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  • Filter---after setting attribute--->Servlet---after getting and setting the attribute---->Jsp How do I do this?

    - by Y.E.P
    This is what I want to do : A servlet is called.Before a servlet is called , the request is intercepted by a filter. Filter gets some details out from the request,sets them as an attribute and the forwards it to a servlet via chain.doFilter(request,response). Request finally reaches the servlet. Servlet gets the attribute set by the filter before and sets a new attribute by another name. Then it forwards it to some jsp page where the page gets the attribute and processes it. How do I do this ? I know how to write a filter and a servlet but how do I forward it to a jsp page from the servlet or is there any other way to achieve this ?

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  • JPA @version - can it be used to calcualate version of a table entry

    - by OpenSource
    Hi, Please consider the following table (created using a corresponding entity) request ------- id requestor type version items 1 a t1 1 5 2 a t1 2 3 3 b t1 1 2 4 a t2 1 4 5 a t1 3 9 The above is what I want to achieve. The version field is a calculated field others are user provided. Basically the request's version needs to be calculated based on the combination of requestor and the type. The first occurance with a given combination will have a version 1 then version 2 and so on. I tried various things using @version on a different entity with just the three columns and joining the two entities using ManytoOne etc but I'm not able to get to the desired outcome. I dont want to confuse you with the things I tried. Since the objective is simple there should be an easier way I suppose? Can you please help? - any help greatly appreciated! thanks in advance

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  • How do I manipulate a tree of immutable objects?

    - by Frederik
    I'm building an entire application out of immutable objects so that multi-threading and undo become easier to implement. I'm using the Google Collections Library which provides immutable versions of Map, List, and Set. My application model looks like a tree: Scene is a top-level object that contains a reference to a root Node. Each Node can contain child Nodes and Ports. An object graph might look like this: Scene | +-- Node | +-- Node | +- Port +-- Node | +- Port +- Port If all of these objects are immutable, controlled by a top-level SceneController object: What is the best way to construct this hierarchy? How would I replace an object that is arbitrarily deep in the object tree? Is there a way to support back-links, e.g. a Node having a "parent" attribute?

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  • Reference to an instance method of a particular object

    - by Andrey
    In the following code, if i try to pass method reference using the class name, works. But passing the reference variable compiler gives an error, i do not understand why? public class User { private String name; public User(String name) { this.name = name; } public void printName() { System.out.println(name); } } public class Main { public static void main(String[] args) { User u1 = new User("AAA"); User u2 = new User("BBB"); User u3 = new User("ZZZ"); List<User> userList = Arrays.asList(u1, u2, u3); userList.forEach(User::printName); // works userList.forEach(u1::printName); // compile error } } Thanks,

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  • @Intertceptors does not work for web bean for JSF page.

    - by Drevlyanin
    @Named @ConversationScoped @Interceptors(MyInterceptor.class) public class BeanWeb implements Serializable { public String methodThrowException throws Exception() { throws new Exception(); } } public class MyInterceptor { @AroundInvoke public Object intercept(InvocationContext ic) throws Exception { try { return ic.proceed(); } catch (Exception e) { return null; } } } For @Stateless beans interceptor works, but for the BeanWeb interceptor does not work. And we have never entered into "intercept" method. Why is this happening? How could intercept method calls in BeanWeb? P.S.: All this spin under Glassfish 3.x.

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  • How to maintain GridPane's fixed-size after adding elemnts dynamically

