org.omnifaces.exceptionhandler

Class ExceptionSuppressor

java.lang.Object

javax.faces.context.ExceptionHandler

javax.faces.context.ExceptionHandlerWrapper

org.omnifaces.exceptionhandler.ExceptionSuppressor

All Implemented Interfaces:

EventListener, FacesListener, SystemEventListener, FacesWrapper<ExceptionHandler>

Direct Known Subclasses:

ViewExpiredExceptionHandler

public class ExceptionSuppressor
extends ExceptionHandlerWrapper

The ExceptionSuppressor will suppress all exceptions which are an instance of the types as listed in context parameter "org.omnifaces.EXCEPTION_TYPES_TO_SUPPRESS" and refresh the current page by redirecting to the current URL with query string. The context parameter value must be a commaseparated string of fully qualified names of exception types. Note that this also covers subclasses of specified exception types.

 <context-param>
     <param-name>org.omnifaces.EXCEPTION_TYPES_TO_SUPPRESS</param-name>
     <param-value>java.nio.channels.ClosedByInterruptException,java.nio.channels.IllegalSelectorException</param-value>
 </context-param>
 

This is useful for exceptions which are technically unavoidable such as those which boil down to that the network connection is abruptly closed by the client by e.g. navigating away while the page is loading, or closing the browser window/tab while the page is loading, or having the physical network connection cut down, or the physical machine crashed, etcetera. All which are beyond control of the server and therefore not really interesting to have logged into server logs.

Installation

This handler must be registered by a factory as follows in faces-config.xml in order to get it to run:

 <factory>
     <exception-handler-factory>org.omnifaces.exceptionhandler.ExceptionSuppressorFactory</exception-handler-factory>
 </factory>
 

In case there are multiple exception handlers, best is to register this handler as last one in the chain. For example, when combined with FullAjaxExceptionHandler, this ordering will prevent the FullAjaxExceptionHandler from taking over the handling of the to-be-suppressed exceptions.

 <factory>
     <exception-handler-factory>org.omnifaces.exceptionhandler.FullAjaxExceptionHandlerFactory</exception-handler-factory>
     <exception-handler-factory>org.omnifaces.exceptionhandler.ExceptionSuppressorFactory</exception-handler-factory>
 </factory>
 

Since:

3.9

Author:

Lenny Primak

See Also:

ExceptionSuppressorFactory

Field Summary

Fields

Modifier and Type	Field and Description
static String	PARAM_NAME_EXCEPTION_TYPES_TO_SUPPRESS The context parameter name to specify exception types to suppress by ExceptionSuppressor.

Constructor Summary

Constructors

Modifier	Constructor and Description
	ExceptionSuppressor(ExceptionHandler wrapped) Construct a new exception suppressor around the given wrapped exception handler.
protected	ExceptionSuppressor(ExceptionHandler wrapped, Class<? extends Throwable>... exceptionTypesToSuppress) Construct a new exception suppressor around the given wrapped exception handler and using the given array of exception types to suppress.

Method Summary

Modifier and Type	Method and Description
static Class<? extends Throwable>[]	getExceptionTypesToSuppress(ServletContext context) Get the exception types to suppress.
void	handle() Inspect all ExceptionHandlerWrapper.getUnhandledExceptionQueuedEvents() if any of them is caused by one of the exception types listed in PARAM_NAME_EXCEPTION_TYPES_TO_SUPPRESS.
protected void	handleSuppressedException(FacesContext context, Throwable suppressedException) Subclasses can override this method to have finer grained control over what must happen when the given exception has been suppressed.

Methods inherited from class javax.faces.context.ExceptionHandlerWrapper

getHandledExceptionQueuedEvent, getHandledExceptionQueuedEvents, getRootCause, getUnhandledExceptionQueuedEvents, getWrapped, isListenerForSource, processEvent

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PARAM_NAME_EXCEPTION_TYPES_TO_SUPPRESS

public static final String PARAM_NAME_EXCEPTION_TYPES_TO_SUPPRESS

The context parameter name to specify exception types to suppress by ExceptionSuppressor. The context parameter value must be a commaseparated string of fully qualified names of exception types. Note that this also covers subclasses of specified exception types.

See Also:

Constant Field Values

Constructor Detail

ExceptionSuppressor

public ExceptionSuppressor(ExceptionHandler wrapped)

Construct a new exception suppressor around the given wrapped exception handler.

Parameters:

wrapped - The wrapped exception handler.

ExceptionSuppressor

@SafeVarargs
protected ExceptionSuppressor(ExceptionHandler wrapped,
                                           Class<? extends Throwable>... exceptionTypesToSuppress)

Construct a new exception suppressor around the given wrapped exception handler and using the given array of exception types to suppress.

Parameters:

wrapped - The wrapped exception handler.

exceptionTypesToSuppress - Array of exception types to suppress.

Method Detail

getExceptionTypesToSuppress

public static Class<? extends Throwable>[] getExceptionTypesToSuppress(ServletContext context)

Get the exception types to suppress. This can be specified via context parameter "org.omnifaces.EXCEPTION_TYPES_TO_SUPPRESS".

Parameters:

context - The involved servlet context.

Returns:

Exception types to suppress.

handle

public void handle()

Inspect all ExceptionHandlerWrapper.getUnhandledExceptionQueuedEvents() if any of them is caused by one of the exception types listed in PARAM_NAME_EXCEPTION_TYPES_TO_SUPPRESS. If so, then drain the ExceptionHandlerWrapper.getUnhandledExceptionQueuedEvents(), and refresh the current URL with query string.

Overrides:

handle in class ExceptionHandlerWrapper

handleSuppressedException

protected void handleSuppressedException(FacesContext context,
                                         Throwable suppressedException)

Subclasses can override this method to have finer grained control over what must happen when the given exception has been suppressed.

Parameters:

context - The involved faces context.

suppressedException - The suppressed exception.