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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.util;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import java.util.Objects;
import javax.annotation.Nullable;
/** An immutable, semantic-free ordered pair of nullable values. Avoid using it in public APIs. */
@AutoCodec
public final class Pair<A, B> {
/**
* Creates a new pair containing the given elements in order.
*/
public static <A, B> Pair<A, B> of(@Nullable A first, @Nullable B second) {
return new Pair<>(first, second);
}
/**
* The first element of the pair.
*/
@Nullable
public final A first;
/**
* The second element of the pair.
*/
@Nullable
public final B second;
/**
* Constructor. It is usually easier to call {@link #of}.
*/
public Pair(@Nullable A first, @Nullable B second) {
this.first = first;
this.second = second;
}
@Nullable
public A getFirst() {
return first;
}
@Nullable
public B getSecond() {
return second;
}
@Override
public String toString() {
return "(" + first + ", " + second + ")";
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Pair)) {
return false;
}
Pair<?, ?> p = (Pair<?, ?>) o;
return Objects.equals(first, p.first) && Objects.equals(second, p.second);
}
@Override
public int hashCode() {
int hash1 = first == null ? 0 : first.hashCode();
int hash2 = second == null ? 0 : second.hashCode();
return 31 * hash1 + hash2;
}
}
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