    - by Eviatar G.
    I need to create board game that can be dynamically change. Its size can be 5x5, 6x6, 7x7 or 8x8. I am jusing JavaFX with NetBeans and Scene builder for the GUI. When the user choose board size greater than 5x5 this is what happens: This is the template on the scene builder before adding cells dynamically: To every cell in the GridPane I am adding StackPane + label of the cell number: @FXML GridPane boardGame; public void CreateBoard() { int boardSize = m_Engine.GetBoard().GetBoardSize(); int num = boardSize * boardSize; int maxColumns = m_Engine.GetNumOfCols(); int maxRows = m_Engine.GetNumOfRows(); for(int row = 0; row < maxRows ; row++) { for(int col = maxColumns - 1; col >= 0 ; col--) { StackPane stackPane = new StackPane(); stackPane.setPrefSize(150.0, 200.0); stackPane.getChildren().add(new Label(String.valueOf(num))); boardGame.add(stackPane, col, row); num--; } } boardGame.setGridLinesVisible(true); boardGame.autosize(); } The problem is the stack panes's size on the GridPane are getting smaller. I tried to set them equal minimum and maximum size but it didn't help they are still getting smaller. I searched on the web but didn't realy find same problem as mine. The only similar problem to mine was found here: Dynamically add elements to a fixed-size GridPane in JavaFX But his suggestion is to use TilePane and I need to use GridPane because this is a board game and it more easier to use GridPane when I need to do tasks such as getting to cell on row = 1 and column = 2 for example. EDIT: I removed the GridPane from the FXML and created it manually on the Controller but now it print a blank board: @FXML GridPane boardGame; public void CreateBoard() { int boardSize = m_Engine.GetBoard().GetBoardSize(); int num = boardSize * boardSize; int maxColumns = m_Engine.GetNumOfCols(); int maxRows = m_Engine.GetNumOfRows(); boardGame = new GridPane(); boardGame.setAlignment(Pos.CENTER); Collection<StackPane> stackPanes = new ArrayList<StackPane>(); for(int row = 0; row < maxRows ; row++) { for(int col = maxColumns - 1; col >= 0 ; col--) { StackPane stackPane = new StackPane(); stackPane.setPrefSize(150.0, 200.0); stackPane.getChildren().add(new Label(String.valueOf(num))); boardGame.add(stackPane, col, row); stackPanes.add(stackPane); num--; } } this.buildGridPane(boardSize); boardGame.setGridLinesVisible(true); boardGame.autosize(); boardGamePane.getChildren().addAll(stackPanes); } public void buildGridPane(int i_NumOfRowsAndColumns) { RowConstraints rowConstraint; ColumnConstraints columnConstraint; for(int index = 0 ; index < i_NumOfRowsAndColumns; index++) { rowConstraint = new RowConstraints(3, Control.USE_COMPUTED_SIZE, Double.POSITIVE_INFINITY, Priority.ALWAYS, VPos.CENTER, true); boardGame.getRowConstraints().add(rowConstraint); columnConstraint = new ColumnConstraints(3, Control.USE_COMPUTED_SIZE, Double.POSITIVE_INFINITY, Priority.ALWAYS, HPos.CENTER, true); boardGame.getColumnConstraints().add(columnConstraint); } }

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  • Third Party Libraries and Technologies every Java Programmer must be aware of?

    - by kunjaan
    I agree that this is a very subjective question but as a student of Java , I get suggested good libraries and technologies for Java by my mentors at work. For example, I was not aware of Google Guice for Dependency Injection, awesomeness of Java Reflection APIs, ORMs like Hibernate or stuffs you could do with libraries like Hadoop. I want to collect and share some of the libraries that exemplifies good java programming (so that beginners like me could code walk and emulate the coding practice), teach unique concepts to Java (for example Dependency Injections or ORM) and/or are really interesting libraries that a student like me would get to do interesting projects on (eg. Hadoop). I redited this question 3 times to make it more specific : ). I am sorry if I am really not clear in my intentions. But some kind of a list of good concepts and third party libraries for Java could really help some of my intern friends here at work. Thank you.

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  • How do I make defensive copy of an object?

    - by kunjaan
    How do I make defensive copies of a Mutable Object which contains a mutable field in an Immutable Object? class ImmutableObject { private final MutableObject immutable_field; ImmutableObject(MutableObject y) { this.immutable_field = y; } MutableObject return_immutable_field() { return immutable_field; } } class MutableObject { public int mutable_field; } The MutableObject does not have a constructor that lets me set the field. The MutableObject's current state should be captured in the Immutable Object and never changed.

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  • In web project can we write core services layer without knowledge of UI ?

