org.apache.mahout.cf.taste.hadoop.EntityEntityWritable.java Source code

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Here is the source code for org.apache.mahout.cf.taste.hadoop.EntityEntityWritable.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.mahout.cf.taste.hadoop;

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

import com.google.common.primitives.Longs;
import org.apache.hadoop.io.WritableComparable;
import org.apache.mahout.math.Varint;

/** A {@link WritableComparable} encapsulating two items. */
public final class EntityEntityWritable implements WritableComparable<EntityEntityWritable>, Cloneable {

    private long aID;
    private long bID;

    public EntityEntityWritable() {
        // do nothing
    }

    public EntityEntityWritable(long aID, long bID) {
        this.aID = aID;
        this.bID = bID;
    }

    long getAID() {
        return aID;
    }

    long getBID() {
        return bID;
    }

    @Override
    public void write(DataOutput out) throws IOException {
        Varint.writeSignedVarLong(aID, out);
        Varint.writeSignedVarLong(bID, out);
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        aID = Varint.readSignedVarLong(in);
        bID = Varint.readSignedVarLong(in);
    }

    @Override
    public int compareTo(EntityEntityWritable that) {
        int aCompare = compare(aID, that.getAID());
        return aCompare == 0 ? compare(bID, that.getBID()) : aCompare;
    }

    private static int compare(long a, long b) {
        return a < b ? -1 : a > b ? 1 : 0;
    }

    @Override
    public int hashCode() {
        return Longs.hashCode(aID) + 31 * Longs.hashCode(bID);
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof EntityEntityWritable) {
            EntityEntityWritable that = (EntityEntityWritable) o;
            return aID == that.getAID() && bID == that.getBID();
        }
        return false;
    }

    @Override
    public String toString() {
        return aID + "\t" + bID;
    }

    @Override
    public EntityEntityWritable clone() {
        return new EntityEntityWritable(aID, bID);
    }

}