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  • Setup for games animation: How do I know JFrame is finished setting itself up?

    - by Jokkel
    I'm using javax.swing.JFrame to draw game animations using double buffer strategy. First, I set up the frame. JFrame frame = new JFrame(); frame.setVisible(true); Now, I draw an object (let it be a circle, doesn't matter) like this. frame.createBufferStrategy(2); bufferStrategy = frame.getBufferStrategy(); Graphics g = bufferStrategy.getDrawGraphics(); circle.draw(g); bufferStrategy.show(); The problem is that the frame is not always fully set-up when the drawing takes place. Seems like JFrame needs up to three steps in resizing itself, until it reaches it's final size. That makes the drawing slide out of frame or hinders it to appear completely from time to time. I already managed to delay things using SwingUtilities.invokeLater(). While this improved the result, there are still times when the drawing slides away / looks prematurely draw. Any idea / strategy? Thanks in advance. EDIT: Ok thanks so far. I didn't mention that I write a little Pong game in the first place. Sorry for the confusion What I actually looked for was the right setup for accelerated game animations done in Java. While reading through the suggestions I found my question answered (though indirectly) here and this example made things clear for me. A resume for this might be that for animating game graphics in Java, the first step is to get rid of the GUI logic overhead.

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  • FTP exception 501 "pathname" more than 8 characters

    - by BigMac66
    I am trying to access a file via a URI using the FTP protocol. For obvious security reasons I had to make some changes but this is where the problems seem to be coming from. My URI is as follows: ftp://user:[email protected]/u/Bigpathname/XYZ/ABC/BigPathname/bigpathname/xyz/abc/MY_LOG.LOG And I see this exception: sun.net.ftp.FtpProtocolException: CWD Bigpathname:501 A qualifier in "Bigpathname" is more than 8 characters This is really confusing as I can access the file from a Windows 7 command line with the CD command just fine. Both one directory at a time and as a full path. I found one article mentioning that MVS file names must be 8 or fewer characters but this does not explain how I can get to these same files from my command line! They do exist there is data there that I can download manual but I can not get there via a URI in Java. PS I use .toURL().openStream() to get files on my local machine just fine, it only fails when I try to get them from my server. EDIT October 1st I am able to access files on the MVS host using FileZilla and the basic FTP client from the Windows 7 command line - but I still cannot get them from a URI/URL. I downloaded a very basic Java built FTP client and tried accessing the same file in my program from there and the path works but because my file name has a dot in it "MY_LOG.LOG" I am getting File does not exist 501 Invalid data set name "MY_LOG.LOG". Use MVS Dsname conventions. I am utterly perplexed by this...

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  • String Index Out Of Bound Exception error

    - by Fd Fehfhd
    Im not really sure why a am getting this error. But here is my code it is meant to test palindromes disregarding punctuation. So here is my code import java.util.Scanner; public class PalindromeTester { public static void main(String [] args) { Scanner kb = new Scanner(System.in); String txt = ""; int left; int right; int cntr = 0; do { System.out.println("Enter a word, phrase, or sentence (blank line to stop):"); txt = kb.nextLine(); txt = txt.toLowerCase(); char yP; String noP = ""; for (int i = 0; i < txt.length(); i++) { yP = txt.charAt(i); if (Character.isLetterOrDigit(txt.charAt(yP))) { noP += yP; } } txt = noP; left = 0; right = txt.length() -1; while (txt.charAt(left) == txt.charAt(right) && right > left) { left++; right--; } if (left > right) { System.out.println("Palindrome"); cntr++; } else { System.out.println("Not a palindrome"); } } while (!txt.equals("")); System.out.println("You found " + cntr + " palindromes. Thank you for using palindromeTester."); } } And if i test it and then i put enter so it will tell me how many palindromes you found the error i am getting is javav.lang.StringIndexOutOfBoundException : String index out of range 0 at PalindromeTester.main(PalindromeTester.java:38) and line 28 is while (txt.charAt(left) == txt.charAt(right) && right > left) Thanks for the help in advance

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  • Selenium - Wait for network traffic

