org.apache.hadoop.io.LongWritable.java Source code

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Here is the source code for org.apache.hadoop.io.LongWritable.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.io;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/** A WritableComparable for longs. */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class LongWritable implements WritableComparable<LongWritable> {
    private long value;

    public LongWritable() {
    }

    public LongWritable(long value) {
        set(value);
    }

    /** Set the value of this LongWritable. */
    public void set(long value) {
        this.value = value;
    }

    /** Return the value of this LongWritable. */
    public long get() {
        return value;
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        value = in.readLong();
    }

    @Override
    public void write(DataOutput out) throws IOException {
        out.writeLong(value);
    }

    /** Returns true iff <code>o</code> is a LongWritable with the same value. */
    @Override
    public boolean equals(Object o) {
        if (!(o instanceof LongWritable))
            return false;
        LongWritable other = (LongWritable) o;
        return this.value == other.value;
    }

    @Override
    public int hashCode() {
        return (int) value;
    }

    /** Compares two LongWritables. */
    @Override
    public int compareTo(LongWritable o) {
        long thisValue = this.value;
        long thatValue = o.value;
        return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
    }

    @Override
    public String toString() {
        return Long.toString(value);
    }

    /** A Comparator optimized for LongWritable. */
    public static class Comparator extends WritableComparator {
        public Comparator() {
            super(LongWritable.class);
        }

        @Override
        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
            long thisValue = readLong(b1, s1);
            long thatValue = readLong(b2, s2);
            return (thisValue < thatValue ? -1 : (thisValue == thatValue ? 0 : 1));
        }
    }

    /** A decreasing Comparator optimized for LongWritable. */
    public static class DecreasingComparator extends Comparator {

        @Override
        public int compare(WritableComparable a, WritableComparable b) {
            return super.compare(b, a);
        }

        @Override
        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
            return super.compare(b2, s2, l2, b1, s1, l1);
        }
    }

    static { // register default comparator
        WritableComparator.define(LongWritable.class, new Comparator());
    }

}