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Compiling a UML model into Java code works in two parts. First, Rhapsody checks the model's syntax and to a certain extent its semantics. This is possible because the model should be logically consistent; the editor doesn't allow things that are illegal in the modeling language. It can also do some checking for internal consistency, primarily to make sure that the model as represented by one diagram coheres with any related diagrams.

In April 2002 Richard and Robert presented a tutorial session on Naked Objects at OT2002, the annual conference of the British Computer Society OO specialist group (BCS OOPS). As an attendee of that session, Dan was struck by the capabilities of Naked Objects in its own right, but he also immediately saw the potential synergy. Together allows the developer to switch instantaneously between UML and code representations of the object model; combining this with Naked Objects would allow an instantaneous switch to a user representation of the object model. During the course of that first afternoon at OT2002, Dan got the two technologies working together. The two screenshots below show a UML diagram and a Naked Objects user representation of a prototype Conference Management system produced that same afternoon in just a couple of hours, by a group of Java programmers that had never previously used Naked Objects.

The following are best practices used in the creation of base processes for holonic software development. Many of these practices have become so commonplace in our industry that they are often overlooked or taken for granted, yet I feel it is worthwhile to list them here. Taken together, the ten best practices below comprise a development process that is:

In this example, you first define a simple class model (see Figure 1), and then illustrate how pureQuery, through the auto-generation of respective DDL commands for each class, can be utilized to assist developers in the implementation and execution of physical data modeling, as expressed earlier.

In the conclusion to my previous column (see Resources), I promised that this column would be dedicated to the various methods of requirements gathering in an agile development process. As I began work on that column, however, I realized it might be worthwhile to begin with the larger discussion of agile software development. But as I began work on that topic, I found myself itching to discuss the related topic of holonic software development.

As the example above shows, generic sequence diagrams -- and in fact all UML diagrams -- closely map the Java language syntax. As a result, most Java developers have an intuitive understanding of these diagrams, and can learn to use them fairly quickly. To further explore the correspondence between generic sequence diagrams and the Java language, we'll diagram the for loop shown in Listing 2.

The Unified Modeling Language (UML) is a standard notation for modeling object-oriented systems. Introduced to the object-oriented programming community in stages between 1995 and 1997, UML was approved by the Object Management Group (OMG) in late 1997. Though it was controversial upon inception -- it was introduced amidst a flurry of protest and counterproposals -- UML has since become the industry standard for system notation. UML is now in version 1.4 and continues to evolve to meet the needs of object-oriented developers. (For more about the history of UML, see Resources.)

This week, our favorite resource(s) from our Resources and Downloads directories are Dingo UML Modeler, an open-source UML modeling tool based on the JavaBeans Component Architecture, and Demeanor for .NET, an assembly obfuscator designed to secure your .NET applications.

A UML formal parameter that is preceded by in or nothing has the value of its actual parameter passed into the operation. However, the operation cannot modify the actual parameter's value. This is similar to a parameter of a Java method or a VB.NET parameter that is preceded by ByVal.

But, Plone goes one step further in letting web developers define content types of their own. By modeling application objects as content types, you can go on to define complete web applications in terms of content management. This has the immediate effect of simplifying web application development by hooking into all of the features that a CMS provides "for free": persistence into a database, authentication and authorization, form and page generation, data validation, and so forth.

The image frame below shows the simulation of some arbitrary (random) stock-price moving average and its Bollinger Bands over discrete time periods. The user is encouraged to run this small application and experiment with varying different parameter values, that is "Number of days" and "Type" (Alpha-level), where the change is reflected instantly from the plottings. You can plot random new generated data by clicking on the button named Generate data. The class that does this simulation is called Bollinger.java; it is named after its inventor, John Bollinger. Interested Java developers who are currently involve in projects developing financial application systems should read the references below:

Although not blood-chillingly exciting, the figure shows a single picture that represents the contents of two source code files. UML class diagrams are very good for communicating the overall structure of a number of classes and the dependencies between them in a single picture. For example, many books on analysis and design patterns use UML class diagrams to show the structure of the classes participating in the patterns they describe.