// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// 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<BuilderType extends 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.
*
* <p>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:
* <pre>
* option optimize_for = LITE_RUNTIME;
* </pre>
*
* <p>This is particularly useful on resource-constrained systems where the
* full protocol buffers runtime library is too big.
*
* <p>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 kenton@google.com 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<? extends MessageLite> 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.
* <p>
* 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.
*
* <p>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:
* <ul>
* <li>Call {@link #isInitialized()} to verify that all required fields
* are set before building.
* <li>Use {@code buildPartial()} to build, which ignores missing
* required fields.
* </ul>
*
* <p>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 <i>entire</i> 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.
* <p>
* 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;
/**
* 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;
}
}