Is it legal to use Vector in EJB?

Chapter 24 of the EJB spec states:
"An enterprise Bean must not use thread synchronization primitives to synchronize execution of multiple instances."
As far as I know Vector ist thread save.
Does this mean you must not use Vector in EJB? Or is it allowed to use Vector as only one bean instance accesses one Vector instance?

I'd sure like to hear a clear answer to this question. I've been tasked with adding an EJB interface to an existing server application. Right now, we have 2 main methods of sending requests to the server, RMI and IP. We have clients that are requesting an EJB interface. What I'd like to do is create a Session bean( haven't decided on Stateless or Stateful yet ) that invokes the same underlying objects that the RMI and IP objects use. However, those classes were not written with EJB's in mind. They start threads. They access files. They have static data which is manipulated. All those things are forbidden( or at least, strongly discouraged ) in the EJB spec, as I understand it.
Of course, I could create a Session bean that used the existing RMI or IP interface to talk to an instance of our application running in a different JVM, which would eliminate the problem. But that seems like a bit of a hack to me.
Marc Robertson
Staff Consultant
DST Systems, Inc.

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Can I use vectors in entity and store them in Tables directly as binary objects.I have tried making that bean but facing problem in retriving data from table using EJB-QL.Here are code snippets:
-------public abstract class CartEntityBean implements EntityBean {
     private EntityContext ctx;
     public abstract String getCartId();
     public abstract Vector getItems();
     public abstract void setCartId(String CartId);
     public abstract void setItems(Vector items);
public String ejbCreate(String cartId,Vector items) throws CreateException {
          setCartId(cartId);
          return cartId;
rest other methods omitted
public interface CartHomeInterface extends EJBHome{
public CartRemoteInterface create (String cartId,Vector items )throws CreateException,RemoteException ;
public CartRemoteInterface findByPrimaryKey(String pk) throws FinderException, RemoteException;
public Collection findmyItems() throws FinderException, RemoteException;
I am using Cloudscape as Database.
Please help weather I can use Complex objects in Entity Beans or Not

this is no good idea to store the cart-items as a java-vector. you should create a entity bean cart and a entity bean cartItem. then create a cmr between the two entity beans.

Exception IndexOutOfBoundsException using Vector. Christmas homework!

Hi everyone, I'm not a java expert (almost a newbie, I would say) and this is the first time I post anything in a Forum. I have the following piece of code:
public class Test extends javax.swing.JFrame {
private java.util.Vector list;
public Test() {
     super("test");
     list = new java.util.Vector();
     javax.swing.JButton add = new javax.swing.JButton("Add");
     add.addActionListener(new java.awt.event.ActionListener() {
          public void actionPerformed(java.awt.event.ActionEvent e) {
          String value = "new element";
          System.out.println("size: "+list.size());
          list.add(value);
          int i = list.size();
          System.out.println("size + 1: "+i);
          /**/System.out.println("elem i: "+ (String)list.get(i));
     getContentPane().add(add);
     pack();
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public static void main(String[] args) {
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and when I run it I have the following printout:
size: 0
size + 1: 1
java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 1
at....
(omissis)
Does anyone have any idea of why? how can I solve the problem? Isn't Vector supposed to be "dynamic"?
Elsewhere I use Vectors with no problems but I am not accessing it right after having added any element, rather I return it as the result of some elaboration and then access it.
I know it's Christmas time and so I wish you all Merry Christmas and Happy new Year. I hope someone has time to answer me over this holydays.
Thanks anyway,
Rosario

Does anyone have any idea of why? how can I solve the
problem? Isn't Vector supposed to be "dynamic"?You try to access an element after the last element. When you set i = list.size(), i will be the index of the last element plus one. This is because indices count from 0.
It is the list.get(i) that causes the problem.
Søren

Is there a way to "mix" colors using vectors?

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Put the legs on one layer and put the water on another layer above/in-front and adjust the opacity of the water-layer to let some of the leg-layer show through. If you don't want to construct your cartoon using layers which is one of Photoshop's main benefits, you can figure out what color to make the wet leg with by creating a swatch of leg color in one layer and then make a water-colored layer in front/above it and adjust the opacity then use the eyedropper to sample the color of the combination.
Of course in a real situation with the observer above the level of the water looking through it at an angle, the leg would become bluer the further into the water it went because there would be more water between the foot and the observer than say the knee and the observer and you'd want to make a gradient of color or gradient of transparency using a layer mask with a black-to-white gradient in the mask instead of just one opacity setting, and there would also be some size and offset of the leg due to refraction of the water, but as you said you're not a detailed artist.

Insert data into table from JSP page using Entity Beans(EJB 3.0)

I want to insert data into a database table from JSP page using Entity Beans(EJB 3.0).
1. I have a table 'FRIENDS', (in Oracle 10g database).
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Anurag

Hi,
I am also trying that scenario. So u can
Post the jsp form data to a Servlet which will act as a Controller.
In the servlet invoke the business method.
Similar kind of app is in www.roseindia.net
Hope this would help u.
Meanwhile if u get any optimal solution, pls post it.
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Happy Java Coding.

