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Posted to user@struts.apache.org by Jim Krygowski <ja...@shaws.com> on 2003/02/14 19:50:33 UTC
[Q] Is Struts use of BeanUtils and PropertyUtils inconsistent?
Hi-
I noticed that when a request is processed by RequestUtils and its values
are copied into an ActionForm, Struts uses the BeanUtils class. Deep inside
BeanUtils, the method for copying (getSimpleProperty) uses ConvertUtils's
convert() method before returning the requested value.
However, all the tags in Struts use RequestUtils.lookup, which in turn uses
PropertyUtils and the getSimpleProperty method on PropertyUtils doesn't use
the converter utilities.
This seems somewhat inconsistent.
I know Craig and a few others on the list advocate creating parallel
String-only value objects and then manually converting (using BeanUtils) in
the action. Their reasons are valid, but add a lot of extra work especially
if you're rendering non-trivial object graphs, (n deep X n wide). My app
has about 70 value objects right now and I'd hate to create and maintain 70
parallel string-only value objects.
Beyond even that issue, what's the point of doing a conversion inbound if
you're only ever going to deal with Strings?
My ideal would be to allow for conversion outbound. This would require
switching from PropertyUtils to BeanUtils in the RequestUtil.lookup. Maybe
this is a good feature for Struts 1.1b4? What do you think?
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RE: [Q] Is Struts use of BeanUtils and PropertyUtils inconsistent?
Posted by "Craig R. McClanahan" <cr...@apache.org>.
See below.
On Mon, 17 Feb 2003, Jim Krygowski wrote:
> Date: Mon, 17 Feb 2003 07:20:27 -0500
> From: Jim Krygowski <ja...@shaws.com>
> Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> To: Struts Users Mailing List <st...@jakarta.apache.org>
> Subject: RE: [Q] Is Struts use of BeanUtils and PropertyUtils
> inconsistent?
>
> Hi Craig-
>
> thanks for the reply. You mention that:
>
> > The conversions on form submit are required because HTTP request
> > parameters are all strings.
>
> which I understood perfectly well. I also understand that, in order for
> that conversion to work for things like date, a common format must used
> inbound and outbound.
>
> > Struts does not have any innate knowledge of
> > your model tier's requirements, and in particular does not know what the
> > caller of RequestUtils.lookup() is going to do with the data that is
> > returned.
> >
> > Doing that by itself would break a huge number of apps that depend on
> > RequestUtils.lookup() working the way it does.
>
> I agree here too. Struts shouldn't know, and it never will. When a date is
> inbound, Struts knows just enough to invoke the converter associated with
> the Class/Type and that's it. And that's how it should be. But, I'd argue
> that since the caller of RequestUtils.lookup in this case is a view
> component (a tag), it should be smart enough to know about the formats I
> want applied to the information it is rendering. I think you're right that
> we shouldn't tamper with RequestUtils.
>
> >
> > It sounds like you'd be better off creating a customized version of the
> > <bean:write> tag that does the conversion for you. That wouldn't be
> > particularly difficult to implement.
> >
>
> However, do you think it's worth considering modifying the bean *and* html
> tags to recognize edit masks/display formats?
The <bean:write> tag already has a "format" attribute that works like
this. I'm not personally interested in adding this kind of thing to the
other tags (my long term plan is to use JavaServer Faces components
instead), but it's possible that other Struts committers will be
interested in this.
> Most of the Struts work I'm
> doing now involves re-creating old Oracle Forms applications as JSP/EJB
> kinds of applications. Edit masks have been a pretty standard view side
> concept for decades now. Adding masks as attributes of the tags might be a
> simple way to implement this feature.
>
> Also, I realize there are a bunch of other hacks I could employ like
> breaking dates into three separate input boxes, but I'd rather hack as a
> last resort. And beyond dates, I can think of many other applications of
> formats to simplify rendering of data in the JSP.
>
The best way to get something like this included in Struts would be to
post enhancement requests to the bug tracking system:
http://nagoya.apache.org/bugzilla/
and then attach patches to implement the proposed changes, as outlined
starting at:
http://jakarta.apache.org/site/getinvolved.html
Then, it's just a matter of talking with the developers about
incorporating the changes in some appropriate version of Struts (we're
trying to lock down 1.1 at the moment, so it won't go there no matter
what).
