Coverage Summary for Class: ReverseOrdering (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 static com.google.common.base.Preconditions.checkNotNull;
20 
21 import com.google.common.annotations.GwtCompatible;
22 import java.io.Serializable;
23 import java.util.Iterator;
24 import org.checkerframework.checker.nullness.qual.Nullable;
25 
26 /** An ordering that uses the reverse of a given order. */
27 @GwtCompatible(serializable = true)
28 final class ReverseOrdering<T> extends Ordering<T> implements Serializable {
29   final Ordering<? super T> forwardOrder;
30 
31   ReverseOrdering(Ordering<? super T> forwardOrder) {
32     this.forwardOrder = checkNotNull(forwardOrder);
33   }
34 
35   @Override
36   public int compare(T a, T b) {
37     return forwardOrder.compare(b, a);
38   }
39 
40   @SuppressWarnings("unchecked") // how to explain?
41   @Override
42   public <S extends T> Ordering<S> reverse() {
43     return (Ordering<S>) forwardOrder;
44   }
45 
46   // Override the min/max methods to "hoist" delegation outside loops
47 
48   @Override
49   public <E extends T> E min(E a, E b) {
50     return forwardOrder.max(a, b);
51   }
52 
53   @Override
54   public <E extends T> E min(E a, E b, E c, E... rest) {
55     return forwardOrder.max(a, b, c, rest);
56   }
57 
58   @Override
59   public <E extends T> E min(Iterator<E> iterator) {
60     return forwardOrder.max(iterator);
61   }
62 
63   @Override
64   public <E extends T> E min(Iterable<E> iterable) {
65     return forwardOrder.max(iterable);
66   }
67 
68   @Override
69   public <E extends T> E max(E a, E b) {
70     return forwardOrder.min(a, b);
71   }
72 
73   @Override
74   public <E extends T> E max(E a, E b, E c, E... rest) {
75     return forwardOrder.min(a, b, c, rest);
76   }
77 
78   @Override
79   public <E extends T> E max(Iterator<E> iterator) {
80     return forwardOrder.min(iterator);
81   }
82 
83   @Override
84   public <E extends T> E max(Iterable<E> iterable) {
85     return forwardOrder.min(iterable);
86   }
87 
88   @Override
89   public int hashCode() {
90     return -forwardOrder.hashCode();
91   }
92 
93   @Override
94   public boolean equals(@Nullable Object object) {
95     if (object == this) {
96       return true;
97     }
98     if (object instanceof ReverseOrdering) {
99       ReverseOrdering<?> that = (ReverseOrdering<?>) object;
100       return this.forwardOrder.equals(that.forwardOrder);
101     }
102     return false;
103   }
104 
105   @Override
106   public String toString() {
107     return forwardOrder + ".reverse()";
108   }
109 
110   private static final long serialVersionUID = 0;
111 }