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