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  * holder.
 package javax.faces.context;

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 javax.faces.event.ExceptionQueuedEvent that wraps the Exception.

    This approach requires manually publishing the javax.faces.event.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().

public abstract class ExceptionHandler implements SystemEventListener {


Take action to handle the Exception instances residing inside the javax.faces.event.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.

javax.faces.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 void handle() throws FacesException;


Return the first ExceptionQueuedEvent handled by this handler.

    public abstract ExceptionQueuedEvent getHandledExceptionQueuedEvent();


Return an Iterable over all ExceptionQueuedEvents that have not yet been handled by the handle() method.

The default implementation must return an Iterable over all ExceptionQueuedEvents that have been handled by the handle() method.

    public abstract void processEvent(SystemEvent exceptionQueuedEventthrows AbortProcessingException;

    public abstract boolean isListenerForSource(Object source);


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.

java.lang.NullPointerException if argument t is null.
    public abstract Throwable getRootCause(Throwable t);
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