1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
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30 
31 // TODO(kenton):  Use generics?  E.g. Builder<BuilderType extends Builder>, then
32 //   mergeFrom*() could return BuilderType for better type-safety.
33 
34 package com.google.protobuf;
35 
36 import java.io.IOException;
37 import java.io.InputStream;
38 import java.util.Map;
39 
40 /**
41  * Abstract interface implemented by Protocol Message objects.
42  * <p>
43  * See also {@link MessageLite}, which defines most of the methods that typical
44  * users care about.  {@link Message} adds to it methods that are not available
45  * in the "lite" runtime.  The biggest added features are introspection and
46  * reflection -- i.e., getting descriptors for the message type and accessing
47  * the field values dynamically.
48  *
49  * @author kenton@google.com Kenton Varda
50  */
51 public interface Message extends MessageLite, MessageOrBuilder {
52 
53   // (From MessageLite, re-declared here only for return type covariance.)
54   @Override
getParserForType()55   Parser<? extends Message> getParserForType();
56 
57 
58   // -----------------------------------------------------------------
59   // Comparison and hashing
60 
61   /**
62    * Compares the specified object with this message for equality.  Returns
63    * {@code true} if the given object is a message of the same type (as
64    * defined by {@code getDescriptorForType()}) and has identical values for
65    * all of its fields.  Subclasses must implement this; inheriting
66    * {@code Object.equals()} is incorrect.
67    *
68    * @param other object to be compared for equality with this message
69    * @return {@code true} if the specified object is equal to this message
70    */
71   @Override
equals(Object other)72   boolean equals(Object other);
73 
74   /**
75    * Returns the hash code value for this message.  The hash code of a message
76    * should mix the message's type (object identity of the descriptor) with its
77    * contents (known and unknown field values).  Subclasses must implement this;
78    * inheriting {@code Object.hashCode()} is incorrect.
79    *
80    * @return the hash code value for this message
81    * @see Map#hashCode()
82    */
83   @Override
hashCode()84   int hashCode();
85 
86   // -----------------------------------------------------------------
87   // Convenience methods.
88 
89   /**
90    * Converts the message to a string in protocol buffer text format. This is
91    * just a trivial wrapper around {@link
92    * TextFormat#printToString(MessageOrBuilder)}.
93    */
94   @Override
toString()95   String toString();
96 
97   // =================================================================
98   // Builders
99 
100   // (From MessageLite, re-declared here only for return type covariance.)
101   @Override
newBuilderForType()102   Builder newBuilderForType();
103 
104   @Override
toBuilder()105   Builder toBuilder();
106 
107   /**
108    * Abstract interface implemented by Protocol Message builders.
109    */
110   interface Builder extends MessageLite.Builder, MessageOrBuilder {
111     // (From MessageLite.Builder, re-declared here only for return type
112     // covariance.)
113     @Override
clear()114     Builder clear();
115 
116     /**
117      * Merge {@code other} into the message being built.  {@code other} must
118      * have the exact same type as {@code this} (i.e.
119      * {@code getDescriptorForType() == other.getDescriptorForType()}).
120      *
121      * Merging occurs as follows.  For each field:<br>
122      * * For singular primitive fields, if the field is set in {@code other},
123      *   then {@code other}'s value overwrites the value in this message.<br>
124      * * For singular message fields, if the field is set in {@code other},
125      *   it is merged into the corresponding sub-message of this message
126      *   using the same merging rules.<br>
127      * * For repeated fields, the elements in {@code other} are concatenated
128      *   with the elements in this message.
129      * * For oneof groups, if the other message has one of the fields set,
130      *   the group of this message is cleared and replaced by the field
131      *   of the other message, so that the oneof constraint is preserved.
132      *
133      * This is equivalent to the {@code Message::MergeFrom} method in C++.
134      */
mergeFrom(Message other)135     Builder mergeFrom(Message other);
136 
137     // (From MessageLite.Builder, re-declared here only for return type
138     // covariance.)
139     @Override
build()140     Message build();
141 
142     @Override
buildPartial()143     Message buildPartial();
144 
145     @Override
clone()146     Builder clone();
147 
148     @Override
mergeFrom(CodedInputStream input)149     Builder mergeFrom(CodedInputStream input) throws IOException;
150 
151     @Override
mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)152     Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
153         throws IOException;
154 
155     /**
156      * Get the message's type's descriptor.
157      * See {@link Message#getDescriptorForType()}.
158      */
159     @Override
getDescriptorForType()160     Descriptors.Descriptor getDescriptorForType();
161 
162     /**
163      * Create a Builder for messages of the appropriate type for the given
164      * field.  Messages built with this can then be passed to setField(),
165      * setRepeatedField(), or addRepeatedField().
166      */
newBuilderForField(Descriptors.FieldDescriptor field)167     Builder newBuilderForField(Descriptors.FieldDescriptor field);
168 
169     /**
170      * Get a nested builder instance for the given field.
