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/*
* Copyright (C) 2011 The Guava Authors
*
* 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.common.base;
import com.google.common.annotations.GwtCompatible;
import java.io.Serializable;
import java.util.Iterator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
@GwtCompatible(serializable = true)
@ElementTypesAreNonnullByDefault
final class PairwiseEquivalence extends Equivalence>
implements Serializable {
final Equivalence elementEquivalence;
PairwiseEquivalence(Equivalence elementEquivalence) {
this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
}
@Override
protected boolean doEquivalent(Iterable iterableA, Iterable iterableB) {
Iterator iteratorA = iterableA.iterator();
Iterator iteratorB = iterableB.iterator();
while (iteratorA.hasNext() && iteratorB.hasNext()) {
if (!elementEquivalence.equivalent(iteratorA.next(), iteratorB.next())) {
return false;
}
}
return !iteratorA.hasNext() && !iteratorB.hasNext();
}
@Override
protected int doHash(Iterable iterable) {
int hash = 78721;
for (T element : iterable) {
hash = hash * 24943 + elementEquivalence.hash(element);
}
return hash;
}
@Override
public boolean equals(@CheckForNull Object object) {
if (object instanceof PairwiseEquivalence) {
PairwiseEquivalence that = (PairwiseEquivalence) object;
return this.elementEquivalence.equals(that.elementEquivalence);
}
return false;
}
@Override
public int hashCode() {
return elementEquivalence.hashCode() ^ 0x46a3eb07;
}
@Override
public String toString() {
return elementEquivalence + ".pairwise()";
}
private static final long serialVersionUID = 1;
}