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/*
* Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
*
* 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.
*/
package net.dv8tion.jda.internal.utils.tuple;
import java.io.Serializable;
import java.util.Objects;
/**
* This class has been copied from Lang 3
* A pair consisting of two elements.
*
* This class is an abstract implementation defining the basic API.
* It refers to the elements as 'left' and 'right'.
*
* Subclass implementations may be mutable or immutable.
* However, there is no restriction on the type of the stored objects that may be stored.
* If mutable objects are stored in the pair, then the pair itself effectively becomes mutable.
*
* @param the left element type
* @param the right element type
*
* @since Lang 3.0
*/
public abstract class Pair implements /*Map.Entry, Comparable>,*/ Serializable {
/**
* Obtains an immutable pair of from two objects inferring the generic types.
*
* This factory allows the pair to be created using inference to
* obtain the generic types.
*
* @param the left element type
* @param the right element type
* @param left the left element, may be null
* @param right the right element, may be null
* @return a pair formed from the two parameters, not null
*/
public static Pair of(final L left, final R right) {
return new ImmutablePair<>(left, right);
}
//-----------------------------------------------------------------------
/**
* Gets the left element from this pair.
*
* When treated as a key-value pair, this is the key.
*
* @return the left element, may be null
*/
public abstract L getLeft();
/**
* Gets the right element from this pair.
*
* When treated as a key-value pair, this is the value.
*
* @return the right element, may be null
*/
public abstract R getRight();
/**
* Compares this pair to another based on the two elements.
*
* @param obj the object to compare to, null returns false
* @return true if the elements of the pair are equal
*/
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof Pair) {
final Pair other = (Pair) obj;
return Objects.equals(getLeft(), other.getLeft())
&& Objects.equals(getRight(), other.getRight());
}
return false;
}
/**
* Returns a suitable hash code.
* The hash code follows the definition in {@code Map.Entry}.
*
* @return the hash code
*/
@Override
public int hashCode() {
// see Map.Entry API specification
return Objects.hashCode(getLeft()) ^ Objects.hashCode(getRight());
}
/**
* Returns a String representation of this pair using the format {@code ($left,$right)}.
*
* @return a string describing this object, not null
*/
@Override
public String toString() {
return "(" + getLeft() + ',' + getRight() + ')';
}
}