1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
/*
* Copyright (C) 2009 Google Inc.
*
* 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.collect;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
/**
* An empty implementation of {@link ImmutableTable}.
*
* @author gak@google.com (Gregory Kick)
*/
@GwtCompatible
@Immutable
final class EmptyImmutableTable extends ImmutableTable<Object, Object, Object> {
static final EmptyImmutableTable INSTANCE = new EmptyImmutableTable();
private EmptyImmutableTable() {}
@Override public int size() {
return 0;
}
@Override public Object get(@Nullable Object rowKey,
@Nullable Object columnKey) {
return null;
}
@Override public boolean isEmpty() {
return true;
}
@Override public boolean equals(@Nullable Object obj) {
if (obj == this) {
return true;
} else if (obj instanceof Table<?, ?, ?>) {
Table<?, ?, ?> that = (Table<?, ?, ?>) obj;
return that.isEmpty();
} else {
return false;
}
}
@Override public int hashCode() {
return 0;
}
@Override public ImmutableSet<Cell<Object, Object, Object>> cellSet() {
return ImmutableSet.of();
}
@Override public ImmutableMap<Object, Object> column(Object columnKey) {
checkNotNull(columnKey);
return ImmutableMap.of();
}
@Override public ImmutableSet<Object> columnKeySet() {
return ImmutableSet.of();
}
@Override public ImmutableMap<Object, Map<Object, Object>> columnMap() {
return ImmutableMap.of();
}
@Override public boolean contains(@Nullable Object rowKey,
@Nullable Object columnKey) {
return false;
}
@Override public boolean containsColumn(@Nullable Object columnKey) {
return false;
}
@Override public boolean containsRow(@Nullable Object rowKey) {
return false;
}
@Override public boolean containsValue(@Nullable Object value) {
return false;
}
@Override public ImmutableMap<Object, Object> row(Object rowKey) {
checkNotNull(rowKey);
return ImmutableMap.of();
}
@Override public ImmutableSet<Object> rowKeySet() {
return ImmutableSet.of();
}
@Override public ImmutableMap<Object, Map<Object, Object>> rowMap() {
return ImmutableMap.of();
}
@Override public String toString() {
return "{}";
}
@Override public ImmutableCollection<Object> values() {
return ImmutableSet.of();
}
Object readResolve() {
return INSTANCE; // preserve singleton property
}
private static final long serialVersionUID = 0;
}
|
