Re: Business Delegate

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 wonï¿½t 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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Re: Business Delegate

Ricardo Moura

2004-04-19