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 floats. */
027@InterfaceAudience.Public
028@InterfaceStability.Stable
029public 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  @Override
043  public void readFields(DataInput in) throws IOException {
044    value = in.readFloat();
045  }
046
047  @Override
048  public void write(DataOutput out) throws IOException {
049    out.writeFloat(value);
050  }
051
052  /** Returns true iff <code>o</code> is a FloatWritable with the same value. */
053  @Override
054  public boolean equals(Object o) {
055    if (!(o instanceof FloatWritable))
056      return false;
057    FloatWritable other = (FloatWritable)o;
058    return this.value == other.value;
059  }
060
061  @Override
062  public int hashCode() {
063    return Float.floatToIntBits(value);
064  }
065
066  /** Compares two FloatWritables. */
067  @Override
068  public int compareTo(FloatWritable o) {
069    float thisValue = this.value;
070    float thatValue = o.value;
071    return (thisValue<thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
072  }
073
074  @Override
075  public String toString() {
076    return Float.toString(value);
077  }
078
079  /** A Comparator optimized for FloatWritable. */ 
080  public static class Comparator extends WritableComparator {
081    public Comparator() {
082      super(FloatWritable.class);
083    }
084    @Override
085    public int compare(byte[] b1, int s1, int l1,
086                       byte[] b2, int s2, int l2) {
087      float thisValue = readFloat(b1, s1);
088      float thatValue = readFloat(b2, s2);
089      return (thisValue<thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
090    }
091  }
092
093  static {                                        // register this comparator
094    WritableComparator.define(FloatWritable.class, new Comparator());
095  }
096
097}
098