Worst case, at least you'll have the tags implemented the way you like so
that *you* can use them. Best case, you'll get an @author tag on a bunch
of Struts classes :-).
> thanks.
Craig
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RE: [Q] Is Struts use of BeanUtils and PropertyUtils inconsistent?
Posted by Jim Krygowski <ja...@shaws.com>.
Hi Craig-
thanks for the reply. You mention that:
> The conversions on form submit are required because HTTP request
> parameters are all strings.
which I understood perfectly well. I also understand that, in order for
that conversion to work for things like date, a common format must used
inbound and outbound.
> Struts does not have any innate knowledge of
> your model tier's requirements, and in particular does not know what the
> caller of RequestUtils.lookup() is going to do with the data that is
> returned.
>
> Doing that by itself would break a huge number of apps that depend on
> RequestUtils.lookup() working the way it does.
I agree here too. Struts shouldn't know, and it never will. When a date is
inbound, Struts knows just enough to invoke the converter associated with
the Class/Type and that's it. And that's how it should be. But, I'd argue
that since the caller of RequestUtils.lookup in this case is a view
component (a tag), it should be smart enough to know about the formats I
want applied to the information it is rendering. I think you're right that
we shouldn't tamper with RequestUtils.
>
> It sounds like you'd be better off creating a customized version of the
> <bean:write> tag that does the conversion for you. That wouldn't be
> particularly difficult to implement.
>
However, do you think it's worth considering modifying the bean *and* html
tags to recognize edit masks/display formats? Most of the Struts work I'm
doing now involves re-creating old Oracle Forms applications as JSP/EJB
kinds of applications. Edit masks have been a pretty standard view side
concept for decades now. Adding masks as attributes of the tags might be a
simple way to implement this feature.
Also, I realize there are a bunch of other hacks I could employ like
breaking dates into three separate input boxes, but I'd rather hack as a
last resort. And beyond dates, I can think of many other applications of
formats to simplify rendering of data in the JSP.
thanks.
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Re: [Q] Is Struts use of BeanUtils and PropertyUtils inconsistent?
Posted by "Craig R. McClanahan" <cr...@apache.org>.
On Fri, 14 Feb 2003, Jim Krygowski wrote:
> Date: Fri, 14 Feb 2003 13:50:33 -0500
> From: Jim Krygowski <ja...@shaws.com>
> Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> To: Struts Users Mailing List <st...@jakarta.apache.org>
> Subject: [Q] Is Struts use of BeanUtils and PropertyUtils inconsistent?
>
> Hi-
>
> I noticed that when a request is processed by RequestUtils and its values
> are copied into an ActionForm, Struts uses the BeanUtils class. Deep inside
> BeanUtils, the method for copying (getSimpleProperty) uses ConvertUtils's
> convert() method before returning the requested value.
>
> However, all the tags in Struts use RequestUtils.lookup, which in turn uses
> PropertyUtils and the getSimpleProperty method on PropertyUtils doesn't use
> the converter utilities.
>
> This seems somewhat inconsistent.
>
> I know Craig and a few others on the list advocate creating parallel
> String-only value objects and then manually converting (using BeanUtils) in
> the action. Their reasons are valid, but add a lot of extra work especially
> if you're rendering non-trivial object graphs, (n deep X n wide). My app
> has about 70 value objects right now and I'd hate to create and maintain 70
> parallel string-only value objects.
>
> Beyond even that issue, what's the point of doing a conversion inbound if
> you're only ever going to deal with Strings?
>
The conversions on form submit are required because HTTP request
parameters are all strings. Struts does not have any innate knowledge of
your model tier's requirements, and in particular does not know what the
caller of RequestUtils.lookup() is going to do with the data that is
returned.
> My ideal would be to allow for conversion outbound. This would require
> switching from PropertyUtils to BeanUtils in the RequestUtil.lookup. Maybe
> this is a good feature for Struts 1.1b4? What do you think?
>
Doing that by itself would break a huge number of apps that depend on
RequestUtils.lookup() working the way it does.
It sounds like you'd be better off creating a customized version of the
<bean:write> tag that does the conversion for you. That wouldn't be
particularly difficult to implement.
Craig
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