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

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 package com.google.common.collect;
15 
16 import com.google.common.annotations.GwtCompatible;
17 import com.google.common.annotations.GwtIncompatible;
18 import java.io.Serializable;
19 import java.util.NoSuchElementException;
20 import java.util.Set;
21 import org.checkerframework.checker.nullness.qual.Nullable;
22 
23 /**
24  * An empty contiguous set.
25  *
26  * @author Gregory Kick
27  */
28 @GwtCompatible(emulated = true)
29 @SuppressWarnings("rawtypes") // allow ungenerified Comparable types
30 final class EmptyContiguousSet<C extends Comparable> extends ContiguousSet<C> {
31   EmptyContiguousSet(DiscreteDomain<C> domain) {
32     super(domain);
33   }
34 
35   @Override
36   public C first() {
37     throw new NoSuchElementException();
38   }
39 
40   @Override
41   public C last() {
42     throw new NoSuchElementException();
43   }
44 
45   @Override
46   public int size() {
47     return 0;
48   }
49 
50   @Override
51   public ContiguousSet<C> intersection(ContiguousSet<C> other) {
52     return this;
53   }
54 
55   @Override
56   public Range<C> range() {
57     throw new NoSuchElementException();
58   }
59 
60   @Override
61   public Range<C> range(BoundType lowerBoundType, BoundType upperBoundType) {
62     throw new NoSuchElementException();
63   }
64 
65   @Override
66   ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) {
67     return this;
68   }
69 
70   @Override
71   ContiguousSet<C> subSetImpl(
72       C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) {
73     return this;
74   }
75 
76   @Override
77   ContiguousSet<C> tailSetImpl(C fromElement, boolean fromInclusive) {
78     return this;
79   }
80 
81   @Override
82   public boolean contains(Object object) {
83     return false;
84   }
85 
86   @GwtIncompatible // not used by GWT emulation
87   @Override
88   int indexOf(Object target) {
89     return -1;
90   }
91 
92   @Override
93   public UnmodifiableIterator<C> iterator() {
94     return Iterators.emptyIterator();
95   }
96 
97   @GwtIncompatible // NavigableSet
98   @Override
99   public UnmodifiableIterator<C> descendingIterator() {
100     return Iterators.emptyIterator();
101   }
102 
103   @Override
104   boolean isPartialView() {
105     return false;
106   }
107 
108   @Override
109   public boolean isEmpty() {
110     return true;
111   }
112 
113   @Override
114   public ImmutableList<C> asList() {
115     return ImmutableList.of();
116   }
117 
118   @Override
119   public String toString() {
120     return "[]";
121   }
122 
123   @Override
124   public boolean equals(@Nullable Object object) {
125     if (object instanceof Set) {
126       Set<?> that = (Set<?>) object;
127       return that.isEmpty();
128     }
129     return false;
130   }
131 
132   @GwtIncompatible // not used in GWT
133   @Override
134   boolean isHashCodeFast() {
135     return true;
136   }
137 
138   @Override
139   public int hashCode() {
140     return 0;
141   }
142 
143   @GwtIncompatible // serialization
144   private static final class SerializedForm<C extends Comparable> implements Serializable {
145     private final DiscreteDomain<C> domain;
146 
147     private SerializedForm(DiscreteDomain<C> domain) {
148       this.domain = domain;
149     }
150 
151     private Object readResolve() {
152       return new EmptyContiguousSet<C>(domain);
153     }
154 
155     private static final long serialVersionUID = 0;
156   }
157 
158   @GwtIncompatible // serialization
159   @Override
160   Object writeReplace() {
161     return new SerializedForm<C>(domain);
162   }
163 
164   @GwtIncompatible // NavigableSet
165   @Override
166   ImmutableSortedSet<C> createDescendingSet() {
167     return ImmutableSortedSet.emptySet(Ordering.natural().reverse());
168   }
169 }