org.lsst.ccs.messaging

Class AgentPresenceManager

java.lang.Object

org.lsst.ccs.messaging.AgentPresenceManager

All Implemented Interfaces:

ClusterDisconnectionsListener, MessageListener, StatusMessageListener

public class AgentPresenceManager
extends Object
implements StatusMessageListener, ClusterDisconnectionsListener

Tracks agent connection and disconnection on the buses.

Author:

emarin

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AgentPresenceManager.AgentPresenceState

Constructor Summary

Constructors

Constructor and Description
AgentPresenceManager(AgentInfo agentInfo)

Method Summary

Modifier and Type	Method and Description
void	addAgentPresenceListener(AgentPresenceListener l)
boolean	agentExists(String agentName) This method returns true as soon as the AgentPresenceManager is aware of the existence of the given agent by name.
boolean	isAgentConnected(AgentPropertyPredicate agentPredicate) This method returns true when the given agent is fully connected, OPERATIONAL and ready to receive commands.
boolean	isAgentConnected(String agentName) This method returns true when the given agent is fully connected, OPERATIONAL and ready to receive commands.
List<AgentInfo>	listConnectedAgents()
void	membersLeft(List<String> left)
void	onStatusMessage(StatusMessage s) Called when a status message is received.
void	removeAgentPresenceListener(AgentPresenceListener l)
boolean	waitForAgent(AgentPropertyPredicate predicate, long timeout, TimeUnit unit)
boolean	waitForAgent(String name, long timeout, TimeUnit unit) Wait for an Agent to be fully connected: all the listeners have been notified on the connected method.
boolean	waitForAgentDisconnection(String name, long timeout, TimeUnit unit) Wait for an Agent to be fully disconnected: all the listeners have been notified on the disconnected method.

Methods inherited from class java.lang.Object

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

Constructor Detail

AgentPresenceManager

public AgentPresenceManager(AgentInfo agentInfo)

Method Detail

onStatusMessage

public void onStatusMessage(StatusMessage s)

Description copied from interface: StatusMessageListener

Called when a status message is received. The implementation should be thread-safe: the framework makes no guarantees on what thread this method will be called on, and it can be called concurrently for several messages. The implementation should also return immediately : any blocking operations should be scheduled on a separate thread.

Specified by:

onStatusMessage in interface StatusMessageListener

Parameters:

s - Status bus message to be processed.

listConnectedAgents

public List<AgentInfo> listConnectedAgents()

Returns:

The list with the currently connected Agents

membersLeft

public void membersLeft(List<String> left)

Specified by:

membersLeft in interface ClusterDisconnectionsListener

addAgentPresenceListener

public void addAgentPresenceListener(AgentPresenceListener l)

removeAgentPresenceListener

public void removeAgentPresenceListener(AgentPresenceListener l)

agentExists

public boolean agentExists(String agentName)

This method returns true as soon as the AgentPresenceManager is aware of the existence of the given agent by name. At this point we don't guarantee that the corresponding agent is ready to receive command requests as it might still be INITIALIZING. To be sure that an agent is fully connected, OPERATIONAL and ready to receive message use method #isAgentConnected(String) instead.

Parameters:

agentName - The name of the agent

Returns:

true if the AgentPresenceManager is aware of the existence of this agent.

isAgentConnected

public boolean isAgentConnected(String agentName)

This method returns true when the given agent is fully connected, OPERATIONAL and ready to receive commands.

Parameters:

agentName - The name of the Agent.

Returns:

true when the given agent is fully connected.

isAgentConnected

public boolean isAgentConnected(AgentPropertyPredicate agentPredicate)

This method returns true when the given agent is fully connected, OPERATIONAL and ready to receive commands.

Parameters:

agentPredicate - The predicate to select the Agent.

Returns:

true when the given agent is fully connected.

waitForAgent

public final boolean waitForAgent(String name,
                                  long timeout,
                                  TimeUnit unit)
                           throws InterruptedException

Wait for an Agent to be fully connected: all the listeners have been notified on the connected method.

Parameters:

name - The name of the Agent

timeout - The time to wait for the agent to become available.

unit - The TimeUnit for the timeout.

Returns:

True if the Agent is fully connected within the provided timeout, false otherwise.

Throws:

InterruptedException

waitForAgent

public final boolean waitForAgent(AgentPropertyPredicate predicate,
                                  long timeout,
                                  TimeUnit unit)
                           throws InterruptedException

Throws:

InterruptedException

waitForAgentDisconnection

public final boolean waitForAgentDisconnection(String name,
                                               long timeout,
                                               TimeUnit unit)
                                        throws InterruptedException

Wait for an Agent to be fully disconnected: all the listeners have been notified on the disconnected method.

Parameters:

name - The name of the Agent

timeout - The time to wait for the agent to become available.

unit - The TimeUnit for the timeout.

Returns:

True if the Agent is disconnected from the buses within the provided timeout, false otherwise.

Throws:

InterruptedException