/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.giraph.writable.kryo.serializers;

 import com.esotericsoftware.kryo.Kryo;

 import com.esotericsoftware.kryo.io.Input;

 import com.esotericsoftware.kryo.serializers.FieldSerializer;

 import com.google.common.base.Preconditions;

 /**

  * Serializer used to deserialize data into object, instead of creating a new

  * value readIntoObject needs to be set right before deserialization is called

  * on it.

  *

  * @param <T> Object type

  */

 public class ReusableFieldSerializer<T> extends FieldSerializer<T> {

   /** Current object into which to deserialize */

   private T readIntoObject;

   /**

    * Creates new reusable field serializer for a given type.

    * @param kryo HadoopKryo object

    * @param type Type of object

    */

   public ReusableFieldSerializer(Kryo kryo, Class type) {

     super(kryo, type);

   }

   public void setReadIntoObject(T value) {

     this.readIntoObject = value;

   }

   @Override

   protected T create(Kryo kryo, Input input, Class<T> type) {

     Preconditions.checkNotNull(readIntoObject);

     Preconditions.checkState(readIntoObject.getClass().equals(type));

     T toReturn = readIntoObject;

     readIntoObject = null;

     return toReturn;

   }

 }