title: A Queue that ensure uniqueness of the elements?
body: <p>I'm looking for a implementation of java.util.Queue or something in the Google collection who behave like a Queue, but also ensure that each element of the queue is unique. (all further insertion will have no effect)</p>
  
  <p>It's that possible, or will I have to do it by hand?</p>
  
  <p>For now I'm using a Queue, with a LinkedList implementation, and I check the uniqueness before insertion. ( I use a side Map for doing this, add / remove element from the side map before / after the queu ). I don't like it too much.</p>
  
  <p>Any input is welcome. If it's not in the java.util package, then maybe it's a bad idea?</p>