i want to make something similar to view scope with the session scope.
i have a session bean, and in my page i have some search result tables, that i want to clear them and clear the input texts on page load, i can't change from session bean to request bean, and my only idea right now is to add a clear button on the page which it's action method would reset the tables and the input texts.
i am using jsf 1.1, please advise about best way to do that.
Check if the request is a GET request (or, at least, not a POST request).
HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();
if ("GET".equals(request.getMethod())) {
// ...
}
On JSF 1.2, you'd have used ResponseStatemanager#isPostback() for this.
On JSF 2.x, you'd have used FacesContext#isPostback() for this.
You could perform this in a getter of a (hidden) output component.
A completely different alternative is to install Tomahawk and use <t:saveState> to simulate the JSF 2.x view scope on a request scoped bean.
Related
First of all, sorry for my english. I have a RequestScoped ManagedBean in order to send parameters to other views, without getting the The scope of the object referenced by expression is shorter than the referring managed beans error. I also have in the same RequestScoped view a p:dataTable showing these beans objects, with an update button for each row, that retrieves this bean to another form in the same view to be update with new values.
The problem is, when I hit the submit button to record the new values, another record is created, instead of the older one being updated. Of course, because the bean is killed when the submit button is pressed (RequestScoped), creating a new bean and another record in the DB. How can I fix it in this scope?
I've seen some alternatives using #PostConstruct here, however I'm not entirely sure it would solve my specific problem.
EDIT:
After researching a bit more into this topic, I came to another doubt: I am using the same Bean in both views (in my case, ProjectBean), should I create a new Bean with RequestScoped annotation (something like ProjectIdBean), set the older one to ViewScoped (so I can reproduce updates naturally on my Database), and let this new Bean handle the requests for other views?
Submit button:
<p:commandButton value="Gravar" action="#{projetoBean.gravar}"
process="#form" update="#form :formTabelaProjetos:tabelaProjetos" />
'Gravar' method:
public void gravar() {
System.out.println("Gravando projeto " + this.projeto.getNome());
ProjetoDAO dao = new ProjetoDAO();
if (this.projeto.getId() == null) {
dao.adiciona(this.projeto);
projetosAtivos = this.getProjetosAtivos();
} else {
dao.atualiza(this.projeto);
}
this.projeto = new Projeto();
}
You can use request scoped backing bean for updating entities. The problem is, that the request life cycle ends when your page is rendered. So anything you loaded will get discarded. The submit creates another request, that will try to reload resources, but it is a different request than the previous one and for example request parameters often do not contain what the programmer expects. But this is what you found out already. There are two ways how to deal with the problem:
1) use simple getters and setters to set "String, Integer" and similar variables in your request scoped bean, that you use to reconstruct and modify the entity you want to update. It is not convenient for the programmer but request scoped beans save resources of your server.
2) change the scope of your backing bean. Session scope is not ideal, because it can stay in memory for a really long time. And you might realize you need to clean it up manually. Much better is ViewScoped bean as it allows you to work with the entities you loaded over several steps. It gets wiped out when the user leaves the page.
#javax.faces.bean.ViewScoped
#javax.faces.bean.ManagedBean
public class SomethingBean {
......
}
I have a browse.xhtml where I browse a list of cars and I want to view the details of the car in details.xhtml when a "View more" button is pressed. Their backing beans are #ViewScoped and are called BrowseBean and DetailsBean, respectively.
Now, I wouldn't like the user/client to see the car ID in the URL, so I would like to avoid using GET params, as presented here and here.
Is there any way to achieve this? I'm using Mojarra 2.2.8 with PrimeFaces 5 and OmniFaces 1.8.1.
Depends on whether you're sending a redirect or merely navigating.
If you're sending a redirect, then put it in the flash scope:
Faces.setFlashAttribute("car", car);
This is available in the #PostConstruct of the next bean as:
Car car = Faces.getFlashAttribute("car");
Or, if you're merely navigating, then put it in the request scope:
Faces.setRequestAttribute("car", car);
This is available in the #PostConstruct of the next bean as:
Car car = Faces.getRequestAttribute("car");
See also:
Injecting one view scoped bean in another view scoped bean causes it to be recreated
How to pass objects from one page to another page in JSF without writing a converter
Note that I assume that you're very well aware about the design choice of having two entirely separate views which cannot exist (be idempotent) without the other view, instead of having e.g. a single view with conditionally rendered content. And that you already know how exactly the view should behave when it's actually being requested idempotently (i.e. via a bookmark, shared link, by a searchbot, etc). If not, then I strongly recommend to carefully read the answer on this question: How to navigate in JSF? How to make URL reflect current page (and not previous one).
