Separate implementation programming design

I would like to have design suggestion for t开发者_运维技巧he following issue:

I am programming for server application.(JBOSS)

It's something very common, but I am not sure how to implement this.

I am implementing an Interface.

each class which implements that interface will have different implementation.

in the future, I am sure that I will need to add more implementations, which means I will need to add additional "new" to my code.

How can I separate the "new" allocations to a different file/package/ear/jar, so if in the future I will have to add additional implementations for this specific interface, I wont need to open the whole source code.

I want to make it plug-ability, as much as I can.

thanks,

ray.

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It sounds like you're looking for dependency injection.

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If you code to the interface instead of the implementation (which you should be doing anyway) then you can use dependency injection to specify the implementation details by configuration. This is a fairly common technique when using Spring.

When you later decide to use a new implementation, the implementing classes can be put in their own jar, added to your application and the dependency injection configuration can be changed.