code: public  void close() {
  		super.clear();
  		if (indexMap != null){
  			indexMap.clear();
  			indexMap = null;
  		}
  		if (this.indexStore != null){
  			getIndexStore().close();
  			this.indexStore = null ;
  		}
  		if (this.cacheStore != null){
  			getCacheStore().close();
  			this.cacheStore = null ;
  		}
  	}
docs: Ensure closing without opening should notbe an issue.