/*
* Copyright 2003-2016 JetBrains s.r.o.
*
* 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 jetbrains.mps.util;
import java.util.function.Function;
/**
* Mutable pair of values
* @param <T1> type of first value
* @param <T2> type of second value
*/
@SuppressWarnings({"InstanceVariableNamingConvention"})
public final class Pair<T1, T2> {
public T1 o1;
public T2 o2;
public Pair(T1 o1, T2 o2) {
this.o1 = o1;
this.o2 = o2;
}
public int hashCode() {
int result = 0;
if (o1 != null) result += o1.hashCode();
if (o2 != null) result += o2.hashCode() * 37;
return result;
}
public boolean equals(Object obj) {
if (this == obj) return true;
if (!(obj instanceof Pair)) return false;
Pair pair = (Pair) obj;
return equalsWithNull(pair.o1, o1) && equalsWithNull(pair.o2, o2);
}
private static boolean equalsWithNull(Object o1, Object o2) {
if (o1 == null && o2 == null) return true;
if (o1 != null && o2 != null) return o1.equals(o2);
return false;
}
public String toString() {
return "(" + o1 + ", " + o2 + ")";
}
/**
* @return Function that extracts {@linkplain #o1 first value} from a pair
*/
public static <P1,P2> Function<Pair<P1, P2>, P1> first() {
return p -> p.o1;
}
/**
* @return Function that extracts {@linkplain #o2 second value} from a pair
*/
public static <P1,P2> Function<Pair<P1, P2>, P2> second() {
return p -> p.o2;
}
}