Combining components

[Udo Schnurpfeil <ud...@atanion.com>]

I've found a way to combine components to new tags.

There was already some discussion on a similar topic:
http://www.mail-archive.com/users@myfaces.apache.org/msg06438.html
http://www.mail-archive.com/users@myfaces.apache.org/msg06369.html

My first approach was to write a tag file (JSP 2.0) like
(this is a non-working short-sample):

file: inWithLabel.tag

<%@ attribute name="label" %>
<%@ attribute name="value" %>
<%@ attribute name="binding" %>

<t:panel>
   <t:label value="${label}">
   <t:in value="${value}" binding="${binding}">
</t:panel>

The first tests with "label" and "value" run well.
But I found a big problem: If I want more advanced features like 
"binding" I have a problem: If the binding is not set the container will 
call setBinding("") with an empty string, which  is not  allowed.

So I write the Tag by hand:
int doStartTag() {
   PanelTag panel = new PanelTag();
   panel.setPageContext(pageContext);
   panel.doStartTag();
   ...
}
You can see a real sample here:
http://www.atanion.net/repos/asf/tobago/trunk/core/src/main/org/apache/myfaces/tobago/taglib/extension/InExtensionTag.java

advantage of tag as java class:
   * Works with JSP 1.2
   * not need rtexpression (JSP EL) inside of JSF tags, which is in
     common not allowed.
   * setter only will be called, if the value != null

advantage of tag file:
   * the tag file looks much more tidy

Regards,

Udo

Re: Combining components

[Martin Marinschek <ma...@gmail.com>]

Cool!

looks good ;)

regards,

Martin

On 10/7/05, Udo Schnurpfeil <ud...@atanion.com> wrote:
> I've found a way to combine components to new tags.
>
> There was already some discussion on a similar topic:
> http://www.mail-archive.com/users@myfaces.apache.org/msg06438.html
> http://www.mail-archive.com/users@myfaces.apache.org/msg06369.html
>
> My first approach was to write a tag file (JSP 2.0) like
> (this is a non-working short-sample):
>
> file: inWithLabel.tag
>
> <%@ attribute name="label" %>
> <%@ attribute name="value" %>
> <%@ attribute name="binding" %>
>
> <t:panel>
>    <t:label value="${label}">
>    <t:in value="${value}" binding="${binding}">
> </t:panel>
>
> The first tests with "label" and "value" run well.
> But I found a big problem: If I want more advanced features like
> "binding" I have a problem: If the binding is not set the container will
> call setBinding("") with an empty string, which  is not  allowed.
>
> So I write the Tag by hand:
> int doStartTag() {
>    PanelTag panel = new PanelTag();
>    panel.setPageContext(pageContext);
>    panel.doStartTag();
>    ...
> }
> You can see a real sample here:
> http://www.atanion.net/repos/asf/tobago/trunk/core/src/main/org/apache/myfaces/tobago/taglib/extension/InExtensionTag.java
>
> advantage of tag as java class:
>    * Works with JSP 1.2
>    * not need rtexpression (JSP EL) inside of JSF tags, which is in
>      common not allowed.
>    * setter only will be called, if the value != null
>
> advantage of tag file:
>    * the tag file looks much more tidy
>
> Regards,
>
> Udo
>


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