Is it possible to have a commandButton that executes a method of a certain backing bean and then also navigates to a different page?
I know that I could return a String in the method that the commandButton calls, but the method is also used on the target-page, meaning it's often called from that same page.
So for calls that come from the same page, the redirect would be unnecessary and I would like to avoid that.
The options that I have in mind right now:
Create a separate method for the "remote" call of the method that does the same logic and also redirects to the page
Use an additional h:button and use JavaScript so that if the commandButton is pressed, the h:button is pressed at the same time (Probably bad practice tho)
Any option I am missing? Is there any way to tell the commandButton itself that it's supposed to navigate somewhere or do I have to implement this in the backing-beans?
Your title and first sentence are 'dangerous' and sort of not on topic since to both, the answer is yes and you sort of describe (= answer) that in your second paragraph already yourself.
The real question further on effectively asks about conditional navigation. But let me state first that your solution of two methods is also not wrong if you just make sure you don't do actual work in the bean (which you should not).
Now conditional navigation is by itself not difficult
returning null (to stay on the same page) without a refresh, "" to stay on the same page with a refesh,
return the new page (with redirect).
All basic JSF which I assume you are already aware of and this just requires something to do one or the other
So then the question remains if you can
detect the page you are on when the method is executed or
pass on a parameter to the action
which in turn can be used to return null or the other new page in an if/else.
Page1:
<h:commandButton action="#{mybean.action(true))" />
Page2:
<h:commandButton action="#{mybean.action(false))" />
Bean:
public String action(boolean navigate) {
doWork();
if (navigate) {
return "page2.xhtml?faces-redirect=true";
} else {
return null;
}
And if you'd want it, you could even pass null or the page name as a parameter to the method call.
Implementing detection of the source page of the action has the advantage that in the UI you do not need any knowledge on how to navigate, you always call the same method without any parameters and each new page you'd use this action on navigates to the right page without the developer needing any knowledge.
So take you pick.
I'm not completely sure if I got you right, but you could do something like this:
<h:commandButton value="Click" action="otherPage.xhtml?faces-redirect=true">
<f:actionListener binding="#{bean.method}" />
</h:commandButton>
Keep in mind that actionListener will be fired first and after that action from commandButton. Hope it helps.
Update:
Due to the fact that there was no further thinking you can use commandButton with or without redirect.
<h:commandButton value="Click" action="{bean.method}"/>
Related
first of all sorry for my english. I have two pages in JSF2, one to list Passengers and another one to create/update passengers. I have also two #ViewScoped beans, one with the list of passengers and one for hold in pageB the selected passenger. I see the ways to pass the passenger through viewParam or #ManagedProperty but i don´t want to write a converter.
What i want to know if there is a way to pass the object from pageA to pageB without passing the id of the passenger and write a converter or without passing the id and then go to the DB to retrieve the passenger.
What i do and works is the following. I set in flash scope through setPropertyActionListener the selected object and navigate to pageB, in the #PostConstruct of the viewScopedBean i get the flashScope and retrieve the object. As i said, this works but i don´t know if it is correct. Here is the code
Page A:
<p:column width="10" style="text-align: center;">
<p:commandButton icon="ui-icon-pencil" action="editClientes?faces-redirect=true">
<f:setPropertyActionListener target="#{flash.pax}" value="#{row}"/>
</p:commandButton>
</p:column>
#PostConstruct of pageB bean
#PostConstruct
private void initBean(){
this.pax = (Passenger) JSFUtils.getFlashScope().get("pax");
if(this.pax == null){
this.pax = new Passenger();
}
}
Is this correct, or the correct way is to write a converter?
Thanks.
Depends on whether you want the /editClientes request to be idempotent ("bookmarkable") or not.
The flash approach is not idempotent. It's not possible to link/share/bookmark the /editClientes URL in order to edit a specific client. When the enduser copies this URL for sharing/bookmarking and re-executes the request on it (even though it's just pressing [enter] in browser's address bar), all the enduser would face is an empty edit form for a new client instead of the one the enduser initially selected via flash scope.
The request parameter approach is idempotent. The enduser is able to get exactly the same response everytime the enduser re-executes the request.
It's not our decision whether your /editClientes page should be idempotent or not. It's yours.
See also:
How to navigate in JSF? How to make URL reflect current page (and not previous one)
I have been using JSF for a few years now, but I still have doubts when it comes to deciding how to pass parameters to a target page/bean.
I do think this question is a bit complex, and that some may tell me to break it down into smaller questions. But, I also think that the answer to all of the questions bellow are related, and that it addresses the lack of intuitiveness when all you want JSF to do is: "Go to that page and pass this as a parameter".
First, how to decide between Forward and Redirect?
After that, how to choose between h:commandLink/h:commandButton, h:link or h:outputLink?
Then, combined with the option I choose above, should I use f:param or f:setPropertyActionListener? Will both properly pass parameters to the target bean, independently of its scope?
Finally, on the target bean/page, when should I use f:viewParam, or recover parameters from the request programmatically?
I'm going to answer your questions based on my own experience. Some of them are so open that more than one answer could fit.
A page forward is the way to go unless you explicitly require the browser url to be changed. A page forward is basically faster than a redirection as it requires less steps. A page redirect is required if you want to make your views bookmarkable.
