Hi
The more I study the J2EE technology, the more I
wonder why I should use it.
The main reasons why I would use it are these:
- Forget about the database layer while only using CMP
entity beans.
- Faster.
- Scalable.
- Easier to manage transactions.
- Clear separation between client-workflow-persistence
(JSP - Session beans - Entity beans).
In our current system we use simple JSP, JavaBeans and
a few connections to our database.
We have made a few mistakes but we envisage cleaning
up the system by starting from scratch. It is
important that we choose the right technology but I
get more and more sceptical about the EJB technology.
We have experienced, when doing listings from a search
page, that reading from the database and instantiating
a few beans (not EJBs) takes a long time. The fastest
way is to loop the resultset in the JSP-page, but it
does have a few drawbacks and I would prefer to use
another architecture.
I thought that the pooled entity beans would speed up
the system and started to study EJB.
Then, Richard Monson-Haefel states in his book that
listings shall be done directly between the Session
bean and the database. Otherwise it would be too slow.
I don't want to bother with SQL anymore and I would
like to forget about the database layer, but it seems
very difficult to get away with this requirement.
To communicate between the JSP, the Session beans and
the Entity beans, I get advised to use Data Access
Objects. If I were to ignore the Monson-Haefel advise
I would first create a bunch of Entity beans from a
finder method, instantiate a collection of DAOs and
send them back to the requesting Session bean. I
wonder what kind of performance I would get from this
system? I guess that this can become very heavy
weight.
It will probably become even more heavy weight when
n-m OR-mapping becomes available.
This will force us into a solution were we would have
to use clusters and the scalability features of EJB
comes handy. Is this the strategy from Sun - to make
us buy more SUN servers?
Now, what did I miss? Is there something that I have
completely misunderstood? Please tell me what strategy
we should use while developing CMP entity beans with
Orion's OR-mapping features.
I have found that another paradigm and framework that
will simplify the development and reduce the amount of
SQL-coding.
http://jrf.sourceforge.net/ejb.html
http://jrf.sourceforge.net/
Why shouldn't we use this framework?
Best regards
/johan
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