1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 package org.apache.hadoop.hbase.codec; 19 20 import java.io.DataInputStream; 21 import java.io.DataOutputStream; 22 import java.io.IOException; 23 import java.io.InputStream; 24 import java.io.OutputStream; 25 26 import org.apache.hadoop.hbase.KeyValue; 27 28 /** 29 * Codec that does KeyValue version 1 serialization. 30 * <p>Encodes by casting Cell to KeyValue and writing out the backing array with a length prefix. 31 * This is how KVs were serialized in Puts, Deletes and Results pre-0.96. Its what would 32 * happen if you called the Writable#write KeyValue implementation. This encoder will fail 33 * if the passed Cell is not an old-school pre-0.96 KeyValue. Does not copy bytes writing. 34 * It just writes them direct to the passed stream. 35 * <p>If you wrote two KeyValues to this encoder, it would look like this in the stream: 36 * <pre> 37 * length-of-KeyValue1 // A java int with the length of KeyValue1 backing array 38 * KeyValue1 backing array filled with a KeyValue serialized in its particular format 39 * length-of-KeyValue2 40 * KeyValue2 backing array 41 * </pre> 42 */ 43 public class KeyValueCodec implements Codec { 44 public static class KeyValueEncoder extends BaseEncoder { 45 public KeyValueEncoder(final DataOutputStream out) { 46 super(out); 47 } 48 49 @Override 50 public void write(KeyValue kv) throws IOException { 51 checkFlushed(); 52 kv.write((DataOutputStream) out); 53 } 54 } 55 56 public static class KeyValueDecoder extends BaseDecoder{ 57 public KeyValueDecoder(final DataInputStream in) { 58 super(in); 59 } 60 61 @Override 62 protected KeyValue parseCell() throws IOException { 63 KeyValue kv = new KeyValue(); 64 kv.readFields((DataInputStream) this.in); 65 return kv; 66 } 67 } 68 69 /** 70 * Implementation depends on {@link InputStream#available()} 71 * <p> 72 * Must be passed a {@link DataInputStream} so KeyValues can be derserialized with the usual 73 * Writable mechanisms 74 */ 75 @Override 76 public Decoder getDecoder(InputStream is) { 77 return new KeyValueDecoder((DataInputStream) is); 78 } 79 80 /** 81 * Must be passed a {@link DataOutputStream} so KeyValues can be serialized using the usual 82 * Writable mechanisms 83 */ 84 @Override 85 public Encoder getEncoder(OutputStream os) { 86 return new KeyValueEncoder((DataOutputStream) os); 87 } 88 }