    - by Joel
    We're using Selenium with the Java API and some Javascript user extensions. We use a lot of AJAX calls in our app. A lot of our tests fail randomly because sometimes the AJAX calls finish slower than other times so the page isn't fully loaded. We fix that by waiting for specific elements or Thread.sleep. I was trying to find a way to instead just wait for the network traffic to finish. So that we could do this: selenium.click("some JS button"); selenium.waitForNetwork(); assertTrue(something); That way we can get rid of the thread sleep and have tests pass faster when the server responds faster and not have so many tests fail due to timing issues. I haven't been able to find a way to do this searching Google. Does anyone have any ideas how we can accomplish this? (Preferably either through Javascript or the Java API but all suggestions are welcome). Note: the other variations of "waitFor" are not what I'm looking for. We're already using those in clicks and other things. I'm looking for something that waits for the NETWORK TRAFFIC. Thanks for all the feedback, I'll be trying out a couple of the suggestions, but I'm still open to other ideas. Thanks.

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  • Help me understand making maven project w/ non-maven jar dependencies usable by others

    - by deet
    Hi, I'm in the process of learning maven (and java packaging & distribution) with a new oss project I'm making as practice. Here's my situation, all java of course: My main project is ProjectA, maven-based in a github repository. I have also created one utility project, maven-based, in github: ProjectB. ProjectA depends on a project I have heavily modified that originally was from a google-code ant-based repository, ProjectC. So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC, and also how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile? (Additionally, what should I do with my modified version of ProjectC? include the class files directly into ProjectA, or fork the project into something that could then be used by as a maven dependency?) I've been reading around, links such as this SO question and this SO question, but I'm unclear how those relate to my particular circumstance. So, any help would be appreciated. Thanks!

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  • Recommended book for Sql Server query optimisation

    - by Patrick Honorez
    Even if I have made a certification exam on Sql Server Design and implementation , I have no clue about how to trace/debug/optimise performance in Sql Sever. Now the database I built is really business critical, and getting big, so it is time for me to dig into optimisation, specially regarding when/where to add indexes. Can you recommend a good book on this subject ? (smaller is better :) Just in case: I am using Sql Server 2008. Thanks

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  • Replacing characters in a non well-formed XML body

    - by ryanprayogo
    In a (Java) code that I'm working on, I sometimes deal with a non well-formed XML (represented as a Java String), such as: <root> <foo> bar & baz < quux </foo> </root> Since this XML will eventually need to be unmarshalled (using JAXB), obviously this XML as is will throw exception upon unmarshalling. What's the best way to replace the & and the < to its character entities? For &, it's as easy as: xml.replaceAll("&", "&amp;") However, for the < symbol, it's a bit tricky since obviously I don't want to replace the < that's used for the XML tag opening 'bracket'. Other than scanning the string and manually replacing < in the XML body with &lt;, what other option can you suggest?

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  • Guice child injector override binding

    - by Roman
    Hi All I am trying to to override a binding in a child injector that was already configured in a base injector. like that : public class PersistenceModule extends Abstract{ @Override protected void configure() { bind(IProductPersistenceHelper.class).to(ProductPersistenceHelper.class); } } then : Injector injector = Guice.createInjector(new PersistenceModule()); injector.createChildInjector(new AbstractModule(){ @Override protected void configure() { bind(IProductPersistenceHelper.class).to(MockProductPersistenceHelper.class); } }) Guice is complaining that it has already a binding for that. Are there any patterns or best practices for that problem ?

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  • Hibernate not loading associated object

    - by Noor
    Hi, i am trying to load a hibernate object ForumMessage but in it contain another object Users and the Users object is not being loaded. My ForumMessage Mapping File: <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated Jan 4, 2011 10:10:29 AM by Hibernate Tools 3.4.0.Beta1 --> <hibernate-mapping> <class name="com.BiddingSystem.Models.ForumMessage" table="FORUMMESSAGE"> <id name="ForumMessageId" type="long"> <column name="FORUMMESSAGEID" /> <generator class="native" /> </id> <property name="ForumMessage" type="java.lang.String"> <column name="FORUMMESSAGE" /> </property> <many-to-one name="User" class="com.BiddingSystem.Models.Users" fetch="join"> <column name="UserId" /> </many-to-one> <property name="DatePosted" type="java.util.Date"> <column name="DATEPOSTED" /> </property> <many-to-one name="Topic" class="com.BiddingSystem.Models.ForumTopic" fetch="join"> <column name="TopicId" /> </many-to-one> </class> </hibernate-mapping> and I am using the follwing code: Session session = gileadHibernateUtil.getSessionFactory().openSession(); SQL="from ForumMessage"; System.out.println(SQL); Query query=session.createQuery(SQL); System.out.println(query.list().size()); return new LinkedList <ForumMessage>(query.list());

