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Re: Business Delegate

George Maggessy

2004-04-20

Replies:

I haven't tested that, but i think it's gonna work out. You
could test the home interface with a try catch and fix it
too.



--- Ricardo de Souza Moura <ricsouzamoura@(protected)>
wrote:
> I am thinking that you aren't understand me!!!!
>
> Imagine the situation:
> All started, ServletContainer on one machine and
> ApplicationServer on
> another machine.
> In this moment your Singleton is in memory.
> Now the ApplicationServer needed restart but the
> ServletContainer didn't
> need.
>
> On this situation your Singleton won't work until your
> ServletContainer
> restart, will it ? Because the home instance at the
> Singleton will be
> "dirty"
>
>
> >From: George Maggessy <gmaggess@(protected)>
> >Reply-To: gjr@(protected)
> >To: J2EEPATTERNS-INTEREST@(protected)
> >Subject: Re: Business Delegate
> >Date: Tue, 20 Apr 2004 06:31:10 -0700
> >
> >I't wont work until the first call. It�s a singleton,
> dude!
> >
> >
> >--- Ricardo de Souza Moura <ricsouzamoura@(protected)>
> >wrote:
> > > So,
> > > if this situation happen this method always will pass
> at
> > > the catch block,
> > > won't it ?
> > > And this situation always will happen untill the
> > > ServletContainer restart.
> > > Only in this time that your Singleton will be reload.
> > >
> > > Thanks
> > >
> > >
> > > >From: George Maggessy <gmaggess@(protected)>
> > > >Reply-To: gjr@(protected)
> > > >To: J2EEPATTERNS-INTEREST@(protected)
> > > >Subject: Re: Business Delegate
> > > >Date: Mon, 19 Apr 2004 11:35:10 -0700
> > > >
> > > >I call it inside each business method.
> > > >
> > > >   public ResponseVO getAllIra() {
> > > >     ResponseVO response = new ResponseVO(null);
> > > >     try {
> > > >       response = getEJB().getAllIra();
> > > >     } catch (Exception ex) {
> > > >
> LogUtility.log(MasterDelegateHandler.class,
> > > >                 ex.getMessage(),
> > > >                 Log4JConstants.FATAL);
> > > >       return new ResponseVO(null,
> > > >                     new
> > > >MessageVO(MessageVO.ERROR,
> > > >
> > > >PropertyManager.getInstance().
> > > >
> > > getProperty(
> > > >         GeneralConstants.FILE_MESSAGES,
> > > >ErrorCode.COMUN_ERROR_GENERAL)));
> > > >     }
> > > >     return response;
> > > >   }
> > > >
> > > >
> > > >--- Ricardo de Souza Moura
> <ricsouzamoura@(protected)>
> > > >wrote:
> > > > > Ok, but your DB implementation is a Singleton, so
> the
> > > > > variables
> > > > >
> > > > > private static MasterDelegateHandler instance =
> null;
> > > > > private static MasterSessionHome home;
> > > > >
> > > > > have already been initialized, haven't it ? So
> when
> > > you
> > > > > call the getEjb
> > > > > method
> > > > >
> > > > > private MasterSession getEJB() {
> > > > >     MasterSession remote = null;
> > > > >     try {
> > > > >       remote = (MasterSession)home.create();
> > > > >     } catch (RemoteException ex) {
> > > > >       ex.printStackTrace();
> > > > >     } catch (CreateException ex) {
> > > > >       ex.printStackTrace();
> > > > >     }
> > > > >     return remote;
> > > > >   }
> > > > >
> > > > > you will get a exception, won't you ?
> > > > > >From: George Maggessy <gmaggess@(protected)>
> > > > > >Reply-To: gjr@(protected)
> > > > > >To: J2EEPATTERNS-INTEREST@(protected)
> > > > > >Subject: Re: Business Delegate
> > > > > >Date: Fri, 16 Apr 2004 14:34:08 -0700
> > > > > >
> > > > > >The BDs are in the client part, that is, it
> won�t
> > > work
> > > > > >until u call it.
> > > > > >
> > > > > >--- Ricardo de Souza Moura
> > > <ricsouzamoura@(protected)>
