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The private implementation classes of the Apache MyFaces Core JSF-2.3 Implementation
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.shared.context;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.el.ELException;
import javax.faces.FacesException;
import javax.faces.context.ExceptionHandler;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.context.PartialResponseWriter;
import javax.faces.context.PartialViewContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ExceptionQueuedEvent;
import javax.faces.event.ExceptionQueuedEventContext;
import javax.faces.event.SystemEvent;
/**
*
* Specialized Ajax Handler, according to JSF 2.0 rev A section 13.3.7.
*/
public class AjaxExceptionHandlerImpl extends ExceptionHandler
{
//The spec says this related to exception handling in ajax requests:
//
//"... JavaServer Faces Ajax frameworks must ensure exception information
// is written to the response in the format:
//
//
//
// ...
// ...
//
//
//
//Implementations must ensure that an ExceptionHandler suitable for writing
//exceptions to the partial response is installed if the current request
//required an Ajax response (PartialViewContext.isAjaxRequest() returns true)
//
//Implementations may choose to include a specialized ExceptionHandler for
//Ajax that extends from javax.faces.context.ExceptionHandlerWrapper, and
//have the javax.faces.context.ExceptionHandlerFactory implementation
//install it if the environment requires it. ..."
private static final Logger log = Logger.getLogger(AjaxExceptionHandlerImpl.class.getName());
private Queue handled;
private Queue unhandled;
private ExceptionQueuedEvent handledAndThrown;
public AjaxExceptionHandlerImpl()
{
}
/**
* {@inheritDoc}
*/
@Override
public ExceptionQueuedEvent getHandledExceptionQueuedEvent()
{
return handledAndThrown;
}
/**
* {@inheritDoc}
*/
@Override
public Iterable getHandledExceptionQueuedEvents()
{
return handled == null ? Collections.emptyList() : handled;
}
/**
* {@inheritDoc}
*/
@Override
public Throwable getRootCause(Throwable t)
{
if (t == null)
{
throw new NullPointerException("t");
}
while (t != null)
{
Class clazz = t.getClass();
if (!clazz.equals(FacesException.class) && !clazz.equals(ELException.class))
{
return t;
}
t = t.getCause();
}
return null;
}
/**
* {@inheritDoc}
*/
@Override
public Iterable getUnhandledExceptionQueuedEvents()
{
return unhandled == null ? Collections.emptyList() : unhandled;
}
/**
* {@inheritDoc}
*/
@Override
public void handle() throws FacesException
{
if (unhandled != null && !unhandled.isEmpty())
{
if (handled == null)
{
handled = new LinkedList();
}
List throwableList = new ArrayList();
FacesContext facesContext = null;
do
{
// For each ExceptionEvent in the list
// get the event to handle
ExceptionQueuedEvent event = unhandled.peek();
try
{
// call its getContext() method
ExceptionQueuedEventContext context = event.getContext();
if (facesContext == null)
{
facesContext = event.getContext().getContext();
}
// and call getException() on the returned result
Throwable exception = context.getException();
// Upon encountering the first such Exception that is not an instance of
// javax.faces.event.AbortProcessingException
if (!shouldSkip(exception))
{
// set handledAndThrown so that getHandledExceptionQueuedEvent() returns this event
handledAndThrown = event;
Throwable rootCause = getRootCause(exception);
throwableList.add(rootCause == null ? exception : rootCause);
//break;
}
else
{
// Testing mojarra it logs a message and the exception
// however, this behaviour is not mentioned in the spec
log.log(Level.SEVERE, exception.getClass().getName() + " occured while processing " +
(context.inBeforePhase() ? "beforePhase() of " :
(context.inAfterPhase() ? "afterPhase() of " : "")) +
"phase " + context.getPhaseId() + ": " +
"UIComponent-ClientId=" +
(context.getComponent() != null ?
context.getComponent().getClientId(context.getContext()) : "") + ", " +
"Message=" + exception.getMessage());
log.log(Level.SEVERE, exception.getMessage(), exception);
}
}
finally
{
// if we will throw the Exception or if we just logged it,
// we handled it in either way --> add to handled
handled.add(event);
unhandled.remove(event);
}
} while (!unhandled.isEmpty());
if (!throwableList.isEmpty())
{
PartialResponseWriter partialWriter = null;
boolean responseComplete = false;
//Retrieve the partial writer used to render the exception
if (facesContext == null)
{
facesContext = FacesContext.getCurrentInstance();
}
facesContext = (facesContext == null) ? FacesContext.getCurrentInstance() : facesContext;
ExternalContext externalContext = facesContext.getExternalContext();
//Clean up the response if by some reason something has been written before.
if (!facesContext.getExternalContext().isResponseCommitted())
{
facesContext.getExternalContext().responseReset();
}
PartialViewContext partialViewContext = facesContext.getPartialViewContext();
partialWriter = partialViewContext.getPartialResponseWriter();
// ajax request --> xml error page
externalContext.setResponseContentType("text/xml");
externalContext.setResponseCharacterEncoding("UTF-8");
externalContext.addResponseHeader("Cache-control", "no-cache");
try
{
partialWriter.startDocument();
for (Throwable t : throwableList)
{
renderAjaxError(partialWriter, t);
}
responseComplete = true;
}
catch (IOException e)
{
if (log.isLoggable(Level.SEVERE))
{
log.log(Level.SEVERE, "Cannot render exception on ajax request", e);
}
}
finally
{
if (responseComplete)
{
try
{
partialWriter.endDocument();
facesContext.responseComplete();
}
catch (IOException e1)
{
if (log.isLoggable(Level.SEVERE))
{
log.log(Level.SEVERE, "Cannot render exception on ajax request", e1);
}
}
}
}
}
}
}
private void renderAjaxError(PartialResponseWriter partialWriter, Throwable ex) throws IOException
{
partialWriter.startError(ex.getClass().getName());
if (ex.getCause() != null)
{
partialWriter.write(ex.getCause().toString());
}
else if (ex.getMessage() != null)
{
partialWriter.write(ex.getMessage());
}
partialWriter.endError();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isListenerForSource(Object source)
{
return source instanceof ExceptionQueuedEventContext;
}
/**
* {@inheritDoc}
*/
@Override
public void processEvent(SystemEvent exceptionQueuedEvent) throws AbortProcessingException
{
if (unhandled == null)
{
unhandled = new LinkedList();
}
unhandled.add((ExceptionQueuedEvent)exceptionQueuedEvent);
}
protected Throwable getRethrownException(Throwable exception)
{
// Let toRethrow be either the result of calling getRootCause() on the Exception,
// or the Exception itself, whichever is non-null
Throwable toRethrow = getRootCause(exception);
if (toRethrow == null)
{
toRethrow = exception;
}
return toRethrow;
}
protected FacesException wrap(Throwable exception)
{
if (exception instanceof FacesException)
{
return (FacesException) exception;
}
return new FacesException(exception);
}
protected boolean shouldSkip(Throwable exception)
{
return exception instanceof AbortProcessingException;
}
}