elastic2.3自定义插件，监测index变化，postIndex，postCreate的执行让我无法理解

package index_listener;



import org.elasticsearch.index.engine.Engine;

import org.elasticsearch.index.engine.Engine.Index;

import org.elasticsearch.index.indexing.IndexingOperationListener;

import org.elasticsearch.index.shard.IndexShard;

import org.joda.time.DateTime;



public class AuditIndexOpListener  extends IndexingOperationListener{



	   private IndexShard indexShard;

		

	   public void AuditIndexOpListener(IndexShard indexShard) {

	      this.indexShard = indexShard;

	   }

	   

//	   @Override

//	   public void postIndex(Engine.Index index) {

//	      System.out.print(index.source());

//	   }

	   

	   @Override

	   public void postIndex(Index index) {

		   System.out.print("索引变化");

		   System.out.print(index.source());

		   System.out.println(index.docs());

		   System.out.println(index.toString());

		   System.out.println("tyep");

		   System.out.println(index.opType());

		   

	   }

	   

       @Override

       public void postCreate(Engine.Create create) {

    	   	    System.out.print("创建index");

            System.out.print(create.id());

            System.out.print(create.type());

            System.out.print((new DateTime()).toString());

            System.out.print(create.source());

           

       }

	   

       @Override

       public void postDelete(Engine.Delete delete) {

    	   		System.out.print("删除index");

    	   		System.out.print(delete.id());

    	   		System.out.print(delete.type());

    	   		System.out.print((new DateTime()).toString());

    	   		System.out.print(delete.version());

       }

		

}