Is there a fixed sized queue which removes excessive elements?

Solution 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.

Solution 2:

Yes, Two

From my own duplicate question with this correct answer, I learned of two:

• EvictingQueue in Google Guava
• CircularFifoQueue in Apache Commons

I made productive use of the Guava EvictingQueue, worked well.

To instantiate an EvictingQueue call the static factory method create and specify your maximum size.

EvictingQueue< Person > people = com.google.common.collect.EvictingQueue.create( 100 ) ;  // Set maximum size to 100.