1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // http://code.google.com/p/protobuf/
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6 // modification, are permitted provided that the following conditions are
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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
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17 // this software without specific prior written permission.
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31 package com.google.protobuf;
33 import java.util.Collections;
34 import java.util.HashMap;
38 * Equivalent to {@link ExtensionRegistry} but supports only "lite" types.
40 * If all of your types are lite types, then you only need to use
41 * {@code ExtensionRegistryLite}. Similarly, if all your types are regular
42 * types, then you only need {@link ExtensionRegistry}. Typically it does not
43 * make sense to mix the two, since if you have any regular types in your
44 * program, you then require the full runtime and lose all the benefits of
45 * the lite runtime, so you might as well make all your types be regular types.
46 * However, in some cases (e.g. when depending on multiple third-party libraries
47 * where one uses lite types and one uses regular), you may find yourself
48 * wanting to mix the two. In this case things get more complicated.
50 * There are three factors to consider: Whether the type being extended is
51 * lite, whether the embedded type (in the case of a message-typed extension)
52 * is lite, and whether the extension itself is lite. Since all three are
53 * declared in different files, they could all be different. Here are all
54 * the combinations and which type of registry to use:
56 * Extended type Inner type Extension Use registry
57 * =======================================================================
58 * lite lite lite ExtensionRegistryLite
59 * lite regular lite ExtensionRegistry
60 * regular regular regular ExtensionRegistry
61 * all other combinations not supported
64 * Note that just as regular types are not allowed to contain lite-type fields,
65 * they are also not allowed to contain lite-type extensions. This is because
66 * regular types must be fully accessible via reflection, which in turn means
67 * that all the inner messages must also support reflection. On the other hand,
68 * since regular types implement the entire lite interface, there is no problem
69 * with embedding regular types inside lite types.
71 * @author kenton@google.com Kenton Varda
73 public class ExtensionRegistryLite {
75 // Set true to enable lazy parsing feature for MessageSet.
77 // TODO(xiangl): Now we use a global flag to control whether enable lazy
78 // parsing feature for MessageSet, which may be too crude for some
79 // applications. Need to support this feature on smaller granularity.
80 private static volatile boolean eagerlyParseMessageSets = false;
82 public static boolean isEagerlyParseMessageSets() {
83 return eagerlyParseMessageSets;
86 public static void setEagerlyParseMessageSets(boolean isEagerlyParse) {
87 eagerlyParseMessageSets = isEagerlyParse;
90 /** Construct a new, empty instance. */
91 public static ExtensionRegistryLite newInstance() {
92 return new ExtensionRegistryLite();
95 /** Get the unmodifiable singleton empty instance. */
96 public static ExtensionRegistryLite getEmptyRegistry() {
100 /** Returns an unmodifiable view of the registry. */
101 public ExtensionRegistryLite getUnmodifiable() {
102 return new ExtensionRegistryLite(this);
106 * Find an extension by containing type and field number.
108 * @return Information about the extension if found, or {@code null}
111 @SuppressWarnings("unchecked")
112 public <ContainingType extends MessageLite>
113 GeneratedMessageLite.GeneratedExtension<ContainingType, ?>
114 findLiteExtensionByNumber(
115 final ContainingType containingTypeDefaultInstance,
116 final int fieldNumber) {
117 return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>)
118 extensionsByNumber.get(
119 new ObjectIntPair(containingTypeDefaultInstance, fieldNumber));
122 /** Add an extension from a lite generated file to the registry. */
123 public final void add(
124 final GeneratedMessageLite.GeneratedExtension<?, ?> extension) {
125 extensionsByNumber.put(
126 new ObjectIntPair(extension.getContainingTypeDefaultInstance(),
127 extension.getNumber()),
131 // =================================================================
134 // Constructors are package-private so that ExtensionRegistry can subclass
137 ExtensionRegistryLite() {
138 this.extensionsByNumber =
139 new HashMap<ObjectIntPair,
140 GeneratedMessageLite.GeneratedExtension<?, ?>>();
143 ExtensionRegistryLite(ExtensionRegistryLite other) {
144 if (other == EMPTY) {
145 this.extensionsByNumber = Collections.emptyMap();
147 this.extensionsByNumber =
148 Collections.unmodifiableMap(other.extensionsByNumber);
152 private final Map<ObjectIntPair,
153 GeneratedMessageLite.GeneratedExtension<?, ?>>
156 private ExtensionRegistryLite(boolean empty) {
157 this.extensionsByNumber = Collections.emptyMap();
159 private static final ExtensionRegistryLite EMPTY =
160 new ExtensionRegistryLite(true);
162 /** A (Object, int) pair, used as a map key. */
163 private static final class ObjectIntPair {
164 private final Object object;
165 private final int number;
167 ObjectIntPair(final Object object, final int number) {
168 this.object = object;
169 this.number = number;
173 public int hashCode() {
174 return System.identityHashCode(object) * ((1 << 16) - 1) + number;
177 public boolean equals(final Object obj) {
178 if (!(obj instanceof ObjectIntPair)) {
181 final ObjectIntPair other = (ObjectIntPair)obj;
182 return object == other.object && number == other.number;