ansaurus

Question

Error accessing a property from a sub class in JSF

Answer 1

A:

If you're having a hard time interpreting the error, what it means is that on your facelets page, it can't figure out what you mean by:

#{grouptableController.selected.grouptablePK.groupid}

Hope this helps.

Jon 2010-02-02 20:47:18

Answer 2

+1 A:

value="#{grouptableController.selected.grouptablePK.groupid}": 
Target Unreachable, 'null'

This basically means that one of the nested properties is null. In this context, it can be can be either selected or grouptablePK which has returned null. Those shouldn't be null whenever JSF needs to set the groupid property.

You need to preinstantiate those nested objects/beans yourself. JSF/EL won't do that for you.

Thus, instead of

public class ParentBean {
    private ChildBean childBean;
}

you need to do

public class ParentBean {
    private ChildBean childBean = new ChildBean();
}

or

public class ParentBean {
    private ChildBean childBean;
    public ParentBean() {
        this.childBean = new ChildBean();
    }
}

Alternatively, if the ChildBean is also a managed bean, or can be one, then you can also make use of managed property injection in faces-config.xml:

<managed-bean>
    <managed-bean-name>parentBean</managed-bean-name>
    <managed-bean-class>com.example.ParentBean</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
    <managed-property>
        <property-name>childBean</property-name>
        <value>#{childBean}</value>
    </managed-property>
</managed-bean>
<managed-bean>
    <managed-bean-name>childBean</managed-bean-name>
    <managed-bean-class>com.example.ChildBean</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
</managed-bean>

BalusC 2010-02-02 21:58:48

I have the same situation BalusC. `#{document.selectedDrawing.name} Target Unreachable, "null"`. `document` is the managed bean. `Drawing selectedDrawing` where `Drawing` is the entity class. What I dont understand is that, it display the name of the selected drawing correctly. But then when I click to the `commandButton` to link to somewhere else, it pop that error. I dont understand if it already display the correct value, then how `selectedDrawing` be `null`. I read your post, and try `selectedDrawing = new Drawing()`, it fix it, but created another drawing inside my database.

Harry Pham 2010-07-05 23:44:40

@Harry: Lazy loading issue in your persistence layer?

BalusC 2010-07-05 23:46:04

In my managed bean, I used lazy loading to load all the `Drawing` to a `list<Drawing>`. I dont think I use any in my session bean

Harry Pham 2010-07-05 23:51:14

I changed lazy loading to inject `@PostConstruct` to `public void init()`. And it still does not fix it. If u can help me a bit, I would greatly appreciated

Harry Pham 2010-07-05 23:55:25

ansaurus

tags:

views:

answers:

Error accessing a property from a sub class in JSF

related questions