Pair.java

package aQute.libg.tuple;

import java.io.Serializable;

public class Pair<A, B> implements Serializable, Cloneable {

	private static final long	serialVersionUID	= 1L;

	private final A				first;
	private final B				second;

	public Pair(A first, B second) {
		assert first != null && second != null : "both parameters must be non-null";
		this.first = first;
		this.second = second;
	}

	public static <A, B> Pair<A,B> newInstance(A first, B second) {
		return new Pair<A,B>(first, second);
	}

	public A getFirst() {
		return first;
	}

	public B getSecond() {
		return second;
	}

	@Override
	public String toString() {
		return "Pair [" + first + ", " + second + "]";
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((first == null) ? 0 : first.hashCode());
		result = prime * result + ((second == null) ? 0 : second.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		@SuppressWarnings("unchecked")
		Pair<A,B> other = (Pair<A,B>) obj;
		if (first == null) {
			if (other.first != null)
				return false;
		} else if (!first.equals(other.first))
			return false;
		if (second == null) {
			if (other.second != null)
				return false;
		} else if (!second.equals(other.second))
			return false;
		return true;
	}

	@Override
	public Pair<A,B> clone() {
		return new Pair<A,B>(first, second);
	}
}