JavaAlgorithms/Couple.java

84 lines
2.6 KiB
Java

/*
* 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.
*/
import java.util.Objects;
/**
* Container to ease passing around a tuple of two objects. This object provides a sensible
* implementation of equals(), returning true if equals() is true on each of the contained
* objects.
*
* @link https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/util/Pair.java
*/
public class Couple<F, S> {
public final F first;
public final S second;
/**
* Constructor for a Couple.
*
* @param first the first object in the Couple
* @param second the second object in the Couple
*/
public Couple(F first, S second) {
this.first = first;
this.second = second;
}
/**
* Checks the two objects for equality by delegating to their respective
* {@link Object#equals(Object)} methods.
*
* @param o the {@link Couple} to which this one is to be checked for equality
* @return true if the underlying objects of the Couple are both considered
* equal
*/
@Override
public boolean equals(Object o) {
if (!(o instanceof Couple)) {
return false;
}
Couple<?, ?> p = (Couple<?, ?>) o;
return Objects.equals(p.first, first) && Objects.equals(p.second, second);
}
/**
* Compute a hash code using the hash codes of the underlying objects
*
* @return a hashcode of the Couple
*/
@Override
public int hashCode() {
return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
}
@Override
public String toString() {
return "Couple{" + String.valueOf(first) + " " + String.valueOf(second) + "}";
}
/**
* Convenience method for creating an appropriately typed couple.
*
* @param a the first object in the Couple
* @param b the second object in the Couple
* @return a Couple that is templatized with the types of a and b
*/
public static <A, B> Couple<A, B> create(A a, B b) {
return new Couple<A, B>(a, b);
}
}