java - Is there a fixed sized queue which removes excessive elements?

Question

I need a queue with a fixed size. When I add an element and the queue is full, it should automatically remove the oldest element.

Is there an existing implementation for this in Java?

Answer 1

Actually the LinkedHashMap does exactly what you want. You need to override the removeEldestEntry method.

Example for a queue with max 10 elements:

  queue = new LinkedHashMap<Integer, String>()
  {
     @Override
     protected boolean removeEldestEntry(Map.Entry<Integer, String> eldest)
     {
        return this.size() > 10;   
     }
  };

If the "removeEldestEntry" returns true, the eldest entry is removed from the map.