Grady Booch

The entire history of software engineering is that of the rise in levels of abstraction.

The class Dog is functionally cohesive if its semantics embrace the behavior of a dog, the whole dog, and nothing but the dog.

Structured design does not scale up well for extremely complex systems, and this method is largely inappropriate for use with object-based and object-oriented programming languages.

Typically, a subclass augments or redefines the existing structure and behavior of its superclasses.

#A proposed profile of UML—Executable UML—supports creating a complete and implementation-neutral self-contained expression of application functionality. Steven J. Mellor and Marc J. Balcer define this profile in their book Executable UML: A Foundation for Model-Driven Architecture

Philosophy and cognitive science have contributed to the advancement of the object model. The idea that the world could be viewed either in terms of objects or processes was a Greek innovation, and in the seventeenth century, we find Descartes observing that humans naturally apply an object-oriented view of the world. In the twentieth century, Rand expanded upon these themes in her philosophy of objectivist epistemology. More recently, Minsky has proposed a model of human intelligence in which he considers the mind to be organized as a society of otherwise mindless agents. Minsky argues that only through the cooperative behavior of these agents do we find what we call intelligence.

The (UML) is a general-purpose visual modeling language that is used to specify, visualize, construct, and document the artifacts of a software system. It captures decisions and understanding about systems that must be constructed. It is used to understand, design, browse, configure, maintain, and control information about such systems. It is intended for use with all development methods, lifecycle stages, application domains, and media. The modeling language is intended to unify past experience about modeling techniques and to incorporate current software best practices into a standard approach. UML includes semantic concepts, notation, and guidelines. It has static, dynamic, environmental, and organizational parts. It is intended to be supported by interactive visual modeling tools that have code generators and report writers. The UML specification does not define a standard process but is intended to be useful with an iterative development process. It is intended to support most existing object-oriented development processes.

… I pounded the doors at the local IBM sales office until a salesman took pity on me. After we chatted for a while, he handed me a Fortran [manual]. I'm sure he gave it to me thinking, "I'll never hear from this kid again." I returned the following week saying, "This is really cool. I've read the whole thing and have written a small program. Where can I find a computer?" The fellow, to my delight, found me programming time on an IBM 1130 on weekends and late-evening hours. That was my first programming experience, and I must thank that anonymous IBM salesman for launching my career. Thank you, IBM.

Whereas object-oriented analysis typically focuses upon one specific problem at a time, domain analysis seeks to identify the classes and objects that are common to all applications within a given domain, such as missile avionics systems, compilers, or accounting software.

Ultimately, discovery and invention are both problems of classification, and classification is fundamentally a problem of finding sameness. When we classify, we seek to group things that have a common structure or exhibit a common behavior.

Today, we're at the beginning stages of the next level. Executable UML is the next logical, and perhaps inevitable, evolutionary step in the ever-rising level of abstraction at which programmers express software solutions. Rather than elaborate an analysis product into a design product and then write code, application developers of the future will use tools to translate abstract application constructs into executable entities. Someday soon, the idea of writing an application in Java or C++ will seem as absurd as writing an application in assembler does today. And the code generated from an Executable UML model will be as uninteresting and typically unexamined as the assembler pass of a third generation language compile is today. This shift is made possible by the confluence of four factors:

Every software system needs to have a simple yet powerful organizational philosophy (think of it as the software equivalent of a sound bite that describes the system's architecture)... [A] step in [the] development process is to articulate this architectural framework, so that we might have a stable foundation upon which to evolve the system's function points.

The amateur software engineer is always in search of magic, some sensational method or tool whose application promises to render software development trivial. It is the mark of the professional software engineer to know that no such panacea exist.

An operation is some action one object performs upon another in order to elicit a reaction.

As a noun, design is the named (although sometimes unnamable) structure or behavior of a system whose presence resolves or contributes to the resolution of a force or forces on that system. A design thus represents one point in a potential decision space. A design may be singular (representing a leaf decision) or it may be collective (representing a set of other decisions).