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package org.checkerframework.javacutil;
/*>>>
import org.checkerframework.dataflow.qual.Pure;
import org.checkerframework.dataflow.qual.SideEffectFree;
*/
/**
* Simple pair class for multiple returns.
*
* TODO: as class is immutable, use @Covariant annotation.
*/
public class Pair<V1, V2> {
public final V1 first;
public final V2 second;
private Pair(V1 v1, V2 v2) {
this.first = v1;
this.second = v2;
}
public static <V1, V2> Pair<V1, V2> of(V1 v1, V2 v2) {
return new Pair<V1, V2>(v1, v2);
}
/*@SideEffectFree*/
@Override
public String toString() {
return "Pair(" + first + ", " + second + ")";
}
private int hashCode = -1;
/*@Pure*/
@Override
public int hashCode() {
if (hashCode == -1) {
hashCode = 31;
if (first != null) {
hashCode += 17 * first.hashCode();
}
if (second != null) {
hashCode += 17 * second.hashCode();
}
}
return hashCode;
}
@Override
public boolean equals(Object o) {
if (!(o instanceof Pair)) {
return false;
}
@SuppressWarnings("unchecked")
Pair<V1, V2> other = (Pair<V1, V2>) o;
if (this.first == null) {
if (other.first != null) return false;
} else {
if (!this.first.equals(other.first)) return false;
}
if (this.second == null) {
if (other.second != null) return false;
} else {
if (!this.second.equals(other.second)) return false;
}
return true;
}
}
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