org.lsst.ccs.bus.messages

Class CommandMessage<T extends Serializable,D>

java.lang.Object

org.lsst.ccs.bus.messages.BusMessage<T,D>

org.lsst.ccs.bus.messages.CommandMessage<T,D>

Type Parameters:

T - The Serializable object embedded in the message.

D - The type of object returned by the encoding

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

CommandReply, CommandRequest

public abstract class CommandMessage<T extends Serializable,D>
extends BusMessage<T,D>

Superclass for all messages sent on the Command Bus. This class contains the following additional fields:

• destination: the destination on the buses of the CommandMessage
• correlationId: the correlation id for this message. This is used internally to match requests and replies. Each CommandRequest will generate a new unique id which will be used by all CommandReply objects related to the CommandRequest.

The embedded object of a CommandMessage depends on the specific subclass. CommandRequests contain the BasicCommand object that initiated the request. CommandReply objects can either contain an object produced by the execution of the CommandRequest or an Throwable if the execution is not successful.

Author:

LSST CCS Team

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CommandMessage(String destination, UUID correlationId, T obj) Default CommandMessage constructor.

Method Summary

Modifier and Type	Method and Description
UUID	getCorrelationId() The correlationId of this CommandMessage.
String	getDestination() The destination of the CommandMessage.

Methods inherited from class org.lsst.ccs.bus.messages.BusMessage

encodeObject, getClassName, getEncodedData, getObject, getOriginAgentInfo, getTimeStamp, setOriginAgentInfo, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CommandMessage

protected CommandMessage(String destination,
                         UUID correlationId,
                         T obj)

Default CommandMessage constructor.

Parameters:

destination - The destination of the CommandMessage.

correlationId - The correlation Id for this command.

obj - The object contained in the CommandMessage.

Method Detail

getDestination

public String getDestination()

The destination of the CommandMessage. This is the name of the CCS Agent on the buses that is the target of this CommandMessage.

Returns:

The destination for this CommandMessage

getCorrelationId

public UUID getCorrelationId()

The correlationId of this CommandMessage. The correlationId is a unique identifier used to correlate CommandMessages related to the same command exchange, as described in the Command State Diagram: https://confluence.slac.stanford.edu/display/LSSTCAM/State+Diagrams The CorrelationId is intended to be used by CommandMessageListeners to correlate messages. The CorrelationId is used internally to route CommandReply messages to the appropriate CommandOriginator

Returns:

The Correlation Id for this message