java - BlockingQueue like container that doesn't allow duplicates -

i want thread-safe container blocks caller until item becomes available. items added @ rate of 1000s per second container not drained same rate. therefore, want container disallow duplicates. wrote simple wrapper around linkedblockingqueue realized i've recreated classic producer-consumer deadlock. had written:

public class activitylistener {     private final blockingqueue<id> activeitems = new linkedblockingqueue<>();      public synchronized id take() throws interruptedexception {         return activeitems.take();     }      public synchronized void registeractivity(final id item) {         if (!activeitems.contains(item)) {             activeitems.add(item);         }     }      public synchronized boolean isitemactive(final id item) {         return activeitems.contains(item);     } } 

i not find established solution problem , appreciate help.

override add() , put() methods of implementation of blockingqueue check first if element within queue.

something -

@override public boolean add(t obj) {     if (contains(obj))         return true;     return super.add(obj); }