com.cloudera.crunch.Pair.java Source code

Introduction

Here is the source code for com.cloudera.crunch.Pair.java

Source

/**
 * Copyright (c) 2011, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. 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
 *
 * This software 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 com.cloudera.crunch;

import org.apache.commons.lang.builder.HashCodeBuilder;

/**
 * A convenience class for two-element {@link Tuple}s.
 */
public class Pair<K, V> implements Tuple, Comparable<Pair<K, V>> {

    private final K first;
    private final V second;

    public static <T, U> Pair<T, U> of(T first, U second) {
        return new Pair<T, U>(first, second);
    }

    public Pair(K first, V second) {
        this.first = first;
        this.second = second;
    }

    public K first() {
        return first;
    }

    public V second() {
        return second;
    }

    public Object get(int index) {
        switch (index) {
        case 0:
            return first;
        case 1:
            return second;
        default:
            throw new ArrayIndexOutOfBoundsException();
        }
    }

    public int size() {
        return 2;
    }

    @Override
    public int hashCode() {
        HashCodeBuilder hcb = new HashCodeBuilder();
        return hcb.append(first).append(second).toHashCode();
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Pair<?, ?> other = (Pair<?, ?>) obj;
        return (first == other.first || (first != null && first.equals(other.first)))
                && (second == other.second || (second != null && second.equals(other.second)));
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder("[");
        sb.append(first).append(",").append(second).append("]");
        return sb.toString();
    }

    private int cmp(Object lhs, Object rhs) {
        if (lhs == rhs) {
            return 0;
        } else if (lhs != null && Comparable.class.isAssignableFrom(lhs.getClass())) {
            return ((Comparable) lhs).compareTo(rhs);
        }
        return (lhs == null ? 0 : lhs.hashCode()) - (rhs == null ? 0 : rhs.hashCode());
    }

    @Override
    public int compareTo(Pair<K, V> o) {
        int diff = cmp(first, o.first);
        if (diff == 0) {
            diff = cmp(second, o.second);
        }
        return diff;
    }
}