I, for one, would recommend an EJB solution w/ JBoss if you're going for a full object model of the database. There are a couple of ways of migrating to EJB, but any of them are going to involve some work and learning a little about EJB containers and JNDI. There is a learning curve, but I thought the EJB model to be relatively easy to learn myself.
Going EJB can slow an application down, it's true, but it all depends on your situation. If you have a small application with a low number of users, the overhead of EJB may negatively impact performance versus a non-EJB solution. However, for large applications/large number of concurrent users, you can't beat JBoss for its thread-pooling, object caching, transaction management, and other wonderful capabilities. A large amount of the slow-down people report with EJB is due to heavy use of Entity beans (the components that form the object data model in EJB), particularly using many fine-grained Entity objects to model the data. This is bad, since retrieving even a small data-set requires the instantiation of many objects, which obviously slows down performance. Many people do not use Entity beans at all, preferring to employ Stateless Session beans (which have great performance) to execute SQL statements to grab data and return values, or populate serializable value objects with the data and return those instead. If you wanted a (relatively) quick solution, you could use Container Managed Persistence (CMP) Entity beans to model the data you already have in tables. Each Entity Class would have field names that correspond to the columns in your table, with corresponding setXXX() and getXXX() methods in the Entity Class. You could then configure the EJB and JBoss deployment descriptors to use your pre-existing database and table names, and JBoss would take care of loading/storing data between the Entity bean and the database. This approach would assume that you wish a 1-to-1 mapping between tables and object types in your system. Check out the JBoss mail list archives for postings by people who have attempted this, as I'm sure there are some "gotchas" involved. Since you already appear to have some value objects created, you could go with the Bean Managed Persistence (BMP) route, which means your Session beans would execute SQL statements against your database, and use the results to populate value objects, which are returned to the front-end parts of your application. The Session beans could also have methods that accept these value objects as parameters, for adding new rows or updating all data for a row in your table. You can, of course, have single-value setXXX() and getXXX() methods too, backed by SQL statements. This approach involves more custom coding than CMP, but you can manage the data model however you like and directly control when and how objects are instantiated. happy coding, Joe Barefoot -----Original Message----- From: James A. Hillyerd [mailto:[EMAIL PROTECTED]] Sent: Saturday, March 23, 2002 2:15 AM To: Struts Users Mailing List Subject: Object Mapping w/ Struts? I am looking for an object-mapping (to sql relational DB) solution for Struts. I have a medium sized database application which I've developed in struts. (around 25 tables in PostgreSQL) I've been using a home-brew lightweight data-access bean system -- using perl scripts to generate beans that interact with the database. The java source these scripts generate need a lot of manual editing, so making changes to the object model can be a nightmare. I tried downloading Torque 2.1, but had problems, so then I tried Torque 3.0b1. It seems like Torque isn't going to integrate well with my already existing tables. I use some postgres types such as TEXT and BOOLEAN, which I would expect to map to LONGVARCHAR and BIT respectively, but in the SQL that torque spit out they were "bytea" and "". I can't find mention of "bytea" in postgres docs, and obviously "" isn't going to do much for me. =) After reading the Torque docs, I really like what it offers but I'm not sure that it will work for me. Are there any other solutions that people can recommend? Or should I try modifying torque to fit my needs? I don't have any EJB experience but I've heard good things about JBoss. I've also heard the going EJB can really slow an application down. I've also noticed some talk of Expresso on this list, would this be worth trying? Thanks for any advice! -james -- [] James A. Hillyerd <[EMAIL PROTECTED]> - Java Developer [] PGP 1024D/D31BC40D F87B 7906 C0DA 32E8 B8F6 DE23 FBF6 4712 D31B C40D -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
