EJB and Tools

Question

Hi there,
3 questions here:
First, does CMP can call stored procedure from a database? or BMP only? or both? Please show me some codes on whichever.
Secondly, can a session bean call a stored procedure? Any codes?
Last, does there any tools or IDE that have source codes control and works with WebLogic servers?
Thanks a lot
Neo

Answer 1

Some further explanation please...
1. What does these method doing inside my EJBean?
- ejbPassivate()As the name suggest this method helps in passivation... i.e. persistence of ejb state.
The container invokes this method on an instance when the container decides to disassociate
the instance from an entity object identity, and to put the instance back into the pool of avail-able
instances. The ejbPassivate() method gives the instance the chance to release any
resources that should not be held while the instance is in the pool. (These resources typically
had been allocated during the ejbActivate() method.)
For session beans in advanced cases, a session object�s conversational state may contain open resources, such as open sockets and open database cursors. A container cannot retain such open resources when a session bean instance is passivated. A developer of such a session bean must close and open the resources in the ejbPassivate and ejbActivate notifications.
- setSessionContext(SessionContext ctx), since my
my codes in the Remote interface does not call this
method which also passes a parameter ctx?setSessiontContext is invoked by container and the ctx required by it is supplied by container. Thus u dont require to pass ctx parameter.
The bean�s container calls the setSessionContext method to associate a session bean instance
with its context maintained by the container. Typically, a session bean instance retains its session context as part of its conversational state.
The context supplied by the container helps you to identify the poperties in deployment descriptor...i.e. your next question..
- Where does this referred in the EJBean ->
-> cntx.lookup("java:comp/env/jdbc/mydatabase");
where that i can see the reference to?
You can refer these statements any where u need to access database. Suppose you need to fire a procedure after you have created a record. You can write these statments in ejbPostCreate method.
2. Inside my ejb-jar.xml file, which is a deployment
descriptor, what are these tags meant?
- <env-entry>, <env-entry-name>, <env-entry-type>,
e>, <env-entry-value>
env-entry stands for environment entries. These are like env. variables which u need to access at runtime.
Each env-entry element describes a single environment entry. The env-entry element consists of
an optional description of the environment entry, the environment entry name relative to the
java:comp/env context, the expected Java type of the environment entry value (i.e., the type of the
object returned from the JNDI lookup method), and an optional environment entry value.
An environment entry is scoped to the enterprise bean whose declaration contains the env-entry ele-ment.
This means that the environment entry is inaccessible from other enterprise beans at runtime, and
that other enterprise beans may define env-entry elements with the same env-entry-name with-out
causing a name conflict.
The environment entry values may be one of the following Java types: String, Character, Inte-ger,
Boolean, Double, Byte, Short, Long, and Float.
If the Bean Provider provides a value for an environment entry using the env-entry-value ele-ment,
the value can be changed later by the Application Assembler or Deployer. The value must be a
string that is valid for the constructor of the specified type that takes a single String parameter, or for
java.lang.Character, a single character.
For example:
<env-entry>
<description>Return the developer of the bean</description>
<env-entry-name>author</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>Neo</env-entry-value>
</env-entry>
Here description tag is optional.
<env-entry-name> specifies the property name, which in our case is author.
<env-entry-type> specifiest the data type of property, i.e String
<env-entry-value>The value for the property i.e Neo
You can imagine this as a java statement like
String author = Neo; //Return the developer of the bean.
TQ
NeoHope this explanation was helpful to u
abhishek