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1 // Protocol Buffers - Google's data interchange format | |
2 // Copyright 2008 Google Inc. All rights reserved. | |
3 // https://developers.google.com/protocol-buffers/ | |
4 // | |
5 // Redistribution and use in source and binary forms, with or without | |
6 // modification, are permitted provided that the following conditions are | |
7 // met: | |
8 // | |
9 // * Redistributions of source code must retain the above copyright | |
10 // notice, this list of conditions and the following disclaimer. | |
11 // * Redistributions in binary form must reproduce the above | |
12 // copyright notice, this list of conditions and the following disclaimer | |
13 // in the documentation and/or other materials provided with the | |
14 // distribution. | |
15 // * Neither the name of Google Inc. nor the names of its | |
16 // contributors may be used to endorse or promote products derived from | |
17 // this software without specific prior written permission. | |
18 // | |
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
30 | |
31 package com.google.protobuf; | |
32 | |
33 import static com.google.protobuf.ExtensionRegistryLite.EMPTY_REGISTRY_LITE; | |
34 | |
35 /** | |
36 * A factory object to create instances of {@link ExtensionRegistryLite}. | |
37 * | |
38 * <p> | |
39 * This factory detects (via reflection) if the full (non-Lite) protocol buffer
libraries | |
40 * are available, and if so, the instances returned are actually {@link Extensio
nRegistry}. | |
41 */ | |
42 final class ExtensionRegistryFactory { | |
43 | |
44 static final String FULL_REGISTRY_CLASS_NAME = "com.google.protobuf.ExtensionR
egistry"; | |
45 | |
46 /* Visible for Testing | |
47 @Nullable */ | |
48 static final Class<?> EXTENSION_REGISTRY_CLASS = reflectExtensionRegistry(); | |
49 | |
50 /* @Nullable */ | |
51 static Class<?> reflectExtensionRegistry() { | |
52 try { | |
53 return Class.forName(FULL_REGISTRY_CLASS_NAME); | |
54 } catch (ClassNotFoundException e) { | |
55 // The exception allocation is potentially expensive on Android (where it
can be triggered | |
56 // many times at start up). Is there a way to ameliorate this? | |
57 return null; | |
58 } | |
59 } | |
60 | |
61 /** Construct a new, empty instance. */ | |
62 public static ExtensionRegistryLite create() { | |
63 if (EXTENSION_REGISTRY_CLASS != null) { | |
64 try { | |
65 return invokeSubclassFactory("newInstance"); | |
66 } catch (Exception e) { | |
67 // return a Lite registry. | |
68 } | |
69 } | |
70 return new ExtensionRegistryLite(); | |
71 } | |
72 | |
73 /** Get the unmodifiable singleton empty instance. */ | |
74 public static ExtensionRegistryLite createEmpty() { | |
75 if (EXTENSION_REGISTRY_CLASS != null) { | |
76 try { | |
77 return invokeSubclassFactory("getEmptyRegistry"); | |
78 } catch (Exception e) { | |
79 // return a Lite registry. | |
80 } | |
81 } | |
82 return EMPTY_REGISTRY_LITE; | |
83 } | |
84 | |
85 static boolean isFullRegistry(ExtensionRegistryLite registry) { | |
86 return EXTENSION_REGISTRY_CLASS != null | |
87 && EXTENSION_REGISTRY_CLASS.isAssignableFrom(registry.getClass()); | |
88 } | |
89 | |
90 private static final ExtensionRegistryLite invokeSubclassFactory(String method
Name) | |
91 throws Exception { | |
92 return (ExtensionRegistryLite) EXTENSION_REGISTRY_CLASS | |
93 .getMethod(methodName).invoke(null); | |
94 } | |
95 } | |
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