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.io.serializer;
020
021import java.io.IOException;
022import java.io.InputStream;
023import java.io.ObjectInputStream;
024import java.io.ObjectOutputStream;
025import java.io.OutputStream;
026import java.io.Serializable;
027import org.apache.hadoop.classification.InterfaceAudience;
028import org.apache.hadoop.classification.InterfaceStability;
029
030/**
031 * <p>
032 * An experimental {@link Serialization} for Java {@link Serializable} classes.
033 * </p>
034 * @see JavaSerializationComparator
035 */
036@InterfaceAudience.Public
037@InterfaceStability.Unstable
038public class JavaSerialization implements Serialization<Serializable> {
039
040  static class JavaSerializationDeserializer<T extends Serializable>
041    implements Deserializer<T> {
042
043    private ObjectInputStream ois;
044
045    @Override
046    public void open(InputStream in) throws IOException {
047      ois = new ObjectInputStream(in) {
048        @Override protected void readStreamHeader() {
049          // no header
050        }
051      };
052    }
053    
054    @Override
055    @SuppressWarnings("unchecked")
056    public T deserialize(T object) throws IOException {
057      try {
058        // ignore passed-in object
059        return (T) ois.readObject();
060      } catch (ClassNotFoundException e) {
061        throw new IOException(e.toString());
062      }
063    }
064
065    @Override
066    public void close() throws IOException {
067      ois.close();
068    }
069
070  }
071
072  static class JavaSerializationSerializer
073    implements Serializer<Serializable> {
074
075    private ObjectOutputStream oos;
076
077    @Override
078    public void open(OutputStream out) throws IOException {
079      oos = new ObjectOutputStream(out) {
080        @Override protected void writeStreamHeader() {
081          // no header
082        }
083      };
084    }
085
086    @Override
087    public void serialize(Serializable object) throws IOException {
088      oos.reset(); // clear (class) back-references
089      oos.writeObject(object);
090    }
091
092    @Override
093    public void close() throws IOException {
094      oos.close();
095    }
096
097  }
098
099  @Override
100  @InterfaceAudience.Private
101  public boolean accept(Class<?> c) {
102    return Serializable.class.isAssignableFrom(c);
103  }
104
105  @Override
106  @InterfaceAudience.Private
107  public Deserializer<Serializable> getDeserializer(Class<Serializable> c) {
108    return new JavaSerializationDeserializer<Serializable>();
109  }
110
111  @Override
112  @InterfaceAudience.Private
113  public Serializer<Serializable> getSerializer(Class<Serializable> c) {
114    return new JavaSerializationSerializer();
115  }
116
117}