I think the beans should be able to access each opther directly, since
that makes the session bean the cleanest. The session bean would call
getData for returning whatever info is necessary to the servlet.
Fred Loney wrote:
>Do you find the M-H pattern worthwhile in practice? More often than not, the
>presentation layer initiates the Bar access with respect to a non-EJB form bean or
>data object rather than the EJB itself, if for no other reason than to avoid network
>round trips (cf. http://theserverside.com/patterns/thread.jsp?thread_id=79). In that
>case, the Bar access alternatives are:
>
> FooData fd = foo.getData();
> BarData bar = null;
> if (fd.getBarId() != 0) {
> foo = getFooHome().findByPrimaryKey(new Integer(fooId));
> Bar bar = foo.getBar();
> bd = bar.getData();
> }
>
>vs.
>
> FooData fd = foo.getData();
> BarData bar = null;
> if (fd.getBarId() != 0) {
> Bar bar = getFooHome().findByPrimaryKey(new Integer(barId));
> bd = bar.getData();
> }
>
>The second form is slightly simpler than the first and considerably more efficient.
>
>Adam Young wrote:
>
>>The Monson-Haefel book suggests using the foreign keys as properties of
>>the beans, and then have accessors that get the related objects.
>>if foo
>>...
>>int getBarId()
>>void setBarId(int id)
>>Bar getBar();
>>..
>>
>>and then in the FooBean:
>>private Bar bar;
>>public Bar getBar(){
>> if (null == bar){
>> foo = getBarHome().findByPrimaryKey(new Integer(foodId));
>> }
>> return foo;
>>}
>>
>>I am ignoring exception handling and the accessor for getBarHome.
>>
>>Is this the way that most people are handling relationships?
>>
>>Kar YEOW wrote:
>>
>>>The relationship stuff is in EJB2.0 and it is still in DRAFT. It is not yet
>>>supported in JBOSS.
>>>Kar
>>>----- Original Message -----
>>>From: "Richard Kasperowski" <[EMAIL PROTECTED]>
>>>To: <[EMAIL PROTECTED]>
>>>Sent: Tuesday, June 19, 2001 7:34 AM
>>>Subject: [JBoss-user] How to specify relationships between CMP EJBs?
>>>
>>>
>>>I'm trying to understand how container managed persistence make this
>>>happen. I have two EJBs like so:
>>>
>>>-----
>>>public interface Foo extends EJBObject {
>>> Long getId() throws RemoteException;
>>> void setId(Long param) throws RemoteException;
>>> String getName() throws RemoteException;
>>> void setName(String param) throws RemoteException;
>>> Bar getBar() throws RemoteException;
>>> void setBar(Bar param) throws RemoteException;
>>>}
>>>
>>>public interface Bar extends EJBObject {
>>> Long getId() throws RemoteException;
>>> void setId(Long param) throws RemoteException;
>>> String getName() throws RemoteException;
>>> void setName(String param) throws RemoteException;
>>>}
>>>-----
>>>
>>>The idea here is that a Foo has a Bar. The Bar must already exist.
>>>
>>>I want this to work through CMP. I can't quite figure out how to tell
>>>JBoss that there's a relationship between Foo and Bar. I've been
>>>playing around with the tags "relationships" and "cmr-field", but I
>>>haven't been able to get it right.
>>>
>>>Does anyone have an example that I could follow?
>>>
>>>Thanks,
>>>
>>>--
>>>Richard Kasperowski (mailto:[EMAIL PROTECTED])
>>>Tel: 617-576-1552, Fax: 617-576-2441
>>>http://www.altisimo.com/
>>>
>>>
>>>_______________________________________________
>>>JBoss-user mailing list
>>>[EMAIL PROTECTED]
>>>http://lists.sourceforge.net/lists/listinfo/jboss-user
>>>
>>>
>>>_______________________________________________
>>>JBoss-user mailing list
>>>[EMAIL PROTECTED]
>>>http://lists.sourceforge.net/lists/listinfo/jboss-user
>>>
>>>
>>_______________________________________________
>>JBoss-user mailing list
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>>
>
>--
>Fred Loney
>Spirited Software, Inc.
>[EMAIL PROTECTED]
>
>
>
>_______________________________________________
>JBoss-user mailing list
>[EMAIL PROTECTED]
>http://lists.sourceforge.net/lists/listinfo/jboss-user
>
>
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