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/*
* Copyright 2012 Goodow.com
*
* 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 com.goodow.realtime.operation.util;
import java.io.Serializable;
/**
* An immutable ordered pair of typed objects.
*
* @param Type of value 1
* @param Type of value 2
*/
public class Pair implements Serializable {
/**
* Static constructor to save typing on generic arguments.
*/
public static Pair of(A a, B b) {
return new Pair(a, b);
}
/**
* The first element of the pair; see also {@link #getFirst}.
*/
public final A first;
/**
* The second element of the pair; see also {@link #getSecond}.
*/
public final B second;
/**
* Pair constructor
*
* @param first Value 1
* @param second Value 2
*/
public Pair(A first, B second) {
this.first = first;
this.second = second;
}
/**
* Copy constructor
*
* @param pair Pair to shallow copy from
*/
public Pair(Pair pair) {
first = pair.first;
second = pair.second;
}
/**
* {@inheritDoc}
*
* NOTE: Not safe to override this method, hence final.
*/
@Override
public final boolean equals(Object o) {
if (o == null) {
return false;
}
if (o == this) {
return true;
}
if (o instanceof Pair) {
Pair p = (Pair) o;
return (p.first == first || (first != null && first.equals(p.first)))
&& (p.second == second || (second != null && second.equals(p.second)));
}
return false;
}
/**
* Returns the first element of this pair; see also {@link #first}.
*/
public A getFirst() {
return first;
}
/**
* Returns the second element of this pair; see also {@link #second}.
*/
public B getSecond() {
return second;
}
/**
* {@inheritDoc}
*
* NOTE: Not safe to override this method, hence final.
*/
@Override
public final int hashCode() {
return (first == null ? 0 : first.hashCode()) + 37 * (second == null ? 0 : second.hashCode());
}
/** {@inheritDoc} */
@Override
public String toString() {
return "(" + String.valueOf(first) + "," + String.valueOf(second) + ")";
}
}