongs? As in (for example, in a game): Graphics g = GraphicsLoader.load(CHAR01); Character c = new Character(..., g); ... c.draw(); Generally speaking which of these two is the more robust solution? GraphicsHandler.instance().getData(WATER_IMAGE) //or GraphicsHandler.instance().WATER_IMAGE //a constant reference

  Read the article

• LIbgdx and android scaling

  - by petervaz

  Following my previous question, I decided to migrate my andengine game to libdgx to have the desktop option. The game assets were planned, at first, to use a 1080x600 resolution and I raised that to 1200x800 which is native for many tablets and would look better on monitors. I followed this blog aproach regarding aspect ratio, which worked nicely on the desktop version, but running the android version (on my smaller tablet), the background would still appear on the original size being cropped by the smaller screen size. How can I force the resize of the background (or for what matter, of everything) on android to fit the screen?

  Read the article

• LibGDX onTouch() method kill on touch

  - by johnny-b

  How can I add this on my application. i want to use the onTouch() method from the implementation of the InputProcessor to kill the enemies on screen. how do i do that? do i have to do anything to the enemy class? please help Thank you M @Override public boolean touchDown(int screenX, int screenY, int pointer, int button) { return false; } here is my enemy class public class Bullet extends Sprite { private Vector2 velocity; private float lifetime; public Bullet(float x, float y) { velocity = new Vector2(0, 0); } public void update(float delta) { float targetX = GameWorld.getBall().getX(); float targetY = GameWorld.getBall().getY(); float dx = targetX - getX(); float dy = targetY - getY(); float distToTarget = (float) Math.sqrt(dx * dx + dy * dy); velocity.x += dx * delta; velocity.y += dy * delta; } } i am rendering all graphics in a GameRender class and a gameworld class if you need more info please let me know Thank you

  Read the article

• Help with Meshes, and Shading

  - by Brian Diehr

  In a game I'm making in LibGdx, I wish to incorporate a ripple effect. I'm confused as to how I get access to the individual pixels on the screen, or any way to influence them (apart from what I can do with sprite batch). I have my suspicions that I have to do it through openGL, and it has something to do with apply a mesh? This brings me to my question, what exactly is a mesh? I've been working on my game for about half a year, and am doing great with the other aspects of the game, but I find this more advance stuff isn't as well documented. Thanks!

  Read the article

• How to stop reducing life? [closed]

  - by SystemNetworks

  CODE Input input = gc.getInput(); int xpos = Mouse.getX(); int ypos = Mouse.getY(); emu = "Enemy Life : " + enemyLife; Life = "Your Life Is" + life; Mousepos = "X:" + xpos + "Y:" + ypos; //test test1 = "Test INT" + test1int; if(!repeatStop) { //if this button is press, the damage will add up. When //pressed fight, it would start reducing the enemy health. if(input.isKeyPressed(Input.KEY_1)) { test1int += 1; } } if((xpos>1007 &xpos<1297)&&(ypos>881 && ypos<971)) { //Fight button if(Mouse.isButtonDown(0)){ finishTurn=true; } } //fight has started if(finishTurn==true) { //this would reduce the enemy life if(floodControl1==false) { enemyLife-=test1int; } //PROBLEM: Does not stop reducing! //the below code was not successful. It did not stop it // from reducing further. if(test1int>10) { floodControl1=true; } } QUESTION: Ok now, this is what is does. When I press the key, 1, it adds up the damage to the enemy. When I press fight, It will then start to reduce the enemy's health. Now my problem is, it kept on reducing and deducting it until negative! How do I deduct it to my desired damage (My desired damage is the one when press key 1)?

  Read the article

• How to disguise a serverside mob as another?

