/*

  * 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.function;

 /**

  * Default object holder, intermediary between producers and consumers.

  *

  * Holds value in memory, so can be used only when producer and consumer

  * are in the same context.

  *

  * Useful when value is set on the master, and later read in block logic

  * (RepeatUntilBlock), or in a different Piece, either on worker or master.

  * If it is read within the same piece - just use local field.

  *

  * @param <T> Type of object to hold.

  */

 public class ObjectHolder<T> implements Supplier<T>, Consumer<T> {

   /** value */

   private T value;

   /**

    * Constructor

    * @param value initial value

    */

   public ObjectHolder(T value) {

     this.value = value;

   }

   /** Constructor */

   public ObjectHolder() {

   }

   @Override

   public T get() {

     return value;

   }

   @Override

   public void apply(T value) {

     this.value = value;

   }

   @Override

   public String toString() {

     return getClass() + " [value=" + value + "]";

   }

 }