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  • How to drop/restart a client connection to a flaky socket server

    - by Steve Prior
    I've got Java code which makes requests via sockets from a server written in C++. The communication is simply that the java code writes a line for a request and the server then writes a line in response, but sometimes it seems that the server doesn't respond, so I've implemented an ExecutorService based timeout which tries to drop and restart the connection. To work with the connection I keep: Socket server; PrintWriter out; BufferedReader in; so setting up the connection is a matter of: server = new Socket(hostname, port); out = new PrintWriter(new OutputStreamWriter(server.getOutputStream())); in = new BufferedReader(new InputStreamReader(socket.getInputStream())); If it weren't for the timeout code the request/receive steps are simply: String request="some request"; out.println(request); out.flush(); String response = in.readLine(); When I received a timeout I was trying to close the connection with: in.close(); out.close(); socket.close(); but one of these closes seems to block and never return. Can anyone give me a clue why one of these would block and what would be the proper way to abandon the connection and not end up with resource leak issues?

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  • JMS message. Model to include data or pointers to data?

    - by John
    I am trying to resolve a design difference of opinion where neither of us has experience with JMS. We want to use JMS to communicate between a j2ee application and the stand-alone application when a new event occurs. We would be using a single point-to-point queue. Both sides are Java-based. The question is whether to send the event data itself in the JMS message body or to send a pointer to the data so that the stand-alone program can retrieve it. Details below. I have a j2ee application that supports data entry of new and updated persons and related events. The person records and associated events are written to an Oracle database. There are also stand-alone, separate programs that contribute new person and event records to the database. When a new event occurs through any of 5-10 different application functions, I need to notify remote systems through an outbound interface using an industry-specific standard messaging protocol. The outbound interface has been designed as a stand-alone application to support scalability through asynchronous operation and by moving it to a separate server. The j2ee application currently has most of the data in memory at the time the event is entered. The data would consist of approximately 6 different objects; a person object and some with multiple instances for an average size in the range of 3000 to 20,000 bytes. Some special cases could be many times this amount. From a performance and reliability perspective, should I model the JMS message to pass all the data needed to create the interface message, or model the JMS message to contain record keys for the data and have the stand-alone Java application retrieve the data to create the interface message?

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  • Experiences wanted: producing a jar artifact in IntelliJ

    - by skiaddict1
    Developing with IntelliJ 9.0.2 Community Edition, on the Mac. This is a follow-up to this post about including jar files in an artifact, which has not received any replies. I'm hoping that the reason is that somehow, in creating my artifact (or setting my project settings), I unwittingly did something which people don't tend to do, and which is causing my problem, and that by asking people here to share how they create jar artifacts and set up projects, I will discover what it is. To recap: I have a Java project which depends on two library files. I need to package up the entire thing, with the jars inlined (such that on doing jar -tfv <filename> I see ALL the classes listed, including the ones in the two libraries), into a single jar file. I can make an artifact, I can add the library files to the Output Layout pane, but I CANNOT, no matter what I do, I cannot get the "Inline Artifact" item in the context menu to be selectable (i.e. non-grey) when I right-click on one or other library file. The thing is, making a jar which contains library files as well as the project code is NOT an unusual situation in the Java world! So I figure there are lots of IntelliJ folks out there who have done what I need to do. And I would really like to hear from you folks. What project settings do you use? (be specific, please :-) And exactly how do you set up your jar artifacts? (again, as many specific details as possible, please :-) Clearly, I'd be particularly interested to hear from folks with similar setups to mine (above) who are successfully doing what I need to do. Grateful thanks in advance, folks.

