I'm using JSF 2.2 (Mojarra) and Faclets in a web application. I use a custom ExceptionHandler to handle exceptions. I leverage the JSF implicit navigation system and cause the server to navigate to the 'error.xhtml' page.
public class FrontEndExceptionHandler extends ExceptionHandlerWrapper {
private ExceptionHandler wrapped;
FrontEndExceptionHandler(ExceptionHandler exception) {
this.wrapped = exception;
}
#Override
public ExceptionHandler getWrapped() {
return wrapped;
}
#Override
public void handle() throws FacesException {
final Iterator<ExceptionQueuedEvent> iter = getUnhandledExceptionQueuedEvents().iterator();
while (iter.hasNext()) {
ExceptionQueuedEvent event = iter.next();
ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
// get the exception from context
Throwable t = context.getException();
final FacesContext fc = FacesContext.getCurrentInstance();
final Flash flash = fc.getExternalContext().getFlash();
final NavigationHandler nav = fc.getApplication().getNavigationHandler();
try {
// redirect error page
flash.put("erorrDetails", t.getMessage());
nav.handleNavigation(fc, null, "/errors/error.xhtml");
fc.renderResponse();
} finally {
// remove it from queue
iter.remove();
}
}
// parent handle
getWrapped().handle();
}
}
This assumes that the exception to be handling is not happening during the Render Response phase. But the exception occurs within an Facelets page also during the Render Response phase.Therefore following code doesn't work correct:
nav.handleNavigation(fc, null, "/errors/error.xhtml");
Does anybody has a Idea how to convey the desired information? Is there a way to navigate to the error.xhtml without using NavigationHandler?
Related
We have implemented a custom ExceptionHandler that attempts to intercept any NonexistentConversationException that are thrown if a user requests a URL with an old cid in it (eg. bookmarked link etc.).
The handler simply removed the cid from the URL and performs a redirect to the updated URL.
This solution seems to work in most cases, we have a number of different user 'roles' within the App each with their own login areas and for one of these user types it seems that fc.getExternalContext().isResponseCommitted() is always true when the ExceptionHandler fires which means we are unable to perform the redirect. All other user types it works ok.
I am not sure exactly what the difference is with this user type for this to happen, I am guessing some CDI bean we using setup differently
Is there a way to unsure the ExceptionHandler kicks in earlier before the response is committed?
Below is the handler...
public class ConversationExpiredExceptionHandler
extends ExceptionHandlerWrapper {
final static Logger log = LoggerFactory.getLogger(ConversationExpiredExceptionHandler.class);
private ExceptionHandler wrapped;
private static String CONVERSATION_PARAM = "cid";
public ConversationExpiredExceptionHandler(ExceptionHandler wrapped) {
this.wrapped = wrapped;
}
#Override
public ExceptionHandler getWrapped() {
return this.wrapped;
}
#Override
public void handle() throws FacesException {
for (Iterator<ExceptionQueuedEvent> i =
getUnhandledExceptionQueuedEvents().iterator();
i.hasNext();) {
ExceptionQueuedEvent event = i.next();
ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
Throwable t = context.getException();
if (t instanceof javax.enterprise.context.NonexistentConversationException
|| t instanceof org.jboss.weld.contexts.NonexistentConversationException
|| t.getCause() instanceof org.jboss.weld.contexts.NonexistentConversationException /* can be wrapped in FacesException */) {
final FacesContext fc = FacesContext.getCurrentInstance();
try {
if (!fc.getExternalContext().isResponseCommitted()) {
if(Faces.getRequestQueryStringMap().containsKey(CONVERSATION_PARAM)) {
String requestedUrl = Faces.getRequestURLWithQueryString();
String updatedUrl = this.removeQueryParameter(requestedUrl,CONVERSATION_PARAM);
log.debug("No conversation active for {}, redirecting to {}",requestedUrl,updatedUrl);
fc.getExternalContext().redirect(updatedUrl);
}
}
fc.renderResponse();
break;
} catch (Exception ex) {
throw new FacesException(ex);
} finally {
i.remove();
}
}
}
getWrapped().handle();
}
private String removeQueryParameter(String url, String parameterName) throws URISyntaxException {
URIBuilder uriBuilder = new URIBuilder(url);
List<NameValuePair> queryParameters = uriBuilder.getQueryParams();
for (Iterator<NameValuePair> queryParameterItr = queryParameters.iterator(); queryParameterItr.hasNext();) {
NameValuePair queryParameter = queryParameterItr.next();
if (queryParameter.getName().equals(parameterName)) {
queryParameterItr.remove();
}
}
uriBuilder.setParameters(queryParameters);
return uriBuilder.build().toString();
}
I have two Classes that extend from ExceptionHandlerWrapper & ExceptionHandlerFactory
for catching any exceptions that occur in the view layer
and navigate to error page and show this error.