  - by Shaun Wild

  I've been working a Minecraft sever mod and i want to be able to add a new entity to the server, but then make the server send the packets to the client, imitating another mob, for example.. Lets say say i have EntityPlayerNPC.class, what i want to do is have all of the packets that get sent to the client look like they are from that of another player which is on the player, therefore allowing me to add custom NPC's... Thinking about the theory i'm sure this can be done. I've tried looking around for where the packets are being sent from and whatnot, can anyone think up a solution? edit: i tried adding a new constructor to the Packet20NamedEntitySpawn class like so: public Packet20NamedEntitySpawn(String username, EntityLiving e){ this.entityId = 0; this.name = username; this.xPosition = MathHelper.floor_double(e.posX * 32.0D); this.yPosition = MathHelper.floor_double(e.posY * 32.0D); this.zPosition = MathHelper.floor_double(e.posZ * 32.0D); this.rotation = (byte)((int)(e.rotationYaw * 256.0F / 360.0F)); this.pitch = (byte)((int)(e.rotationPitch * 256.0F / 360.0F)); this.metadata = e.getDataWatcher(); } unfortunatley, that didn't work :(

  Read the article

• How do I combine the two methods of cryptography, CBC cipher block and Vingenere Chiper [on hold]

  - by Bangpe

  Code Vingenere static String encrypt(String text, final String key) { String res = ""; text = text.toUpperCase(); for (int i = 0, j = 0; i < text.length(); i++) { char c = text.charAt(i); if (c < 'A' || c > 'Z') continue; res += (char)((c + key.charAt(j) - 2 * 'A') % 26 + 'A'); j = ++j % key.length(); } return res; } Code CBC Chiper public CbcBlockCipher( BlockCipher blockCipher ) { super( blockCipher.keySize(), blockCipher.blockSize() ); this.blockCipher = blockCipher; iv = new byte[blockSize()]; zeroBlock( iv ); temp = new byte[blockSize()]; }

  Read the article

• Why do we need private variables?

  - by rak

  Why do we need private variables in classes in the context of programming? Every book on programming I've read says this is a private variable, this is how you define it but stops there. The wording of these explanations always seemed to me like we really have a crisis of trust in our profession. The explanations always sounded like other programmers are out to mess up our code. Yet, there are many programming languages that do not have private variables. What do private variables help prevent? How do you decide if a particular of properties should be private or not? If by default every field SHOULD be private then why are there public data members in a class? Under what circumstances should a variable be made public?

  Read the article

• Android real time multiplayer over LAN

  - by Heigo

  I've developed several games for the android platform and now planning to create my first multiplayer game. What I have in mind is basically just a 2-player game witch you can play with 2 phones over local area connection/WiFi. Both phones need to be able to pass 3 integer values to the other phone in real time. So far I have considered using Socket's, but before I dig into it too deep I wanted to ask if there might be a better approach? Thanks!

  Read the article

• How to manage the images for my Desktop Application

  - by NonExistent

  What's the better way to manage the image files of my app? i've been thinking about the way that i do right now (save the image as a BLOB IN db), and i ask myself if would be better to manage the image as text in my DB, i mean, convert the image to hex(length of 500), then save in the db as text, and when calling it convert it from hex to image, or something like that, but what do you consider as an Experienced Progammer that is the better way? Maybe the question is too broad, but i need to know that, and nobody answers me anywhere...

  Read the article

• Collision Detection within Player/Enemy Class

  - by user1264811

  I'm making a 2D platform game. Right now I'm just working on making a very generic Player class. I'm wondering if it would be more efficient/better practice to have an ActionListener within the Player class to detect collisions with Enemy objects (also have an ActionListener) or to handle all the collisions in the main world. Furthermore, I'm thinking ahead about how I will handle collisions with the platforms themselves. I've looked into the double boolean arrays to see which tiles players can go to and which they can't. I don't understand how to use this class and the player class at the same time. Thank you.

  Read the article

• Access Token Verification

  - by DecafCoder

  I have spent quite a few days reading up on Oauth and token based security measures for REST API's and I am currently looking at implementing an Oauth based authentication approach almost exactly like the one described in this post (OAuth alternative for a 2 party system). From what I understand, the token is to be verified upon each request to the resource server. This means the resource server would need to retrieve the token from a datastore to verify the clients token. Given this would have to happen upon every request I am concerned about the speed implications of hitting a datastore like MySQL or NoSQL upon every request just to verify the token. Is this the standard way to verify tokens by having them stored in a RDBMS or NoSQL database and retrieved upon each request? Or is it a suitable solution to have them cached (baring in mind that we are talking millions of users)?

