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      @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