Will writing Actions in script make sense?

[purpureleaf lee <pu...@hotmail.com>]

Hi all
I have implemented a experimental extention to Struts.
The idea is to write some scripts in the body of <action> tag to implement 
the business logics.

For example:

<action    path="/saveCustomer"
               type="scriptedaction.ScriptedAction"
              scope="request"
           validate="false">
	<forward name="success"              path="/success.jsp"/>
	<forward name="failure"              path="/error.jsp"/>
	<parameter name="id"/>
	<parameter name="firstName"/>
	<parameter name="lastName"/>

	if (id.length() == 0) return "failure";
	System.out.println("id=" + id);
	System.out.println("His name is \"" + firstName + "." + lastName + "\"");
	return "success";
</action>

This is simple action.It uses "ScriptedAction" as it type,defines three 
parameters and 4 lines of scripts.Scripts are written in beanshell,a script 
environment for java(for more information ,visit www.beanshell.org).
When it is invoked, the "ScriptedAction" will initialize the script 
environment,get the parameters from request parameters(and attributes),set 
them as predefined variables of the script environment,and invoke the 
codes.Writing a new Action class is not needed.

If the script is long and complex(for example,with many "try...catch" or 
many EJB lookup),this approach doesn't make sense.Sinse a java class can do 
the some thing but easier to debug.On the other hand,if the business logic 
is simple and can be written in ten lines,we can gain flexibility and save 
time.
But in most case, business logic is hard to script.May be with well designed 
business component (Sun's J2EE Patterns?),we can write script to handle 
them.After all,Struts acts as a mediator bettwen GUI layer and data layer 
,there could be a good place to write srcipt if data layer is ease to use.

There is a web application includes my extentions and a simple 
demo(struts.jar is not included).Just drop it to tomcat "webapps" to see 
what will happen(Please copy struts.jar to WEB-INF/lib).
It won't amaze you :),just a idea.

Any comments?


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Re: Will writing Actions in script make sense?

[Ted Husted <hu...@apache.org>]

purpureleaf lee wrote:
> Any comments?

I think it makes sense for a number of use-cases, and is the same
general direction that is taken by the Workflow Proposal. A declared
goal there is to enable business domain experts to program workflows
without being Java engineers, using the equivalent of a
struts-config.xml. This also doesn't have to be an all-or-nothing
approach. Scripting can be used where it makes sense, and we still have
custom Actions when it does not.

Have you looked at BSF? There's been talk of having this donated to
Jakarta. 

http://www-124.ibm.com/developerworks/projects/bsf

I'm having a lot of success using a small number of "framework" actions
that are scripted from the Struts configuration, using a combination of
objects specified as the parameter and ActionForwards. 

-Ted.

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