/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.
 */
package org.apereo.portal.utils;

import java.io.Serializable;

/**
 * Simple object that contains two values who's references are immutable once initialized.
 *
 */
public class Tuple<A, B> implements Serializable {
    private static final long serialVersionUID = 1L;

    public final A first;
    public final B second;
    private final boolean immutable;
    private final int hash;

    public static <A1, B1> Tuple<A1, B1> of(A1 a1, B1 b1) {
        return new Tuple<A1, B1>(a1, b1);
    }

    public Tuple(A first, B second) {
        this(first, second, false);
    }

    public Tuple(A first, B second, boolean immutable) {
        this.first = first;
        this.second = second;
        this.immutable = immutable;

        if (this.immutable) {
            hash = internalHashCode();
        } else {
            hash = 0;
        }
    }

    public A getFirst() {
        return first;
    }

    public B getSecond() {
        return second;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        Tuple other = (Tuple) 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 int hashCode() {
        if (this.immutable) {
            return this.hash;
        }

        return internalHashCode();
    }

    private int internalHashCode() {
        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 String toString() {
        return "Tuple [first=" + first + ", second=" + second + "]";
    }
}