Use <h:commandLink />/<h:commandButton /> only when you need to POST the server. Later on, you'll be able to perform a page forward or a redirection depending on what the method returns. As an example:
<h:commandLink action="#{bean.processForm}" value="Submit" />
public String processForm(){
try{
save();
return "list";
}
catch(Excepcion e){
addFacesMessage("Error saving");
//Error saving the object, keep in the same view
return null;
}
}
Use <h:link outcome="list" value="Go to list" /> for pure page to page navigation within the JSF application. You can use either page forward and redirect. Use <f:param /> to pass view parameters.
<h:outputLink value="www.stackoverflow.com" /> could be used for external links to other sites (not into your application). Use <f:param /> to pass view parameters. I however prefer to use plain HTML with <a href="www.stackoverflow.com" /> myself for this case.
As for passing parameters to action methods in POST requests, you've got several options. f:setPropertyActionListener was so popular in JSF 1.x, but if you're already at 2.x I would recommend you going with EL 2.2, which allows method parameter declaration. Being able to use it depends on the application server you're using, but even if not available you could import yourself. Then, you'll be able to do things like that:
<h:commandButton action="#{bean.saveCar(currentCar)}" value="Save Car" />
Use it wherever you can, it'll make things just easier.
For the view parameters, use <f:viewParam /> too. It's the standard JSF way of parsing the parameters from the GET request, so just let the framework do the retrieving work for you!
See also:
JSF 2 link, commandLink and outputLink example
Using EL 2.2 with Tomcat 6.0.24
What is the difference between redirect and navigation/forward and when to use what?
How can I control what customscope is created during request. Right now I have solution that when I click the commandLink:
<h:commandLink action="orders">
<f:actionListener type="com.mk.web.jsf.scope.ResetScopeListener" />
<span data-shortcut="F6" class="start_link">Orders</span>
</h:commandLink>
The custom scope is destroyed and a new one is created. But the problem is that the custom scope only resets if I enter the customers action using this commandLink from above.
When I enter to customers action by directly entering the url in browser the custom scope is not reset. How can I make that is customers action is loading even by commandLink or by url then always this custom scope should be reset. Can somebody give me some advice how to achieve this?
Thanks...
Typically you use a custom scope when you want your beans to live longer than the original request but shorter than the session. Based on your scenario though, it seems to me that your custom scope is behaving slightly like a request scope. Anyway, maybe I'm not understanding your scenario fully but one thing that comes to mind is that you can use system events in case a user decides to go to the next page when they type the address directly. So suppose the user tries to go to nextPage.xhtml, it could be defined like this
<f:event type="preRenderView" listener="#{bean.performPossibleCustomScopeCleanUp}" />
<h:head>
</head>
The (pseudo) method above will fire before the view root (aka nextPage.xhtml) is rendered. Inside the method you can check to see if your custom scope is still "alive" and you will handle it as needed. Keep in mind though that this event will be fired every time the page is requested. For instance, if you click the h:commandLink performPossibleCustomScopeCleanUp will still be invoked. There are ways around that
What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?
Just scroll down to the section Performing business action on GET parameters of the answer
An even better approach would be to implement a custom NavigationHandler through JSF's ConfigurableNavigationHandler API so you can keep track of the URL and perform actions as needed.
I didn't dig too dig so you might actually find a better code sample. Hope this helps.
I am using the jsf along with primefaces. I want to call reset functionality when my form loads. But so far i am unable to achieve it.
<script type="text/javascript">
function reset(){
alert("dsdsd");
document.getElementById('A1938:create-ticket').reset();
}
window.onload=function(){reset();};
</script>
<h:form id="create-ticket">
<p:dialog id="dialog" header="Select different user" widgetVar="dlg" modal="true">
<ui:include src="searchpopup.xhtml" />
</p:dialog>
which definately not gona work as jsf translates the page in different way. Any idea.
The alert is getting called.So again i want the form to reset itself when it gets loaded similar to form.reset()
thanks,
Cyd
Calling reset when the page loads makes no utter sense. Perhaps you misunderstood the meaning of reset(). The form.reset() does not clear the input fields, instead it resets the input values to their initial values. I.e. when you get a form with prefilled inputs and then change them, then the reset() would reinitialize them with initial values as it was when the page was loaded. So, the form would only be cleared out on reset() when the initial values are already empty by itself.
So, to achieve your concrete functional requirement, you need to clear out the bean properties directly instead of fiddling with form.reset() which doesn't do what you think it does. Or, better, put the bean in the request or view scope and make sure that the form is opened by a fresh new GET request.
I have read many answers written mainly by BalusC but still no luck.
So I included via ajax rendering, a page in the part of the main page and it works perfect, whenever I click the button on the main bar the subpage xhtml is shown in the proper place. Now the problem is that i want to implement in that subpage a "selectOneMenu" so whenever a user clicks on one of the options he will be redirected to another xhtml which should appear on the same part of the page (instead of the previous page). I have already thought of many ideas to solve that(including conditional rendering), but I believe that there has to be much simpler and more correct way to solve it. Maybe JSF has some kind of container tag which could be used?
PS
By the way that is my first post so sorry if I didnt make something clear.
UPDATE
It appeared to me that maybe I should somehow use ajax onValueChange which would read the value (via the actionListener ?) so when the user clicks on subpage the main page would read the value and render part with the new content. Is that even possible?
You can use valueChange Listener to get the new value and in your bean using FacesContext you can redirect the page but make sure that you add ajax call to your selectonemenu if you dont want your page to refreshed.
<h:selectOneMenu value="#{some.value}"
valueChangeListener="#{some.valuechanged}">
<f:ajax event="change" listener="#{some.listen}" />
</h:selectOneMenu>