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  • Can JAXB generate a generic class?

    - by dinesh
    Can I get JAXB 2.0 XJC compiler to generate a generic class for me? Something as simple as:- public class Shape<T> { T myShape; // getter / setter } I see references for this in the spec but am not sure I'm reading it right. I always get Object references.

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  • Correct handling of return data

    - by Serhiy
    Hello, I have a question related to correct handling of returns of the DAO library I'm writing for one project. This library probably is going to be used by another people and I want to do it correctly. So I would like to know, how I should deal with return statements of the functions of my DAO. Example 1 I have function to getCustomer which should return String. In case query doesn't return any result should I return null, empty string or throw some kind of Exception? Example 2 I have function getCutomerList which return ArrayList. In case query doesn't return any result should I return null, empty ArrayList or throw some Exception? Example 3 Some sql exception was detected, what should I do: throw exception or do try..catch of the block where it can occur? What is the "good" practice or "best" practice to apply in my case? Thanks on advance, Serhiy.

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  • checking boolean property in XML(Spring)

    - by Abhishek Bhandari
    I am using Spring Framework . While writing coustum SQL queries , i am unable check a parameter of boolean value. For example this is not working .. do some SQl cods The above checking is not working , it is evaluating as equal in both the cases when booleanVariable is true and false . i tried to replace compareValue ="tree" and "false". As that is a monkey work i do sometimes . is it possible to check the boolean property in XML like above .

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  • How do I calculate a good hash code for a list of strings?

    - by Ian Ringrose
    Background: I have a short list of strings. The number of strings is not always the same, but are nearly always of the order of a “handful” In our database will store these strings in a 2nd normalised table These strings are never changed once they are written to the database. We wish to be able to match on these strings quickly in a query without the performance hit of doing lots of joins. So I am thinking of storing a hash code of all these strings in the main table and including it in our index, so the joins are only processed by the database when the hash code matches. So how do I get a good hashcode? I could: Xor the hash codes of all the string together Xor with multiply the result after each string (say by 31) Cat all the string together then get the hashcode Some other way So what do people think? (If you care we are using .NET and SqlServer)

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  • Why does every thread in my application use a different hibernate session?

    - by Ittai
    Hi, I have a web-application which uses hibernate and for some reason every thread (httprequest or other threads related to queueing) uses a different session. I've implemented a HibernateSessionFactory class which looks like this: public class HibernateSessionFactory { private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>(); private static Configuration configuration = new AnnotationConfiguration(); private static org.hibernate.SessionFactory sessionFactory; static { try { configuration.configure(configFile); sessionFactory = configuration.buildSessionFactory(); } catch (Exception e) {} } private HibernateSessionFactory() {} public static Session getSession() throws HibernateException { Session session = (Session) threadLocal.get(); if (session == null || !session.isOpen()) { if (sessionFactory == null) { rebuildSessionFactory();//This method basically does what the static init block does } session = (sessionFactory != null) ? sessionFactory.openSession(): null; threadLocal.set(session); } return session; } //More non relevant methods here. Now from my testing it seems that the threadLocal member is indeed initialized only once when the class is first loaded by the JVM but for some reason when different threads access the getSession() method they use different sessions. When a thread first accesses this class (Session) threadLocal.get(); will return null but as expected all other access requests will yeild the same session. I'm not sure how this can be happening as the threadLocal variable is final and the method threadLocal.set(session) is only used in the above context (which I'm 99.9% sure has to yeild a non null session as I would have encountered a NullPointerException at a different part of my app). I'm not sure this is relevant but these are the main parts of my hibernate.cfg.xml file: <hibernate-configuration> <session-factory> <property name="connection.url">someURL</property> <property name="connection.driver_class"> com.microsoft.sqlserver.jdbc.SQLServerDriver</property> <property name="dialect">org.hibernate.dialect.SQLServerDialect</property> <property name="hibernate.connection.isolation">1</property> <property name="hibernate.connection.username">User</property> <property name="hibernate.connection.password">Password</property> <property name="hibernate.connection.pool_size">10</property> <property name="show_sql">false</property> <property name="current_session_context_class">thread</property> <property name="hibernate.hbm2ddl.auto">update</property> <property name="hibernate.cache.use_second_level_cache">false</property> <property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <!-- Mapping files --> I'd appreciate any help granted and of course if anyone has any questions I'd be happy to clarify. Ittai

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  • Simple explaination of Arraylists

    - by Jeremy
    I'm new to programming and I'm looking for a simple answer to build my foundation of understanding Arrays. I've used google and searched this site. After a bit of trial and error I get how to make and reference Arrays like thing[3] gets you the fourth thing in the thing array(since 0 is the first). which lets me do something like thing[3].getStupidNumber() to get the StupidNumber of the 4th thing in the thing array. Then I get to ArrayLists which seem to have much more utility but I cant make logical sense of them like Arrays. When i search I cant find this or word this correctly and thus far everything else I've learned clicked easily. so say I make an ArrayList thing with 5 things in it. how do i get to the .getStupidNumber() method inside the fourth thing, if possible? I think if I learn this I can learn the rest on my own. Thanks!