171      * <p>
172      * Normally, we hold a reference to the immutable message object for the
173      * message type field. Some implementations(the generated message builders),
174      * however, can also hold a reference to the builder object (a nested
175      * builder) for the field.
176      * <p>
177      * If the field is already backed up by a nested builder, the nested builder
178      * will be returned. Otherwise, a new field builder will be created and
179      * returned. The original message field (if exist) will be merged into the
180      * field builder, which will then be nested into its parent builder.
181      * <p>
182      * NOTE: implementations that do not support nested builders will throw
183      * <code>UnsupportedOperationException</code>.
184      */
getFieldBuilder(Descriptors.FieldDescriptor field)185     Builder getFieldBuilder(Descriptors.FieldDescriptor field);
186 
187     /**
188      * Get a nested builder instance for the given repeated field instance.
189      * <p>
190      * Normally, we hold a reference to the immutable message object for the
191      * message type field. Some implementations(the generated message builders),
192      * however, can also hold a reference to the builder object (a nested
193      * builder) for the field.
194      * <p>
195      * If the field is already backed up by a nested builder, the nested builder
196      * will be returned. Otherwise, a new field builder will be created and
197      * returned. The original message field (if exist) will be merged into the
198      * field builder, which will then be nested into its parent builder.
199      * <p>
200      * NOTE: implementations that do not support nested builders will throw
201      * <code>UnsupportedOperationException</code>.
202      */
getRepeatedFieldBuilder(Descriptors.FieldDescriptor field, int index)203     Builder getRepeatedFieldBuilder(Descriptors.FieldDescriptor field,
204                                     int index);
205 
206     /**
207      * Sets a field to the given value.  The value must be of the correct type
208      * for this field, i.e. the same type that
209      * {@link Message#getField(Descriptors.FieldDescriptor)} would return.
210      */
setField(Descriptors.FieldDescriptor field, Object value)211     Builder setField(Descriptors.FieldDescriptor field, Object value);
212 
213     /**
214      * Clears the field.  This is exactly equivalent to calling the generated
215      * "clear" accessor method corresponding to the field.
216      */
clearField(Descriptors.FieldDescriptor field)217     Builder clearField(Descriptors.FieldDescriptor field);
218 
219     /**
220      * Clears the oneof.  This is exactly equivalent to calling the generated
221      * "clear" accessor method corresponding to the oneof.
222      */
clearOneof(Descriptors.OneofDescriptor oneof)223     Builder clearOneof(Descriptors.OneofDescriptor oneof);
224 
225     /**
226      * Sets an element of a repeated field to the given value.  The value must
227      * be of the correct type for this field, i.e. the same type that
228      * {@link Message#getRepeatedField(Descriptors.FieldDescriptor,int)} would
229      * return.
230      * @throws IllegalArgumentException The field is not a repeated field, or
231      *           {@code field.getContainingType() != getDescriptorForType()}.
232      */
setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value)233     Builder setRepeatedField(Descriptors.FieldDescriptor field,
234                              int index, Object value);
235 
236     /**
237      * Like {@code setRepeatedField}, but appends the value as a new element.
238      * @throws IllegalArgumentException The field is not a repeated field, or
239      *           {@code field.getContainingType() != getDescriptorForType()}.
240      */
addRepeatedField(Descriptors.FieldDescriptor field, Object value)241     Builder addRepeatedField(Descriptors.FieldDescriptor field, Object value);
242 
243     /** Set the {@link UnknownFieldSet} for this message. */
setUnknownFields(UnknownFieldSet unknownFields)244     Builder setUnknownFields(UnknownFieldSet unknownFields);
245 
246     /**
247      * Merge some unknown fields into the {@link UnknownFieldSet} for this
248      * message.
249      */
mergeUnknownFields(UnknownFieldSet unknownFields)250     Builder mergeUnknownFields(UnknownFieldSet unknownFields);
251 
252     // ---------------------------------------------------------------
253     // Convenience methods.
254 
255     // (From MessageLite.Builder, re-declared here only for return type
256     // covariance.)
257     @Override
mergeFrom(ByteString data)258     Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
259 
260     @Override
mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)261     Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
262         throws InvalidProtocolBufferException;
263 
264     @Override
mergeFrom(byte[] data)265     Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
266 
267     @Override
mergeFrom(byte[] data, int off, int len)268     Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
269 
270     @Override
mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)271     Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
272         throws InvalidProtocolBufferException;
273 
274     @Override
mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)275     Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
276         throws InvalidProtocolBufferException;
277 
278     @Override
mergeFrom(InputStream input)279     Builder mergeFrom(InputStream input) throws IOException;
280 
281     @Override
mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)282     Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
283         throws IOException;
284 
285     @Override
mergeDelimitedFrom(InputStream input)286     boolean mergeDelimitedFrom(InputStream input) throws IOException;
287 
288     @Override
mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)289     boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
290         throws IOException;
291   }
292 }
293