hive/src/main/java/org/apache/apex/malhar/hive/HiveStreamCodec.java

/**
 * 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 com.datatorrent.contrib.hive;

import java.io.ByteArrayOutputStream;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;

import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;

import com.datatorrent.lib.codec.KryoSerializableStreamCodec;

/**
 * Stream codec for uniform distribution of tuples on upstream operator. This is
 * used to make sure that data being sent to a particular hive partition goes to
 * a specific operator partition by passing FSRollingOutputOperator to the
 * stream codec.
 *
 * @since 2.1.0
 */
public class HiveStreamCodec<T> extends KryoSerializableStreamCodec<T> implements Externalizable
{
  private static final long serialVersionUID = 201412121604L;

  protected AbstractFSRollingOutputOperator<T> rollingOperator;

  @Override
  public void writeExternal(ObjectOutput out) throws IOException
  {

    ByteArrayOutputStream os = new ByteArrayOutputStream();
    ObjectOutputStream obj = new ObjectOutputStream(os);
    Output output = new Output(obj);
    kryo.writeClassAndObject(output, rollingOperator);
    byte[] outBytes = output.toBytes();
    out.writeInt(outBytes.length);
    out.write(outBytes, 0, outBytes.length);
    out.flush();
  }

  @Override
  @SuppressWarnings("unchecked")
  public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
  {
    int size = in.readInt();
    byte[] data = new byte[size];
    in.readFully(data);
    Input input = new Input(data);
    input.setBuffer(data);
    rollingOperator = (AbstractFSRollingOutputOperator)kryo.readClassAndObject(input);
  }

  @Override
  public int getPartition(T o)
  {
    return rollingOperator.getHivePartition(o).hashCode();
  }

}