java多返回值javafx.util.Pair

源码:

/*
 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javafx.util;

import java.io.Serializable;
import javafx.beans.NamedArg;

 /**
  * 
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(@NamedArg("key") K key, @NamedArg("value") 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;
     }
 }

    public static void main(String[] args) {
        Pair<String, Integer> test = test();
        System.out.println(test.getKey());
        System.out.println(test.getValue());
    }


    private static Pair<String, Integer> test() {
        return new Pair<>("hello", 1);
    }