/*

  * 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.giraph.factories.MessageValueFactory;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import java.io.IOException;

 /**

  * Stores a message and a list of target vertex ids.

  *

  * @param <I> Vertex id

  * @param <M> Message data

  */

 @SuppressWarnings("unchecked")

 public class ByteArrayOneMessageToManyIds<I extends WritableComparable,

   M extends Writable> extends ByteArrayVertexIdData<I, M>

   implements VertexIdMessages<I, M> {

   /** Message value class */

   private MessageValueFactory<M> messageValueFactory;

   /**

    * Constructor.

    *

    * @param messageValueFactory Class for messages

    */

   public ByteArrayOneMessageToManyIds(

       MessageValueFactory<M> messageValueFactory) {

     this.messageValueFactory = messageValueFactory;

   }

   @Override

   public M createData() {

     return messageValueFactory.newInstance();

   }

   @Override

   public void writeData(ExtendedDataOutput out, M message) throws IOException {

     message.write(out);

   }

   @Override

   public void readData(ExtendedDataInput in, M message) throws IOException {

     message.readFields(in);

   }

   /**

    * Add a message.

    * The order is: the message > id count > ids .

    *

    * @param ids   The byte array which holds target ids

    *              of this message on the worker

    * @param idPos The end position of the ids

    *              information in the byte array above.

    * @param count The number of ids

    * @param msg   The message sent

    */

   public void add(byte[] ids, int idPos, int count, M msg) {

     try {

       msg.write(extendedDataOutput);

       extendedDataOutput.writeInt(count);

       extendedDataOutput.write(ids, 0, idPos);

     } catch (IOException e) {

       throw new IllegalStateException("add: IOException", e);

     }

   }

   @Override

   public void add(I vertexId, M data) {

     throw new UnsupportedOperationException();

   }

   @Override

   public void add(byte[] serializedId, int idPos, M data) {

     throw new UnsupportedOperationException();

   }

   @Override

   public VertexIdMessageBytesIterator<I, M> getVertexIdMessageBytesIterator() {

     return null;

   }

   @Override

   public VertexIdMessageIterator<I, M> getVertexIdMessageIterator() {

     return new OneMessageToManyIdsIterator<>(this);

   }

 }