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
022 import java.io.DataInput;
023 import java.io.DataOutput;
024 import java.io.IOException;
025
026 import org.apache.hadoop.classification.InterfaceAudience;
027 import org.apache.hadoop.classification.InterfaceStability;
028
029 /** A WritableComparable for longs. */
030 @InterfaceAudience.Public
031 @InterfaceStability.Stable
032 public class LongWritable implements WritableComparable<LongWritable> {
033 private long value;
034
035 public LongWritable() {}
036
037 public LongWritable(long value) { set(value); }
038
039 /** Set the value of this LongWritable. */
040 public void set(long value) { this.value = value; }
041
042 /** Return the value of this LongWritable. */
043 public long get() { return value; }
044
045 public void readFields(DataInput in) throws IOException {
046 value = in.readLong();
047 }
048
049 public void write(DataOutput out) throws IOException {
050 out.writeLong(value);
051 }
052
053 /** Returns true iff <code>o</code> is a LongWritable with the same value. */
054 public boolean equals(Object o) {
055 if (!(o instanceof LongWritable))
056 return false;
057 LongWritable other = (LongWritable)o;
058 return this.value == other.value;
059 }
060
061 public int hashCode() {
062 return (int)value;
063 }
064
065 /** Compares two LongWritables. */
066 public int compareTo(LongWritable o) {
067 long thisValue = this.value;
068 long thatValue = o.value;
069 return (thisValue<thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
070 }
071
072 public String toString() {
073 return Long.toString(value);
074 }
075
076 /** A Comparator optimized for LongWritable. */
077 public static class Comparator extends WritableComparator {
078 public Comparator() {
079 super(LongWritable.class);
080 }
081
082 public int compare(byte[] b1, int s1, int l1,
083 byte[] b2, int s2, int l2) {
084 long thisValue = readLong(b1, s1);
085 long thatValue = readLong(b2, s2);
086 return (thisValue<thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
087 }
088 }
089
090 /** A decreasing Comparator optimized for LongWritable. */
091 public static class DecreasingComparator extends Comparator {
092
093 @Override
094 public int compare(WritableComparable a, WritableComparable b) {
095 return -super.compare(a, b);
096 }
097 public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
098 return -super.compare(b1, s1, l1, b2, s2, l2);
099 }
100 }
101
102 static { // register default comparator
103 WritableComparator.define(LongWritable.class, new Comparator());
104 }
105
106 }
107