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JSF 1.2
EJB 3.0
Glassfish v1
Summary:
Managed bean injected EJB is null when referencing EJB var in constructor.
Details:
In my managed bean, I have a constructor that tries to reference an injected EJB, such as:
public class CustomerBean implements Serializable {
@EJB private CustomerSessionRemote customerSessionRemote;
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--Todd

OK, I was reading the article Web Tier to Go With Java EE 5: A Look at Resource Injection and I understand your statement too.
Is there any way possible to Inject the EJB prior to the bean instance creation at all?
Maybe, I need to approach it with the old fashion Java EE 1.4 route and using JNDI in the PostConstruct annotated method to reference the EJB in the managed bean.
This had to been thought out before, I don't understand why a manged bean's life cycle places any injections at the end of the bean creation.
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How to use Vector or other ArrayList etc to store my JTree??

How to use Vector or other ArrayList etc to store my JTree??
Dear friends,
I have following I posted before, but not get satisfactory answer, so I modify and repost again here.
I have following code can add classes and students in the JTree,
in class Computer Science, it has student Bill Brien,
in Math, no,
Then I I add Student Nancy, Laura, Peter into Computer Science Class,
add AAAA, BBB, CCC into Math class,
I create a new class called Chemistry, then I add DDD int Chemistry;
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[1]. How can I dynamically save my current JTree with all above tree structure and its nodes in a Vector or ArrayList(not sure which one is best)??
see code below:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class ModelJTreeTest extends JFrame {
private JTree tree;
private DefaultTreeModel model;
private DefaultMutableTreeNode rootNode;
public ModelJTreeTest() {
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      public void actionPerformed(ActionEvent event) {
        addPhilosopher();
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    removeButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        removeSelectedPhilosopher();
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    inputPanel.add(addButton);
    inputPanel.add(removeButton);
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    container.add(inputPanel, BorderLayout.NORTH);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(400, 300);
    setVisible(true);
private void addPhilosopher() {
    DefaultMutableTreeNode parent = getSelectedNode();
    if (parent == null) {
      JOptionPane.showMessageDialog(ModelJTreeTest.this, "Select Class", "Error",
          JOptionPane.ERROR_MESSAGE);
      return;
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    model.insertNodeInto(new DefaultMutableTreeNode(name), parent, parent.getChildCount());
private void removeSelectedPhilosopher() {
    DefaultMutableTreeNode selectedNode = getSelectedNode();
    if (selectedNode != null)
      model.removeNodeFromParent(selectedNode);
private DefaultMutableTreeNode getSelectedNode() {
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private DefaultMutableTreeNode getPhilosopherTree() {
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    rootNode.add(ancient);
    ancient.add(new DefaultMutableTreeNode("Bill Brian"));
    DefaultMutableTreeNode math = new DefaultMutableTreeNode("Maths");
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    DefaultMutableTreeNode physics = new DefaultMutableTreeNode("Physics");
    rootNode.add(physics);
    return rootNode;
public static void main(String args[]) {
    new ModelJTreeTest();
}the actual Tree dynamically created somehow looks like following:
                         |            1.Peter
                         |---CS---    2. Nancy
                         |            3. Laura
                         |            4.Brian
                         |
Root(University): -------|---Math- 1.AAA
                         |            2.BBB
                         |            3.CCC
                         |
                         |
                         |---Chemistry- 1. DDDThanks a lot
Good weekends

you can't directly store a tree in a list.Ummm... Just to be contrary... Yes you CAN store a tree in a table.... In fact that's how the windows file system works.
Having said that... you would be well advised to investigate tree data-structures before resorting to flattening a tree into a list.
So... Do you have a specific requirement to produce a List? Your umming-and-erring about Vector vs ArrayList makes it sound like you're still at the stage of choosing a datastructure.
Cheers. Keith.

How to use vector in JTable? Please help......

Hi there
I can use JTable using object array to manupulate data but it has a limitation of defining number of rows of the array. Alternatively i want to use vector. Anyone help me how to convert to using vector.
Regards.
mortoza, Dhaka

hi,
you could either use javax.swing.table.DefaultTableModel because this class uses a java.util.Vector for data storage or you could implements your own TableModel by extending javax.swing.table.AbstractTableModel.
best regards, Michael

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http://java.sun.com/products/jndi/tutorial/
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James
James Manning | Principal Engineer
Porivo Technologies, Inc.
919.806.0566 | [email protected]
http://www.porivo.com/
Measuring end-to-end Web performance.
Register for a FREE Performance appraisal:
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Do i have to use JMS with EJBS?

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"Paul Rooney" <[email protected]> wrote:
>
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hai
this Guru.
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Hi ...
I want to show files data in a jtable which consist of files (Name,size,path) I want to use vectors for remove and add methods. The problem is with data vector I tried to define it as
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Is it legal to use Vector in EJB?

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