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.DataInput; 022import java.io.DataOutput; 023import java.io.IOException; 024 025import org.apache.hadoop.classification.InterfaceAudience; 026import org.apache.hadoop.classification.InterfaceStability; 027 028/** 029 * Writable for Double values. 030 */ 031@InterfaceAudience.Public 032@InterfaceStability.Stable 033public class DoubleWritable implements WritableComparable<DoubleWritable> { 034 035 private double value = 0.0; 036 037 public DoubleWritable() { 038 039 } 040 041 public DoubleWritable(double value) { 042 set(value); 043 } 044 045 @Override 046 public void readFields(DataInput in) throws IOException { 047 value = in.readDouble(); 048 } 049 050 @Override 051 public void write(DataOutput out) throws IOException { 052 out.writeDouble(value); 053 } 054 055 public void set(double value) { this.value = value; } 056 057 public double get() { return value; } 058 059 /** 060 * Returns true iff <code>o</code> is a DoubleWritable with the same value. 061 */ 062 @Override 063 public boolean equals(Object o) { 064 if (!(o instanceof DoubleWritable)) { 065 return false; 066 } 067 DoubleWritable other = (DoubleWritable)o; 068 return this.value == other.value; 069 } 070 071 @Override 072 public int hashCode() { 073 return (int)Double.doubleToLongBits(value); 074 } 075 076 @Override 077 public int compareTo(DoubleWritable o) { 078 return (value < o.value ? -1 : (value == o.value ? 0 : 1)); 079 } 080 081 @Override 082 public String toString() { 083 return Double.toString(value); 084 } 085 086 /** A Comparator optimized for DoubleWritable. */ 087 public static class Comparator extends WritableComparator { 088 public Comparator() { 089 super(DoubleWritable.class); 090 } 091 092 @Override 093 public int compare(byte[] b1, int s1, int l1, 094 byte[] b2, int s2, int l2) { 095 double thisValue = readDouble(b1, s1); 096 double thatValue = readDouble(b2, s2); 097 return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1)); 098 } 099 } 100 101 static { // register this comparator 102 WritableComparator.define(DoubleWritable.class, new Comparator()); 103 } 104 105} 106