  Read the article

• Android game scrolling background

  - by Stevanicus

  Hi There, I'm just trying to figure out the best approach for running a scolling background on an android device. The method I have so far.... its pretty laggy. I use threads, which I believe is not the best bet for android platforms @Override public void run() { // Game Loop while(runningThread){ //Scroll background down bgY += 1; try { this.postInvalidate(); t.sleep(10); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } } where postinvalidate in the onDraw function simply pushings the background image down canvas.drawBitmap(backgroundImage, bgX, bgY, null); Thanks in advance

  Read the article

• What OO Design to use ( is there a Design Pattern )?

  - by Blundell

  I have two objects that represent a 'Bar/Club' ( a place where you drink/socialise). In one scenario I need the bar name, address, distance, slogon In another scenario I need the bar name, address, website url, logo So I've got two objects representing the same thing but with different fields. I like to use immutable objects, so all the fields are set from the constructor. One option is to have two constructors and null the other fields i.e: class Bar { private final String name; private final Distance distance; private final Url url; public Bar(String name, Distance distance){ this.name = name; this.distance = distance; this.url = null; } public Bar(String name, Url url){ this.name = name; this.distance = null; this.url = url; } // getters } I don't like this as you would have to null check when you use the getters In my real example the first scenario has 3 fields and the second scenario has about 10, so it would be a real pain having two constructors, the amount of fields I would have to declare null and then when the object are in use you wouldn't know which Bar you where using and so what fields would be null and what wouldn't. What other options do I have? Two classes called BarPreview and Bar? Some type of inheritance / interface? Something else that is awesome?

  Read the article

• Where Are Multiple JUnit Test Methods Typically Placed in Code?

  - by Thunderforge

  I've just read the Vogella JUnit tutorial and found it very helpful in understanding how to use JUnit. However, I'm a bit confused about what the convention is for placing multiple test methods in code. The tutorial only places one test method in a class, then describes how you can use a test suite to group multiple test classes together. Does this mean that it's common practice for each test class to only have one test method and then test suites are used to chain them together? Or was that just unintended and instead common practice is to put multiple test methods in a class?

  Read the article

• using NetBeans for rotate a figure in a label [migrated]

  - by user134812

  I was reading this post: http://forums.netbeans.org/post-8864.html and what I have done so far is to make a jFrame in NetBeans, on it I have drawn a jPanel and inisde the panel I have drawn a jLabel on it and use the icon property to put an image on it; until now all is so far so good. I would like to make a program that everytime I click on the figure it rotates it to the right. Actually I have found the following code: public class RotateImage extends JPanel{ // Declare an Image object for us to use. Image image; // Create a constructor method public RotateImage(){ super(); // Load an image to play with. image = Toolkit.getDefaultToolkit().getImage("Duke_Blocks.gif"); } public void paintComponent(Graphics g){ Graphics2D g2d=(Graphics2D)g; // Create a Java2D version of g. g2d.translate(170, 0); // Translate the center of our coordinates. g2d.rotate(1); // Rotate the image by 1 radian. g2d.drawImage(image, 0, 0, 200, 200, this); } but for what I see this code is for making the panel and other components from scratch, for my purposes it is not so good because I need to put several figures on my jFrame. Could somebody can give me a hint how to do this?

  Read the article

• What would be the market life of a JVM based software framework?

  - by Nav

  I saw how Struts 1 lasted from 2000 to 2013. I hear that people are moving from Struts 2 to Spring. But for a project that may need to be maintained for a decade or two, would it be advisable to opt for a framework or directly code with servlets and jquery? Can a system architecture really be designed keeping in mind a particular framework? What really is the market life of a framework? Do the creators of the framework create it with the assumption that it would become obsolete in a decade?