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  • Detecting TCP dropout over an unreliable network

    - by yx
    I am doing some experimentation over an unreliable radio network (home brewed) using very rudimentary java socket programming to transfer messages back and forth between the end nodes. The setup is as follows: Node A --- Relay Node --- Node B One problem I am constantly running into is that somehow the connection drops out and neither Node A or B knows that the link is dead, and yet continues to transmit data. The TCP connection does not time out either. I have added in a heartbeat message that causes a timeout after a while, but I still would like to know what is the underlying cause of why TCP does not time out. Here are the options I am enabling when setting up a socket: channel.socket().setKeepAlive(false); channel.socket().setTrafficClass(0x08); // for max throughput This behavior is strange since it is totally different than when I have a wired network. On a wired network, I can simulate a disconnected connection by pulling out the ethernet cord, however, once I plug the cord back in, the connection becomes restablished and messages begin to be passed through once more. On the radio network, the connection is never reestablished and once it silently dies, the messages never resume. Is there some other unknown java implentation or setting for a socket that I can use, also, why am I seeing this behavior in the first place? And yes, before anyone says anything, I know TCP is not the preffered choice over an unreliable network, but in this case I wanted to ensure no packet loss.

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  • when to use Hibernate vs. Simple ResultSets for small application

    - by luke
    I just started working on upgrading a small component in a distributed java application. The main application is a rather complicated applet/servlet combo running on JBoss and it extensively uses Hibernate for its DataAccess. The component i am working on however is very a very straightforward data importing service. Basically the workflow is Listen for a network event Parse the data packet, extract a set of identifiers Map the identifier set to a primary key in our database Parse the rest of the packet and insert items in a related table using the foreign key found in step 3 Repeat in the previous version of this component it used a hibernate based DAL, that is no longer usable for a variety of reasons (in particular it is EOL), so I am in charge of replacing the Data Access layer for this component. So on the one hand I think i should use Hibernate because that's what the rest of the application does, but on the other i think i should just use regular java.sql.* classes because my requirements are really straightforward and aren't expected to change any time soon. So my question is (and i understand it is subjective) at what point do you think that the added complexity of using an ORM tool (in terms of configuration, dependencies...) is worth it? UPDATE due to the way the DataAccesLayer for the main application was written (weird dependencies) i cannot easily use it, i would have to implement it myself.

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  • why this code not works?

    - by badgirl
    Hello. I want to create new node of BeanTreeView, and when I add some node in constructor, then run the app, and then I try to view the window with tree, it throws this error java.lang.AssertionError: Component cannot be created for {component=null, displayName=Exploirer, instanceCreate=AlwaysEnabledAction[Exploirer]} at org.openide.windows.OpenComponentAction.getTopComponent(OpenComponentAction.java:71) Why? And how to add node there? See the code. private ProjectsChildren projectsChildren; private ProjectNode projectNode = new ProjectNode(new MainProject("ggg"), projectsChildren); public ExploirerTopComponent() { initComponents(); setName(NbBundle.getMessage(ExploirerTopComponent.class, "CTL_ExploirerTopComponent")); setToolTipText(NbBundle.getMessage(ExploirerTopComponent.class, "HINT_ExploirerTopComponent")); // setIcon(ImageUtilities.loadImage(ICON_PATH, true)); //map.put("delete", ExplorerUtils.actionDelete(mgr, true)); associateLookup (ExplorerUtils.createLookup(mgr, getActionMap())); //projectsChildren.createProject("demence"); /* somewhere here is the problem*/ mgr.setRootContext(projectNode); ProjectNode[] pr = null; pr[0] = projectNode; mgr.getRootContext().getChildren().add(pr); }

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  • Is there a way to make sure classes implementing an Interface implement static methods?

    - by Tobias Kienzler
    Frist of all, I read erickson's usefull reply to "Why can’t I define a static method in a Java interface?". This question is not about the "why" but about the "how then?". So basically I want one Interface to provide both usual methods and e.g. a getSimilarObject method. For (a made up) example public interface ParametricFunction { /** @return f(x) using the parameters */ static abstract public double getValue(double x, double[] parameters); /** @return The function's name */ static abstract public String getName(); } and then public class Parabola implements ParametricFunction { /** @return f(x) = parameters[0] * x² + parameters[1] * x + parameters[2] */ static public double getValue(double x, double[] parameters) { return ( parameters[2] + x*(parameters[1] + x*parameters[0])); } static public String getName() { return "Parabola"; } } Since this is not allowed in the current Java standard, what is the closest thing to this? The idea behind this is putting several ParametricFunction's in a package and use Reflection to list them all, allowing the user to pick e.g. which one to plot. Obviously one could provide a loader class containing an array of the available ParametricFunction's, but every time a new one is implemented one has to remember adding it there, too.

