Pair.java

package com.laytonsmith.PureUtilities;

import java.util.Map;
import java.util.Objects;

/**
 * Creates an object pair. The hashcode and equals functions have been overridden
 * to use the underlying object's hash code and equals combined. The underlying
 * objects may be null.
 * @param <A> The first object's type
 * @param <B> The second object's type
 */
public class Pair<A, B> implements Map.Entry<A, B> {

    private final A fst;
    private B snd;

	/**
	 * Creates a new Pair with the specified values.
	 * @param a
	 * @param b 
	 */
    public Pair(A a, B b) {
        fst = a;
        snd = b;
    }

    @Override
    public String toString() {
        return "<" + Objects.toString(fst) + ", " + Objects.toString(snd) + ">";
    }

	@Override
	public int hashCode() {
		int hash = 7;
		hash = 47 * hash + Objects.hashCode(this.fst);
		hash = 47 * hash + Objects.hashCode(this.snd);
		return hash;
	}

	@Override
	public boolean equals(Object obj) {
		if (obj == null) {
			return false;
		}
		if (getClass() != obj.getClass()) {
			return false;
		}
		final Pair<?, ?> other = (Pair<?, ?>) obj;
		if (!Objects.equals(this.fst, other.fst)) {
			return false;
		}
		if (!Objects.equals(this.snd, other.snd)) {
			return false;
		}
		return true;
	}
	
	

	@Override
    public A getKey() {
        return fst;
    }

	@Override
    public B getValue() {
        return snd;
    }

	@Override
    public B setValue(B value) {
        B old = snd;
        snd = (B)value;
        return old;
    }
}