Update: in case you're not using OmniFaces, use respectively the following:
FacesContext.getCurrentInstance().getExternalContext().getFlash().put("car", car);
Car car = (Car) FacesContext.getCurrentInstance().getExternalContext().getFlash().get("car");
FacesContext.getCurrentInstance().getExternalContext().getRequestMap().put("car", car);
Car car = (Car) FacesContext.getCurrentInstance().getExternalContext().getRequestMap().get("car");
I am trying to make my app "Bookmarkable", and i am using view parameters to achieve it.
And i think i still do not get the right way to do it right in JSF, even after reading this, and many others.
My problem is that the get parameters get lost after any non-ajax postback, i mean, the parameter value is still set in the bean and the app works correctly, but it gets removed from the URL making the URL invalid.
For instance, having an URL like http://company.com/users?id=4, as soon as that page executes a non-ajax postback (for uploading data, for instance) the URL becomes just http://company.com/users. The app continues to work correctly, but the link is not any more "Bookmarkable".
Is there any way to prevent the non-ajax postbacks removing the viewParams from the URL?
My use case is to be able to bookmark a page to EDIT an object, and there i need to be able to upload data (if not i would not use non-ajax postbacks). I know i would not need any postback if i would want to bookmark the page to only VIEW the data of the object, but that is not my case.
I could also do a redirect to the same page with the same params, and let the app to recreate the view scoped bean, but then i really do not see any benefit over request scoped beans...
Any suggestion is very appreciated.
This behaviour is "by design". The <h:form> generates a HTML <form> element with an action URL without any view parameters. The synchronous POST request just submits to exactly that URL which thus get reflected as-is in browser's address bar. If you intend to keep the view parameters in the URL, while using ajax is not an option, then you basically need to create a custom ViewHandler which has the getActionURL() overridden to include the view parameters. This method is used by <h:form> to generate the action URL.
public String getActionURL(FacesContext context, String viewId) {
String originalActionURL = super.getActionURL(context, viewId);
String newActionURL = includeViewParamsIfNecessary(context, originalActionURL);
return newActionURL;
}
Or, as you're based on the comments already using OmniFaces, you could also use its <o:form> component which basically extends the <h:form> with the includeViewParams attribute which works much like the same as in <h:link> and <h:button>.
<o:form includeViewParams="true">
...
</o:form>
This way all <f:viewParam> values will end up in the form action URL.
See also:
Handling view parameters in JSF after post
How to create a paginated table in JSF 1.2
where backing bean is request scoped.
To the point, you want to retain a specific set of parameters in the subsequent request, such as the current page. You can pass those extra parameters as <h:inputHidden> so that they are available in the next request, or use the Tomahawk's <t:saveState> to simulate a scope which is similar to the JSF 2.0 view scope.
Long story and a lot of code short, there's a blog article about this with complete code snippets: effective datatable paging and sorting.
if you get all the table data with query i'd strongly suggest storing it in session bean.
You can use another bean just for the data.
Another way is to just get the data thats currently displayed (limit).
On switching the page you also send the "position"
For doing it only in client side you have to use somekind of javascript/ajax library ( http://www.jsfmatrix.net/ ) ...
I'm currently learning about JSF 2.0 and i dont know how to initialize something in my CDI bean everytime a jsf page is accessed ?
For example, let's say in my case, i have one CDI bean that is used in one JSF page. Somewhere inside the bean, i would like to query and initialize something, or check authorization everytime the page is accessed (not everytime the action method is called).
I could put it into the bean's constructor, but that doesnt guarantee that the constructor would be called for every calls of the jsf page ? Or should i call using the #{myBean.initialize()} on the JSF page ?
Regards,
Albert Kam
If you declare the managed bean #RequestScoped, then it will be created for every HTTP request (yes, that's "everytime a JSF page is accessed" as you say in enduser's terms). You can just do the initialization job in the bean's constructor or #PostConstruct method. This has nothing to do with CDI.
check authorization everytime the page is accessed (not everytime the action method is called).
For that, a javax.servlet.Filter or very maybe a javax.faces.event.PhaseListener is a much better solution.
You could have a look at https://cwiki.apache.org/confluence/display/EXTCDI/JSF+Usage
If I am not mistaken, the constructor is called every time the page loads - as soon as you apply your bean to the jsf page, that object is constructed. Hence, must have a constructor without any parameters