com.google.protobuf.MessageLite Maven / Gradle / Ivy
Show all versions of protobuf-java Show documentation
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// TODO(kenton): Use generics? E.g. Builder, then
// mergeFrom*() could return BuilderType for better type-safety.
package com.google.protobuf;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Abstract interface implemented by Protocol Message objects.
*
* This interface is implemented by all protocol message objects. Non-lite messages additionally
* implement the Message interface, which is a subclass of MessageLite. Use MessageLite instead when
* you only need the subset of features which it supports -- namely, nothing that uses descriptors
* or reflection. You can instruct the protocol compiler to generate classes which implement only
* MessageLite, not the full Message interface, by adding the follow line to the .proto file:
*
*
* option optimize_for = LITE_RUNTIME;
*
*
* This is particularly useful on resource-constrained systems where the full protocol buffers
* runtime library is too big.
*
*
Note that on non-constrained systems (e.g. servers) when you need to link in lots of protocol
* definitions, a better way to reduce total code footprint is to use {@code optimize_for =
* CODE_SIZE}. This will make the generated code smaller while still supporting all the same
* features (at the expense of speed). {@code optimize_for = LITE_RUNTIME} is best when you only
* have a small number of message types linked into your binary, in which case the size of the
* protocol buffers runtime itself is the biggest problem.
*
* @author [email protected] Kenton Varda
*/
public interface MessageLite extends MessageLiteOrBuilder {
/**
* Serializes the message and writes it to {@code output}. This does not flush or close the
* stream.
*/
void writeTo(CodedOutputStream output) throws IOException;
/**
* Get the number of bytes required to encode this message. The result is only computed on the
* first call and memoized after that.
*/
int getSerializedSize();
/** Gets the parser for a message of the same type as this message. */
Parser getParserForType();
// -----------------------------------------------------------------
// Convenience methods.
/**
* Serializes the message to a {@code ByteString} and returns it. This is just a trivial wrapper
* around {@link #writeTo(CodedOutputStream)}.
*/
ByteString toByteString();
/**
* Serializes the message to a {@code byte} array and returns it. This is just a trivial wrapper
* around {@link #writeTo(CodedOutputStream)}.
*/
byte[] toByteArray();
/**
* Serializes the message and writes it to {@code output}. This is just a trivial wrapper around
* {@link #writeTo(CodedOutputStream)}. This does not flush or close the stream.
*
*
NOTE: Protocol Buffers are not self-delimiting. Therefore, if you write any more data to the
* stream after the message, you must somehow ensure that the parser on the receiving end does not
* interpret this as being part of the protocol message. This can be done e.g. by writing the size
* of the message before the data, then making sure to limit the input to that size on the
* receiving end (e.g. by wrapping the InputStream in one which limits the input). Alternatively,
* just use {@link #writeDelimitedTo(OutputStream)}.
*/
void writeTo(OutputStream output) throws IOException;
/**
* Like {@link #writeTo(OutputStream)}, but writes the size of the message as a varint before
* writing the data. This allows more data to be written to the stream after the message without
* the need to delimit the message data yourself. Use {@link
* Builder#mergeDelimitedFrom(InputStream)} (or the static method {@code
* YourMessageType.parseDelimitedFrom(InputStream)}) to parse messages written by this method.
*/
void writeDelimitedTo(OutputStream output) throws IOException;
// =================================================================
// Builders
/** Constructs a new builder for a message of the same type as this message. */
Builder newBuilderForType();
/**
* Constructs a builder initialized with the current message. Use this to derive a new message
* from the current one.
*/
Builder toBuilder();
/** Abstract interface implemented by Protocol Message builders. */
interface Builder extends MessageLiteOrBuilder, Cloneable {
/** Resets all fields to their default values. */
Builder clear();
/**
* Constructs the message based on the state of the Builder. Subsequent changes to the Builder
* will not affect the returned message.
*
* @throws UninitializedMessageException The message is missing one or more required fields
* (i.e. {@link #isInitialized()} returns false). Use {@link #buildPartial()} to bypass this
* check.
