Watcher.v2_1
Class Watcher

java.lang.Object
  |
  +--PaP.Actor
        |
        +--PaP.ApplicationActor
              |
              +--Watcher.v2_1.Watcher

All Implemented Interfaces:

ActorInterface, ControlInterface, java.rmi.Remote, java.io.Serializable

public class Watcher

extends ApplicationActor

Watcher is the Plug-and-Play (PaP) specific class of the Watcher application. It extends ApplicationActor and therefore has access to functionality provided by the PaP system. Watcher has an internal state model with three states. The method stateTransition() defines the class' behavior in the different states when it receives a request through the method applicationActorEntry().

Watcher subscribes for reports on the events generated in the PaP system. Each time such an event occurs, the Director calls subscribeReport() with information regarding the event.

Version:

December 2001

Author:

Lars Erik Liljebäck

See Also:

Serialized Form

Field Summary

private RoleSession	initialRoleSession The initial RoleSession created when this Actor is created.
private boolean	initiated Indicates wether initial ActorPlugIn has been performed or not
private int	state Indicates which state the application is in
private int	STATE_INITIAL
private int	STATE_SERVER_ACTIVE State where it subscribes and shows the received reports
private int	STATE_SERVER_PASSIVE State where subscriptions are canceled and the Window are disposed
private java.lang.String	subscribeId The unique subscription id returned when SubscribeRequest is done
private WatcherWindow	window A reference to an instance of WatcherWindow

Fields inherited from class PaP.Actor

bf, context, fh

Constructor Summary

Watcher()
Creates a new instance of Watcher and sets the initial state to STATE_INITIAL.

Method Summary

RequestResult	applicationActorEntry(RequestPars rpars) This method is the common entry point for all external requests to this actor.
void	changeSubscription(int interval) Switches between the defined subscription types; Immediate, 15 seconds intervals and 30 seconds intervals.
void	closeApplication() This method is used by WatcherWindow to tell Watcher that the user wants to close the application.
private void	dbg(java.lang.String dbg) Sends debug information to this actor's BaseFrame window, which is an interactive debug client window for several entities.
java.lang.String	getWatcherGAI() Returns the GAI of this ApplicationActor.
private RequestResult	stateTransition(GAI sender, GAI receiver, ApplicationMessage message) This method defines the main behaviour of this actor.
RequestResult	subscribeReport(java.lang.String[] report) This method is an overloading of the corresponding method in the super class ApplicationActor.

Methods inherited from class PaP.ApplicationActor

actorBehaviourPlugIn, actorBehaviourPlugOut, actorCapabilities, actorChangeBehaviour, actorEntry, actorPlay, actorPlugIn, actorPlugOut, anyOtherRequestType, callActorChangeBehaviour, control, init, loginUser, logoutUser, playChangesPlugIn, playPlugIn, playPlugOut, requestToActor, roleFigurePlugIn, roleFigurePlugOut, roleSessionAction, sessionResume, sessionSuspend, sessionUpdate, subscribeCancel, subscribeRequest

Methods inherited from class PaP.Actor

findRoleSession, getGAI, start, status, term

Methods inherited from class java.lang.Object

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

Field Detail

STATE_INITIAL

private final int STATE_INITIAL

STATE_SERVER_ACTIVE

private final int STATE_SERVER_ACTIVE

State where it subscribes and shows the received reports

STATE_SERVER_PASSIVE

private final int STATE_SERVER_PASSIVE

State where subscriptions are canceled and the Window are disposed

state

private int state

Indicates which state the application is in

initiated

private boolean initiated

Indicates wether initial ActorPlugIn has been performed or not

initialRoleSession

private RoleSession initialRoleSession

The initial RoleSession created when this Actor is created. Used when the Actor is terminated.

subscribeId

private java.lang.String subscribeId

The unique subscription id returned when SubscribeRequest is done

window

private WatcherWindow window

A reference to an instance of WatcherWindow

Constructor Detail

Watcher

public Watcher()

Creates a new instance of Watcher and sets the initial state to STATE_INITIAL.

Method Detail

applicationActorEntry

public RequestResult applicationActorEntry(RequestPars rpars)
                                    throws java.lang.Exception

This method is the common entry point for all external requests to this actor.

Overrides:

applicationActorEntry in class ApplicationActor

Parameters:

rpars - Instance of RequestPars which specifies type of request and additional parametres.

Returns:

An instance of RequestResult which indicates success or failure in treatment of the request.

Throws:

java.lang.Exception -

changeSubscription

public void changeSubscription(int interval)
                        throws java.lang.Exception

Switches between the defined subscription types; Immediate, 15 seconds intervals and 30 seconds intervals. It first tries to cancel the current subscription before it sends a new Subscription request of the correct type. If something goes wrong it throws an Exception to notify WatcherWindow.

Parameters:

interval - Indicates the subscription type. If interval = 0 it means immediate subscription.

Throws:

java.lang.Exception -

closeApplication

public void closeApplication()

This method is used by WatcherWindow to tell Watcher that the user wants to close the application. It tries to cancel its subscriptions and to plug out the actor before it returns.

getWatcherGAI

public java.lang.String getWatcherGAI()

Returns the GAI of this ApplicationActor.

Returns:

The GAI represented as a string.

stateTransition

private RequestResult stateTransition(GAI sender,
                                      GAI receiver,
                                      ApplicationMessage message)
                               throws java.lang.Exception

This method defines the main behaviour of this actor. It defines the way it responds to different messages sent from the actor's Director depending on which state the actor is in. The methods subscribeReport() and closeWatcherWindow() is also part of the actor's behaviour but they are executed asynchronous to the main behaviour defined in this method.

Parameters:

sender - The GAI to the source of the received request.

receiver - This actor's GAI.

message - The specification of the request.

Returns:

An instance of RequestResult which indicates success or failure in treatment of the ApplicationMessage.

Throws:

java.lang.Exception -

subscribeReport

public RequestResult subscribeReport(java.lang.String[] report)
                              throws java.lang.Exception

This method is an overloading of the corresponding method in the super class ApplicationActor. It is called every time a new report is received from the DirectorActor for an event that Watcher is subscribing for. The subscriber receives a list of reported events where each event consist of four parametres:
a) Event type - as defined in the class SubscribeRequest.
b) Textual representation of the GAI address for the actor the report event concerns.
c) Event type dependent information
d) The point of time (in milliseconds since 1 Jan. 1970) where the event was reported to the DirectorActor.

Overrides:

subscribeReport in class ApplicationActor

Parameters:

report - A list of newly reported events.

Returns:

An instance of RequestResult which indicates success or failure in treatment of the results.

Throws:

java.lang.Exception -

dbg

private void dbg(java.lang.String dbg)

Sends debug information to this actor's BaseFrame window, which is an interactive debug client window for several entities.

Overrides:

dbg in class ApplicationActor

Parameters:

dbg - The debug information to be sent.