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This is a backport of OpenJFX 8 to run on Java 7.
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/*
 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package javafx.util;

import java.io.Serializable;

 /**
  * A convenience class to represent name-value pairs.
  * @since JavaFX 2.0
  */
public class Pair implements Serializable{

    /**
     * Key of this Pair.
     */
    private K key;

    /**
     * Gets the key for this pair.
     * @return key for this pair
     */
    public K getKey() { return key; }

    /**
     * Value of this this Pair.
     */
    private V value;

    /**
     * Gets the value for this pair.
     * @return value for this pair
     */
    public V getValue() { return value; }

    /**
     * Creates a new pair
     * @param key The key for this pair
     * @param value The value to use for this pair
     */
    public Pair(K key, V value) {
        this.key = key;
        this.value = value;
    }

    /**
     * String representation of this
     * Pair.
     *
     * The default name/value delimiter '=' is always used.
     *
     *  @return String representation of this Pair
     */
    @Override
    public String toString() {
        return key + "=" + value;
    }

    /**
     * Generate a hash code for this Pair.
     *
     * The hash code is calculated using both the name and
     * the value of the Pair.
     *
     * @return hash code for this Pair
     */
    @Override
    public int hashCode() {
        // name's hashCode is multiplied by an arbitrary prime number (13)
        // in order to make sure there is a difference in the hashCode between
        // these two parameters:
        //  name: a  value: aa
        //  name: aa value: a
        return key.hashCode() * 13 + (value == null ? 0 : value.hashCode());
    }

     /**
      * Test this Pair for equality with another
      * Object.
      *
      * If the Object to be tested is not a
      * Pair or is null, then this method
      * returns false.
      *
      * Two Pairs are considered equal if and only if
      * both the names and values are equal.
      *
      * @param o the Object to test for
      * equality with this Pair
      * @return true if the given Object is
      * equal to this Pair else false
      */
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o instanceof Pair) {
             Pair pair = (Pair) o;
             if (key != null ? !key.equals(pair.key) : pair.key != null) return false;
             if (value != null ? !value.equals(pair.value) : pair.value != null) return false;
             return true;
         }
         return false;
     }
 }