org.apache.reef.driver.context

Interface ContextMessage

All Superinterfaces:

Identifiable, Message, Numberable

All Known Implementing Classes:

ContextMessageImpl

public interface ContextMessage
extends Message, Identifiable, Numberable

Driver-side representation of a message sent by a Context to the Driver.

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	get() Message payload.
String	getId() Returns an identifier of this object.
String	getMessageSourceID()
long	getSequenceNumber()

Method Detail

get

byte[] get()

Description copied from interface: Message

Message payload.

Specified by:

get in interface Message

Returns:

the message sent by the Context.

getId

String getId()

Description copied from interface: Identifiable

Returns an identifier of this object.

Specified by:

getId in interface Identifiable

Returns:

the ID of the sending Context.

getMessageSourceID

String getMessageSourceID()

Returns:

the ID of the ContextMessageSource that sent the message on the Context.

getSequenceNumber

long getSequenceNumber()

Specified by:

getSequenceNumber in interface Numberable

Returns:

the sequence number of the message Terminology: a source sends a message to a target. Example sources are Tasks or Contexts. Example targets are Drivers. The method guarantees that sequence numbers increase strictly monotonically per message source. So numbers of messages from different sources should not be compared to each other. Clients of this method must not assume any particular method implementation because it may change in the future. The current implementation returns the timestamp of a heartbeat that contained the message. A heartbeat may contain several messages; all such message will get the same sequence number. A source can attach only one message to a single heartbeat, so the strict sequence number monotonicity per source is guaranteed.