1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // https://developers.google.com/protocol-buffers/
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
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
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16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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31 package com.google.protobuf;
34 * Interface that generated extensions implement.
36 * @author liujisi@google.com (Jisi Liu)
38 public abstract class Extension<ContainingType extends MessageLite, Type> {
39 /** Returns the field number of the extension. */
40 public abstract int getNumber();
42 /** Returns the type of the field. */
43 public abstract WireFormat.FieldType getLiteType();
45 /** Returns whether it is a repeated field. */
46 public abstract boolean isRepeated();
48 /** Returns the descriptor of the extension. */
49 public abstract Descriptors.FieldDescriptor getDescriptor();
51 /** Returns the default value of the extension field. */
52 public abstract Type getDefaultValue();
55 * Returns the default instance of the extension field, if it's a message
58 public abstract MessageLite getMessageDefaultInstance();
60 // All the methods below are extension implementation details.
63 * The API type that the extension is used for.
65 protected enum ExtensionType {
71 protected ExtensionType getExtensionType() {
72 // TODO(liujisi): make this abstract after we fix proto1.
73 return ExtensionType.IMMUTABLE;
77 * Type of a message extension.
79 public enum MessageType {
85 * If the extension is a message extension (i.e., getLiteType() == MESSAGE),
86 * returns the type of the message, otherwise undefined.
88 public MessageType getMessageType() {
89 return MessageType.PROTO2;
92 protected abstract Object fromReflectionType(Object value);
93 protected abstract Object singularFromReflectionType(Object value);
94 protected abstract Object toReflectionType(Object value);
95 protected abstract Object singularToReflectionType(Object value);