    - by Silent Warrior
    I am working on web project. We are using flex as UI layer. My question is often we are writing core service layer separately from web/UI layer so we can reuse same services for different UI layer/technology. So practically is it possible to reuse same core layer services without any changes/addition in API with different kind of UI technologies/layers. For e.g. same core service layer with UI technology which supports synchronized request response (e.g. jsp etc.) and non synchronize or event driven UI technology (e.g Ajax, Flex, GWT etc.) or with multiple devices like (computers, mobiles, pdas etc.). Personally I feel its very tough to write core service layer without any knowledge of UI. Looking for thoughts from other people.

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  • How to pass sockets created to another Java Process

    - by whoi
    Hi; We have an application which creates many sockets which belongs to its thread, By design if this application somehow fails, all threads stop which is not wanted. So to overcome this issue, each thread must be separated from the main application, if one of the threads fails, the other ones should be running. One thing in our mind is to pass created socket to another java process, so what is the correct way? An other approach also is welcome? Waiting for your suggestions...

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  • Separating code logic from the actual data structures. Best practices?

    - by Patrick
    I have an application that loads lots of data into memory (this is because it needs to perform some mathematical simulation on big data sets). This data comes from several database tables, that all refer to each other. The consistency rules on the data are rather complex, and looking up all the relevant data requires quite some hashes and other additional data structures on the data. Problem is that this data may also be changed interactively by the user in a dialog. When the user presses the OK button, I want to perform all the checks to see that he didn't introduce inconsistencies in the data. In practice all the data needs to be checked at once, so I cannot update my data set incrementally and perform the checks one by one. However, all the checking code work on the actual data set loaded in memory, and use the hashing and other data structures. This means I have to do the following: Take the user's changes from the dialog Apply them to the big data set Perform the checks on the big data set Undo all the changes if the checks fail I don't like this solution since other threads are also continuously using the data set, and I don't want to halt them while performing the checks. Also, the undo means that the old situation needs to be put aside, which is also not possible. An alternative is to separate the checking code from the data set (and let it work on explicitly given data, e.g. coming from the dialog) but this means that the checking code cannot use hashing and other additional data structures, because they only work on the big data set, making the checks much slower. What is a good practice to check user's changes on complex data before applying them to the 'application's' data set?

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  • Returning a href within a string

    - by user701254
    How can I return a href within a string, I can access the start position but not sure how to get last position : Here is what I have so far : String str = "sadf ad fas dfa http:\\www.google.com sdfa sadf as dfas"; int index = str.indexOf("http"); String href = str.substring(index , ???); What should the end index be ? Note, this is targeted at j2me & I need to minimise download footprint so I cannot use regular expressions or third party regular expressions libraries.

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  • JAAS : on Callback ( Interesting based on HTTP headers )

    - by VJS
    I am using NameCallback and PasswordCallback for username and password.For username and password, popup comes on browser and when i enter username ans password, JAAS authenticates my request. On the wireshark, I have seen that 401 Unauthorized message (WWW-Authenticate header)comes and when i enter username/password HTTP request with credentials generate ( with Authorization header) and goes to server. My requirement : I don't want pop up to come.My application on other server having username / password, so once it received 401 then based on some logic it will generate HTTP request with Authorization header / credentials and sent it back. FLow : User - Other Server - My Tomcat5.5 Here on Other Server, nobody is available to enter username/password manually.Application is deployed and it will only generate HTTP request with credential and sent it back to tomcat. Can we have any other callback which behave like this.Need your help.Please provide me feedback as well related to approach.

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  • Why did you stop using Tapestry?

    - by ntownsend
    This question goes out to those who have used Tapestry as a web framework and then either gave it up or switched to something else, or even ported their application from Tapestry to something else. The question is why? What led you to make this change? EDIT: Also, what framework (if any) did you change to?

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  • replicating master tables mapping in transaction tables

    - by NoDisplay
    I have three master tables for location information Country {ID, Name} State {ID, Name, CountryID} City {ID, Name, StateID} Now I have one transcation table called Person which hold the person name and his location information. My Question is shall I have only CityID in the Person table like this: Person {ID, Name, CityID}' And have view of join query which give me detail like "Person{ID,Name,City,State,Country}" or Shall I replicate the mapping Person {ID, Name, CityID, StateID, CountryID} Please suggest which do you feel is to be selected and why? if there is any other option available, please suggest. Thanks in advance.

