Bounded PriorityBlockingQueue

java collections priority-queue
nanda picture nanda · Feb 26, 2010 · Viewed 11.1k times · Source

PriorityBlockingQueue is unbounded, but I need to bound it somehow. What is the best way to achieve that?

For information, the bounded PriorityBlockingQueue will be used in a ThreadPoolExecutor.

NB: By bounded I don't want to throw Exception if that happens, I want to put the object in the queue and then cut it based on its priority value. Is there any good way to do this cut thingie?

Answer

Frank V picture Frank V · Mar 4, 2010

I actually wouldn't subclass it. While I can't put together example code right now, I'd suggest a version of the decorator pattern.

Create a new class and implement the interfaces implemented by your class of interest: PriorityBlockingQueue. I've found the following interfaces used by this class:

Serializable, Iterable<E>, Collection<E>, BlockingQueue<E>, Queue<E>

In the constructor for a class, accept a PriorityBlockingQueue as a constructor parameter.

Then implement all the methods required by the interfaces via the instances of the PriorityblockingQueue. Add any code required to make it Bounded. This is a fairly standard implementation of a Decorator pattern.

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