Background Cut-and-Paste Programming is a very common, but degenerate form of software reuse which creates maintenance nightmares. It comes from the notion that it's easier to modify existing software than program from scratch. This is usually true and represents good software instincts. However, the technique can be easily over used....

AntiPattern Problem Using today's software technology is analogous to walking through a high-technology mine field. This mini-AntiPattern is also known as Nothing Works or Do You Believe in Magic? Numerous bugs occur in released software products; in fact, experts estimate that original source code contains two to five bugs per...

AntiPattern Problem Software that fails straightforward behavioral tests may be an example of an Input Kludge, which occurs when ad hoc algorithms are employed for handling program input. For example, if the program accepts free text input from the user, an ad hoc algorithm will mishandle many combinations of legal...

Background The Spaghetti Code AntiPattern is the classic and most famous AntiPattern; it has existed in one form or another since the invention of programming languages. Nonobject-oriented languages appear to be more susceptible to this AntiPattern, but it is fairly common among developers who have yet to fully master the...

AntiPattern Problem A Dead End is reached by modifying a reusable component, if the modified component is no longer maintained and supported by the supplier. When these modifications are made, the support burden transfers to the application system developers and maintainers. Improvements in the reusable component cannot be easily integrated,...

Background This is one of the most common AntiPatterns in the industry. Frequently, a vendor, specifically a database vendor, will advocate using its growing product suite as a solution to most of the needs of an organization. Given the initial expense of adopting a specific database solution, such a vendor...

AntiPattern Problem A Boat Anchor is a piece of software or hardware that serves no useful purpose on the current project. Often, the Boat Anchor is a costly acquisition, which makes the purchase even more ironic. The reasons for acquiring a Boat Anchor are usually compelling at the time. For...

Background When Michael Akroyd presented the Gypsy AntiPattern at Object World West in 1996, he likened the transient appearance and then discrete vanishing of the gypsy class to a "Gypsy Wagon" that is there one day and gone the next. As we studied Akroyd's model, we wanted to convey more...

Background Functional Decomposition is good in a procedural programming environment. It's even useful for understanding the modular nature of a larger-scale application. Unfortunately, it doesn't translate directly into a class hierarchy, and this is where the problem begins. In defining this AntiPattern, the authors started with Michael Akroyd's original thoughts...

AntiPattern Problem Object-oriented analysis and design (OOA&D) models are often presented without clarifying the viewpoint represented by the model. By default, OOA&D models denote an implementation viewpoint that is potentially the least useful. Mixed viewpoints don't allow the fundamental separation of interfaces from implementation details, which are one of the...

Background In a data-mining expedition, we began looking for insight into developing a standard interface for a particular kind of system. The system we were mining was very similar to those we hoped would eventually support the standard we were working on. It was also a research-originated system and highly...

AntiPattern Problem Technology is changing so rapidly that developers have trouble keeping up with the current versions of software and finding combinations of product releases that work together. Given that every commercial product line evolves through new product releases, the situation has become increasingly difficult for developers to cope with....

Background Do you remember the original black-and-white movie The Blob? Perhaps you saw only the recent remake. In either case, the story line was almost the same: A drip-sized, jellylike alien life form from outer space somehow makes it to Earth. Whenever the jelly thing eats (usually unsuspecting earthlings), it...

Good software structure is essential for system extension and maintenance. Software development is a chaotic activity, therefore the implemented structure of systems tends to stray from the planned structure as determined by architecture, analysis, and design. Software refactoring is an effective approach for improving software structure. The resulting structure does not have to resemble the original planned structure. The structure changes because programmers learn constraints and approaches that alter the context of the coded solutions. When used properly, refactoring is a natural activity in the programming process.