I tried this over the weekend, starting with form beans.
Here's what my sample app had:
<!-- the form I extend -->
<form-bean name="baseForm"
type="o.a.s.a.DynaActionForm">
<form-property name="firstName" type="java.lang.String"/>
<form-property name="lastName" type="java.lang.String"/>
<form-property name="score" type="java.lang.String"/>
</form-bean>
<!-- this is the form my actions used -->
<form-bean name="basicForm"
extends="baseForm">
<form-property name="score" initial="100"/>
<form-property name="attempts" type="java.lang.String"/>
</form-bean>
The idea is that basicForm will end up with:
<form-bean name="basicForm"
type="o.a.s.a.DynaActionForm">
<form-property name="firstName" type="java.lang.String"/>
<form-property name="lastName" type="java.lang.String"/>
<form-property name="score" type="java.lang.String" initial="100"/>
<form-property name="attempts" type="java.lang.String"/>
</form-bean>
The following values would be inherited:
FormBeanConfig.type
...and for each property:
FormPropertyConfig class
FormPropertyConfig.name
FormPropertyConfig.type
FormPropertyConfig.initial
FormPropertyConfig.size
...unless a "subform" overrides it.
So in the example above, if basicForm included an entry
stating the "score" field should use "java.lang.Integer", that's
what the end result would have. It would still inherit "initial"
and "size" if the "superform" specified it.
For something like this, I had to remove the "type"
requirement for the <form-bean> and <form-property> elements.
The extension gets realized before the loop which creates and
registers the DynaActionFormClass instances. This code is still
in the ActionServlet.initModuleConfig() method, so I've extracted
this into its own method. Simple checks for circular inheritance
can be easily done by FormBeanConfig, but more complex checking
should probably be done by a separate method in ActionServlet, or
maybe in a util class, such as ModuleUtils.
Comments, please.
I can start working on some unit tests next.
I may have some time tomorrow night.
On Mon, 14 Feb 2005 17:39:34 -0600, Joe Germuska <[EMAIL PROTECTED]> wrote:
> One thing which has been talked about in a few places, and which
> would be valuable, but which no one has done any work on is
> implementing "extends" in as many places in struts-config.xml as it
> would be useful, to eliminate repeated chunks of XML. For
> Validation, this would really be an enhancement to commons-validator,
> but perhaps the same general strategy could be applied. I haven't
> even looked at what would be involved in trying to implement it.
Which other places would this make sense to do?
Exception handlers, forwards, and action mappings?
I haven't taken a look at these yet.
For exception handlers and forwards, should action-specific config be
allowed to extend global config? Hmm... I'm thinking yes; I haven't thought
of a reason not to, yet.
As for Validator, 1.2 already supports extensions. I'm not that familiar
with Validator, so I don't know what issues are preventing that version's
release, nor if the extends feature can be applied to the 1.1.x versions.
Hubert
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