/*

  * 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.utils;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 /**

  * VertexIdMessages

  *

  * @param <I> vertexId type parameter

  * @param <M> message type parameter

  */

 public interface VertexIdMessages<I extends WritableComparable,

   M extends Writable> extends VertexIdData<I, M> {

   /**

    * Get specialized iterator that will instantiate the vertex id and

    * message of this object.  It will only produce message bytes, not actual

    * messages and expects a different encoding.

    *

    * @return Special iterator that reuses vertex ids (unless released) and

    *         copies message bytes

    */

   VertexIdMessageBytesIterator<I, M> getVertexIdMessageBytesIterator();

   /**

    * Get specialized iterator that will instiantiate the vertex id and

    * message of this object.

    *

    * @return Special iterator that reuses vertex ids and messages unless

    *         specified

    */

   VertexIdMessageIterator<I, M> getVertexIdMessageIterator();

 }