/*

  * 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.comm.requests;

 import java.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfigurable;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 /**

  * Interface for requests to implement

  *

  * @param <I> Vertex id

  * @param <V> Vertex data

  * @param <E> Edge data

  */

 public abstract class WritableRequest<I extends WritableComparable,

     V extends Writable, E extends Writable> implements Writable,

     ImmutableClassesGiraphConfigurable<I, V, E> {

   /**

    * Value to use when size of the request in serialized form is not known

    * or too expensive to calculate

    */

   public static final int UNKNOWN_SIZE = -1;

   /** Configuration */

   protected ImmutableClassesGiraphConfiguration<I, V, E> conf;

   /** Client id */

   private int clientId = -1;

   /** Request id */

   private long requestId = -1;

   public int getClientId() {

     return clientId;

   }

   public void setClientId(int clientId) {

     this.clientId = clientId;

   }

   public long getRequestId() {

     return requestId;

   }

   public void setRequestId(long requestId) {

     this.requestId = requestId;

   }

   /**

    * Get the size of the request in serialized form. The number returned by

    * this function can't be less than the actual size - if the size can't be

    * calculated correctly return WritableRequest.UNKNOWN_SIZE.

    *

    * @return The size (in bytes) of serialized request,

    * or WritableRequest.UNKNOWN_SIZE if the size is not known

    * or too expensive to calculate.

    */

   public int getSerializedSize() {

     // 4 for clientId, 8 for requestId

     return 4 + 8;

   }

   /**

    * Get the type of the request

    *

    * @return Request type

    */

   public abstract RequestType getType();

   /**

    * Serialize the request

    *

    * @param input Input to read fields from

    */

   abstract void readFieldsRequest(DataInput input) throws IOException;

   /**

    * Deserialize the request

    *

    * @param output Output to write the request to

    */

   abstract void writeRequest(DataOutput output) throws IOException;

   @Override

   public final ImmutableClassesGiraphConfiguration<I, V, E> getConf() {

     return conf;

   }

   @Override

   public final void setConf(ImmutableClassesGiraphConfiguration<I, V, E> conf) {

     this.conf = conf;

   }

   @Override

   public final void readFields(DataInput input) throws IOException {

     clientId = input.readInt();

     requestId = input.readLong();

     readFieldsRequest(input);

   }

   @Override

   public final void write(DataOutput output) throws IOException {

     output.writeInt(clientId);

     output.writeLong(requestId);

     writeRequest(output);

   }

 }