Hello,
I have been doing some reading on Framework and components,
trying to understand the basic concepts behind their design.
I have some honest questions, not intended to express any
opinion on anything at all, just looking for answers. In fact, I
think I know the answers to some of the questions, but I'm asking
them anyway to check my understanding.
Say I write a class with some kind of business logic:
class Foo { public String getAnswer(String data) { ... } }
The class would in principle benefit with some of the life cycle
abstractions in Framework. For example, the class could need
some kind of configuration and logging, so it could be declared
as:
class Foo implements LogEnabled, Configurable { ... }
Now, I start by testing this class from a simple command line
program. At this point:
1. Do I gain anything by having Foo implement LogEnabled and
Configurable?
2. Who will call the proper configure() method in the class?
Does the class have to be put into a component manager? This
seems to me to be the case, and if this is so, then it is kind of
useless to have a component "living by itself", not as part of a
component manager. Is this correct?
3. If the "component by itself" does indeed not make sense: the
docos talk about running components as stand-alone programs (such
as my test case). In this case, the test program is responsible
for taking the component through the life cycle, right? In this
case, and supposing the component will ONLY be run from a test
program, is there any value at all in making this class a
component and having it implement Configurable? I mean, someone
will have to call the configure() method anyway; why not have the
component call it itself when appropriate?
The second scenario is running this business logic from a
servlet-based application. Under this scenario, the user
interface is handled with Struts; the user enters some data,
clicks on a button, and a Struts Action class is reached. At
this point, the Action class grabs the entered data and is ready
to call the business logic component.
4. Is there any benefit in using a ComponentManager here? After
all, the Action class could simply create an instance of Foo,
pass the parameters and grab the result, right?
5. My understanding is that the ComponentManager at least would
be helpful in providing some kind of pooling of components. If
this is the case, would the ComponentManager be a Singleton? If
yes, who instantiates it? Who ensures it really IS a singleton?
The Struts scenario is more than just an hypothetic example; it
is EXACTLY the way we plan to build our applications. So, my
last questions are:
6. Anybody is using Struts + Framework? Can anybody share
comments, hints, caveats, etc.? For example, can you use LogKit
on the Struts Action classes and on the Components, and have all
output treated uniformly? Or does Struts REQUIRE using log4j?
7. Anybody can provide a real working example of the Struts +
Framework combination?
Sorry if the questions seem basic or confused, and thanks in
advance for any help.
--
Gonzalo A. Diethelm
[EMAIL PROTECTED]
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