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Designing the Project? EJBs Stored Procedure JTree etc.

Posted on 2002-04-18
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Last Modified: 2013-11-24
Well I am here in middle of a project which is using Java Swing as the GUI. We are still not decided the middleware tough our database is ORACLE.

BTW: Options of middleware is JSP/Servlet/Oracle Stored Procedure
or
JSP/Servlet/EJB

Now this JTree is hosting data which will have concurrent access.

Swing is divided in two panels : PanelA is JTree with all its nodes and PanelB is with Display area which is nothing but retirves info about the node when the node is clicked.

JTree(PanelA) is downloaded once and then subsequent hits on the node gets data of the node dynamically.

The tree is dynamic and nodes can be added to the existing tree.

Now just imagine the scenario:  

User A is working on the JTree and is viewing the data on the Display panel.

User B is working on the JTree and is viewing the data on the Display panel.

Now: User B adds a node to the tree.

User A is working on the JTree and wants access some node.

But now how does this user A gets to have the most fresh copy of the JTree since User B has added a node.

Now refreshing the tree on every request is very very expensive process.

So what is the way to pass some mechanism which makes the User A session aware that the tree is updated and the user refreshes the tree by calling the relevant method.

If I am not further clear I can go in more depth.

A strong strategy will be very very helpful and what is better appraoch to use in middleware. I have mentioned both the approches we are exploring.

we are using websphere as our appserver.

Thanx in advance to all experts.









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Question by:dumdum420
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Jim Cakalic earned 75 total points
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What you probably want is something akin to a distributed event service. Given that you are familiar with Swing, you are no doubt accustomed to the event notification typically employed in a Swing application. Distributed event notification simply extends this pattern outside the JVM.

One implementation of such a service is described in this IBM tutorial (which I admit to not having completed):
http://www-105.ibm.com/developerworks/education.nsf/java-onlinecourse-bytitle/F1AB349B0FDC49A586256B590050ADD7?OpenDocument

Certainly, you might do something like this using publish/subscribe through a JMS messaging server. Each Swing application could both publish its changes on a topic and subscribe to the topic so it could receive published changes from other applications.
http://java.sun.com/products/jms/faq.html#event_model

Another possible alternative might be to consider using Jini technologies as described in the Java Developer Connection article:
http://developer.java.sun.com/developer/technicalArticles/jini/JiniEvents/

And a lightweight equivalent might be achieved using multicast sockets. The problem with mutlicasting is that it relies on datagram sockets using UDP which is not reliable. An alternative would be LRMP (Lightweight Reliable Multicast Protocol).
http://java.sun.com/docs/books/tutorial/networking/datagrams/index.html
http://webcanal.inria.fr/lrmp/

Whichever route you go, the idea is that modifiers  broadcast their changes so as to notify interested parties.

Best regards,
Jim Cakalic

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Zero response by Asker nor Expert closing recommendations, therefore this was finalized today by
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Thanks, Moondancer. Sorry for not being responsive.
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