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Re: Business Delegate

Ricardo Moura

2004-04-19

Replies:

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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> > >
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