public abstract class ExceptionHandler extends Object implements SystemEventListener
ExceptionHandler is the
central point for handling unexpected
Exceptions that are thrown during the Faces
lifecycle. The ExceptionHandler must not be notified of
any Exceptions that occur during application startup or
shutdown.
See the specification prose document for the requirements for the
default implementation. Exceptions may be passed to the
ExceptionHandler in one of two ways:
by ensuring that Exceptions are not caught, or
are caught and re-thrown.
This approach allows the ExceptionHandler
facility specified in section JSF.6.2 to operate on the
Exception.
By using the system event facility to publish an ExceptionQueuedEvent that wraps the Exception.
This approach requires manually publishing the ExceptionQueuedEvent, but allows more information about the
Exceptionto be stored in the event. The
following code is an example of how to do this.
//...
} catch (Exception e) {
FacesContext ctx = FacesContext.getCurrentInstance();
ExceptionQueuedEventContext eventContext = new ExceptionQueuedEventContext(ctx, e);
eventContext.getAttributes().put("key", "value");
ctx.getApplication().publishEvent(ExceptionQueuedEvent.class, eventContext);
}
Because the Exception must not be re-thrown
when using this approach, lifecycle processing may continue
as normal, allowing more Exceptions to be
published if necessary.
With either approach, any ExceptionQueuedEvent instances
that are published in this way are accessible to the handle()
method, which is called at the end of each lifecycle phase, as
specified in section JSF.6.2.
Instances of this class are request scoped and are created by
virtue of FacesContextFactory.getFacesContext(java.lang.Object, java.lang.Object, java.lang.Object, javax.faces.lifecycle.Lifecycle) calling ExceptionHandlerFactory.getExceptionHandler().
| Constructor and Description |
|---|
ExceptionHandler () |
| Modifier and Type | Method and Description |
|---|---|
abstract ExceptionQueuedEvent |
getHandledExceptionQueuedEvent ()
Return the first
|
abstract Iterable<ExceptionQueuedEvent> |
getHandledExceptionQueuedEvents ()
The default implementation must
return an |
abstract Throwable |
getRootCause (Throwable t)
Unwrap the argument |
abstract Iterable<ExceptionQueuedEvent> |
getUnhandledExceptionQueuedEvents ()
Return an |
abstract void |
handle ()
Take action to handle the
|
abstract boolean |
isListenerForSource (Object source)
This method must return
true if and only if this
listener instance is interested in receiving events from the
instance referenced by the source parameter. |
abstract void |
processEvent (SystemEvent exceptionQueuedEvent)
When called, the listener can assume that any guarantees given
in the javadoc for the specific
SystemEvent
subclass are true. |
public ExceptionHandler()
public abstract void handle() throws FacesException
Take action to handle the
Exception instances residing inside the ExceptionQueuedEvent instances that have been queued by calls to
Application().publishEvent(ExceptionQueuedEvent.class,
eventContext). The requirements of the default
implementation are detailed in section JSF.6.2.1.
FacesException - if and only if a problem occurs while
performing the algorithm to handle the Exception, not
as a means of conveying a handled Exception itself.public abstract ExceptionQueuedEvent getHandledExceptionQueuedEvent()
Return the first
ExceptionQueuedEvent handled by this handler.
public abstract Iterable<ExceptionQueuedEvent> getUnhandledExceptionQueuedEvents()
Return an Iterable over
all ExceptionQueuedEvents that have not yet been handled
by the handle() method.
public abstract Iterable<ExceptionQueuedEvent> getHandledExceptionQueuedEvents()
The default implementation must
return an Iterable over all
ExceptionQueuedEvents that have been handled by the handle() method.
public abstract void processEvent(SystemEvent exceptionQueuedEvent) throws AbortProcessingException
When called, the listener can assume that any guarantees given
in the javadoc for the specific SystemEvent
subclass are true.
processEvent in interface SystemEventListener exceptionQueuedEvent - the SystemEvent instance that
is being processed.AbortProcessingException - if lifecycle processing should
cease for this request.public abstract boolean isListenerForSource(Object source)
This method must return true if and only if this
listener instance is interested in receiving events from the
instance referenced by the source parameter.
isListenerForSource in interface SystemEventListener source - the source that is inquiring about the
appropriateness of sending an event to this listener instance.public abstract Throwable getRootCause(Throwable t)
Unwrap the argument t
until the unwrapping encounters an Object whose
getClass() is not equal to
FacesException.class or
javax.el.ELException.class. If there is no root cause, null is returned.
NullPointerException - if argument t is
null.Copyright © 1996-2015, Oracle and/or its affiliates. All Rights Reserved. Use is subject to license terms.