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  • A simple, clean web layout

    - by Shaun_web
    Ok, so I hate CSS/HTML graphic design... What do you guys recommend as a sample template or website that you think has great CSS and html layout? From my past experience it's best to get a page that has a white background and little dependency on graphics -- that's clean, and easy to modify ;-).

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  • Suitable web framework for the following scenario

    - by Paralife
    I have the following scenario: I have a view in an Oracle server and all Iwant is to show that view in a web browser, along with an input field or two for basic filtering. No users, no authentication, just this view maybe with a column or two linking to a second page for master detail viewing. The children are just string descriptions of the columns of the master that contain IDs. No inserts or updates. The question is which is the JAVA based web framework of choice that can accomplish the above in the minimum amount of code lines code time(subjective but also kind of objective if someone has expirience with more than one or two frameworks) configuration effort deployment effort and requirements. dependencies and mem footprint Also: 6. Oracle APEX is not an option. 3,4 and 5 are maybe the same in the sense that they are everything except the functionality coding. I want something that I can compile, deploy by just FTPing to the database host, run and forget. (e.g. For the deployment aspect, Hudson way comes in mind (java -jar hudson.war and that's all)). Also: 3,4 have priority over 1 and 2. (Explanation with a rant: I dont mind coding a lot as long as it is application code and not "why the fuck do we still use javascript over http for everything" code) Thanks.

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  • Using enum values to represent binary operators (or functions)

    - by Bears will eat you
    I'm looking for an elegant way to use values in a Java enum to represent operations or functions. My guess is, since this is Java, there just isn't going to be a nice way to do it, but here goes anyway. My enum looks something like this: public enum Operator { LT, LTEQ, EQEQ, GT, GTEQ, NEQ; ... } where LT means < (less than), LTEQ means <= (less than or equal to), etc - you get the idea. Now I want to actually use these enum values to apply an operator. I know I could do this just using a whole bunch of if-statements, but that's the ugly, OO way, e.g.: int a = ..., b = ...; Operator foo = ...; // one of the enum values if (foo == Operator.LT) { return a < b; } else if (foo == Operator.LTEQ) { return a <= b; } else if ... // etc What I'd like to be able to do is cut out this structure and use some sort of first-class function or even polymorphism, but I'm not really sure how. Something like: int a = ..., b = ...; Operator foo = ...; return foo.apply(a, b); or even int a = ..., b = ...; Operator foo = ...; return a foo.convertToOperator() b; But as far as I've seen, I don't think it's possible to return an operator or function (at least, not without using some 3rd-party library). Any suggestions?

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  • Calling an Overridden Method from a Parent-Class Constructor

    - by Vaibhav Bajpai
    I tried calling an overridden method from a constructor of a parent class and noticed different behavior across languages. C++ - echoes A.foo() class A{ public: A(){foo();} virtual void foo(){cout<<"A.foo()";} }; class B : public A{ public: B(){} void foo(){cout<<"B.foo()";} }; int main(){ B *b = new B(); } Java - echoes B.foo() class A{ public A(){foo();} public void foo(){System.out.println("A.foo()");} } class B extends A{ public void foo(){System.out.println("B.foo()");} } class Demo{ public static void main(String args[]){ B b = new B(); } } C# - echoes B.foo() class A{ public A(){foo();} public virtual void foo(){Console.WriteLine("A.foo()");} } class B : A{ public override void foo(){Console.WriteLine("B.foo()");} } class MainClass { public static void Main (string[] args) { B b = new B(); } } I realize that in C++ objects are created from top-most parent going down the hierarchy, so when the constructor calls the overridden method, B does not even exist, so it calls the A' version of the method. However, I am not sure why I am getting different behavior in Java and C#.

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  • What is the business case for a dependency injection (DI) framework?

    - by kalkie
    At my company we want to start using a dependency injection (DI) framework for managing our dependencies. I have some difficulty with explaining the business value of such a framework. Currently I have come up with these reasons. Less source code, delete all the builder patterns in the code. Increase in flexibility. Easier to switch dependencies. Better separation of concern. The framework is responsible for creating instances instead of our code. Has anybody else had to persuade management? How did you do that? What reasons did you use?

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