Not so long ago I read a great article from a senior level developer, who wrote that as we mature we learn when to look for available libraries before we rush in and build our own. He was referring to the plentiful number of open source projects that exist. Well, there are certainly plenty of those around, but there are also a number of emerging APIs coming right from Sun and the Java Community Process (JCP) - these specifications are known as Java Specification Requests (JSRs). This column will focus on the as many of the JSRs as possible going through the JCP and strive to keep you, the reader, informed of the comings and goings over at the JCP.

Now, as it turns out, about the same time I read that wonderful article I was thinking about building a Rules Engine. So, instead of diving right in and writing one from scratch, I went out and started looking for one on the Web. That is when I came across the JCP Web site and JSR 94, the Java Rule Engine API. More on JSR-94 a little later; first let's learn about the JCP.

The JCP, as defined at www.jcp.org: "The JCP holds the responsibility for the development of Java technology. As an open, inclusive organization of active members and non-member public input, it primarily guides the development and approval of Java technical specifications. Anyone can join the JCP and have a part in its process, and you don't even have to join to contribute as a public participant."

What this means is that any of us can join the process - power to the people! More than just having a say in the process, for $100 any individual can submit a JSR (it does cost more for companies to submit something). The point is that the process is open to anyone, so if you have an idea for an API, you can submit it - visit the following URL for an overview of the process: http://jcp.org/introduction/overview/

The process basically works like this: when a JSR is submitted, first it is reviewed and voted on within 14 days by the EC (Executive Committee. If the committee approves the JSR; the second step occurs: the creation of a community draft and the formation of an expert group. Following the draft and formation of the expert group, there is a community review (30-90 days) and another EC vote (7 days). If it is approved, then the third step is where the JSR team completes the specification and creates a public draft/final release, followed by another review and then a proposed final draft and then a final release. The fourth and last step in the process is the maintenance of the JSR.

Okay, back to the Rules engine. The detail for the Rule Engine API is located at http://jcp.org/jsr/detail/94.jsp. You can get a good bit of information about the Rule Engine API from this page. The format on this page is the same format for all of the JSR's. The page describes the proposed spec, the target platform (J2SE, J2EE, or J2ME), what need the JSR will address, and so on. Near the top of the page is very important section entitled "Status'". This section is ordered with the most recent status at the top. As you can tell from the JSR 94 page, the status just completed the Public Review stage (it closed on September 11, 2002). By clicking on the Public Review link, you are taken to the details of the public review, and there is a link on the page where you can download the specification - after agreeing to the license.

After downloading the specification, you can see that there is plenty of stuff in the 6+mg distribution including a Reference Implementation (RI), the full JavaDoc as well as a PDF of the specification that includes a complete overview of the architecture and example code. The distribution also includes all the third party, open-source libraries that the Rule Engine uses as well as the full Technology Compatibility Kit (TCK) with all of the test code for proving that the RI is compatible with the JDK. Is Java great or what?

Now that we have covered the JCP, JSR 94 - Java Rule Engine API, the only things left for future columns are the numerous other specifications that are currently going through the process. My aim for the weeks and months ahead is to keep you informed of the status of these proposed JSRs, as well as provide some technical details about them.

Please feel free to let me know what you think; I am always available to talk about Java!

Resources:

Java Community Process site - http://www.jcp.org

The Java Community Process(SM) Program - JSRs: Java Specification Requests - Detail (http://jcp.org/jsr/detail/94.jsp)

http://herzberg.ca.sandia.gov/jess/ri_overview.shtml (Missing file from the JSR public review package)