com.intellij.openapi.util.Pair Maven / Gradle / Ivy
// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
package com.intellij.openapi.util;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.Comparator;
/**
* Generic wrapper around two related values.
*/
public class Pair {
public final A first;
public final B second;
@NotNull
public static Pair create(A first, B second) {
return new Pair<>(first, second);
}
@NotNull
public static NonNull createNonNull(@NotNull A first, @NotNull B second) {
return new NonNull<>(first, second);
}
@NotNull
public static Pair pair(A first, B second) {
return new Pair<>(first, second);
}
public static T getFirst(@Nullable Pair pair) {
return pair != null ? pair.first : null;
}
public static T getSecond(@Nullable Pair pair) {
return pair != null ? pair.second : null;
}
@SuppressWarnings({"rawtypes", "unchecked"})
private static final Pair EMPTY = create(null, null);
@NotNull
@SuppressWarnings("unchecked")
public static Pair empty() {
return EMPTY;
}
/**
* @see #create(Object, Object)
*/
public Pair(A first, B second) {
this.first = first;
this.second = second;
}
public final A getFirst() {
return first;
}
public final B getSecond() {
return second;
}
@Override
public final boolean equals(Object o) {
return o instanceof Pair oo && Comparing.equal(first, oo.first) && Comparing.equal(second, oo.second);
}
@Override
public int hashCode() {
int result = first != null ? first.hashCode() : 0;
result = 31 * result + (second != null ? second.hashCode() : 0);
return result;
}
@Override
public String toString() {
return "<" + first + "," + second + ">";
}
public static class NonNull extends Pair {
public NonNull(@NotNull A first, @NotNull B second) {
super(first, second);
}
}
/**
* @param first value type (Comparable)
* @param second value type
* @return a comparator that compares pair values by first value
*/
public static , B> Comparator> comparingByFirst() {
return Comparator.comparing(o -> o.first);
}
/**
* @param first value type
* @param second value type (Comparable)
* @return a comparator that compares pair values by second value
*/
public static > Comparator> comparingBySecond() {
return Comparator.comparing(o -> o.second);
}
}