Coverage Summary for Class: PairwiseEquivalence (com.google.common.base)

1 /*
2  * Copyright (C) 2011 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.base;
16 
17 import com.google.common.annotations.GwtCompatible;
18 import java.io.Serializable;
19 import java.util.Iterator;
20 import javax.annotation.CheckForNull;
21 import org.checkerframework.checker.nullness.qual.Nullable;
22 
23 @GwtCompatible(serializable = true)
24 @ElementTypesAreNonnullByDefault
25 final class PairwiseEquivalence<E, T extends @Nullable E> extends Equivalence<Iterable<T>>
26     implements Serializable {
27   final Equivalence<E> elementEquivalence;
28 
29   PairwiseEquivalence(Equivalence<E> elementEquivalence) {
30     this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
31   }
32 
33   @Override
34   protected boolean doEquivalent(Iterable<T> iterableA, Iterable<T> iterableB) {
35     Iterator<T> iteratorA = iterableA.iterator();
36     Iterator<T> iteratorB = iterableB.iterator();
37 
38     while (iteratorA.hasNext() && iteratorB.hasNext()) {
39       if (!elementEquivalence.equivalent(iteratorA.next(), iteratorB.next())) {
40         return false;
41       }
42     }
43 
44     return !iteratorA.hasNext() && !iteratorB.hasNext();
45   }
46 
47   @Override
48   protected int doHash(Iterable<T> iterable) {
49     int hash = 78721;
50     for (T element : iterable) {
51       hash = hash * 24943 + elementEquivalence.hash(element);
52     }
53     return hash;
54   }
55 
56   @Override
57   public boolean equals(@CheckForNull Object object) {
58     if (object instanceof PairwiseEquivalence) {
59       PairwiseEquivalence<?, ?> that = (PairwiseEquivalence<?, ?>) object;
60       return this.elementEquivalence.equals(that.elementEquivalence);
61     }
62 
63     return false;
64   }
65 
66   @Override
67   public int hashCode() {
68     return elementEquivalence.hashCode() ^ 0x46a3eb07;
69   }
70 
71   @Override
72   public String toString() {
73     return elementEquivalence + ".pairwise()";
74   }
75 
76   private static final long serialVersionUID = 1;
77 }