/*

  * 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 java.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 import org.apache.giraph.factories.MessageValueFactory;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 /**

  * Stores vertex id and message pairs in a single byte array.

  *

  * @param <I> Vertex id

  * @param <M> Message data

  */

 @SuppressWarnings("unchecked")

 public class ByteArrayVertexIdMessages<I extends WritableComparable,

   M extends Writable> extends ByteArrayVertexIdData<I, M>

   implements VertexIdMessages<I, M> {

   /** Message value class */

   private final MessageValueFactory<M> messageValueFactory;

   /** Add the message size to the stream? (Depends on the message store) */

   private boolean useMessageSizeEncoding = false;

   /**

    * Constructor

    *

    * @param messageValueFactory Class for messages

    */

   public ByteArrayVertexIdMessages(

       MessageValueFactory<M> messageValueFactory) {

     this.messageValueFactory = messageValueFactory;

   }

   /**

    * Set whether message sizes should be encoded.  This should only be a

    * possibility when not combining.  When combining, all messages need to be

    * de-serialized right away, so this won't help.

    */

   private void setUseMessageSizeEncoding() {

     if (!getConf().useOutgoingMessageCombiner()) {

       useMessageSizeEncoding = getConf().useMessageSizeEncoding();

     } else {

       useMessageSizeEncoding = false;

     }

   }

   @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);

   }

   @Override

   public void initialize() {

     super.initialize();

     setUseMessageSizeEncoding();

   }

   @Override

   public void initialize(int expectedSize) {

     super.initialize(expectedSize);

     setUseMessageSizeEncoding();

   }

   @Override

   public ByteStructVertexIdMessageIterator<I, M> getVertexIdMessageIterator() {

     return new ByteStructVertexIdMessageIterator<>(this);

   }

   @Override

   public void add(I vertexId, M message) {

     if (!useMessageSizeEncoding) {

       super.add(vertexId, message);

     } else {

       try {

         vertexId.write(extendedDataOutput);

         writeMessageWithSize(message);

       } catch (IOException e) {

         throw new IllegalStateException("add: IOException occurred");

       }

     }

   }

   @Override

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

     if (!useMessageSizeEncoding) {

       super.add(serializedId, idPos, message);

     } else {

       try {

         extendedDataOutput.write(serializedId, 0, idPos);

         writeMessageWithSize(message);

       } catch (IOException e) {

         throw new IllegalStateException("add: IOException occurred");

       }

     }

   }

   /**

    * Write a size of the message and message

    *

    * @param message Message to write

    */

   private void writeMessageWithSize(M message) throws IOException {

     int pos = extendedDataOutput.getPos();

     extendedDataOutput.skipBytes(4);

     writeData(extendedDataOutput, message);

     extendedDataOutput.writeInt(

         pos, extendedDataOutput.getPos() - pos - 4);

   }

   @Override

   public ByteStructVertexIdMessageBytesIterator<I, M>

   getVertexIdMessageBytesIterator() {

     if (!useMessageSizeEncoding) {

       return null;

     }

     return new ByteStructVertexIdMessageBytesIterator<I, M>(this) {

       @Override

       public void writeCurrentMessageBytes(DataOutput dataOutput) {

         try {

           dataOutput.write(extendedDataOutput.getByteArray(),

             messageOffset, messageBytes);

         } catch (NegativeArraySizeException e) {

           VerboseByteStructMessageWrite.handleNegativeArraySize(vertexId);

         } catch (IOException e) {

           throw new IllegalStateException("writeCurrentMessageBytes: Got " +

               "IOException", e);

         }

       }

     };

   }

   @Override

   public void write(DataOutput dataOutput) throws IOException {

     dataOutput.writeBoolean(useMessageSizeEncoding);

     super.write(dataOutput);

   }

   @Override

   public void readFields(DataInput dataInput) throws IOException {

     useMessageSizeEncoding = dataInput.readBoolean();

     super.readFields(dataInput);

   }

 }