iSeries Interface Green screen Web browser Web service Transport 5250 WebFacing Presentation and navigation Display file Struts/JSF Connectors JDBC, MQ, etc. Application logic RPG or COBOL program Session bean There are 2 slides, firstly an iSeries version and secondly a Unix version. The red arrows indicate the ‘legacy’ setup. In the iSeries environment I would count WebFacing as ‘legacy’. The blue arrows indicate first steps towards a J2EE deployment using either Struts or Java ServerFaces. The need arises at this stage to decouple the 5250 interface from its accompanying back end logic, but this work should require no new skills. Navigation and presentation are taken over by Struts or JSF, interfacing with the back end logic via appropriate connector technology (JDBC+stored procedures, MQ, etc.). This is the point at which IDE (e.g. Eclipse) and Java skills start to be acquired. There is little requirement at this stage for detailed OO understanding, since the vast majority of the code is either generated automatically by the Java IDE or remains within the legacy code base (‘thin layer of Java, fat layer of RPG’). The green arrows indicate J2EE Enterprise JavaBeans deployment. Here the logic has been migrated to session beans, and the data is held as entity beans, persistence involving storage within the existing relational database. At this stage there is a need for detailed OO understanding and extensive Java skills. Physical or logical file Entity bean Interface to data store Database DB2/400

Unix Interface Web browser Client/server Web service Green screen Transport Telnet Presentation and navigation Struts/JSF Programs written in COBOL, C, etc. Connectors JDBC, MQ, etc. Application logic Session bean I have looked up Powerhouse & it appears to be able to generate 3 types of application: straight green screen, client/server and Web. Thus I have allowed for all of these in the diagram. For clarity the diagram does not show the ‘fat client’ client/server model where the Unix box is used only as a database server and the database client API (or ODBC) runs on the client PC. I don’t think Powerhouse generates this sort of application anyway. The red arrows indicate the ‘legacy’ setup. The blue arrows indicate first steps towards a J2EE deployment using either Struts or Java ServerFaces. The need arises at this stage to decouple the 5250 interface from its accompanying back end logic, but this work should require no new skills. Navigation and presentation are taken over by Struts or JSF, interfacing with the back end logic via appropriate connector technology (JDBC+stored procedures, MQ, etc.). This is the point at which IDE (e.g. Eclipse) and Java skills start to be acquired. There is little requirement at this stage for detailed OO understanding, since the vast majority of the code is either generated automatically by the Java IDE or remains within the legacy code base. The green arrows indicate J2EE Enterprise JavaBeans deployment. Here the logic has been migrated to session beans, and the data is held as entity beans, persistence involving storage within the existing relational database. At this stage there is a need for detailed OO understanding and extensive Java skills. Database client APIs Entity bean Interface to data store Database Relational database (Oracle, DB2, etc.)