sorry for the cross posting marc -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Peter Antman Sent: Tuesday, July 11, 2000 2:06 AM To: jBoss Subject: [jBoss-User] Jboss and EJB 2.0 Hi, I would like to ask a couple of question regarding the strategy for Jboss and EJB 2.0 - to be able to know in what direction Jboss in particular and EJB servers more generally are heading; this to be able know how to position the EJB tool Percolator (http://www.percolator.org). 1. What is the time frame for EJB 2.0 support? Will we see experimental EJB 2.0 support before the spec is final? Will parts of EJB 2.0 be integrated incrementally i Jboss 2.0 or will it be a completly new release with full EJB 2.0 support? 2. Will J2EE connectors be supported? The spec is out and looks promissing; and the EJB 2.0 spec says that resources should also be possible to be connectors. Will Jboss support Connectors in the near future? (OpenEJB are moving their resource management to the Connector architechure). Personal view: I think that Connectors are realy good. Not only does it make it possible to connect to legacy systems in a portable way, it generally makes it possible to connect to external resources that othervise would be forbidden to do according to the EJB spec. And it does it in a way that will be portable between servers; and there are even an XML description to configure the Connection. I.e, today an external resource will have to be configured in a proprierary way for each EJB server; and you could generally not even be shure that there are a way to instantiate a resource other than JDBC. 3. What is the strategy concerning CMP? In 1.0 and 1.1 CMP persistence was delegated to container; visable in JAWS for example. This is not so in 2.0 (at least accordning to my interpretation). Instead the persistence should be governed by a PersistenceManager (PM). If you read the spec caerfully one may note that the contract between the Container and the PM is basicly the same contract as between the Container and the Bean in BMP. In 2.0 a CMP bean will have to be an abstract class; the dependant object classes should also be abtract. I is then upp to the persistence manager to create subclasses that implements the persistence. These subclasses are EJB Entity beans (possibly with some extensions to handle transaction synchronization). Accoring to my interpretation this means that at CMP container is basicly a BMP container which makes the TransactionManager available in the PM namespace (JNDI) to the bean. Seen from this perspectiv CMP in 2.0 is basiclly a specification of how to design (the bean provider) and autogenerate (the PM provider) BMP beans. When done accorning to the spec, these are called CMP beans. It also means that external generation tools may be used to implement CMP in 2.0 without any knowlage of the CMP container of a specific EJB server. How will Jboss solve this? Will you build a container that is dependant of an external PersistenceManager? Will you create a PersistenceManager? Will you integrate the PercistenceManager in the Container, i.e JAWS? Will is be possible to deploy PM generated impl beans? Without really making any promisses (or threats ;-)) I am contemplating the idea of making Percolator a PersistenceManager for EJB 2.0 since it already have a lot of the code generation logic in place. But if all EJB server will chose to make their own proprietary PM (as Weblogic) and not making a CMP container where you may use an external PM this would be of little use. There are a lot of open issues, I know - its is not shure how you should treat Uniquing of dependant objects, manage Caches at the container level or even how you get the container to deploy the generated Beans in the container. I still think the approach of making the PM external to the container is interesting. Put together with Connectors and JDO the PM begins to look like a universal switching system to connect diverse backends together in a portable way. In what direction is Jboss heading? Greetings Peter ----------------------------------------------------------- Peter Antman Technology in Media, Box 34105 100 26 Stockholm Systems Architect WWW: http://www.tim.se Email: [EMAIL PROTECTED] WWW: http://www.backsource.org Phone: +46-(0)8-506 381 11 Mobile: 070-675 3942 ------------------------------------------------------------ -- -------------------------------------------------------------- To subscribe: [EMAIL PROTECTED] To unsubscribe: [EMAIL PROTECTED] Problems?: [EMAIL PROTECTED]