So I need store or save this exceptions somewhere
but I can`t get this exception message.
I tried to get this message in session but I need another way to save this message with out ViewScope and PageFlowScope and RequestScope since the latter ones return 'null'
import javax.faces.context.ExceptionHandler;
import javax.faces.context.ExceptionHandlerFactory;
public class CustomExceptionHandlerFactory extends ExceptionHandlerFactory {
private ExceptionHandlerFactory parent;
public CustomExceptionHandlerFactory(ExceptionHandlerFactory parent) {
this.parent = parent;
}
#Override
public ExceptionHandler getExceptionHandler() {
ExceptionHandler result = new CustomExceptionHandler(parent.getExceptionHandler());
return result;
}
}
public class CustomExceptionHandler extends ExceptionHandlerWrapper {
private ExceptionHandler wrapped;
public CustomExceptionHandler(ExceptionHandler wrapped) {
this.wrapped = wrapped;
}
#Override
public ExceptionHandler getWrapped() {
return wrapped;
}
#Override
public void handle() throws FacesException {
Iterator iterator = getUnhandledExceptionQueuedEvents().iterator();
while (iterator.hasNext()) {
ExceptionQueuedEvent event = (ExceptionQueuedEvent) iterator.next();
ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
Throwable throwable = context.getException();
FacesContext fc = FacesContext.getCurrentInstance();
// Map<String, Object> sessionMap = fc.getExternalContext().getSessionMap();
NavigationHandler navigator = fc.getApplication().getNavigationHandler();
AdfFacesContext adfc = AdfFacesContext.getCurrentInstance();
Map<String,Object> valueViewScope = adfc.getViewScope();
try {
// Flash flash = fc.getExternalContext().getFlash();
// Put the exception in the flash scope to be displayed in the error
// page if necessary ...
// flash.put("errorDetails", throwable.getMessage());
ADFContext.getCurrent().getSessionScope().put("errorDetails", throwable.getMessage());
valueViewScope.put("errorDetails", throwable.getMessage());
System.out.println("the error is put in the Session: " + throwable.getMessage());
//NavigationHandler navigationHandler = fc.getApplication().getNavigationHandler();
navigator.handleNavigation(fc, null, "ErrorPage?faces-redirect=true");
// navigationHandler.handleNavigation(fc, null, "ErrorPage?faces-redirect=true");
fc.renderResponse();
} finally {
iterator.remove();
}
}
// Let the parent handle the rest
getWrapped().handle();
}
I have an own ExceptionHandler added to my jsf 2.2 project.
web.xml
<factory>
<exception-handler-factory>package.exceptionhandler.MyExceptionHandlerFactory</exception-handler-factory>
</factory>
The exceptionHandlerFactory contains
public ExceptionHandler getExceptionHandler() {
ExceptionHandler handler = new MyExceptionHandler(parent.getExceptionHandler());
return handler;
}
and the ExceptionHandler contains
#Override
public void handle() throws FacesException {
LOGGER.debug("handle exception...");
}
My dummy Converter throw everytime an exception:
#FacesConverter(value = "MyConverter")
public class MyConverter implements Converter {
#Override
public Object getAsObject(final FacesContext context, final UIComponent comp, final String value) {
throw new RuntimeException("error");
}
//...
But the exception is not handled by my own excpetion handler. Why?
I found my problem.
That was not an issue from jsf. I had a PhaseListener in the application, which makes only some of the error messages visible on the page. But this PhaseListener was in the INVOKE_APPLICATION Phase and therefore never executed.
in my preRender code for a page i add faces message then make navigation to another page as follows:
if(error){
addMessageToComponent(null,"AN ERROR HAS OCCURRED");
FacesContext.getCurrentInstance().getExternalContext().getFlash()
.setKeepMessages(true);
navigateActionListener("myoutcome");
}
and the util methods for adding message and navigation are:
public static String getClientId(String componentId)
{
FacesContext context = FacesContext.getCurrentInstance();
UIViewRoot root = context.getViewRoot();
UIComponent c = findComponent(root, componentId);
return c.getClientId(context);
}
public static UIComponent findComponent(UIComponent c, String id)
{
if (id.equals(c.getId())) { return c; }
Iterator<UIComponent> kids = c.getFacetsAndChildren();
while (kids.hasNext())
{
UIComponent found = findComponent(kids.next(), id);
if (found != null) { return found; }
}
return null;
}
/**
* #param componentId
* : the id for the jsf/primefaces component without formId:
* prefix. <br>
* if you use null then the message will be added to the
* h:messages component.
