Hello Howard,
It turns out the error occurs only when the child wants to provide its
own default binding for a parameter originally defined in parent;
example:
public class Parent {
@Parameter
private String name;
void setupRender() {
name.toUpperCase(); // NPE happens here
}
}
public class Child extends Parent{
@Parameter("prop:name")
private String name;
public String getName() {
return "Tom";
}
}
Page class:
public class ChildExample {
@Component
private Child child;
}
Template ChildExample.tml:
<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd";>
<h3>Test</h3>
<t:child t:id="child"/>
</html>
I am sorry for my previous inaccurate information and thanks for
looking into it.
Yunhua
On Wed, Feb 11, 2009 at 2:15 PM, Howard Lewis Ship <hls...@gmail.com> wrote:
> I'm not aware of anything that's changed in this area; could you elaborate?
>
> On Wed, Feb 11, 2009 at 10:56 AM, Yunhua Sang <yunhua.s...@gmail.com> wrote:
>> Hello all,
>>
>> It seems there is no clear document about how to access a parameter
>> defined in parent component; previous to 5.0.18, I was using the way
>> of declaring the parameter again in child class and it worked well;
>> however looks like some changes in 5.1.0.0 broke the way, seems there
>> is no link between the parameter with same name in parent and child
>> now.
>>
>> The problem is when I am USING a tapestry component, it's such a
>> comfortable experience; but when I write a sub-class of a component, I
>> am getting frustrated: a lot of methods are package visible; there is
>> no clear way for parameter manipulation, a typical question: can I
>> update an attibute of parameter in parent class? If inheritance is not
>> a good practice in Tapestry, there should be a document about it.
>>
>> Thanks in advance for any help,
>> Yunhua
>>
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>>
>
>
>
> --
> Howard M. Lewis Ship
>
> Creator Apache Tapestry and Apache HiveMind
>
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