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  • Java encryption : with method can get me a shorter message ?

    - by Frank
    I don't know too much about encryption, I just want to ask, which method can get me the shortest result message ? For instance, the message looks like this : "This is the secret input message", I wonder if the encrypted message can be shorter then the above 32 characters long ? Maybe something like "dfkfjkvf12". Frank

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  • How to authenticate my own provider( only for testing purposes)

    - by user308806
    Dear all Now, I wrote a new provider (ESMJCE provider), and I also write a simple application to test it, but I have some exceptions like that java.lang.SecurityException: JCE cannot authenticate the provider ESMJCE at javax.crypto.Cipher.getInstance(DashoA13*..) at javax.crypto.Cipher.getInstance(DashoA13*..) at testprovider.main(testprovider.java:27) Caused by: java.util.jar.JarException: Cannot parse file:/C:/Program%20Files/Java/jre1.6.0_02/lib/ext/abc.jar at javax.crypto.SunJCE_c.a(DashoA13*..) at javax.crypto.SunJCE_b.b(DashoA13*..) at javax.crypto.SunJCE_b.a(DashoA13*..) ... 3 more And here is my source code import java.security.Provider; import java.security.Security; import javax.crypto.Cipher; import esm.jce.provider.ESMProvider; public class testprovider { / @param args / public static void main(String[] args) { // TODO Auto-generated method stub ESMProvider esmprovider = new esm.jce.provider.ESMProvider(); Security.insertProviderAt(esmprovider,2); Provider[] temp = Security.getProviders(); for (int i= 0; i<temp.length; i++){ System.out.println("Providers: " temp[i].getName()); } try{ Cipher cipher = Cipher.getInstance("DES", "ESMJCE"); System.out.println("Cipher: " cipher); int blockSize= cipher.getBlockSize(); System.out.println("blockSize= " + blockSize); }catch (Exception e){ e.printStackTrace(); } } } Please help me solve this issue Thanks

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  • What's the best way to learn .NET?

    - by duffymo
    I've been developing Java EE for quite a while now. I've used WebLogic, Tomcat, Spring, and Hibernate extensively, so I have a mental model of what features are available and how things are developed and deployed. The problem that I have with .NET is that I don't have a clear mapping of its features onto Java EE. Here's what I know so far: Java EE - .NET Java - C# JAR - DLL WAR - ? (deployment in general) EAR - ? (deployment in general) Tomcat - IIS web server JSP - ASP? JDBC - ODBC JMS - MSMQ JTA - Microsoft Transaction Manager So much of the functionality that WebLogic handles appears to be dispersed throughout the Windows OS. My confusion kicks in when I see the waves of books at Borders - VB.NET, ASP.NET, C#, etc. If I'm not a VB programmer, would it be possible to stick with C# and write enterprise apps that are the equivalent of what I'm used to with Java EE? If there were a Top Three list of books to learn from, what would they be? The "Head First" series has certainly been successful for Java. http://www.amazon.com/Head-First-C-Brain-Friendly-Guides/dp/0596514824/ref=sr_1_1?ie=UTF8&s=books&qid=1224121193&sr=8-1 Equally well recommended for .NET learning? Thanks. - %

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  • Read from one large file and write to many (tens, hundreds, or thousands) files in Java?

    - by Rudiger
    I have a large-ish file (4-5 GB compressed) of small messages that I wish to parse into approximately 6,000 files by message type. Messages are small; anywhere from 5 to 50 bytes depending on the type. Each message starts with a fixed-size type field (a 6-byte key). If I read a message of type '000001', I want to write append its payload to 000001.dat, etc. The input file contains a mixture of messages; I want N homogeneous output files, where each output file contains only the messages of a given type. What's an efficient a fast way of writing these messages to so many individual files? I'd like to use as much memory and processing power to get it done as fast as possible. I can write compressed or uncompressed files to the disk. I'm thinking of using a hashmap with a message type key and an outputstream value, but I'm sure there's a better way to do it. Thanks!

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  • Separate functionality depending on Role in ASP.NET MVC

    - by Andrew Bullock
    I'm looking for an elegant pattern to solve this problem: I have several user roles in my system, and for many of my controller actions, I need to deal with slightly different data. For example, take /Users/Edit/1 This allows a Moderator to edit a users email address, but Administrators to edit a user's email address and password. I'd like a design for separating the two different bits of action code for the GET and the POST. Solutions I've come up with so far are: Switch inside each method, however this doesn't really help when i want different model arguments on the POST :( Custom controller factory which chooses a UsersController_ForModerators and UsersController_ForAdmins instead of just UsersController from the controller name and current user role Custom action invoker which choose the Edit_ForModerators method in a similar way to above Have an IUsersController and register a different implementation of it in my IoC container as a named instance based on Role Build an implementation of the controller at runtime using Castle DynamicProxy and manipulate the methods to those from role-based implementations Im preferring the named IoC instance route atm as it means all my urls/routing will work seamlessly. Ideas? Suggestions?