**/
public static void addMessageToComponent(String componentId, String message)
{
if (componentId != null)
componentId = GeneralUtils.getClientId(componentId);
FacesContext.getCurrentInstance().addMessage(componentId,
new FacesMessage(message));
}
public static void navigateActionListener(String outcome)
{
FacesContext context = FacesContext.getCurrentInstance();
NavigationHandler navigator = context.getApplication()
.getNavigationHandler();
navigator.handleNavigation(context, null, outcome);
}
but messages are not saved and so it doesn't appear after redirect.
please advise how to fix that.
The preRenderView event runs in the very beginning of the RENDER_RESPONSE phase. It's too late to instruct the Flash scope to keep the messages. You can do this at the latest during the INVOKE_APPLICATION phase.
Since there's no standard JSF component system event for this, you'd need to homebrew one:
#NamedEvent(shortName="postInvokeAction")
public class PostInvokeActionEvent extends ComponentSystemEvent {
public PostInvokeActionEvent(UIComponent component) {
super(component);
}
}
To publish this, you need a PhaseListener:
public class PostInvokeActionListener implements PhaseListener {
#Override
public PhaseId getPhaseId() {
return PhaseId.INVOKE_APPLICATION;
}
#Override
public void beforePhase(PhaseEvent event) {
// NOOP.
}
#Override
public void afterPhase(PhaseEvent event) {
FacesContext context = FacesContext.getCurrentInstance();
context.getApplication().publishEvent(context, PostInvokeActionEvent.class, context.getViewRoot());
}
}
After registering it as follows in faces-config.xml:
<lifecycle>
<phase-listener>com.example.PostInvokeActionListener</phase-listener>
</lifecycle>
You'll be able to use the new event as follows:
<f:event type="postInvokeAction" listener="#{bean.init}" />
You only need to make sure that you've at least a <f:viewParam>, otherwise JSF won't enter the invoked phase at all.
The JSF utility library OmniFaces already supports this event and the preInvokeAction event out the box. See also the showcase page which also demonstrates setting a facesmessage for redirect.
I wrote myself a custom NavigationHandler very similar to following one but just using a stack to save the history:
http://jsfatwork.irian.at/book_de/custom_component.html#!idx:/custom_component.html:fig:backnavigationhandler-code
public class HistoryNavigationHandler extends NavigationHandler
{
private final NavigationHandler navigationHandler;
private final Stack<String> outcomes;
public HistoryNavigationHandler(final NavigationHandler navigationHandler)
{
this.navigationHandler = navigationHandler;
this.outcomes = new Stack<String>();
}
#Override
public void handleNavigation(final FacesContext context, final String fromAction, final String outcome)
{
if (outcome != null)
{
if (outcome.equals("back"))
{
final String lastViewId = this.outcomes.pop();
final ViewHandler viewHandler = context.getApplication().getViewHandler();
final UIViewRoot viewRoot = viewHandler.createView(context, lastViewId);
context.setViewRoot(viewRoot);
context.renderResponse();
return;
}
else
{
this.outcomes.push(context.getViewRoot().getViewId());
}
}
this.navigationHandler.handleNavigation(context, fromAction, outcome);
}
}
Registering this one in the faces-config.xml:
<navigation-handler>
package.HistoryNavigationHandler
</navigation-handler>
Results in following log warning and a message where a previously working link was present:
Warning: jsf.outcome.target.invalid.navigationhandler.type
Something like: this link is disabled because a navigation case could not be matched
What is the problem?
Since JSF 2, the NavigationHandler has been replaced by ConfigurableNavigationHandler. All JSF 2 specific tags/components like <h:link> and so on are relying on it. The NavigationHandler is kept for backwards compatibility.
Here's a kickoff example how to properly extend ConfigurableNavigationHandler:
public class HistoryNavigationHandler extends ConfigurableNavigationHandler {
private NavigationHandler wrapped;
public HistoryNavigationHandler(NavigationHandler wrapped) {
this.wrapped = wrapped;
}
#Override
public void handleNavigation(FacesContext context, String from, String outcome) {
// TODO: Do your job here.
wrapped.handleNavigation(context, from, outcome);
}
#Override
public NavigationCase getNavigationCase(FacesContext context, String fromAction, String outcome) {
return (wrapped instanceof ConfigurableNavigationHandler)
? ((ConfigurableNavigationHandler) wrapped).getNavigationCase(context, fromAction, outcome)
: null;
}
#Override
public Map<String, Set<NavigationCase>> getNavigationCases() {
return (wrapped instanceof ConfigurableNavigationHandler)
? ((ConfigurableNavigationHandler) wrapped).getNavigationCases()
: null;
}
}