Java blocking queue containing only unique elements

Question

sort of like a \"blocking set\". How can I implement a blocking queue where adding a member that is already in the set is ignored?

Answer 1

You can create a new class that composes a BlockingQueue, a Set, and a lock. When you put() you test against the set while holding a lock that prevents get() from running. When you get() you remove the item from the set so that it can be put() again in the future.