package org.robolectric.util;

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * 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.
 */

/**
 * Container to ease passing around a tuple of two objects.
 *
 * @param <F> First type.
 * @param <S> Second type.
 */
public class Pair<F, S> {
  public final F first;
  public final S second;

  public Pair(F first, S second) {
    this.first = first;
    this.second = second;
  }

  @Override
  public boolean equals(Object o) {
    if (!(o instanceof Pair)) {
      return false;
    }
    Pair<?, ?> p = (Pair<?, ?>) o;
    return equal(p.first, first) && equal(p.second, second);
  }

  @Override
  public int hashCode() {
    return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
  }

  public static <A, B> Pair <A, B> create(A a, B b) {
    return new Pair<>(a, b);
  }

  private static boolean equal(Object a, Object b) {
    return a == b || (a != null && a.equals(b));
  }
}