Grady Booch

… 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.

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.

Good people with a good process will outperform good people with no process every time.

Is object-oriented technology mature enough upon which to build indus­trial-strength systems? Absolutely. Does this technology scale? Indeed. Is it the sole technology worth considering? No way. Is there some better technology we should be using in the future? Possibly, but I am clueless as to what that might be. It is dangerous to make predictions, especially in a discipline that changes so rapidly, but one thing I can say with confidence is that I have seen the future, and it is object-oriented.

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.

The function of good software is to make the complex appear to be simple.

[A class category is] a collection of classes, some of which are visible to other class categories, and others of which are hidden.

Object-oriented design is a method of design encompassing the process of object-oriented decomposition and a notation for depicting both logical and physical as well as static and dynamic models of the system under design.

#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

#The adoption of the Precise Action Semantics for the Unified Modeling Language specification by the OMG in November of 2001

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.

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:

Object-oriented programming is a method of implementation in which programs are organized as cooperative collections of objects, each of which represents an instance of some class, and whose classes are all members of a hierarchy of classes united via inheritance relationships.

In a quality object-oriented software system, you will find many classes that speak the language of the domain expert