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Hi Nico, I find your approach very interesting. I
have not thought about saving the viewState at all. Thinking more about it, saving viewState
would work for request scoped backing beans – but I think it could cause inconsistencies
with session scoped backing beans, for example if the bean is shared with other
pages, or if we loop to the same page twice. So for the scheme to work we would
have to save both the viewState plus the backing beans. Did you do anything to limit the size of
the stack so it won’t cumulate references and prevent garbage collection? What problems did you had with navigation
handler? Since the reply from Onur I did some google search and found the
following blog http://jroller.com/comments/cenkcivici/Weblog/custom_jsf_navigation_handler_for
detailing an approach using navigation handler. That approach only stores the
navigation in the stack so it requires all beans to be session scope. Also ‘back’
will not guarantee to get back the same state. But I think the scheme could be
modified to save the viewState so it will work for request scoped beans. I am just beginning to learn about custom navigation
handler so I would appreciate if you could share your experiences. Thanks again. Best regards, Yee From: Nico Krijnen
[mailto:[EMAIL PROTECTED] Hi, I had some trouble doing
this in a navigation handler so I implemented a similar mechanism some time ago
and have been using it succesfully for some time now. It is not exactly what
you describe, but might be just what you need. It basicly works as following: HistoryManager (request
scope managed bean)
.addCurrentViewState()
Pushes viewstate on internal stack
.returnToLast()
Pops and restores last viewstate from stack Each button-action that
needs to save the current state has the following ActionListener: AddViewStateListener
.processAction()
Calls historyManager.addCurrentViewState() The pages following the
button-action store the historyManager using <t:saveState/> tags. To
return to the previous state the a button-action can call
“historyManager.returnToLast”. We also have a
HistoryMarkers bean (session scope) that allows you to mark a specific state
and return to it later by calling a specific url. We use this to return to our
application after redirecting to an external website url. If there is any interest
for this mechanism we could put these classes in the myfaces sandbox. Kind regards, Van: Yee CN
[mailto:[EMAIL PROTECTED] Hi, I am thinking of providing a ‘back’ button on
all my pages. Below is a sketch on how I intended to do it, but before
embarking on it I would like to know whether anybody has done similar and to
hear from you Gurus whether my approach is workable. 1) I have a stack<backingBean, nagivgationResult> to
store the pages being visited and the associated backing bean. The stack will be limited to store (say)
the last 10 pages visited, so it won’t grow continuously. I think a
circular list could probably be used for this. 2) A phase listener will push the current page’s
backing bean and navigation to the stack; it will happen at the AFTER RENDER_RESPONSE phase. 3) The ‘back’ button will pop the stack –
restores the backing bean and navigates back to the page concerned. 4) Some pages can be marked to not to participate in this
scheme. I am assuming a) the beans are in request scope, b) there is
only one backing bean per page. For session scope beans I would have to serialize the bean. Please – any comments? Best regards, Yee // getting an restoring a manage bean public static Object getManagedBean(String beanName) {
Object o = getValueBinding( “#{“ + beanName + “}”
).getValue(FacesContext.getCurrentInstance());
return o; }
public static void setManageBean(String beanName, Object
bean) {
getValueBinding( “#{“ + beanName + “}”
).setValue(FacesContext.getCurrentInstance(), bean); } // some helper methods private static Application getApplication() {
ApplicationFactory appFactory = (ApplicationFactory)FactoryFinder.getFactory(FactoryFinder.APPLICATION_FACTORY);
return appFactory.getApplication(); }
private static ValueBinding getValueBinding(String el) {
return getApplication().createValueBinding(el); }
private static Object getElValue(String el) {
return getValueBinding(el).getValue(FacesContext.getCurrentInstance()); }
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- RE: How to implement 'back' button Yee CN
- RE: How to implement 'back' button Nico Krijnen
- RE: How to implement 'back' button Yee CN
