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package org.apache.velocity.util;

/*
 * 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.
 */

/**
 *  Combine two objects in a hashable pair
 *
 * @version $Id: Pair.java $
 * @since 2.0
 */

public class Pair<A, B>
{
    private final A first;
    private final B second;

    public Pair(final A first, final B second)
    {
        this.first = first;
        this.second = second;
    }

    public int hashCode()
    {
        int hashFirst = first != null ? first.hashCode() : 0;
        int hashSecond = second != null ? second.hashCode() : 0;

        return (hashFirst + hashSecond) * hashSecond + hashFirst;
    }

    public boolean equals(Object other)
    {
        if (other instanceof Pair)
        {
            Pair otherPair = (Pair) other;
            return
                    (( this.first == otherPair.first ||
                            ( this.first != null && otherPair.first != null &&
                                    this.first.equals(otherPair.first))) &&
                            ( this.second == otherPair.second ||
                                    ( this.second != null && otherPair.second != null &&
                                            this.second.equals(otherPair.second))) );
        }

        return false;
    }

    public String toString()
    {
        return "(" + first + ", " + second + ")";
    }

    public A getFirst()
    {
        return first;
    }

    public B getSecond()
    {
        return second;
    }
}