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  • Java IO (javase 6)- Help me understand the effects of my sample use of Streams and Writers...

    - by Daddy Warbox
    BufferedWriter out = new BufferedWriter( new OutputStreamWriter( new BufferedOutputStream( new FileOutputStream("out.txt") ) ) ); So let me see if I understand this: A byte output stream is opened for file "out.txt". It is then fed to a buffered output stream to make file operations faster. The buffered stream is fed to an output stream writer to bridge from bytes to characters. Finally, this writer is fed to a buffered writer... which adds another layer of buffering? Hmm...

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  • Why does using Collections.emptySet() with generics work in assignment but not as a method parameter

    - by Karl von L
    So, I have a class with a constructor like this: public FilterList(Set<Integer> labels) { ... } and I want to construct a new FilterList object with an empty set. Following Joshua Bloch's advice in his book Effective Java, I don't want to create a new object for the empty set; I'll just use Collections.emptySet() instead: FilterList emptyList = new FilterList(Collections.emptySet()); This gives me an error, complaining that java.util.Set<java.lang.Object> is not a java.util.Set<java.lang.Integer>. OK, how about this: FilterList emptyList = new FilterList((Set<Integer>)Collections.emptySet()); This also gives me an error! Ok, how about this: Set<Integer> empty = Collections.emptySet(); FilterList emptyList = new FilterList(empty); Hey, it works! But why? After all, Java doesn't have type inference, which is why you get an unchecked conversion warning if you do Set<Integer> foo = new TreeSet() instead of Set<Integer> foo = new TreeSet<Integer>(). But Set<Integer> empty = Collections.emptySet(); works without even a warning. Why is that?

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  • Reports in Java. What tool to use?

    - by Tom
    Hi, I need to create some reports, in different formats (xls, pdf, rtf). I am currently using JasperReports, in conjunction with IReport. I have no major complaints about it (except for the cases when IReport messes up my xml files), but i've been having some problems with it, when exporting to xls files and with some "special" characters, such as '&'. Is there a widely use alternative? Is JasperReports the right choice?

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  • How to represent a Board Panel in Java for a game ? [+code]

    - by FILIaS
    I wanna fix a 2D board for a game. I've already fixed other panels for the Gui and everything goes well. But the panel for the board cant be printed on the window. I'm a bit confused about it as i think i've followed the same ideas as for the others panels i need. Here's what i've done: EDIT:*EDIT* what i'm trying to do is fix a board panel for the game according to the dimensions of the it,hold every square in an array in order to use it after wherever it;s needed. I draw each little square of it with the method draw and put it back to the panel. So, each square on the board is a panel. This is the idea. But as u can see. There are troubles/errors on it. EDIT: code updated. just found a part of the problem. i thought first that i had set background to squared, but i didnt. with this one it appears on the panel a wide black "column". Unfortunately,still none squares. :( One More EDIT: Also,i realized that draw method is never called. when i put the draw method in the following method i can see the squares but they remain small. I redefine them with setSize but still no change. /** *Method used to construct the square in the area of the *gui's grid. In this stage a GUISquare array is being constructed, * used in the whole game as *a mean of changing a square graphical state. *@param squares is the squares array from whom the gui grid will be *constructed. *@see getSquare about the correspondance beetween a squareModel and * a GUISquare. */ private void initBoardPanel(SquareModel[][] squares){ BoardPanel.setLayout(new GridLayout(height ,width )); //set layout SquareRenderer[][] Squares; JPanel[][] grid; Squares=new GUISquare[height][width()]; grid=new JPanel[height()][width()]; for (int i=0; i<height(); i++){ for (int j=0; j<width() ; j++){ grid[i][j] = new JPanel( ); SquareRenderer kout=new SquareRenderer(i,j); koutaki.setSquare(myGame.getSquares()[i][j]); if (myGame.getSquares()[i][j] instanceof SimpleSquareModel){ kout.draw(i,j,"");} else { kout.draw(i,j); } kout.setVisible(true); kout.setBackground(Color.BLACK); kout.setSize(50,50); Squares[i][j]= kout; grid[i][j].setSize(50,50); grid[i][j].setVisible(true); grid[i][j].setBackground(Color.BLACK); BoardPanel.add(kout); BoardPanel.setVisible(true); BoardPanel.setBackground(Color.WHITE); } } this.add(BoardPanel,BorderLayout.WEST); // this.pack(); //sets appropriate size for frame this.setVisible(true); //makes frame visible } IMPLEMENTED BY SQUARERENDERER: /** * Transformer for Snake/Ladder * <br>This method is used to display a square on the screen. */ public void draw(int i,int j) { JPanel panel = new JPanel(); panel.setLayout(new BorderLayout()); JLabel label1 = new JLabel("Move To"+myGame.getSquares()[i][j].getGoTo()); JLabel label2 = new JLabel(""+myGame.getSquares()[i][j].getSquare()); JSeparator CellSeparator = new JSeparator(orientation); panel.add(CellSeparator); panel.setForeground(Color.ORANGE); panel.add(label2, BorderLayout.NORTH); panel.add(label1, BorderLayout.CENTER); }

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  • why PaintComponent event in Java happen everytime I use its Graphics Event?

