/*
    * 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 org.apache.giraph.utils.VertexIdData;
  import org.apache.giraph.utils.PairList;
  import org.apache.hadoop.io.WritableComparable;
  import org.apache.log4j.Logger;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  
  /**
   * Abstract request to send a collection of data, indexed by vertex id,
   * for a partition.
   *
   * @param <I> Vertex id
   * @param <T> Data
   * @param <B> Specialization of
   * {@link org.apache.giraph.utils.VertexIdData} for T
   */
  @SuppressWarnings("unchecked")
  public abstract class SendWorkerDataRequest<I extends WritableComparable, T,
      B extends VertexIdData<I, T>>
      extends WritableRequest implements WorkerRequest {
    /** Class logger */
    private static final Logger LOG =
        Logger.getLogger(SendWorkerDataRequest.class);
    /**
     * All data for a group of vertices, organized by partition, which
     * are owned by a single (destination) worker. This data is all
     * destined for this worker.
     * */
    protected PairList<Integer, B> partitionVertexData;
  
    /**
     * Constructor used for reflection only
     */
    public SendWorkerDataRequest() { }
  
    /**
     * Constructor used to send request.
     *
     * @param partVertData Map of remote partitions =&gt; VertexIdData
     */
    public SendWorkerDataRequest(
        PairList<Integer, B> partVertData) {
      this.partitionVertexData = partVertData;
    }
  
    /**
     * Create a new {@link org.apache.giraph.utils.VertexIdData}
     * specialized for the use case.
     *
     * @return A new instance of
     * {@link org.apache.giraph.utils.VertexIdData}
     */
    public abstract B createVertexIdData();
  
    @Override
    public void readFieldsRequest(DataInput input) throws IOException {
      int numPartitions = input.readInt();
      partitionVertexData = new PairList<Integer, B>();
      partitionVertexData.initialize(numPartitions);
      while (numPartitions-- > 0) {
        final int partitionId = input.readInt();
        B vertexIdData = createVertexIdData();
        vertexIdData.setConf(getConf());
        vertexIdData.readFields(input);
        partitionVertexData.add(partitionId, vertexIdData);
      }
    }
  
    @Override
    public void writeRequest(DataOutput output) throws IOException {
      output.writeInt(partitionVertexData.getSize());
      PairList<Integer, B>.Iterator
          iterator = partitionVertexData.getIterator();
      while (iterator.hasNext()) {
        iterator.next();
        output.writeInt(iterator.getCurrentFirst());
        iterator.getCurrentSecond().write(output);
     }
   }
 
   @Override
   public int getSerializedSize() {
     int size = super.getSerializedSize() + 4;
     PairList<Integer, B>.Iterator iterator = partitionVertexData.getIterator();
     while (iterator.hasNext()) {
       iterator.next();
       size += 4 + iterator.getCurrentSecond().getSerializedSize();
     }
     return size;
   }
 }