C++の標準ライブラリにあるPairみたいなやつ． javadocに書いてある通り，StackOverflowにあったコードほぼママ． What is the equivalent of the C++ Pair<L,R> in Java? - Stack Overflow http://stackoverflow.com/questions/156275/what-is-the-equivalent-of-the-c-pairl-r-in-java

Pair.java

/**
 * immutable pair class, like c++'s Pair<br>
 * from <a href=
 * "http://stackoverflow.com/questions/156275/what-is-the-equivalent-of-the-c-pairl-r-in-java"
 * > What is the equivalent of the C++ Pair&lt;L,R&gt; in Java? - Stack Overflow </a>
 * 
 * @param <A>
 *            first
 * @param <B>
 *            second
 */
public class Pair<A, B> {
	private final A first;
	private final B second;

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

	@Override
	public int hashCode() {
		int hashFirst = first == null ? 0 : first.hashCode();
		int hashSecond = second == null ? 0 : second.hashCode();
		return (hashFirst + hashSecond) * hashSecond + hashFirst;
	}

	@Override
	public boolean equals(Object other) {
		if (!(other instanceof Pair)) {
			return false;
		}
		Pair<?, ?> otherPair = (Pair<?, ?>) other;
		if ((first == otherPair.first) && (second == otherPair.second)) {
			return true;
		}
		if (first == null || otherPair.first == null) {
			return false;
		}
		if (second == null || otherPair.second == null) {
			return false;
		}
		return first.equals(otherPair.first) && second.equals(otherPair.second);
	}

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

	public A getFirst() {
		return first;
	}

	public B getSecond() {
		return second;
	}
}

PairTest.java

import static org.hamcrest.core.IsEqual.equalTo;
import static org.hamcrest.core.IsNot.not;
import static org.junit.Assert.assertThat;

import org.junit.Test;

public class PairTest {
  
	@Test
	public void testEquals() {
		Pair<Integer, String> pair1 = new Pair<Integer, String>(1, "abc");
		Pair<Integer, String> pair2 = new Pair<Integer, String>(1, "abd");
		Pair<Integer, String> pair3 = new Pair<Integer, String>(1, "abc");
		assertThat(pair1, equalTo(pair1));
		assertThat(pair1, not(pair2));
		assertThat(pair2, not(pair1));
		assertThat(pair1, equalTo(pair3));
		assertThat(pair3, equalTo(pair1));

		Pair<Integer, String> pairNull = new Pair<Integer, String>(null, null);
		assertThat(pairNull, equalTo(pairNull));

		Pair<Integer, String> pair4 = new Pair<Integer, String>(null, "xyz");
		Pair<Integer, String> pair5 = new Pair<Integer, String>(null, "xyz");
		Pair<Integer, String> pair6 = new Pair<Integer, String>(2, null);
		Pair<Integer, String> pair7 = new Pair<Integer, String>(2, null);
		assertThat(pair4, equalTo(pair4));
		assertThat(pair6, equalTo(pair6));
		assertThat(pair4, equalTo(pair5));
		assertThat(pair5, equalTo(pair4));
		assertThat(pair6, equalTo(pair7));
		assertThat(pair7, equalTo(pair6));
	}
}