The classes I want to refactor are delegate objects that help my web tier connect to the ejb tier. My servlets and also my Strut's action classes use these delegates to get references to the session beans in the backend tier. At this moment, the servlets and action classes create new delegates with every request that they handle. I was hoping to avoid this by making the delegate a static class or maybe a singleton. However, I'm not sure if that could bring any synchronization issues. The beanBag example is what I was attempting to do minus the synchronized key word. I don't want to use the synchronized keyword b/c I'm sure it will affect performance and our site has a heavy load.
--- On Sun, 6/14/09, David Blevins <david.blev...@visi.com> wrote: From: David Blevins <david.blev...@visi.com> Subject: Re: using static helper classes within servlets To: "Tomcat Users List" <users@tomcat.apache.org> Date: Sunday, June 14, 2009, 9:12 PM That's too bad. A workable solution in EJB 2.1 would be to use a stateless bean and set the pool size to 1. That will effectively give you a singleton, though keep in mind it won't be multithreaded so code appropriately. -David On Jun 14, 2009, at 5:17 PM, Sid Sidney wrote: > Thanks David, but we are stuck with Struts and EJB 2.1 at the moment. > > --- On Sun, 6/14/09, David Blevins <david.blev...@visi.com> wrote: > > From: David Blevins <david.blev...@visi.com> > Subject: Re: using static helper classes within servlets > To: "Tomcat Users List" <users@tomcat.apache.org> > Date: Sunday, June 14, 2009, 5:43 PM > > Hey all, > > If the goal is to ensure that only one instance is in the webapp, I'd > recommend the new EJB 3.1 bean type @Singleton which is supported in OpenEJB > 3.1 and 3.1.1. > > http://openejb.apache.org/3.0/singleton-example.html > http://openejb.apache.org/singleton-ejb.html > > Instantiation can be done at startup or lazily. All method access > synchronization is handled for you via @ConcurrencyManagement(CONTAINER) or > by you @ConcurrencyManagement(BEAN). Regardless of that choice we will still > handle sychronization of instantiation, so double-check-locking or other > things will not be necessary. > > > -David > > > On Jun 14, 2009, at 11:19 AM, Martin Gainty wrote: > >> >> that would be the simplest solution >> >> i *think* the OP wanted a complete EJB jar implementation (using either >> annotations and or ejb-jar.xml) >> which can be accomplished with OpenEJB except he would need to know the type >> vis-a-vis Stateless/Stateful Local/Remote beforehand >> http://openejb.apache.org/3.0/examples.html >> >> thanks, >> Martin >> ______________________________________________ >> Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité >> >> Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene >> Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte >> Weiterleitung oder Fertigung einer Kopie ist unzulaessig. 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Étant donné que les email >> peuvent facilement être sujets à la manipulation, nous ne pouvons accepter >> aucune responsabilité pour le contenu fourni. >> >> >> >> >>> Date: Sun, 14 Jun 2009 13:01:31 -0400 >>> Subject: Re: using static helper classes within servlets >>> From: jhmast.develo...@gmail.com >>> To: users@tomcat.apache.org >>> >>> I've not done anything with EJBs and I'm not sure what exactly you mean by >>> static "properties". I have however dealt with reducing instantiations in >>> servlets. I simply created a BeanBag class with static methods to each one >>> of my beans; these are not "proper" beans, but where simply objects that >>> were formerly used in JSP via the jsp:useBean directive. >>> >>> Here is the general pattern: >>> >>> class BeanBag { >>> private static SomeBean someBean = null; >>> >>> public static synchronized getSomeBean() { >>> if (someBean == null) someBean = new SomeBean(); >>> return someBean; >>> } >>> } >>> >>> I have now numerous Servlets, JSPs and POJOs that use BeanBag to obtain >>> singleton instances of my beans. Its worked great for me. >>> >>> >>> On Sun, Jun 14, 2009 at 8:28 AM, Sid Sidney <pvcsv...@yahoo.com> wrote: >>> >>>> >>>> >>>> >>>> HI, >>>> >>>> >>>> >>>> In my web app, my servlets user several delegate classes that connect >>>> to ejbs (session beans.) I was thinking >>>> about putting these delegates into a helper class as static properties. >>>> That way my servlets can just reference the same delegates. I >>>> don't want to have to create a new instance of a delegate with every >>>> request that my servlet(s) handles. >>>> >>>> >>>> >>>> However, I'm wondering if this will cause synchronization issues with >>>> multiple requests being handled, as our site handles a heavy load of >>>> requests. Any suggestions would be appreciated? >>>> >>>> >>>> >> >> _________________________________________________________________ >> Insert movie times and more without leaving Hotmail®. >> http://windowslive.com/Tutorial/Hotmail/QuickAdd?ocid=TXT_TAGLM_WL_HM_Tutorial_QuickAdd_062009 > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