  Read the article

• Lwjgl camera causing movement to be mirrored

  - by pangaea

  I'm having a problem in that everything is rendered and the movement is fine. However, everything seems to be mirrored. In the sense that the TriangleMob should move towards me, but it doesn't instead it mirrors my action. I move forward the TriangleMob moves backwards. I move left, it moves right. I move backwards, it moves forward. The code works if I do this glPushMatrix(); glTranslatef(-position.x, -position.y, -position.z); glCallList(objectDisplayList); glPopMatrix(); However, I'm scared this will cause a problem later on. I suppose the code works. However, shouldn't the call be glPushMatrix(); glTranslatef(position.x, position.y, position.z); glCallList(objectDisplayList); glPopMatrix(); I think the problem could be caused by how I'm doing the camera, which is this glLoadIdentity(); glRotatef(player.getRotation().x, 1.0f, 0.0f, 0.0f); glRotatef(player.getRotation().y, 0.0f, 1.0f, 0.0f); glRotatef(player.getRotation().z, 0.0f, 0.0f, 1.0f); glTranslatef(player.getPosition().x, player.getPosition().y, player.getPosition().z);

  Read the article

• Use constructor or setter method?

  - by user633600

  I am working on a UI code where I have an Action class, something like this - public class MyAction extends Action { public MyAction() { setText("My Action Text"); setToolTip("My Action Tool tip"); setImage("Some Image"); } } When this Action class was created it was pretty much assumed that the Action class wont be customizable (in a sense- its text, tooltip or image will be not be changed anywhere in the code). Of late, now we are in need of changing the action text at some location in code. So I suggested my co-worker to remove the hardcoded action text from the constructor and accept it as an argument, so that everybody is forced to pass the action text. Something like this code below - public class MyAction extends Action { public MyAction(String actionText) { setText(actionText); setTooltip("My Action tool tip); setImage("My Image"); } } He however thinks that since setText() method belongs to base class. It can be flexibly used to pass the action text wherever action instance is created. That way, there is no need to change the existing MyAction class. So his code would look something like this. MyAction action = new MyAction(); //this creates action instance with the hardcoded text action.setText("User required new action text"); //overwrite the exisitng text. I am not sure if that is a correct way to deal with problem. I think in above mentioned case user is anyway going to change the text, so why not force him while constructing the action. The only benefit I see with the original code is that user can create Action class without much thinking about setting text.

  Read the article

• Legality of modifying and distributing the JRE

  - by herpylderp

  I see that Google App Engine apps run on a so-called secured sandbox JRE; that is, a JRE that Google modified and that makes changes to certain JRE types. This is how GAE prevents developers from writing apps that can do things like: Access the local file system via File Make remote JDBC calls Use JNDI Lots of other restrictions We have a similar need where we have an app that developers will be able to write plugins for. These plugins will need to utilize an API (a JAR) that we distribute with our app. We cannot afford for plugins to do certain things, particularly on the end user's file system, and need to modify the File class in a similar manner that GAE does. Long back-story short, this means we'll need to ship our app with a custom, modified JRE. My question: is this legal to do, or did Google likely pay Oracle some fee to modify/distribute their own JRE for app engine?

  Read the article

• How come I cannot make this file executable (chmod permissions)?

  - by bappi48

  I downloaded Android Development Tool for linux (ADT) and placed it in home directory. After unzipping the files, when I double click the "eclipse" executable file; the eclipse works perfectly fine. But If I unzip the ADT in a different directory, in my case directory E: (is shown when I boot in windows 7) There double clicking the same "eclipse" executable file does not run eclipse. It shows error message: Could not display /media/Software/00.AndroidLinux/ADT/eclipse/eclipse. There is no application installed for executable files. Do you want to search for an application to open this file? If I press yes in the Dialog, it finds "Pypar2" which is not my solution. I found that the "eclipse" file permission is following -rw------- 1 tanvir tanvir 63050 Feb 4 19:05 eclipse I tried to change the permission by "chmod +x eclipse" , but no use. This command does not change the file permission at all in this case. what should I do? Relevant output of cat /proc/mounts: /dev/sda6 /media/Software fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0 Please not that I'm new to Ubuntu and still learning day by day.

  Read the article

< Previous Page | 468 469 470 471 472 473 474 475 476 477 478 479  | Next Page >