The road to a fully encapsulated layered business model

About 20 years ago, during the time that I was working on my bachelor, I came in contact with a small company selling wall decorations. They had a need for some simple software, so I wrote a MSAccess application for them. During the years they grew and so did their software requirements, which resulted in a major overhaul about 10 years later when the whole code base was moved to Java 1.2 on top of an Informix database (back then considered a real competitor of Oracle’s RDBMS). The best way to access the database was using JDBC, so that was the approach that was chosen. Persistency frameworks were still immature (SDO) or expensive (Oracle’s Toplink).

The whole JDBC-combined-with-Swing did not work really well, partially because I had not figured Swing out when setting up the application’s architecture, but also because Swing uses objects and I had resultsets. Jumping forward another 5 years or so and persistency frameworks finally became an affordable foundation, so it was time to slowly migrate the code base over to Toplink (which soon was renamed to Eclipselink). Using Eclipselink made my Swing life that much easier, more than I expected, but also introduced new challenges.

reinders webshop
reinders webshop

Up until then, using JDBC in the 10 years old style, business logic was spread throughout the application screens. Initially this was a nuisance, but it could be dealt with. But soon, because of the growth of the company, it became a problem; there were additional interfaces required on top of the database for EDIFACT, website, webshop, email data exchange and support of mobile devices. The whole thing had grown into a full-fledged ERP and all these interfaces needed to make sure business rules were followed; it became clear that another approach was needed. (more…)

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Maven is the EJB2 of build tools

KnowledgePlaza has a rapid development platform called Cheyenne. Cheyenne is based on Java and produces in the end a WAR file, that can be run inside any servlet 2.5 / jsp 2.1 compatible container (like Tomcat 6). Cheyenne projects are build using Maven.

One of the features in the build is that there is the option of overlays; a Cheyenne project can be overlaid with other Cheyenne projects, who provide generic Java classes, JSP files, resources, etc. This feature is very similar to the overlay feature in the default WAR plugin, but Cheyenne has a few tweaks and differences that have forced us to write our own Maven plugin.

Initially the concept of Maven is very straight forward; there is a default build cycle consisting of about 20 steps (phases), and certain actions are bound to the phases based on the packaging type. For example: building JARs require different actions than building WARs. Simple? Simple. So in order to implement our tweaked build for Cheyenne all that needs to be done is write some custom actions and bind them to the build cycle. But there is this huge gap between theory and actually getting it to work. (more…)

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