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