> > > > > >wrote:
> > > > > > > Ok, I got it.
> > > > > > >
> > > > > > > But I still have some doubts about to do
> cache:
> > > > > > >
> > > > > > > > > My ServletContainer an my EJBContainer
> are in
> > > two
> > > > > > > > > differents machines. If
> > > > > > > > > only the EJBContainer restart what happen
> > > with my
> > > > > > > cache at
> > > > > > > > > the ServletConainer's machine
> > > > > > > > > ? it won't work anymore, will it ?
> > > > > > > In your sample, your method getEJB won't work
> > > untill
> > > > > the
> > > > > > > ServletContainer
> > > > > > > restart.
> > > > > > > am I right ?
> > > > > > >
> > > > > > >
> > > > > > > >From: George Maggessy <gmaggess@(protected)>
> > > > > > > >Reply-To: gjr@(protected)
> > > > > > > >To: J2EEPATTERNS-INTEREST@(protected)
> > > > > > > >Subject: Re: Business Delegate
> > > > > > > >Date: Fri, 16 Apr 2004 13:02:00 -0700
> > > > > > > >
> > > > > > > >I think this sample could clear things
> out...
> > > > > > > >
> > > > > > > >public class MasterDelegateHandler
> > > > > > > >   extends DelegateHandler {
> > > > > > > >
> > > > > > > >   private static MasterDelegateHandler
> > > instance =
> > > > > > > null;
> > > > > > > >   private static MasterSessionHome home;
> > > > > > > >
> > > > > > > >   /**
> > > > > > > >   * Constructor
> > > > > > > >   */
> > > > > > > >   private MasterDelegateHandler() throws
> > > > > > > LookupException {
> > > > > > > >
> > > > > > > >     Reloj cron = new Reloj();
> > > > > > > >     cron.start();
> > > > > > > >
> > > > > > > >     home =
> > > > > > >
> > > >(MasterSessionHome)ServiceLocator.getHomeSession(
> > > > > > > >
> > > GeneralConstants.JNDI_MAESTRAS_SESSION);
> > > > > > > >
> > > > > > > >
> > > LogUtility.log(MasterDelegateHandler.class,
> > > > > > > >               "Tiempo lookup
> > > MasterSession "
> > > > > +
> > > > > > > >
> > > > > > > >Reloj.formatTime(cron.getElapsedTime()),
> > > > > > > >               Log4JConstants.DEBUG);
> > > > > > > >   }
> > > > > > > >
> > > > > > > >   public static synchronized
> > > MasterDelegateHandler
> > > > > > > >getInstance() {
> > > > > > > >
> > > > > > > >     if (home == null) {
> > > > > > > >       try {
> > > > > > > >         instance = new
> > > MasterDelegateHandler();
> > > > > > > >       } catch (LookupException ex) {
> > > > > > > >         ex.printStackTrace();
> > > > > > > >       }
> > > > > > > >     }
> > > > > > > >     return instance;
> > > > > > > >   }
> > > > > > > >
> > > > > > > >   private MasterSession getEJB() {
> > > > > > > >
> > > > > > > >     MasterSession remote = null;
> > > > > > > >     try {
> > > > > > > >       remote =
> (MasterSession)home.create();
> > > > > > > >     } catch (RemoteException ex) {
> > > > > > > >       ex.printStackTrace();
> > > > > > > >     } catch (CreateException ex) {
> > > > > > > >       ex.printStackTrace();
> > > > > > > >     }
> > > > > > > >     return remote;
> > > > > > > >   }
> > > > > > > >
> > > > > > > >   public ResponseVO getAllIra() {
> > > > > > > >     ResponseVO response = new
> > > ResponseVO(null);
> > > > > > > >     try {
> > > > > > > >       response = getEJB().getAllIra();
> > > > > > > >     } catch (Exception ex) {
> > > > > > > >
> > > > > LogUtility.log(MasterDelegateHandler.class,
> > > > > > > >                 ex.getMessage(),
> > > > > > > >
> Log4JConstants.FATAL);
> > > > > > > >       return new ResponseVO(null,
> > > > > > > >                     new
> > > > > > > >MessageVO(MessageVO.ERROR,
> > > > > > > >
> > > > > > > >PropertyManager.getInstance().
> > > > > > > >
> > > > > > > getProperty(
