Re: Javadocs and other doubts

Hola Hernán

responses inline

On Sun, Dec 21, 2008 at 9:30 PM, El Acuariano <acuariano@...> wrote:
> Hi all,
> (...)

> Is there any reason why the Javadocs don't have more
> information on intended use?

  Mostly my laziness :( and also writter's block. I'm sorry, I know I
should write more and better documentation but I always end up
postponing it so I can code some more (and I know is wrong).

> I found in the "Trails gotchas" page an old link to the examples in the
> repository. It points to the 1.0 SNAPSHOT version
> in http://trails.inspiring.nl/svn/trunk/trails/examples/. It would be nice
> to update it to point
> to http://svn.codehaus.org/trails/tags/trails-1.2/examples.
>

  fixed. Remember it's a wiki, if you found something like this you
help us editing it your self.

> - I need to fill-in an incremental invoice number. It should be editable for
> flexibility, but when creating a new invoice it should be initialized to the
> current invoice number. How can I set the initial value for a new invoice?

  There is a builder pattern implementation. But I just realize that
in Trails 1.2.x there is no way to contribute your builder
(org.trails.builder.Builder) to the builder director. Take a look at
it (org.trails.builder.BuilderDirector), if that is what you need I
can quickly fix it to allow contributions to the map.

> - Each line of the invoice correspond to a product. I need that the unit
> price of the line be independent of the product, to avoid changing old
> invoices if a product price changes. Also, it should be editable, to reflect
> special prices (promotions, etc.). When editing a line, if I change the
> product, the unit price for the line should change to reflect the current
> price of the new product. It would be nice to make it work in the browser,
> using JavaScript. I need to create an edition page to do this, right? How
> can I get all available products and their prices to be usable with JS? I
> would add JSON containing the products to the page so I can access them, but
> I don't understand enough of the Trails "plumbing" to really know how to do
> it.

 You don't need to use custom javascript to do this. Tapestry (and
Trails) can take of this for you.
 You need a custom edit page with both template & java code and then
some Tapestry love :)

Add this blocks in your invoice line edit page template (I've used
category instead of product):

               <div jwcid="category@Block">
                       <li>
                               <label><span jwcid="@Insert"
                                                        value="ognl:classDescriptor.getPropertyDescriptor('category').displayName"/></label>
                               <select jwcid="categoryField@trails:AssociationSelect"
value="ognl:model.category"
                                               class="field select medium"
                                               propertyDescriptor="ognl:classDescriptor.getPropertyDescriptor('category')"/>
                       </li>
               </div>
               <div jwcid="price@Block">
                       <li>
                               <label><span jwcid="@Insert"
                                                        value="ognl:priceDescritor.displayName"/></label>
                               <input jwcid="priceField@TextField" value="ognl:model.price"
class="field text medium"
                                          translator="ognl:validatorTranslatorService.getTranslator(priceDescritor)"
                                          validator="ognl:validatorTranslatorService.getValidator(priceDescritor)"
                                               />
                       </li>
               </div>

Then add this code to you invoice line edit page java code (remember
to extend from HibernateEditPage).

   @InjectObject("service:trails.core.ValidatorTranslatorService")
   public abstract ValidatorTranslatorService getValidatorTranslatorService();

   public IPropertyDescriptor getPriceDescritor()
   {
       return getClassDescriptor().getPropertyDescriptor("price");
   }

   @EventListener(targets = "categoryField", events = "onchange")
   public void onCategoryFieldSelectOption(IRequestCycle cycle)
   {
       InvoiceLine model = (InvoiceLine) getModel();
       if (model.getCategory() != null)
       {
           model.setPrice(model.getCategory().getPrice());
           cycle.getResponseBuilder().updateComponent("priceField");
       }
   }

That's it. That's all you need.
More docs: http://tapestry.apache.org/tapestry4.1/ajax/eventlistener.html

> - For several object I need to be able to "freeze" some properties. For
> example, an invoice could have a "status" field. When the status changes to
> "approved" then no more edition is allowed. Is there a nice and simple way
> to do this?

The first thing I can think of is to have a block for that property
and then check for the "approved" status in an @If component.

               <div jwcid="status@Block">
                       <span jwcid="@If" condition="CHECK FOR STATUS HERE">
                               <span jwcid="@trails:SimplePropertyEditor" property="status"/>
                       </span><span jwcid="@Else">
                               SOMETHING ELSE
                       </span>
               </div>

> Thanks,
> Hernán
>

Felices fiestas!
Saludos!
Alejandro.