Container to ease passing around a tuple of three objects.

Triple.java

/*
 * Copyright (C) 2016 Daniel Gallego Vico.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.Objects;

/**
 * Container to ease passing around a tuple of three objects.
 * This object provides a sensible implementation of equals(),
 * returning true if equals() is true on each of the contained objects.
 *
 * @param <F> first object type to store in the Triple
 * @param <S> second object type to store in the Triple
 * @param <T> third object type to store in the Triple
 */
public class Triple<F, S, T> {
    public final F first;
    public final S second;
    public final T third;

    /**
     * Constructor for a Triple
     *
     * @param first the first object in the Triple
     * @param second the second object in the Triple
     * @param third the third object in the Triple
     */
    public Triple(F first, S second, T third) {
        this.first = first;
        this.second = second;
        this.third = third;
    }

    /**
     * Checks the two Triple objects for equality by delegating to their respective
     * {@link Object#equals(Object)} methods.
     *
     * @param o the {@link Triple} to which this one is to be checked for equality
     * @return true if the underlying objects of the Triple are considered equal
     */
    @Override
    public boolean equals(Object o) {
        if(!(o instanceof Triple)) {
            return false;
        }
        Triple<?,?,?> t = (Triple<?,?,?>) o;
        return Objects.equals(t.first, first)
                && Objects.equals(t.second, second)
                && Objects.equals(t.third, third);
    }

    /**
     * Compute a hash code using the hash codes of the underlying objects.
     *
     * @return a hashcode on the Triple
     */
    @Override
    public int hashCode() {
        return (first == null ? 0 : first.hashCode())
                ^ (second == null ? 0 : second.hashCode())
                ^ (third == null ? 0 : third.hashCode());
    }

    /**
     * Convenience method for creating an appropriately typed triple.
     *
     * @param a the first object in the Triple
     * @param b the second object in the Triple
     * @param c the third object in the Triple
     * @param <A> first object type of the Triple
     * @param <B> second object type of the Triple
     * @param <C> third object type of the Triple
     *           
     * @return a Triple that is templatized with the types of a, b and c
     */
    public static <A, B, C> Triple<A, B, C> create(A a, B b, C c) {
        return new Triple<>(a, b, c);
    }

}