> > > > > > > >         GeneralConstants.FILE_MESSAGES,
> > > > > > > >ErrorCode.COMUN_ERROR_GENERAL)));
> > > > > > > >     }
> > > > > > > >     return response;
> > > > > > > >   }
> > > > > > > >
> > > > > > > >...
> > > > > > > >
> > > > > > > >Did I help u?
> > > > > > > >
> > > > > > > >
> > > > > > > >--- Ricardo de Souza Moura
> > > > > <ricsouzamoura@(protected)>
> > > > > > > >wrote:
> > > > > > > > > I would like very much. thank you.
> > > > > > > > >
> > > > > > > > > But I was thinking about construct my
> > > Business
> > > > > > > > > Delegate(BD) not like a EJB.
> > > > > > > > > The BD would be a normal class. therefore
> my
> > > web
> > > > > tier
> > > > > > > > > don't need to worry
> > > > > > > > > about look up or RemoteException for
> example.
> > > > > Only my
> > > > > > > Bd
> > > > > > > > > would need to worry
> > > > > > > > > about this. is it OK ? Do you agree ?
> > > > > > > > >
> > > > > > > > > About to do cache I have some doubts.
> > > > > > > > > My ServletContainer an my EJBContainer
> are in
> > > two
> > > > > > > > > differents machines. If
> > > > > > > > > only the EJBContainer stop what happen
> with
> > > my
> > > > > cache
> > > > > > > at
> > > > > > > > > the ServletConainer
> > > > > > > > > ? it won't work anymore, will it ?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >From: George Maggessy
> <gmaggess@(protected)>
> > > > > > > > > >Reply-To: gjr@(protected)
> > > > > > > > > >To: J2EEPATTERNS-INTEREST@(protected)
> > > > > > > > > >Subject: Re: Business Delegate
> > > > > > > > > >Date: Fri, 16 Apr 2004 12:20:35 -0700
> > > > > > > > > >
> > > > > > > > > >Hi Ricardo,
> > > > > > > > > >
> > > > > > > > > >Yes. This is a good structure. In fact,
> I
> > > use
> > > > > this
> > > > > > > > > patterns
> > > > > > > > > >and my app works fine. The only thing
> you
> > > have
> > > > > to
> > > > > > > worry
> > > > > > > > > >about is the business delegate or
> delegate
> > > > > handler.
> > > > > > > > > There
> > > > > > > > > >are diferent types for diferent session
> > > beans.
> > > > > > > Like...
> > > > > > > > > >Cache the EJB Handle for stateful beans
> or
> > > cache
> > > > > the
> > > > > > > > > >EJBHome for stateless beans... I could
> send
> > > u a
> > > > > > > sample
> > > > > > > > > if u
> > > > > > > > > >want.
> > > > > > > > > >
> > > > > > > > > >Cheers,
> > > > > > > > > >George Maggessy
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >--- Ricardo de Souza Moura
> > > > > > > <ricsouzamoura@(protected)>
> > > > > > > > > >wrote:
> > > > > > > > > > > Hi folks,
> > > > > > > > > > > I have a doubt.
> > > > > > > > > > >
> > > > > > > > > > > I am projecting my application with
> the
> > > > > structure
> > > > > > > > > below:
> > > > > > > > > > >
> > > > > > > > > > > web tier => business Delegate(BD) =>
> > > > > > > > > ServiceLocator(SL)
> > > > > > > > > > > => Session
> > > > > > > > > > > Facade(SF) => EJBs
> > > > > > > > > > >
> > > > > > > > > > > The web tier use the BD to call
> business
> > > > > methos.
> > > > > > > > > > > The BD use the SL to get a SF
> > > > > > > > > > > The BD use the SF to call business
> > > methods
> > > > > > > > > > > SF is a Session Bean and use Entity
> Beans
> > > and
> > > > > > > others
> > > > > > > > > > > Session Beans to do its
> > > > > > > > > > > work.
> > > > > > > > > > >
> > > > > > > > > > > Is this strutcture a good practice ?
> > > > > > > > > > >
> > > > > > > > > > > Does Somebody have another suggestion
> ?
> > > > > > > > > > >
> > > > > > > > > > > Thanks
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
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