/*

  * 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.edge;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import java.util.Map;

 /**

  * Helper class for a mutable edge that modifies the backing map entry.

  *

  * @param <I> Vertex id

  * @param <E> Edge value

  */

 public class MapMutableEdge<I extends WritableComparable, E extends Writable>

     implements MutableEdge<I, E> {

   /** Backing entry for the edge in the map. */

   private Map.Entry<I, E> entry;

   /**

    * Set the backing entry for this edge in the map.

    *

    * @param entry Backing entry

    */

   public void setEntry(Map.Entry<I, E> entry) {

     this.entry = entry;

   }

   @Override

   public void setValue(E value) {

     // Replace the value in the map.

     entry.setValue(value);

   }

   @Override

   public I getTargetVertexId() {

     return entry.getKey();

   }

   @Override

   public E getValue() {

     return entry.getValue();

   }

 }