Business logic "beans"

[Daniel Steinberg <Da...@gale.com>]

The Struts User's Guide suggests that business logic be encapsulated in
beans.  Business logic modules are generally stateless, so one would
generally implement them as static utility classes (with only static
methods) or singletons (with private constructors and static factory
methods), neither of which can be "beans" (which, by definition, have public
constructors).  To effectively manage stateless classes as beans (without
re-instantiating them for each use), one would have to implement a
lookup/mapping mechanism (an "EJB-lite").  Are the Struts developers
suggesting that we develop such mechansisms?  Might such a mechanism be
slated for a future version of Struts?


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RE: Business logic "beans"

[Robert <rm...@bull-enterprises.com>]

Perhaps the term "business logic" is misleading to an extent. To some,
business logic in JavaBeans can mean that a JavaBean is a stateful
representation of data in a database, that also has 'logic' in it for
other means, such as validation, computation, etc. The term used like
you suggest would fit in a model like stateless session beans, although
something could be developed that isn't EJB. Now you mention a
lookup/mapping mechanism, well look at Avalon
(http://jakarta.apache.org/avalon). It has just such a mechanism. 

I believe in using both approaches, using beans as data and logic as
well as stateless logic components. We use both for our eQ! product and
(slowly) I'm convincing others that we should build it upon Avalon. Our
Struts adapters and our scripting engine (both of which I wrote) use
Avalon for looking up other components. I'm trying to convince the boss
to let me port our persistence layer to use the same framework.

- Robert

-----Original Message-----
From: Daniel Steinberg [mailto:Daniel.Steinberg@gale.com] 
Sent: Wednesday, February 20, 2002 12:06 PM
To: 'struts-user@jakarta.apache.org'
Subject: Business logic "beans"

The Struts User's Guide suggests that business logic be encapsulated in
beans.  Business logic modules are generally stateless, so one would
generally implement them as static utility classes (with only static
methods) or singletons (with private constructors and static factory
methods), neither of which can be "beans" (which, by definition, have
public
constructors).  To effectively manage stateless classes as beans
(without
re-instantiating them for each use), one would have to implement a
lookup/mapping mechanism (an "EJB-lite").  Are the Struts developers
suggesting that we develop such mechansisms?  Might such a mechanism be
slated for a future version of Struts?


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<ma...@jakarta.apache.org>
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