Re: [RFC] simple method subsections

[David E Jones]

-David


On Nov 16, 2007, at 10:47 AM, Chris Howe wrote:

I'm still not totally sure what you're trying to accomplish, or maybe more accurately, what you want to make easier. Could you throw out some ofbiz-oriented pseudo code for the way you would do this now that you don't like? I don't think I really like this section approach in the simple- methods. It adds a lot of otherwise meaningless stuff to the routines, and you'd still have to instrument a LOT of code in order to really be able to use it without modifying the original code, and any code that was instrumented this way would result in more lines of code to maintain, and they may not be maintained the way you like, especially if the purpose or intent isn't clear. Based on more info about what you're trying to do I'm guessing we can find a better alternative that is more "automatic" and not so intrusive in existing code.

I gave several ideas, the parameterized one is probably the least plausible because of security considerations. I'm leaning towards the <section-begin/section-end> tagging that would be otherwise inert to an ofbiz application.

example:
MySimpleMehtods.xml
<simple-method method-name="myMehtod>
...some logic...

...some more logic...
</simple-method>

OfbizServices.xml
<simple-method method-name="ofbizMethod">
...some ofbiz logic that I don't want to run in myMethod...
<section-begin>
 <section name="sectionA">
</section-begin>
...some ofbiz logic that I want to run in myMethod...
<section-end>
 <section name="sectionA">
</section-end>
...some more ofbiz logic that I don't want to run in myMethod...
</simple-method>





----- Original Message ----
From: Jonathon -- Improov <[EMAIL PROTECTED]>
To: dev@ofbiz.apache.org
Sent: Friday, November 16, 2007 10:02:09 AM
Subject: Re: simple method subsections

Are you suggesting something like abstract classes in Java, where some
methods are implemented and
some are not (blanks to be filled)?

Parameterized simple methods. Sounds interesting.

Some effort is needed to refactor the existing "OFBiz maintained"
simple methods to publish such
"hooks" where you can insert your own custom logics.


just hack it and get the
job done.

Unless we can identify numerous use cases for such elegant mechanisms,
there's little ROI in doing
such fanciful stuff.

<get-simple-method-section method-name="ofbizMethod" location="org/ ofbiz/ofbizApp/OfbizServices.xml" section="sectionA"> This would be similar to how <call-simple-method> works except you would be pulling a node that is a child of <simple-method> instead of a child node of <simple-methods>. And instead of pulling a node, you're pulling all elements between a section-begin and a section- end tag (this would allow for overlapping sections as well as being able to keep an iteration open). I'd really appreciate more comments, especially from the framework committers as this only has value if project simple-methods are allowed to be salted with <section-begin/section-end> tags. Because that kind of elegant refactor takes time, it is often easier to

My choices are either to bring he recursion service into my custom
application and make the minor modification or to iterate back
through the list adding the result of the service and then sorting.

I would just reuse the recursion service "as is", and go through the
list with some
after-processing. Maximize reuse, minimize maintenance cost. Project
time frame is seldom less
than cruel!

If that ever becomes a performance bottle-neck, I'll then do something
about it.

Jonathon

Chris Howe wrote:

Thanks for the reply.  Scope isn't my problem.  My problem is a

trade-off between code reuse and performance. Lets say I'm doing one of the

recursive party relationship services that returns a list of related
parties, but I also need to run the partyNameForDate service before

custom application and make the minor modification or to iterate back
through the list adding the result of the service and then sorting.

adding it to the list and I need to sort by name before displaying it on the screen. My choices are either to bring he recursion service into my

----- Original Message ----
From: Jonathon -- Improov <[EMAIL PROTECTED]>
To: dev@ofbiz.apache.org
Sent: Thursday, November 15, 2007 9:38:42 PM
Subject: Re: simple method subsections


Chris,

Have a look at a thread I started at
http://www.nabble.com/forum/ViewPost.jtp?post=10803536&framed=y . You
also responded to that
thread too.

When you say "extend" a simple method, it might be easier to simply
think of how you would extend
a Java method. We would create a new method that first calls the old
method, and then perform some
custom actions after that (or the order could be flipped).

Your suggestion with "selective reuse of parts of a simple method"
would mean changing the
original method (by inserting <section-begin> <section-end>), to
"generic-ize" the original
method. Then you might as well not call it "extension", but
"customization" or "enhancement" or
"refactor" instead.

In that thread I pointed to, I had implemented a
<call-simple-method-scoped> which allows simple
methods to call other simple methods *exactly like how Java methods

can

call other Java methods*.
Unfortunately, the client I worked for now has exclusive rights to

that

new and convenient
artifact. :/

So what's the problem of having simple methods call other simple
methods now, you may ask? Scope
is all mixed up into a single bowl of alphabet soup, single

namespace.

For those of us who know
Java (or C or VB or just about any programming language at all), we
know this isn't conventional,
barely "right".

To offer a solution to your question, I've found that the only way to
call other methods in
Minilang with proper scope (stored in call stack) is to use the

Service

Engine. Yeah, it means
that for every simple method you want to call, wrap them in a service
and call the service instead.

Jonathon

Chris Howe wrote:

I'm looking for some feedback on an idea I'm tossing around

Problem: When creating a custom application, often times you will be

creating business logic that is exactly like what is in OFBiz but

needs

to be slightly modified before sending it to the entity engine for
storage or before creating a result.  (changing the way a price is
calculated, adding specialized field information, etc).

It would helpful to be able to call the OFBiz maintained method and

then extend it through a custom call.

A couple ideas on how to accomplish this
1) Add two new element groups,
<section-begin>
 <section name="sectionA"/>
</section-begin
...some logic...
<section-end>
 <section name="sectionA"/>
</section-end>
...more logic...


and salt the ofbiz method so that you can pull only the logic

between the two

2) mimic the screen-widget's decorator pattern

3) add a map of simple-methods to the method's context that allows

running extended code

extendMethod.myLocation#myMethod

and then salt the ofbiz method to call if it exist.


TIA for any thoughts

,Chris

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