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)
Related
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}"/>
Lets say I have a #ViewScoped Bean behind my current page A. Now the user navigates to page B via a normal get request, lets say to www.google.com.
When the user clicks the back button of the browser, I would like to restore the #ViewScope of the previous page, so that it appears exactly as it was left. Is that possible to achieve somehow?
I dont want to make my page A #SessionScoped so that the backing beans do not disturb each others state when opened in two browser tabs.
Since version 2.6 OmniFaces has this feature, is called #ViewScoped(saveInViewState = true) But with some caution!
It's very important that you understand that this setting has potentially a major impact in the size of the JSF view state, certainly when the view scoped bean instance holds "too much" data, such as a collection of entities for a data table, and that such beans will in fact never expire as they are stored entirely in the javax.faces.ViewState hidden input field in the HTML page. Moreover, the #PreDestroy annotated method on such bean will explicitly never be invoked, even not on an unload as it's quite possible to save or cache the page source and re-execute it at a (much) later moment.
A more programmatical solution is the #ConversationScoped. With the convertsation id as parameter can you restore the view.
conversationscope example
Yes it is possible, pass parameter like this using f:param this will pass your parameter to the next screen.
<h:commandLink action="screenName" value="#{search.participantName}">
<f:param value="#{searchcus.participantId}" name="PARTICIPANT_ID"/>
<f:param name="PARENT_SCREEN_CODE" value="SEARCH_PARTICIPANT"/>
</h:commandLink>
After that in init() method get value as a parameter to fetch the result.
We're using JSF 2.0 on WebSphere v8.5 with several component libraries PrimeFaces 4.0, Tomahawk 2.0, RichFaces, etc.
I am looking for generic mechanism to avoid form re-submission when the page is refreshed, or when the submit button is clicked once again. I have many applications with different scenarios.
For now I have considered disabling the button with a piece of JavaScript in onclick attribute, but this is not satisfying. I'm looking for a pure Java implementation for this purpose, something like the Struts2 <s:token>.
I am looking for generic mechanism to avoid form re-submission when the page is refreshed
For that there are at least 2 solutions which can not be combined:
Perform a redirect after synchronous post. This way the refresh would only re-execute the redirected GET request instead of the initial request. Disadvantage: you can't make use of the request scope anymore to provide any feedback to the enduser. JSF 2.0 has solved this by offering the new flash scope. See also How to show faces message in the redirected page.
Perform the POST asynchronously in the background (using ajax). This way the refresh would only re-execute the initial GET request which opened the form. You only need to make sure that those forms are initially opened by a GET request only, i.e. you should never perform page-to-page navigation by POST (which is at its own already a bad design anyway). See also When should I use h:outputLink instead of h:commandLink?
or when the submit button is clicked once again
For that there are basically also at least 2 solutions, which could if necessary be combined:
Just block the enduser from being able to press the submit button during the submit and/or after successful submit. There are various ways for this, all depending on the concrete functional and design requirements. You can use JavaScript to disable the button during submit. You can use JSF's disabled or rendered attributes to disable or hide the button after submit. See also How to do double-click prevention in JSF 2. You can also use an overlay window during processing ajax requests to block any enduser interaction. PrimeFaces has <p:blockUI> for the purpose.
Validate uniqueness of the newly added entity in the server side. This is way much more robust if you absolutely want to avoid duplication for technical reasons rather than for functional reasons. It's fairly simple: put a UNIQUE constraint on the DB column in question. If this constraint is violated, then the DB (and DB interaction framework like JPA) will throw a constraint violation exception. This is best to be done in combination with a custom JSF validator which validates the input beforehand by performing a SELECT on exactly that column and checking if no record is returned. A JSF validator allows you to display the problem in flavor of a friendly faces message. See also among others Validate email format and uniqueness against DB.
Instead of creating a token manually, you can use BalusC' solution. He proposed a Post-Redirect-GET pattern in his blog
Alternative solutions can be found in these answers:
Simple flow management in Post-Redirect-Get pattern
How can Flash scope help in implementing the PostRedirectGet (PRG) pattern in JSF2.0
<!--Tag to show message given by bean class -->
<p:growl id="messages" />
<h:form>
<h:inputText a:placeholder="Enter Parent Organization Id" id="parent_org_id" value="#{orgMaster.parentOrganization}" requiredMessage="Parent org-id is required" />
<h:commandButton style="margin-bottom:8px;margin-top:5px;" class="btn btn-success btn-block " value="Save" type="submit" action="#{orgMaster.save}" onclick="resetform()" />
</h:form>
public String save() {
FacesContext context = FacesContext.getCurrentInstance();
context.getExternalContext().getFlash().setKeepMessages(true); //This keeps the message even on reloading of page
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "Your submission is successful.", " ")); // To show the message on clicking of submit button
return "organizationMaster?faces-redirect=true"; // to reload the page with resetting of all fields of the form.. here my page name is organizationMaster...you can write the name of form whose firlds you want to reset on submission
}
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.
How can I open new tab when user clicks p:commandButton? I also want to pass some parameters to new page using FlashScope. Here's the code:
<h:form>
<p:commandButton value="open new tab" action="#{myBean.newTab}"/>
</h:form>
public String newTab() {
Faces.setFlashAttribute("foo", bar);
return "otherView";
}
On the otherView page I use f:event type="preRenderView" to read Flash parameters.
Two notes:
I need to use FlashScope, not URL parameters.
If possible, I don't want to change newTab() and preRenderView() methods.
Thanks for help
Use target="_blank" on the form to tell the browser that the synchronous response of the form should be presented in a new (blank) tab/window. You only need to turn off ajax behaviour of the <p:commandButton> in order to make it a synchronous request.
<h:form target="_blank">
<p:commandButton value="open new tab" action="#{myBean.newTab}" ajax="false" />
</h:form>
No changes are necessary in the backing beans, it'll just work as you intented. I would only recommend to use POST-Redirect-GET pattern in the action method.
return "otherView?faces-redirect=true";
Otherwise the new tab would show the URL of the originating page and a F5 would re-invoke the POST. Also, this way the flash scope is also really used as it is been designed for (if you didn't redirect, just storing in request scope was been sufficient).
Update: as per the comments, the view scoped bean in the initial tab/window get killed this way. by returning a String navigation case outcome. That's right, if you'd like to keep the view scoped bean alive, replace the navigation case by a Faces#redirect() call (assuming that it's indeed OmniFaces which you're using there for Faces#setFlashAttribute()). You only need to set Flash#setRedirect() to true beforehand to instruct the flash scope that a redirect will occur.
public void newTab() throws IOException {
Faces.setFlashAttribute("foo", bar);
Faces.getFlash().setRedirect(true);
Faces.redirect("otherView.xhtml");
}