*/
MessageLite build();
/**
* Like {@link #build()}, but does not throw an exception if the message is missing required
* fields. Instead, a partial message is returned. Subsequent changes to the Builder will not
* affect the returned message.
*/
MessageLite buildPartial();
/**
* Clones the Builder.
*
* @see Object#clone()
*/
Builder clone();
/**
* Parses a message of this type from the input and merges it with this message.
*
*
Warning: This does not verify that all required fields are present in the input message.
* If you call {@link #build()} without setting all required fields, it will throw an {@link
* UninitializedMessageException}, which is a {@code RuntimeException} and thus might not be
* caught. There are a few good ways to deal with this:
*
*
* - Call {@link #isInitialized()} to verify that all required fields are set before
* building.
*
- Use {@code buildPartial()} to build, which ignores missing required fields.
*
*
* Note: The caller should call {@link CodedInputStream#checkLastTagWas(int)} after calling
* this to verify that the last tag seen was the appropriate end-group tag, or zero for EOF.
*/
Builder mergeFrom(CodedInputStream input) throws IOException;
/**
* Like {@link Builder#mergeFrom(CodedInputStream)}, but also parses extensions. The extensions
* that you want to be able to parse must be registered in {@code extensionRegistry}. Extensions
* not in the registry will be treated as unknown fields.
*/
Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
throws IOException;
// ---------------------------------------------------------------
// Convenience methods.
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
*
* @return this
*/
Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
*
* @return this
*/
Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
throws InvalidProtocolBufferException;
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
*
* @return this
*/
Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
*
* @return this
*/
Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
*
* @return this
*/
Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
throws InvalidProtocolBufferException;
/**
* Parse {@code data} as a message of this type and merge it with the message being built. This
* is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
*
* @return this
*/
Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
throws InvalidProtocolBufferException;
/**
* Parse a message of this type from {@code input} and merge it with the message being built.
* This is just a small wrapper around {@link #mergeFrom(CodedInputStream)}. Note that this
* method always reads the entire input (unless it throws an exception). If you want it
* to stop earlier, you will need to wrap your input in some wrapper stream that limits reading.
* Or, use {@link MessageLite#writeDelimitedTo(OutputStream)} to write your message and {@link
* #mergeDelimitedFrom(InputStream)} to read it.
*
*
Despite usually reading the entire input, this does not close the stream.
*
* @return this
*/
Builder mergeFrom(InputStream input) throws IOException;
/**
* Parse a message of this type from {@code input} and merge it with the message being built.
* This is just a small wrapper around {@link
* #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
*
* @return this
*/
Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
throws IOException;
/**
* Merge {@code other} into the message being built. {@code other} must have the exact same type
* as {@code this} (i.e. {@code getClass().equals(getDefaultInstanceForType().getClass())}).
*
*
Merging occurs as follows. For each field:
* * For singular primitive fields, if the field is set in {@code other}, then {@code other}'s
* value overwrites the value in this message.
* * For singular message fields, if the field is set in {@code other}, it is merged into the
* corresponding sub-message of this message using the same merging rules.
* * For repeated fields, the elements in {@code other} are concatenated with the elements in
* this message. * For oneof groups, if the other message has one of the fields set, the group
* of this message is cleared and replaced by the field of the other message, so that the oneof
* constraint is preserved.
*
*
This is equivalent to the {@code Message::MergeFrom} method in C++.
*/
Builder mergeFrom(MessageLite other);
/**
* Like {@link #mergeFrom(InputStream)}, but does not read until EOF. Instead, the size of the
* message (encoded as a varint) is read first, then the message data. Use {@link
* MessageLite#writeDelimitedTo(OutputStream)} to write messages in this format.
*
* @return True if successful, or false if the stream is at EOF when the method starts. Any
* other error (including reaching EOF during parsing) will cause an exception to be thrown.
*/
boolean mergeDelimitedFrom(InputStream input) throws IOException;
/** Like {@link #mergeDelimitedFrom(InputStream)} but supporting extensions. */
boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
throws IOException;
}
}