ptolemy.actor.lib

Interface ExceptionSubscriber

All Known Implementing Classes:

ExceptionAnalyzer, ExceptionEmailer, HttpActor, HttpRequestHandler

public interface ExceptionSubscriber

An ExceptionSubscriber is an entity that is informed of exceptions and the handling policy for exceptions caught by CatchExceptionAttribute. The ExceptionSubscriber can then take some action, if desired. For example, actors that communicate with outside clients may want to pass along information about the error that has occurred, instead of returning a generic message or a timeout error response. This follows the Command design pattern, where the invoker is CatchExceptionAttribute, the client is the Ptolemy developer (defines commands by dragging and dropping attributes into the model), and the receiver is a Ptolemy entity (such as an attribute that writes to a file, or an actor such as HttpActor which sends a retry message upon exception with restart policy.

Since:

Ptolemy II 10.0

Version:

$Id: ExceptionSubscriber.java 69467 2014-06-29 14:35:19Z beth@berkeley.edu$

Author:

Elizabeth Latronico

See Also:

CatchExceptionAttribute

Pt.AcceptedRating:

Red (beth)

Pt.ProposedRating:

Red (beth)

Method Summary

Modifier and Type	Method and Description
boolean	exceptionHandled(boolean successful, java.lang.String message) Invoked by an exception handler (e.g.
boolean	exceptionOccurred(java.lang.String policy, java.lang.Throwable exception) Action to execute upon the occurrence of an exception.

Method Detail

exceptionOccurred

boolean exceptionOccurred(java.lang.String policy,
                          java.lang.Throwable exception)

Action to execute upon the occurrence of an exception. Some ExceptionReactions may need to set up and close access to resources (such as opening and closing a file). These could extend AbstractInitalizableAttribute to do so.

Parameters:

policy - The handling policy of the exception manager (for example, restart); see CatchExceptionAttribute

exception - The exception

Returns:

True if the subscriber successfully processed the information; false otherwise (for example, an ExceptionEmailer that fails to send an email)

exceptionHandled

boolean exceptionHandled(boolean successful,
                         java.lang.String message)

Invoked by an exception handler (e.g. ExceptionManager) after an exception has been handled.

Parameters:

successful - True if the exception was successfully handled; false otherwise

message - A status message from the exception handler

Returns:

True if the subscriber successfully processed the information; false otherwise (for example, an ExceptionEmailer that fails to send an email)