001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.mapred.nativetask.serde;
020
021import java.io.DataInput;
022import java.io.DataOutput;
023import java.io.IOException;
024import org.apache.hadoop.classification.InterfaceAudience;
025import org.apache.hadoop.classification.InterfaceStability;
026
027/**
028 * an INativeSerializer serializes and deserializes data transferred between
029 * Java and native. {@link DefaultSerializer} provides default implementations.
030 *
031 * Note: if you implemented your customized NativeSerializer instead of DefaultSerializer,
032 * you have to make sure the native side can serialize it correctly.
033 * 
034 */
035@InterfaceAudience.Public
036@InterfaceStability.Evolving
037public interface INativeSerializer<T> {
038
039  /**
040   * get length of data to be serialized. If the data length is already known (like IntWritable)
041   * and could immediately be returned from this method, it is good chance to implement customized
042   * NativeSerializer for efficiency
043   */
044  public int getLength(T w) throws IOException;
045
046  public void serialize(T w, DataOutput out) throws IOException;
047
048  public void deserialize(DataInput in, int length, T w) throws IOException;
049}