code: private void init(){
  		// We are going to use a linked hash map to maintain our sliding window
  		slidingWindow=new LinkedHashMap<String,Integer>(windowSize+1, .75F, false){
              protected boolean removeEldestEntry(Map.Entry<String,Integer> eldest){
                  return size()>windowSize;                                  
              }
          };
  	}
docs: Initializes the internal sliding window data structure.