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  • JDBC Pagination

    - by Zeeshan
    Hi, I want to implement pagination using JDBC. The actual thing I want to know is "How can i get first 50 and then next 50 records from database for page 1 and 2 respectively" My Query is Select * from data [data table contains 20,000 rows] For page #1 I get 50 records and for page #2 I want to get next 50 records. How can I implement it efficiently in JDBC? I have searched and found that rs.absolute(row) is the way to skip first page records but it takes some amount of time on large result sets and I don't want to bear this amount of time. Also, I don't want to use rownum and limit + offset in query because these are not good to use in query, I dont know why, still I don't want to use it in query. Can anyone help me how to get limited ResultSet for pagination or is there any way JDBC is giving us?

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  • Add list type to association

    - by teucer
    Hi All, I am using the eUML2 (Free version) plugin to draw a UML class diagram. Now, let's assume I have a class Person and a class Car. I want the class Person to have a member cars which is a List<Car>, i.e. private List<Car> cars = null. My question is how do I include this information in the class diagram? To be more precise, how do I include the type information for the List in the eUML2 association? Regards

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  • How do I run compiled java classes with GPU libraries (Jogamp JOCL)?

    - by jam383
    Does anyone know how to run the java code from the command line with dependency on GPU libraries in this case Jogamps JOCL. I have compiled a test program HelloJOCL.java but I get an error during run time. I tried javac -classpath "./lib/jocl.jar:./lib/jocl-natives-macosx-universal.jar:./lib/jocl-natives-linux-i586.jar:./lib/jocl-natives-linux-amd64.jar:./lib/gluegen-rt.jar:./lib/gluegen-rt-natives-linux-amd64.jar:./lib/gluegen-rt-natives-macosx-universal.jar:./lib/gluegen-rt-natives-linux-i586.jar" ./HelloJOCL.java java -classpath "./lib/jocl.jar:./lib/jocl-natives-macosx-universal.jar:./lib/jocl-natives-linux-i586.jar:./lib/jocl-natives-linux-amd64.jar:./lib/gluegen-rt.jar:./lib/gluegen-rt-natives-linux-amd64.jar:./lib/gluegen-rt-natives-macosx-universal.jar:./lib/gluegen-rt-natives-linux-i586.jar:." HelloJOCL but get this error Exception in thread "main" java.lang.NoClassDefFoundError: com/jogamp/opencl/CLContext at java.lang.Class.getDeclaredMethods0(Native Method)

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  • two log4j files for EAR with two modules

    - by nicktmro
    Hi, I have an EAR that is made up of two modules. Both expose services and share common code. Imagine that the ear has a common.jar shared by a webservices.war and webapp.war. I use log4j to log the activities. I would like to be able to have two log files (webservices.log and webapp.log) capturing the events that are specific to each of them plus all the stuff that is handled by the common.jar. How should I configure my categories and my appenders to achieve this? At the moment I have the following packages: com.myapp for shared stuff com.myapp.webservices for the webservices and com.myapp.webapp for the webapp. My problem is that I don't know how I can capture the com.myapp (common stuff) in both log files by using a single log4j configuration file. I have tried setting up multiple configuration files but when JBoss would work OK Websphere would break and the other way round... Thank you

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  • Adding interfaces that won't be actually used

    - by devoured elysium
    I currently have two interfaces(that I'll name here IA and IB): interface IA { int Width; int Height; ... } interface IB { int Width; int Height; ... } that share the same two properties: they both have a Width and a Height property. I was thinking if there is any point in defining an IMatrix interface containing a Width and Height properties: interface IMatrix { int Width; int Height; } The thing is that although they share both the same properties, I won't make use of polymorphism with IMatrix in any of my coding: i.e., there won't by any situation where I'll want to use an IMatrix, I'll just want to use IA and IB. Adding an IMatrix seems more like over-engineering than other thing, but I'd like to ask you guys what your opinion is on the matter. Thanks

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  • database deign advice wanted: double data entry

    - by john
    hi, I'm designing a database for capturing clinical trial data. The data are entered twice by two persons, independently and the results must be matched. What are the best database tools to use to achieve the best results. Any one has similar experiences? Your helps are highly appreciated. thanks.

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