[digester] PathCallParamRule

[Simon Kitching <si...@ecnetwork.co.nz>]

Hi,

I think we need a CallParamRule variant which saves the matching tagname
as a method call parameter. This mail was prompted by a user question
about building a HashMap using this kind of data:
  <item>
    <foo>1</foo>
    <bar>2</bar>
  </item>
where the tagnames within an item are not known in advance.

There is in CVS a new class PathCallParamRule which passes the whole
path. I suggest that we add a flag to this method to pass just the
tagname rather than the whole path. Alternatively, we could have a
completely separate rule for just the tag name. 

On the subject of CallParamRule variants: they are getting a little
messy now. 

I suggest that we adopt a naming standard of:
 CallParamWithXXXRule
for all call-param-rule variants, so that it is easier for users to find
the available param rules. This would mean renaming PathCallParamRule to
CallParamWithPathRule. I would also suggest creating a
CallParamWithObjectRule which is a copy of ObjectCallParamRule, and
marking ObjectCallParamRule as deprecated.

Or even more alternatively, we could roll all existing param-related
rule functionality into the CallParamRule, and have a constructor which
takes some enum-like flag to say which behaviour we want:
  digester.addCallParam(pattern, CallParamRule.TAGNAME, 0);
  digester.addCallParam(pattern, CallParamRule.ATTR, 0);
  digester.addCallParam(pattern, CallParamRule.BODY, 0);
  digester.addCallParam(pattern, CallParamRule.MATCHPATH, 0);

This would clean up the existing CallParamRule constructor API, which
has grown rather ugly as features have been added.


Thoughts?

Regards,

Simon


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Re: [digester] PathCallParamRule

[robert burrell donkin <ro...@blueyonder.co.uk>]

On 2 Mar 2004, at 21:09, Simon Kitching wrote:

> Hi,
>
> I think we need a CallParamRule variant which saves the matching 
> tagname
> as a method call parameter. This mail was prompted by a user question
> about building a HashMap using this kind of data:
>   <item>
>     <foo>1</foo>
>     <bar>2</bar>
>   </item>
> where the tagnames within an item are not known in advance.
>
> There is in CVS a new class PathCallParamRule which passes the whole
> path. I suggest that we add a flag to this method to pass just the
> tagname rather than the whole path. Alternatively, we could have a
> completely separate rule for just the tag name.

either seems fine to me (though possible another rule might possible be 
a little easy for a user to find). anyone else have any views on this?

> On the subject of CallParamRule variants: they are getting a little
> messy now.
>
> I suggest that we adopt a naming standard of:
>  CallParamWithXXXRule
> for all call-param-rule variants, so that it is easier for users to 
> find
> the available param rules. This would mean renaming PathCallParamRule 
> to
> CallParamWithPathRule. I would also suggest creating a
> CallParamWithObjectRule which is a copy of ObjectCallParamRule, and
> marking ObjectCallParamRule as deprecated.

i think that tidying up the CallParam stuff is overdue.

the proposed naming scheme sounds pretty intuitive to me. if anyone 
disagrees, then now's a good time to jump in.

> Or even more alternatively, we could roll all existing param-related
> rule functionality into the CallParamRule, and have a constructor which
> takes some enum-like flag to say which behaviour we want:
>   digester.addCallParam(pattern, CallParamRule.TAGNAME, 0);
>   digester.addCallParam(pattern, CallParamRule.ATTR, 0);
>   digester.addCallParam(pattern, CallParamRule.BODY, 0);
>   digester.addCallParam(pattern, CallParamRule.MATCHPATH, 0);
>
> This would clean up the existing CallParamRule constructor API, which
> has grown rather ugly as features have been added.

i think either of these proposals sounds like definite improvements. i 
have a slight dislike of enum-like flags so i that

   digester.addCallParamWithTagName(pattern, 0);
   digester.addCallParamWithAttribute(pattern, 0);
   digester.addCallParamWithBody(pattern, 0);
   digester.addCallParamWithMatchingPath(pattern, 0);

might be better. i don't feel very strongly about this so i'd be 
interested to hear what other people think.

- robert


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