I've two JSF 1.1 pages that I'm currently working with. One of them is viewDevices.jsp and the other is vewDevicesPrint.jsp. They are both running under the view scope (using tomahawk savestate, that is). In viewDevices, it has a img that user can click on to go to the viewDevicesPrint.jsp. Like so:
<img src="redesign/images/printicon2.png" alt="print records" border="0" width="16" height="16" onClick="javascript:window.open('/viewDevicesPrint.jsf','_blank','height=500,width=900,menubar=yes, toolbar=yes,scrollbars=yes')"/>
When this img is clicked, I would like to pass the current instance of viewDevicesBean to the viewDevicesPrintBean. Is there a way to do this?
I've the following in faces-config.xml. In debug, viewDevicesPrintBean is getting a new instance of viewDevicesBean, instead of the current instance of it.
<managed-bean>
<managed-bean-name>viewDevicesPrintBean</managed-bean-name>
<managed-bean-class>com.arch.myaccount.jsf.ViewDevicesPrintBean</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
<managed-property>
<property-name>param_viewDevicesBean</property-name>
<value>#{viewDevicesBean}</value>
</managed-property>
</managed-bean>
<managed-bean>
<managed-bean-name>viewDevicesBean</managed-bean-name>
<managed-bean-class>com.arch.myaccount.jsf.ViewDevicesBean</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
<managed-property>
<property-name>param_flow</property-name>
<value>#{param.Flow}</value>
</managed-property>
</managed-bean>
A view scoped bean is tied to the current view. When you change the current view by navigating to a different view, then that different view would get a brand new instance of the view scoped bean. Note that it works also that way in JSF2.
Your best bet is to pass the desired data as request parameters in window.open() URL (escape them!), so that the print bean can get them as request parameters (via either managed property or ExternalContext). An alternative, especially if you've rather a lot of data, is to store the bean instance in the session scope under an unique and autogenerated key (e.g. java.util.UUID) and pass that key as request parameter so that the bean associated with the print page can obtain the data from the session scope by that key.
Related
I want to use a ManagedBean class, Users.java, to create 2 bean instances with different scopes. I tried to do this in 2 ways:
1.
Use ManagedBean and SessionScope annotations for Users (this creates a "users" with a session scope), and declare in faces-config.xml another MenagedBean from User, with request scope.
#ManagedBean
#Component
#SessionScoped
public class Users implements Serializable {...}
Note: "Component" is from Spring framework, this can be ignored for the moment.
In faces-config.xml:
<managed-bean>
<managed-bean-name>newUser</managed-bean-name>
<managed-bean-class>ro.telacad.model.Users</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
In login page I use "#{users.}" inside . For this case, the login works fine (is made with Spring Security). I created also a "Sign up" page, and there, I need the "Users" bean with request scope to create a new user in database, "#{newUser.}". I put a breakpoint inside a method, and when the application stopes there, all the attributes of this object are null, and the application throws a NullPointerException.
2.
Remove annotations "ManagedBean" and "SessionsScoped" from Users.java, and declare the 2 managed beans in faces-config.xml:
<managed-bean>
<managed-bean-name>currentUser</managed-bean-name>
<managed-bean-class>ro.telacad.model.Users</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
<managed-bean>
<managed-bean-name>newUser</managed-bean-name>
<managed-bean-class>ro.telacad.model.Users</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
Of course, this time I use in login page and in welcome page "#{currentUser.}". This time, the NullPointerException is thrown in both cases (login and sign up).
The file faces-config.xml is loaded. I tested this by creating a class TempBean.java with 1 attribute and 1 method, declaring a managed bean of this class in faces-config.xml and use this in a h:form. It worked.
I extended "Users" class, exactly like Selaron said in the comment. It works fine. But I think it is not a good idea to do this in a real application, but for the moment I don't have any better idea.
I have two region and two taskflow on a page. On first taskflow manage bean is on pageflow scope where in second taskflow its on backing bean scope. My requirement is I want to call method of one bean from econd bean and vice-versa.
For example: on first jsff if some action happen then it action will go to its bean and from there I need to call method of second bean and vice-versa.
How can I achieve this?
Since both task flow will be running at same time so I need to get running instance of bean so that I can get the current status/value UI components.