    - by Pooya
    Consider this code: public class StateChartPanel extends JPanel { private LightContext LC; public StateChartPanel(LightContext lc){ LC=lc; } public void paintComponent( Graphics G ){ super.paintComponent( G ); LC.DrawStateChart((Graphics2D)G); } } StateChartPanel is a panel to draw something (a state chart). It sends its Graphics object to LC which use it to draw shapes but whenever it draws something the PaintComponent event of StateChartPanel happens again and it causes my application to hang.

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  • using compareTo in Binary Search Tree program

    - by Scott Rogener
    I've been working on this program for a few days now and I've implemented a few of the primary methods in my BinarySearchTree class such as insert and delete. Insert seemed to be working fine, but once I try to delete I kept getting errors. So after playing around with the code I wanted to test my compareTo methods. I created two new nodes and tried to compare them and I get this error: Exception in thread "main" java.lang.ClassCastException: TreeNode cannot be cast to java.lang.Integer at java.lang.Integer.compareTo(Unknown Source) at TreeNode.compareTo(TreeNode.java:16) at BinarySearchTree.myComparision(BinarySearchTree.java:177) at main.main(main.java:14) Here is my class for creating the nodes: public class TreeNode<T> implements Comparable { protected TreeNode<T> left, right; protected Object element; public TreeNode(Object obj) { element=obj; left=null; right=null; } public int compareTo(Object node) { return ((Comparable) this.element).compareTo(node); } } Am I doing the compareTo method all wrong? I would like to create trees that can handle integers and strings (seperatly of course)

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  • How can I print the argument value that caused Exception in Java?

    - by Sanoj
    I am writing a parser for csv-files, and sometimes I get NumberFormatException. Is there an easy way to print the argument value that caused the exception? For the moment do I have many try-catch blocks that look like this: String ean; String price; try { builder.ean(Long.parseLong(ean)); } catch (NumberFormatException e) { System.out.println("EAN: " + ean); e.printStackTrace(); } try { builder.price(new BigDecimal(price)); } catch (NumberFormatException e) { System.out.println("Price: " + price); e.printStackTrace(); } I would like to be able to write something like: try { builder.ean(Long.parseLong(ean)); } catch (NumberFormatException e) { e.printMethod(); // Long.parseLong() e.printArgument(); // should print the string ean "99013241.23" e.printStackTrace(); } Is there any way that I at least can improve my code? And do this kind of printing/logging more programmatically?

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  • How to perform different operations within Observer's update() in Java?

    - by Nazgulled
    I just started playing with Observable, Observer and it's update() method and I can't understand what should I do when different actions call notifyObservers(). I mean, my Observable class has a few different methods that call setChanged() and notifyObservers() in the end. Depending on the called method, some part of the UI (Swing) needs to be updated. However, there is only one update() method implemented in the Observer class. I though of passing something to the notifyObservers() method and then I can check the argument on update() but it doesn't seem feel like a good way to do it. Even if it did, what should I pass? A string with a short description of the action/method? And int, like an action/method code? Something else? What's the best way to handle this situation?

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  • How to make video in Java captured from webcam through lti-Civil CaptureDeviceStream ?

    - by i.Psi
    Can I do it only with the lti-Civil classes or I need FMJ or JMF ? do I use the actual Stream or set of captured Images from CaptureObserver? Thanks. captureStream = system.openCaptureDeviceStream(info.getDeviceID()); captureStream.setObserver(new CaptureObserver(){ public void onError(CaptureStream arg0, CaptureException arg1) { } public void onNewImage(CaptureStream streamSource, Image image) { try { imageFrame.setImage(AWTImageConverter.toBufferedImage(image)); bufferedImage = AWTImageConverter.toBufferedImage(image); } catch (Throwable t) { t.printStackTrace(); } } }); captureStream.start();

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  • Can I call make runtime decided method calls in Java?

