com.google.protobuf
Interface MessageLite

All Known Subinterfaces:

Message

All Known Implementing Classes:

AbstractMessage, AbstractMessageLite, DynamicMessage, GeneratedMessage, GeneratedMessage.ExtendableMessage, GeneratedMessageLite, GeneratedMessageLite.ExtendableMessage, UnknownFieldSet

public interface MessageLite

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 optimize_for = CODE_SIZE. This will make the generated code smaller while still supporting all the same features (at the expense of speed). 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

Nested Class Summary

static interface

MessageLite.Builder Abstract interface implemented by Protocol Message builders.

Method Summary

MessageLite	getDefaultInstanceForType() Get an instance of the type with all fields set to their default values.
int	getSerializedSize() Get the number of bytes required to encode this message.
boolean	isInitialized() Returns true if all required fields in the message and all embedded messages are set, false otherwise.
MessageLite.Builder	newBuilderForType() Constructs a new builder for a message of the same type as this message.
MessageLite.Builder	toBuilder() Constructs a builder initialized with the current message.
byte[]	toByteArray() Serializes the message to a byte array and returns it.
ByteString	toByteString() Serializes the message to a ByteString and returns it.
void	writeDelimitedTo(java.io.OutputStream output) Like writeTo(OutputStream), but writes the size of the message as a varint before writing the data.
void	writeTo(CodedOutputStream output) Serializes the message and writes it to output.
void	writeTo(java.io.OutputStream output) Serializes the message and writes it to output.

Method Detail

getDefaultInstanceForType

MessageLite getDefaultInstanceForType()

Get an instance of the type with all fields set to their default values. This may or may not be a singleton. This differs from the getDefaultInstance() method of generated message classes in that this method is an abstract method of the MessageLite interface whereas getDefaultInstance() is a static method of a specific class. They return the same thing.

isInitialized

boolean isInitialized()

Returns true if all required fields in the message and all embedded messages are set, false otherwise.

writeTo

void writeTo(CodedOutputStream output)
             throws java.io.IOException

Serializes the message and writes it to output. This does not flush or close the stream.

Throws:

java.io.IOException

getSerializedSize

int getSerializedSize()

Get the number of bytes required to encode this message. The result is only computed on the first call and memoized after that.

toByteString

ByteString toByteString()

Serializes the message to a ByteString and returns it. This is just a trivial wrapper around writeTo(CodedOutputStream).

toByteArray

byte[] toByteArray()

Serializes the message to a byte array and returns it. This is just a trivial wrapper around writeTo(CodedOutputStream).

writeTo

void writeTo(java.io.OutputStream output)
             throws java.io.IOException

Serializes the message and writes it to output. This is just a trivial wrapper around 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 writeDelimitedTo(OutputStream).

Throws:

java.io.IOException

writeDelimitedTo

void writeDelimitedTo(java.io.OutputStream output)
                      throws java.io.IOException

Like 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 MessageLite.Builder.mergeDelimitedFrom(InputStream) (or the static method YourMessageType.parseDelimitedFrom(InputStream)) to parse messages written by this method.

Throws:

java.io.IOException

newBuilderForType

MessageLite.Builder newBuilderForType()

Constructs a new builder for a message of the same type as this message.

toBuilder

MessageLite.Builder toBuilder()

Constructs a builder initialized with the current message. Use this to derive a new message from the current one.