Coverage Summary for Class: LexicographicalOrdering (com.google.common.collect)

1 /*
2  * Copyright (C) 2007 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.google.common.collect;
18 
19 import com.google.common.annotations.GwtCompatible;
20 import java.io.Serializable;
21 import java.util.Comparator;
22 import java.util.Iterator;
23 import org.checkerframework.checker.nullness.qual.Nullable;
24 
25 /** An ordering which sorts iterables by comparing corresponding elements pairwise. */
26 @GwtCompatible(serializable = true)
27 final class LexicographicalOrdering<T> extends Ordering<Iterable<T>> implements Serializable {
28   final Comparator<? super T> elementOrder;
29 
30   LexicographicalOrdering(Comparator<? super T> elementOrder) {
31     this.elementOrder = elementOrder;
32   }
33 
34   @Override
35   public int compare(Iterable<T> leftIterable, Iterable<T> rightIterable) {
36     Iterator<T> left = leftIterable.iterator();
37     Iterator<T> right = rightIterable.iterator();
38     while (left.hasNext()) {
39       if (!right.hasNext()) {
40         return LEFT_IS_GREATER; // because it's longer
41       }
42       int result = elementOrder.compare(left.next(), right.next());
43       if (result != 0) {
44         return result;
45       }
46     }
47     if (right.hasNext()) {
48       return RIGHT_IS_GREATER; // because it's longer
49     }
50     return 0;
51   }
52 
53   @Override
54   public boolean equals(@Nullable Object object) {
55     if (object == this) {
56       return true;
57     }
58     if (object instanceof LexicographicalOrdering) {
59       LexicographicalOrdering<?> that = (LexicographicalOrdering<?>) object;
60       return this.elementOrder.equals(that.elementOrder);
61     }
62     return false;
63   }
64 
65   @Override
66   public int hashCode() {
67     return elementOrder.hashCode() ^ 2075626741; // meaningless
68   }
69 
70   @Override
71   public String toString() {
72     return elementOrder + ".lexicographical()";
73   }
74 
75   private static final long serialVersionUID = 0;
76 }