Class ibm.aglets.patterns.Notifier
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Class ibm.aglets.patterns.Notifier

java.lang.Object
   |
   +----aglet.Aglet
           |
           +----aglet.a4compatibility.OldAglet
                   |
                   +----ibm.aglets.patterns.Notifier

public class Notifier
extends OldAglet
Create a notifier by calling the static method create. The notifier will get dispatched automatically. The notifier performs successive checks (at its destination) within a specified time duration. Upon every successfull check (one the encounters a change in a local state), it notifies its master. The notifier can be defined (see
 create 
) to complete its job after the first successive check (although its time duration has not been reached yet). If a notifier cannot be dispatched or it encounters an error during a check, it notifies its master and disposed itself.

Variable Index

 o ARGUMENT
The protected variable that carries any arguments for the checks that this notifier performs.
 o EXCEPTION
 o EXPIRY
 o MESSAGE
The protected variable that carries any messages that should go along with the notification back to the subscriber.
 o NOTIFICATION

Constructor Index

 o Notifier()

Method Index

 o create(URL, String, AgletContext, Aglet, Itinerary, double, double, boolean, Object)
Creates a notifier.
 o doCheck()
This method should be overridden to specify the check method for this notifier.
 o getOrigin()
Gets the URL of the Origin of the aglet.
 o getReceiver()
Gets the URL of this notifier's receiver.
 o initializeCheck()
This method should be overridden to specify any intialization before the checks performed by this notifier.
 o onCreation(Object)
Initializes the notifier.
 o run()
Universal entry point for the notifier's execution thread.

Variables

 o NOTIFICATION
  public final static int NOTIFICATION
 o EXPIRY
  public final static int EXPIRY
 o EXCEPTION
  public final static int EXCEPTION
 o MESSAGE
  protected Object MESSAGE
The protected variable that carries any messages that should go along with the notification back to the subscriber.
 o ARGUMENT
  protected Object ARGUMENT
The protected variable that carries any arguments for the checks that this notifier performs.

Constructors

 o Notifier
  public Notifier()

Methods

 o initializeCheck
  protected abstract void initializeCheck() throws Exception
This method should be overridden to specify any intialization before the checks performed by this notifier.
Throws: AgletException
if fails to complete.
 o doCheck
  protected abstract boolean doCheck() throws Exception
This method should be overridden to specify the check method for this notifier.
Returns:
boolean result of the check.
Throws: AgletException
if fails to complete.
 o getReceiver
  protected AgletIdentifier getReceiver()
Gets the URL of this notifier's receiver.
 o getOrigin
  protected URL getOrigin()
Gets the URL of the Origin of the aglet.
 o create
  public static AgletProxy create(URL url,
                                  String source,
                                  AgletContext context,
                                  Aglet master,
                                  Itinerary destination,
                                  double interval,
                                  double duration,
                                  boolean stay,
                                  Object argument) throws IOException, AgletException
Creates a notifier.
Parameters:
url - the URL of the aglet class.
source - the name of the aglet class.
context - the aglet context in which the notifier should be created.
master - the master aglet.
destination - the URL of the destination.
interval - the time in hours between to checks.
duration - the life time of the notifier.
stay - whether the notifier should remain after a notification.
argument - the
 argument 
object.
Returns:
an aglet proxy for the notifier.
Throws: AgletException
if the creation fails.
 o onCreation
  public synchronized void onCreation(Object object)
Initializes the notifier. Only called the very first time this notifier is created. The initialization argument includes the needed parameters for the checks as defined in
 create 
.
Parameters:
obj - the initialization argument.
Throws: AgletException
if the initialization fails.
Overrides:
onCreation in class OldAglet
 o run
  public void run()
Universal entry point for the notifier's execution thread.
Overrides:
run in class Aglet

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