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Class com.ibm.agletx.patterns.Notifier 

java.lang.Object
   |
   +----com.ibm.aglet.Aglet
           |
           +----com.ibm.agletx.patterns.Notifier
public abstract class Notifier
extends Aglet
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, URL, double, double, boolean, Object)
Creates a notifier.
o doCheck()
This method should be overridden to specify the check method for this notifier.
o handleMessage(Message)
Handles the message form outside.
o initializeCheck()
This method should be overridden to specify any intialization before the checks performed by this notifier.
o onCreation(Object)
Initializes the notifier.

Variables

o NOTIFICATION 
 public static final int NOTIFICATION
o EXPIRY 
 public static final int EXPIRY
o EXCEPTION 
 public static final 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 create 
 public static AgletProxy create(URL url,
                                 String source,
                                 AgletContext context,
                                 Aglet master,
                                 URL 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. Called only the 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 Aglet
o handleMessage 
 public boolean handleMessage(Message msg)
Handles the message form outside.

Overrides:
handleMessage in class Aglet 
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