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Re: Business Delegate

George Maggessy

2004-04-19

Replies:

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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> > > >
> > >
> >
>
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