    - by Catalin Marin
    I know there is an invoke function that does the stuff, I am overall interested in the "correctness" of using such a behavior. My issue is this: I have a Service Object witch contains methods which I consider services. What I want to do is alter the behavior of those services without later intrusion. For example: class MyService { public ServiceResponse ServeMeDonuts() { do stuff... return new ServiceResponse(); } after 2 months I find out that I need to offer the same service to a new client app and I also need to do certain extra stuff like setting a flag, or make or updating certain data, or encode the response differently. What I can do is pop it up and throw down some IFs. In my opinion this is not good as it means interaction with tested code and may result in un wanted behaviour for the previous service clients. So I come and add something to my registry telling the system that the "NewClient" has a different behavior. So I'll do something like this: public interface Behavior { public void preExecute(); public void postExecute(); } public class BehaviorOfMyService implements Behavior{ String method; String clientType; public void BehaviorOfMyService(String method,String clientType) { this.method = method; this.clientType = clientType; } public void preExecute() { Method preCall = this.getClass().getMethod("pre" + this.method + this.clientType); if(preCall != null) { return preCall.invoke(); } return false; } ...same for postExecute(); public void preServeMeDonutsNewClient() { do the stuff... } } when the system will do something like this if(registrySaysThereIs different behavior set for this ServiceObject) { Class toBeCalled = Class.forName("BehaviorOf" + usedServiceObjectName); Object instance = toBeCalled.getConstructor().newInstance(method,client); instance.preExecute(); ....call the service... instance.postExecute(); .... } I am not particularly interested in correctness of code as in correctness of thinking and approach. Actually I have to do this in PHP, witch I see as a kind of Pop music of programming which I have to "sing" for commercial reasons, even though I play POP I really want to sing by the book, so putting aside my more or less inspired analogy I really want to know your opinion on this matter for it's practical necessity and technical approach. Thanks

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  • Java Properties and References -- I'm not getting what I expect.

    - by Blumer
    I'm a little embarrassed to ask this as I ought to know better, but here's what I've got. I have an object "Pitcher" with an int property of "runsAllowed". I have an object Batter that has a property of "responsiblePitcher". I have an object Team that has a property "pitcher". When the batter reaches base: Batter.responsiblePitcher = Team.pitcher; All that's well and good. However, if we have a pitching change while the runner is on base, I set a new pitcher in Team.pitcher: Team.pitcher = new Pitcher(); ... and of course this changes the value of Batter.pitcher. How should I be doing things differently such that the Batter.responsiblePitcher property continues to point to the pitcher who let him on base instead of pointing at whever is in the Team.pitcher property? Again, I feel like I ought to know this already ... Thanks.

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  • Open-source and client-side IRC-Client

    - by user125197
    I'm administrating a homepage with an IRC-Webclient. At the moment, it uses a Java-client, modified to be SSL-compatible and compatible with whatever design I want to use. The usual PJIRC thing, with users wishes and concerns implemented (I'll give you SSL-PJIRC if you want - no problem. The login-script will be improved for IE6-support this weekend, means write the object tag if an old IE is found, that's it. Rest runs perfectly well). But still, the better user experience would be a client that only requires the user to enable JavaScript. So, before I go into rewriting and customizing a complete Java-IRC-solution, I'd like to ask some other people - after researching for half a year of time. The requirements are: a) Free hosting, no cgi-bin is acceptable. A lot of hosters also have CGI supported, but it doesn't allow IRC-access. So, seems you are limited to x10-hosting for CGI:IRC. b) Solution must be open source (not free as in free beer, but free as in free speech - I want to be able to read every line of the code). c) Hosting cannot be limited to Windows-hosting. Free operation systems (anything with Linux, BSD, whatever - I think you get what I mean) must be possible. d) No server-side technology. I'm limited to everything that runs client-side only. (Well, a Java-Applet does...). d) Solution must support SSL. e) The side must be able to move. Means, you register to a new free hoster, load your things up via FileZilla and the thing simply runs. No server-concerning implementations needed. f) Old browsers must be supported. From all my research, there are two ways a) Java-Applet b) Use HTML5-Websockets (it is impossible to use the JavaScript-library I found, as it depends on ActiveX - means, Windows hosting). b) means "you are going to enter very unstable content". I worked with HTML5 for month, and, well ... Though, HTML5 also is not suitable for older browsers (old browser support is an absolutely necessary requirement). PHP by the way is a server side solution ... so no line of PHP. My idea now was a Java Applet, and a fallback which again is embedded and proprietary, but only requieres JavaScript (wsirc or Mibbit are great here, whilst I prefer wsirc ... and zooming fonts that are plainly to small, but worse, cannot read the code). So my question is - with free hosting, not installation on server, plain upload - do you see and open source, complelety client-side, ssl-compatible way to use or write a client? This wouldn't be my first programming project, I'm not afraid of the code. If there was a way and I had to write it, even from scratch, I'd do. From all I know, there sadly is none. But maybe some experienced admin has an idea? Best Wishes, yetanotheruser Sry my English isn't perfect. It's enough for programming at least.

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