----- Original Message -----
From: "Craig R. McClanahan" <[EMAIL PROTECTED]>
To: "Struts Developers List" <[EMAIL PROTECTED]>
Sent: Wednesday, October 01, 2003 11:24 AM
Subject: Re: [struts-chain] Writing a command to process a Tiles Definition
>
> There's a "conditional behavior" use case in the existing code as well;
> when validation fails, we want to redisplay the input form. Originally,
> I modelled this command as a Chain that conditionally executed its child
> commands, but that seemed a little hokey. Now, this command definition
> says:
>
> <command
className="org.apache.struts.chain.servlet.ValidateActionForm"
> failureCommand="servlet-validation-failure"/>
>
> so I'm declaring the name of another chain to go execute if validation
> fails. The actual code that does the conditional execution looks like
> this (in the abstract base class):
>
> // Call the environment-specific protected validate() method in our
> implementation class
> ActionErrors errors = validate(context, actionConfig, actionForm);
>
> // If there were no errors, proceed normally
> if ((errors == null) || (errors.isEmpty()) {
> return (false); // Proceed with the main chain
> }
>
> // Execute the specified validation failure command
> try {
> Catalog catalog = (Catalog)
> context.get(getCatalogKey());
> Command command = catalog.getCommand(getFailureCommand());
> command.execute(context);
> } catch (Exception e) {
> ... deal with exception ...
> }
> return (true); // Terminate the main chain
>
> This approach seems more scalable -- for example, you can have several
> different conditional options, you aren't binding all the behavior
> definitions into a single chain definition, and you can decide based on
> your needs whether to return false or true from the main command (which
> dictates whether the owning chain thinks processing is complete or not).
>
>
> Craig
>
I am wondering how I could implement a "jump behavior" in the main
chain. The use case for a "jump behavior" is that the main chain should
continue with several commands skipped over. For example, I would like
to jump to the last command in the main chain after the current command.
Any ideas?
Jing
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