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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* Copyright (C) 2009 The Guava Authors
*
* 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 com.google.common.primitives.Primitives;
import java.util.Map;
/**
* A class-to-instance map backed by an {@link ImmutableMap}. See also {@link
* MutableClassToInstanceMap}.
*
* @author Kevin Bourrillion
* @since 2.0 (imported from Google Collections Library)
*/
public final class ImmutableClassToInstanceMap<B> extends
ForwardingMap<Class<? extends B>, B> implements ClassToInstanceMap<B> {
/**
* Returns a new builder. The generated builder is equivalent to the builder
* created by the {@link Builder} constructor.
*/
public static <B> Builder<B> builder() {
return new Builder<B>();
}
/**
* A builder for creating immutable class-to-instance maps. Example:
* <pre> {@code
*
* static final ImmutableClassToInstanceMap<Handler> HANDLERS =
* new ImmutableClassToInstanceMap.Builder<Handler>()
* .put(FooHandler.class, new FooHandler())
* .put(BarHandler.class, new SubBarHandler())
* .put(Handler.class, new QuuxHandler())
* .build();}</pre>
*
* After invoking {@link #build()} it is still possible to add more entries
* and build again. Thus each map generated by this builder will be a superset
* of any map generated before it.
*
* @since 2.0 (imported from Google Collections Library)
*/
public static final class Builder<B> {
private final ImmutableMap.Builder<Class<? extends B>, B> mapBuilder
= ImmutableMap.builder();
/**
* Associates {@code key} with {@code value} in the built map. Duplicate
* keys are not allowed, and will cause {@link #build} to fail.
*/
public <T extends B> Builder<B> put(Class<T> key, T value) {
mapBuilder.put(key, value);
return this;
}
/**
* Associates all of {@code map's} keys and values in the built map.
* Duplicate keys are not allowed, and will cause {@link #build} to fail.
*
* @throws NullPointerException if any key or value in {@code map} is null
* @throws ClassCastException if any value is not an instance of the type
* specified by its key
*/
public <T extends B> Builder<B> putAll(
Map<? extends Class<? extends T>, ? extends T> map) {
for (Entry<? extends Class<? extends T>, ? extends T> entry
: map.entrySet()) {
Class<? extends T> type = entry.getKey();
T value = entry.getValue();
mapBuilder.put(type, cast(type, value));
}
return this;
}
private static <B, T extends B> T cast(Class<T> type, B value) {
return Primitives.wrap(type).cast(value);
}
/**
* Returns a new immutable class-to-instance map containing the entries
* provided to this builder.
*
* @throws IllegalArgumentException if duplicate keys were added
*/
public ImmutableClassToInstanceMap<B> build() {
return new ImmutableClassToInstanceMap<B>(mapBuilder.build());
}
}
/**
* Returns an immutable map containing the same entries as {@code map}. If
* {@code map} somehow contains entries with duplicate keys (for example, if
* it is a {@code SortedMap} whose comparator is not <i>consistent with
* equals</i>), the results of this method are undefined.
*
* <p><b>Note:</b> Despite what the method name suggests, if {@code map} is
* an {@code ImmutableClassToInstanceMap}, no copy will actually be performed.
*
* @throws NullPointerException if any key or value in {@code map} is null
* @throws ClassCastException if any value is not an instance of the type
* specified by its key
*/
public static <B, S extends B> ImmutableClassToInstanceMap<B> copyOf(
Map<? extends Class<? extends S>, ? extends S> map) {
if (map instanceof ImmutableClassToInstanceMap) {
@SuppressWarnings("unchecked") // covariant casts safe (unmodifiable)
// Eclipse won't compile if we cast to the parameterized type.
ImmutableClassToInstanceMap<B> cast = (ImmutableClassToInstanceMap) map;
return cast;
}
return new Builder<B>().putAll(map).build();
}
private final ImmutableMap<Class<? extends B>, B> delegate;
private ImmutableClassToInstanceMap(
ImmutableMap<Class<? extends B>, B> delegate) {
this.delegate = delegate;
}
@Override protected Map<Class<? extends B>, B> delegate() {
return delegate;
}
@Override
@SuppressWarnings("unchecked") // value could not get in if not a T
public <T extends B> T getInstance(Class<T> type) {
return (T) delegate.get(type);
}
/**
* Guaranteed to throw an exception and leave the map unmodified.
*
* @throws UnsupportedOperationException always
*/
@Override
public <T extends B> T putInstance(Class<T> type, T value) {
throw new UnsupportedOperationException();
}
}
|
