io.vertx.core.eventbus

Interface MessageCodec<S,R>

Type Parameters:

S - the type of the message being sent

R - the type of the message being received.

All Known Implementing Classes:

ServiceExceptionMessageCodec

public interface MessageCodec<S,R>

A message codec allows a custom message type to be marshalled across the event bus.

Usually the event bus only allows a certain set of message types to be sent across the event bus, including primitive types, boxed primitive types, byte[], JsonObject, JsonArray, Buffer.

By specifying a message codec you can pass any other type across the event bus, e.g. POJOs.

With a message codec the type sent does not have to be the same as the type received, e.g. you could send a Buffer and have it be received as a JsonObject.

Instances of this class must be thread-safe as they may be used concurrently by different threads.

Author:

Tim Fox

Method Summary

Modifier and Type	Method and Description
R	decodeFromWire(int pos, Buffer buffer) Called by Vert.x when a message is decoded from the wire.
void	encodeToWire(Buffer buffer, S s) Called by Vert.x when marshalling a message to the wire.
String	name() The codec name.
byte	systemCodecID() Used to identify system codecs.
R	transform(S s) If a message is sent locally across the event bus, this method is called to transform the message from the sent type S to the received type R

Method Detail

encodeToWire

void encodeToWire(Buffer buffer,
                  S s)

Called by Vert.x when marshalling a message to the wire.

Parameters:

buffer - the message should be written into this buffer

s - the message that is being sent

decodeFromWire

R decodeFromWire(int pos,
                 Buffer buffer)

Called by Vert.x when a message is decoded from the wire.

Parameters:

pos - the position in the buffer where the message should be read from.

buffer - the buffer to read the message from

Returns:

the read message

transform

R transform(S s)

If a message is sent locally across the event bus, this method is called to transform the message from the sent type S to the received type R

Parameters:

s - the sent message

Returns:

the transformed message

name

String name()

The codec name. Each codec must have a unique name. This is used to identify a codec when sending a message and for unregistering codecs.

Returns:

the name

systemCodecID

byte systemCodecID()

Used to identify system codecs. Should always return -1 for a user codec.

Returns:

-1 for a user codec.