Thanks for the suggestion. This looks like a great idea, but it didn't work
for me exactly as-is. I still get an NPE when Tapestry is trying to bind
component parameters in the level just above ViewDonkeyInlineEdit.
The point of code with the problem is where I'm passing
<t:viewDonkeyInlineEdit donkey="fooLoopVar.donkey"/>
in Test.tml. When Tapestry tries to process this parameter binding when
attempting to fire my startEditDonkey event, it sees that fooLoopVar is
null, so I get the NPE. I need to get fooLoopVar to be NOT NULL when T5 is
processing the parameter binding.
This did get me to think of another possible solution, though. I could use
your suggestion of a context parameter, but also make a change to Test.java:
<t:viewDonkeyInlineEdit donkey="fooLoopVar.donkey"/>
becomes
<t:viewDonkeyInlineEdit donkey="fooLoopVarDotDonkey"/>
Then add this to Test.java:
public getFooLoopVarDotDonkey() { if(fooLoopVar!=null) return
fooLoopVar.getDonkey() else return null; }
This will allow Tapestry to process the parameter binding without hitting a
null pointer exception and thus allow it to actually trigger my event code
so that I can actually retrieve the donkey using the ID passed in the
EventLink's action context.
I'll test this out and let you know how it works.
-Nathan
On Mon, Feb 15, 2010 at 3:32 PM, Thiago H. de Paula Figueiredo <
thi...@arsmachina.com.br> wrote:
> Try this:
>
> <t:container xmlns:t="http://tapestry.apache.org/schema/tapestry_5_1_0.xsd
> "
> xmlns:p="tapestry:parameter">
> Donkey's name: ${donkey.name}<br/>
> <t:if test="editing">
> <t:form context="donkey.id">
> <t:errors/>
> Description: <t:textfield value="editDonkey.descr" size="50"/>
> <t:submit value="Save" event="saveEditDonkey"/> <t:eventlink
> event="cancelEditDonkey">Cancel</t:eventlink><br/>
> </t:form>
> <p:else>
> Description: ${donkey.descr} <t:eventlink
> event="startEditDonkey" context="donkey.id">Edit</t:eventlink><br/>
> </p:else>
> </t:if>
> </t:container>
>
> The only differences here are the use of the context parameter to Form and
> EventLink. You can replace id by any field or info that is unique for all
> donkeys.
>
> public class ViewDonkeyInlineEdit
> {
> @Property @Parameter private Donkey donkey;
> @Persist @Property private Donkey editDonkey;
> public boolean isEditing() {
> return (editDonkey!=null &&
> editDonkey.getName().equals(donkey.getName()));
> }
> public void onStartEditDonkey(Integer id) {
> // get donkey by id and do any processing needed.
> }
> public void onSaveEditDonkey(Integer id) {
> // get donkey by id
> donkey.setDescr(editDonkey.getDescr());
> editDonkey = null;
> }
> public void onCancelEditDonkey() {
> editDonkey = null;
> }
> }
>
> By the way, I guess you don't need to @Persist the editDonkey field.
>
> --
> Thiago H. de Paula Figueiredo
> Independent Java, Apache Tapestry 5 and Hibernate consultant, developer,
> and instructor
> Owner, software architect and developer, Ars Machina Tecnologia da
> Informação Ltda.
> http://www.arsmachina.com.br
>
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