All you need to do is to inject the bean whose method you want to use in the other bean. In ADF there is an easy way to achieve this. You should have a file called adfc-config.xml inside your WEB-INF folder. If you open it's source, you'll notice that each bean is described inside the <managed-bean> tag. It will be something like:
<managed-bean id="__2">
<managed-bean-name>bean1</managed-bean-name>
<managed-bean-class>com.domain.Bean1</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
</managed-bean>
for each bean. You have to insert a <managed-property> tag inside with a reference of the bean you want to inject, just like this:
<managed-bean id="__2">
<managed-bean-name>bean1</managed-bean-name>
<managed-bean-class>com.domain.Bean1</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
<managed-property>
<property-name>bean2</property-name>
<value>#{Bean2}</value>
</managed-property>
</managed-bean>
Also, inside the Bean1 class you have to create an instance variable of Bean2, and then you can use it to get its current state.
I have a selectOneMenu that manages a relation between two Objects A and B.
Where A is fixed and B is selectable via the menu.
On form submit B is send to the bean for further processing (creating and saving relationship object AToB).
Not working case!
<h:selectOneMenu value=#{b}>
<!-- b items from bean -->
</h:selectOneMenu>
<h:commandButton action="#{bean.addBToSelA(b)}"/>
<managed-bean>
<description>B Entity Request Bean</description>
<managed-bean-name>b</managed-bean-name>
<managed-bean-class>B</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
Working case!
But if the selectOneMenu value is a nested property of a different managed bean it works. (as example AToB)
<h:selectOneMenu value=#{aToB.b}>
<!-- b items from bean -->
</h:selectOneMenu>
<h:commandButton action="#{bean.addBToSelA(aToB.b)}"/>
<managed-bean>
<description>AToB Entity Request Bean</description>
<managed-bean-name>aToB</managed-bean-name>
<managed-bean-class>AToB</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
Note: It is enough if my "b" is just a property of a different request managed bean.
Can someone be so kind and explain why?
Because JSF has already created the bean instance beforehand. It won't be overridden with the model value if the instance already exist in the scope. Remove the <managed-bean> from faces-config.xml and it'll work just fine.
Unrelated to the concrete problem, you seem to be already using JSF 2.x. Why sticking to the old JSF 1.x style faces-config.xml configuration? Just use #ManagedBean annotation (on real backing bean classes only, of course).
Is it possible to have a managed bean created only on some pages i.e. bean != null on page1.faces and bean == null on other pages?
No, it is not possible to limit the accessibility of a managed bean under JSF to an specific page. Just use it in those pages that, according to your desing, you consider appropiate.
It is common to have a JSF application that uses a given managed bean for some pages in particular, especially form beans. For example if you have a form used to create and/or update certain type of entities in your application, lets say a product definition, you will find yourself declaring code like the following:
<managed-bean>
<managed-bean-name>productForm</managed-bean-name>
<managed-bean-class>com.example.forms.ProductForm</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
<managed-property>
<property-name>someProperty</property-name>
<value>propertyValue</value>
</managed-property>
</managed-bean>
And then reusing it in your actual viewProduct.jsp like the following
Product Name: <h:inputText value="#{productForm.productName}" styleClass="someClass"/>
Managed beans are a core component in the JSF development process. There is much more to managed beans than just initializing certain properties and helping tie your presentation to your models.To gain a better understanding of the rationale and philosophy, including IoC, behind the use of managed beans see: http://www.oracle.com/technology/tech/java/newsletter/articles/jsf_pojo/index.html
I have a data table in JSF which gets populated when user selects a drop-down menu. The list that table shows comes from a backing bean. This backing bean is in the session scope. So when user clicks on other links of the webpage and comes back to this page, it still shows the data from the data list with the previous selections.
Question is - how to make sure, that data gets reset when user leaves the page so that when user comes back in, they can see a fresh page with no data in it.
I can not put the backing bean in request scope as that will make it impossible to have a cart type application.
Keep the datamodel in the session scoped bean, add a request scoped bean which copies the reference from the session scoped bean and let the form submit to that request scoped bean and let the view use the request scoped bean instead. You can access the session scoped bean from inside a request scoped bean by under each managed property injection. E.g.
<managed-bean>
<managed-bean-name>cart</managed-bean-name>
<managed-bean-class>com.example.Cart</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
<managed-bean>
<managed-bean-name>showCart</managed-bean-name>
<managed-bean-class>com.example.ShowCart</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
<managed-property>
<property-name>cart</property-name>
<value>#{cart}</value>
</managed-property>
</managed-bean>
wherein the ShowCart can look like:
public class ShowCart {
private Cart cart;
private Cart show;
// +getters+setters
public String submit() {
show = cart;
// ...
}
}
and the view uses #{showCart.show} instead.