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; 020 021import java.io.*; 022 023import org.apache.hadoop.classification.InterfaceAudience; 024import org.apache.hadoop.classification.InterfaceStability; 025 026/** A WritableComparable for a single byte. */ 027@InterfaceAudience.Public 028@InterfaceStability.Stable 029public class ByteWritable implements WritableComparable<ByteWritable> { 030 private byte value; 031 032 public ByteWritable() {} 033 034 public ByteWritable(byte value) { set(value); } 035 036 /** Set the value of this ByteWritable. */ 037 public void set(byte value) { this.value = value; } 038 039 /** Return the value of this ByteWritable. */ 040 public byte get() { return value; } 041 042 @Override 043 public void readFields(DataInput in) throws IOException { 044 value = in.readByte(); 045 } 046 047 @Override 048 public void write(DataOutput out) throws IOException { 049 out.writeByte(value); 050 } 051 052 /** Returns true iff <code>o</code> is a ByteWritable with the same value. */ 053 @Override 054 public boolean equals(Object o) { 055 if (!(o instanceof ByteWritable)) { 056 return false; 057 } 058 ByteWritable other = (ByteWritable)o; 059 return this.value == other.value; 060 } 061 062 @Override 063 public int hashCode() { 064 return (int)value; 065 } 066 067 /** Compares two ByteWritables. */ 068 @Override 069 public int compareTo(ByteWritable o) { 070 int thisValue = this.value; 071 int thatValue = o.value; 072 return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1)); 073 } 074 075 @Override 076 public String toString() { 077 return Byte.toString(value); 078 } 079 080 /** A Comparator optimized for ByteWritable. */ 081 public static class Comparator extends WritableComparator { 082 public Comparator() { 083 super(ByteWritable.class); 084 } 085 086 @Override 087 public int compare(byte[] b1, int s1, int l1, 088 byte[] b2, int s2, int l2) { 089 byte thisValue = b1[s1]; 090 byte thatValue = b2[s2]; 091 return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1)); 092 } 093 } 094 095 static { // register this comparator 096 WritableComparator.define(ByteWritable.class, new Comparator()); 097 } 098} 099