On Wed, 2003-12-31 at 02:05, Stephen Ting wrote: > Hi Adrian, > > > Happy new year 2004. > > You mention about Interceptor stuff, where can I find information and > example on Interceptor stuff? I believe this stuff is Jboss specific, > right. >
Yes, Interceptors are JBoss specific. > My objective to use Mbean is to act as a caching layer (where the cached > object is stored), I only require a simple caching algorithm to store > object retrieved from database in the static variable of the mbean. > Why static? An MBean is a singleton. > Now, if I will to use the Interceptor, is there any caching tool which > works in Jboss. Sorry for all this novice questions, I am very new to > most of the Jboss services. > There is a LRU cache implementation that is commonly used within jboss. org.jboss.util.LRUCachePolicy Regards, Adrian > > Regards, > Stephen > > >-----Original Message----- > >From: [EMAIL PROTECTED] > >[mailto:[EMAIL PROTECTED] On Behalf Of > >Adrian Brock > >Sent: 31 December 2003 00:27 > >To: [EMAIL PROTECTED] > >Subject: Re: [JBoss-user] Asking about Mbean usage > > > > > >On Tue, 2003-12-30 at 06:59, Stephen Ting wrote: > >> Hello, > >> > >> I am a JMX newbie, i have successfully write some standard mbean > >> follows the example in the Jboss docs. I plan to do some serious > >> component using this model, therefore i post this message to verify > >> with you gurus and hope to get some comments and feedbacks. > >> > >> My objective of using mbean is to create a caching layer at > >the server > >> side where some data retrieve through session bean will be cached at > >> the mbean. The client (web-client, java client) will access > >the mbean > >> to retrieve data, only if the data is not available in the cache it > >> will invoke the session bean(which will retrieve data from > >database). > >> So rougly the flow would be > >> > >> client -> mbean -> session bean -> database. > >> > >> What i currently did were; > >> > >> 1. Create a mbean that's serializable and bind the mbean to a jndi > >> server using the following code. The mbean have some static Map for > >> caching. > >> > >> private void bind(Context ctx, String name, Object val)throws > >> NamingException{ > >> Name n; > >> for (n = ctx.getNameParser("").parse(name); n.size() > > >> 1; n = n.getSuffix(1)){ > >> String ctxName = n.get(0); > >> try{ > >> ctx = (Context) ctx.lookup(ctxName); > >> }catch (NameNotFoundException > >> namenotfoundexception){ > >> ctx = ctx.createSubcontext(ctxName); > >> } > >> } > >> ctx.bind(n.get(0), val); > >> } > >> > >> 2. invoke the mbean through jboss RMIConnector, using the RMIAdapter > >> bind at the Following jndi name "jmx/rmi/RMIAdaptor". Then I will > >> invoke the mbean using the > >> RemoteMBeanServer instance. > >> > >> RMIAdaptor adaptor = (RMIAdaptor)context.lookup(jndiName); > >> RemoteMBeanServer server = new RMIConnectorImpl(adaptor); > >> > >> > >> My questions are: > >> > >> 1. Is it appropriate to implement my objective using mbean > >or there is > >> better altenatives? > > > >You could just implement it as an interceptor on the session bean. > > > >import org.jboss.ejb.plugins.AbstractInterceptor; > >import org.jboss.invocation.Invocation; > > > >public IdempotentInterceptor extends AbstractInterceptor > >{ > > public Object invoke(Invocation invocation) throws Exception > > { > > Object result = getResultFromCache(invocation); > > if (result != null) > > return result; > > else > > // Not in cache invoke the session bean > > return getNext().invokeNext(invocation); > > } > >} > > > > > > >> 2. I notice in the example there is NonSerializable binding. What is > >> the different in binding A serializable or non serializable > >mbean? If > >> I require to access the mbean remotely which is more appropriate? > > > >Neither. > >If you use non serializable it won't be available outside the > >jvm. If you use serializable you will receive a clone of the > >mbean object > >on the client. > >You have a number of options: > >1) Make the MBean an RMI remote object (the client will > >receive a stub rather than the mbean). > >2) Use the RMIAdapter to access the MBean. > >3) Make your MBean invokable via a JBoss invoker and use a > >proxy factory to bind a proxy to the mbean in jndi (there is > >an example in chapter 2 of the admin docs). > > > >> 3. If I had a serializable mbean, does that meant each time I invoke > >> the mbean I will get a copy of the mbean or a 'proxy' of the mbean? > >> From my testing I found that whenver I invoke the mbean through the > >> connector, the changes is reflect at the server. > > > >The connector is option 2 above. > > > >> 4. Does the mbean only instantiated once in the server JVM, meaning > >> all the client will access the same mbean instance? If no, can I > >> create a singleton mbean? > >> > > > >MBeans are singletons. > > > >> 5. what's the different between RMIAdaptor and RMIConnector? > > > >The RMIAdaptor allows you to remotely invoke the MBeanServer. > >The RMIConnector adds extra behaviour like remote > >notifications. Both are remote proxies/stubs for the MBeanServer. > > > >Regards, > >Adrian > > > >> > >> Thanks. > >> > >> Any comments and suggestions are very much appreciated. > >> > >> > >> Regards, > >> Stephen > >> > >> > >> > >> ------------------------------------------------------- > >> This SF.net email is sponsored by: IBM Linux Tutorials. Become an > >> expert in LINUX or just sharpen your skills. Sign up for IBM's Free > >> Linux Tutorials. Learn everything from the bash shell to sys admin. > >> Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click > >> _______________________________________________ > >> JBoss-user mailing list > >> [EMAIL PROTECTED] > >> https://lists.sourceforge.net/lists/listinfo/jboss-user > >-- > >xxxxxxxxxxxxxxxxxxxxxxxx > >Adrian Brock > >Director of Support > >Back Office > >JBoss Group, LLC > >xxxxxxxxxxxxxxxxxxxxxxxx > > > > > > > >------------------------------------------------------- > >This SF.net email is sponsored by: IBM Linux Tutorials. > >Become an expert in LINUX or just sharpen your skills. Sign > >up for IBM's Free Linux Tutorials. Learn everything from the > >bash shell to sys admin. Click now! > >http://ads.osdn.com/?ad_id=1278&alloc_id=3371>&op=click > > > >_______________________________________________ > > > >JBoss-user mailing list > >[EMAIL PROTECTED] > >https://lists.sourceforge.net/lists/listinfo/jb>oss-user > > > > > > ------------------------------------------------------- > This SF.net email is sponsored by: IBM Linux Tutorials. > Become an expert in LINUX or just sharpen your skills. Sign up for IBM's > Free Linux Tutorials. Learn everything from the bash shell to sys admin. > Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click > _______________________________________________ > JBoss-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/jboss-user -- xxxxxxxxxxxxxxxxxxxxxxxx Adrian Brock Director of Support Back Office JBoss Group, LLC xxxxxxxxxxxxxxxxxxxxxxxx ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. 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