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MDB + Entity Bean / MDB + SB + EB

 
kri shan
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JMS client/JMS destineation(Queue / Topic) sends messages to the MDB instances. Then MDB sends the message to the Entity Bean. Can i add
session bean as a asynchronous wrapper between MDB and Entity Bean.
 
Hong Anderson
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I'm not sure what you want. MDB is a special kind of Session Bean. Why do you want an another session bean?
 
Jimmy Clark
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What is the message? Or, what is in the message? What is the purpose of the message?
 
kri shan
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MDS is stateless. Session Bean may be statefull.
Message is Queue. The purpose of the message is integration between different systems.
 
Jimmy Clark
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Then MDB sends the message to the Entity Bean.


Are these beans in the same EJB container or are they in different containers? Please explain.

The purpose of the message is integration between different systems.


Are you saying that the MDB and the Entity Bean are not in the same system?
 
kri shan
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MDB and Entity Beans are in the different containers.
 
Jimmy Clark
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Which application servers are involved? How many nodes are there?
 
kri shan
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Which application servers are involved? JBoss application server

How many nodes are there? two nodes
 
Jimmy Clark
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Yes, you can add a Session EJB on the node hosting the Entity EJB. The Message EJB would then communication with the Session EJB instead of attempting to directly communicate with the Entity EJB.
 
kri shan
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Hi James, If MDB and Entity Beans are in the same container, can i need Session Bean for wrapper ?
 
Jimmy Clark
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Message-Driven Beans are for handling messages from message queues.

Session Beans are for executing business logic.

Entity Beans
are a temporary object-oriented representation of data.

The code in a Message-Driven bean should not contain business logic. You can certainly code business logic in it, but it would bad design in my opinion. So, if there is any business logic that is associated with the data (Entity Bean) then it should be coded in a Session EJB.

The Entity Bean code should not contain business logic either.

Whether they are in the same container or not is not really relevant. Each bean has a purpose.
 
It is sorta covered in the JavaRanch Style Guide.
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