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  • Which technology should I choose for 3d globe web application

    - by uther-lightbringer
    Hello, i would like to ask you for an advice. I'm currently developing application in Spring consisting of Spring CRUD application as backend, SpringMVC application as tool for management and third part is where my problem lies as I need have application that renders 3d globe which is fed by data from backend from a data set selected by user (user may switch those at will). It has to be web application (though I would prefer not to implement this in flash/flex), composed of two main parts - main part is classic web GUI where user makes his choices and second part is 3d globe which renders the globe with selected set of data visualised. My question is, what do you think is the best option to implement this? Would be SpringMVC framework usable for this kind of application? I will be gratefull for any leads or directions, thank you.

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  • how to log digester with apache commons?

    - by Bruce
    Hi all I'm having trouble getting digester to log anything. I'd be hugely grateful for any light anyone can shed. In my code I'm doing this: Digester digester = new Digester(); .. some digester set up stuff // What on earth should go in here???? digester.setLogger(LogFactory.getLog("org.apache.commons.logging.Log")); I have a commons-logging.properties file in my classpath as follows: org.apache.commons.logging.Log=org.apache.commons.logging.impl.SimpleLog org.apache.commons.logging.simplelog.log.org.apache.commons.digester.Digester=debug org.apache.commons.logging.simplelog.log.org.apache.commons.digester.Digester.sax=info I just get no debug info at all.. Thanks for your help!

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  • Obtaining FontMetrics before getting a Graphics instance

    - by Tom Castle
    Typically, I'd obtain a graphics instance something like this: BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); Graphics2D g = img.createGraphics(); However, in the current project I'm working on, the width and height variables above are dependent upon the size of a number of text fragments that will later be drawn onto the graphics instance. But, to obtain the dimensions of the font being used I would usually use the FontMetrics that I get from the graphics object. FontMetrics metrics = g.getFontMetrics(); So, I have a nasty little dependency cycle. I cannot create the graphics object until I know the size of the text, and I cannot know the size of the text until I have a graphics object. One solution is just to create another BufferedImage/Graphics pair first in order to get the FontMetrics instance I need, but this seems unnecessary. So, is there a nicer way? Or is it the case that the width, height etc. properties for a Font are somehow dependent upon what (graphics, component...) the text is to be drawn on?

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  • Android pattern for activity "flows"

    - by Otto
    I'm developing an android app that has a bunch of screens (activities) that are supposed to have "continue" and "back" buttons at the top. Can you tell me the right pattern for implementing this? I've seen some iPhone apps that have this but Android apps usually don't (I think partly because the back button is part of the phone). I found a post online about an Activity class that has "sub activities" which kind of seems like what I want to do, but I'm wondering if there's a simpler solution or pattern for creating flows like this (in which several activities are linked with continue/back buttons).

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  • How to design authentication in a thick client, to be fail safe?

    - by Jay
    Here's a use case: I have a desktop application (built using Eclipse RCP) which on start, pops open a dialog box with 'UserName' and 'Password' fields in it. Once the end user, inputs his UserName and Password, a server is contacted (a spring remote-servlet, with the client side being a spring httpclient: similar to the approaches here.), and authentication is performed on the server side. A few questions related to the above mentioned scenario: If said this authentication service were to go down, what would be the best way to handle further proceedings? Authentication is something that I cannot do away with. Would running the desktop client in a "limited" mode be a good idea? For instance, important features/menus/views will be disabled, rest of the application will be accessible? Should I have a back up authentication service running on a different machine, working as a backup? What are the general best-practices in this scenario? I remember reading about google gears and how it would let you edit and do stuff offline - should something like this be designed? Please let me know your design/architectural comments/suggestions. Appreciate your help.

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  • Determining if a coordinate is on a line

    - by TGCBraun
    I´m coding a little app that allows the user to draw multiple shapes and then remove or resize them. It´s working perfectly on rectangles and ovals, but I´m having issues with lines. Here´s a method that I wrote to find if the clicked spot on the screen is part of a specific line: public boolean containsLocation(int x, int y) { int m = (getY2() - getY()) / (getX2() - getX()); int b = getY() - (m * getX()); if (y == (m * x) + b) { return true; } return false; I´m using the famous y = mx + b formula and replacing y and x to find if the clicked spot is part of the line. The problem is when I click on the screen to remove the line, it only works if I click on the very fist coordinate (x,y) where the line starts. Nothing happens when I click anywhere else along the line. Can anyone shed a light on what I´m doing wrong? Thanks a lot.

