Is there a fixed sized queue which removes excessive elements?

java queue
c0d3x picture c0d3x · Dec 26, 2009 · Viewed 74.5k times · Source

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

Mavrik picture Mavrik · Dec 26, 2009

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.

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