org.lsst.ccs.messaging

Class ConcurrentMessagingUtils

java.lang.Object

org.lsst.ccs.messaging.ConcurrentMessagingUtils

public class ConcurrentMessagingUtils
extends Object

Utility class to synchronously or asynchronously invoke or listen for events on the buses.

Author:

The LSST CCS Team

Constructor Summary

Constructors

Constructor and Description
ConcurrentMessagingUtils(AgentMessagingLayer agentMessagingLayer)

Method Summary

Modifier and Type	Method and Description
Object	getAckForCommand(CommandRequest command, long millisTimeout) Send a CommandRequest on the buses and synchronously wait for the Ack to come back.
Future<Object>	sendAsynchronousCommand(CommandRequest command) Send a command on the buses and immediately return a Future that will asynchronously listen for the command reply.
Object	sendSynchronousCommand(CommandRequest command, long millisTimeout) Send a command on the Buses and wait for the reply.
Future<StatusMessage>	startListeningForStatusBusMessage(BusMessageFilter filter) Get a Future on a StatusBusMessage.
Future<StatusMessage>	startListeningForStatusBusMessage(BusMessageFilter filter, long timeout) Get a Future on a StatusBusMessage.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcurrentMessagingUtils

public ConcurrentMessagingUtils(AgentMessagingLayer agentMessagingLayer)

Method Detail

sendSynchronousCommand

public Object sendSynchronousCommand(CommandRequest command,
                                     long millisTimeout)
                              throws Exception

Send a command on the Buses and wait for the reply.

Parameters:

command - The CommandRequest object to be sent on the buses.

millisTimeout - Timeout in milliseconds. If the reply is not received within the timeout a TimeoutException will be thrown.

Returns:

The reply of the CommandRequest.

Throws:

Exception - If an exception was fired by the remote execution of the command or the timeout expired.

sendAsynchronousCommand

public Future<Object> sendAsynchronousCommand(CommandRequest command)

Send a command on the buses and immediately return a Future that will asynchronously listen for the command reply.

Parameters:

command - The CommandRequest object to be sent on the buses.

Returns:

A Future on the reply of the command execution. The future will also contain any possible exception thrown during the command execution.

getAckForCommand

public Object getAckForCommand(CommandRequest command,
                               long millisTimeout)
                        throws Exception

Send a CommandRequest on the buses and synchronously wait for the Ack to come back.

Parameters:

command - The CommandRequest object to be sent on the buses.

millisTimeout - Timeout in milliseconds. If the ack is not received within the timeout a TimeoutException will be thrown.

Returns:

The CommandAck for the CommandRequest.

Throws:

Exception - If an exception was fired by the remote execution of the command or the timeout expired.

startListeningForStatusBusMessage

public Future<StatusMessage> startListeningForStatusBusMessage(BusMessageFilter filter,
                                                               long timeout)

Get a Future on a StatusBusMessage. The content of the Future is filled when the first StatusBusMessage that satisfies the ScriptingStatusBusMessageFilter is received. When the Future is exercised it will return the first ScriptingStatusBusMessage or an ExecutionException will be thrown when the timeout is reached.

Parameters:

filter - ScriptingStatusBusMessageFilter The message filter

timeout - Timeout in milliseconds, after which a ScriptiongTimeoutException is thrown. This timeout is from the time the method is invoked. If this timeout is reached an exception will be thrown if/when the Future is exercised.

Returns:

A Future on a ScriptingStatusBusMessage.

startListeningForStatusBusMessage

public Future<StatusMessage> startListeningForStatusBusMessage(BusMessageFilter filter)

Get a Future on a StatusBusMessage. The content of the Future is filled when the first StatusBusMessage that satisfies the ScriptingStatusBusMessageFilter is received. When the Future is exercised it will return the first ScriptingStatusBusMessage.

Parameters:

filter - ScriptingStatusBusMessageFilter The message filter

Returns:

A Future on a ScriptingStatusBusMessage.