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  • Multi-Threaded Application - Help with some pseudo code!!

    - by HonorGod
    I am working on a multi-threaded application and need help with some pseudo-code. To make it simpler for implementation I will try to explain that in simple terms / test case. Here is the scenario - I have an array list of strings (say 100 strings) I have a Reader Class that reads the strings and passes them to a Writer Class that prints the strings to the console. Right now this runs in a Single Thread Model. I wanted to make this multi-threaded but with the following features - Ability to set MAX_READERS Ability to set MAX_WRITERS Ability to set BATCH_SIZE So basically the code should instantiate those many Readers and Writers and do the work in parallel. Any pseudo code will really be helpful to keep me going!

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  • Eclipse error: This project needs to migrate WTP metadata

    - by larf311
    We started a Web Project in Eclipse 3.2 a ways back and we've since upgraded to Eclipse 3.4 but now the Project has the error: "This project needs to migrate WTP metadata" We've tried right-clicking and doing the "quick-fix" which is in fact to Migrate WTP Metadata. Unfortunately nothing happens and the error remains. We can delete that error from the Problems and everything works as it should, however, every time we re-import the project from source control, the error re-appears. Any ideas on how to permanently get rid of this error or how to ACTUALLY migrate WTP metadata? UPDATE: Everyone, please vote on the answer that works for you rather than adding your own answer that references a previous person's answer.

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  • How can I set the Jbuttons in a preferred order?

    - by Umzz Mo
    I have a grid of 30 buttons, and I want to have it from left to right then goes down, right to left, down again left to right. Basically the numbering would be as follow: 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 29 30 So if I have a piece on the button 10 and I instruct it to move up 2 bits it would land on 12 not 19. Below is my Code: //Creates the button using the loop, adds it into the panel and frame. JPanel panel = new JPanel(); panel.setLayout(new GridLayout(3,10)); JButton [] buttons = new JButton[30]; for(int i=0;i<30;i++){ buttons[i] = new JButton("label" + i); buttons[i].setBackground(Color.white); //Puts the player 1 piece on button 1,3,5,7,9 and player 2 piece on button 2,4,6,8,10 if (i < 10) { if (i%2 == 0) { buttons[i].setIcon(piece1); } else { buttons[i].setIcon(piece2); } } panel.add(buttons[i]); } frame.add(panel, BorderLayout.CENTER);

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  • "Forwarding" keypresses from an applet to a JFrame

    - by hansengel
    I have a JFrame which contains a JApplet. There are shortcut keys that I have configured for the JFrame that work fine when the focus is on some panel of it, but once I click into the applet, none of the shortcut keys work anymore. Is there any way that I can forward these key presses to the JFrame so that the events are still fired?

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  • 3D array initialization

    - by xdevel2000
    I need to represent some spatial points: x,y,z when I try to initialize the array like this: int[][][] points { { {100, 120, 10}, {100, 120, 18}, ... } } I got an error: Uncompilable source code - not a statement where is the error?

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  • JTA Transaction: What happens if an exception happens but rollback is not called on the transaction?

    - by kellyfj
    We have some third party code wherein they do the following 1) Create a User Transaction e.g. txn = (UserTransaction)ctx.lookup( "UserTransaction" ); txn.begin( ); 2) Do some work persisting to the database (via JPA) to a MySQL database 3) txn.commit() They have Exception blocks but NONE of them call txn.rollback. Good coding practice says they NEED to call rollback if an exception occurs but my question is If the txn is not commited, and an exception occurs what is the negative effect of them NOT calling rollback?

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  • IllegalAccessError and proxy

    - by konr
    Hi there, I'm translating this code to Clojure. As you can see, I have to extend the class ArthurFrame, yet I'm getting an IllegalAccessError everytime I use (proxy [ArthurFrame] [] ...). Any idea why? Here is the class's source. Thanks!

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  • Bitmap size exceeds VM budget after second load

    - by jonny
    This is driving me crazy. I have a game which has a bitmap as the background, this is big so I scale it down and this works fine. However when I navigate to another activity and then reload the game screen it crashes on drawing the background. I am calling recycle on all the bitmaps and setting them to null on onDestroy() but this doesn't help. Any ideas and if not how can I debug the memory to see at which step its growing. I looked at getting the heap but nothing of any size is on there really. Thanks.

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