Grady Booch Quotes

If an abstraction is a kind of some other abstraction, or if it is exactly equal to the sum of its components, then inheritance is a better approach

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.

As Cox points out, "Without inheritance, every class would be a free-standing unit, each developed from the ground up. Different classes would bear no relationship with one another, since the developer of each provides methods in whatever manner he chooses. Any consistency across classes is the result of discipline on the part of the programmers. Inheritance makes it possible to define new software in the same way we introduce any concept to a newcomer, by comparing it with something that is already familiar."

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).

In the early days of modern computing - the 40s, 50s and 60s - computing was a priesthood. Only a few were allowed to commune directly with the machine; all others would give their punched card offerings to the anointed, who would in turn genuflect before their card readers and perform their rituals amid the flashing of lights, the clicking of relays, and the whirring of fans and motors. If the offering was well-received, the anointed would call the communicants forward and in solemn silence hand them printed manuscripts, whose signs and symbols would be studied with fevered brow.

#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

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

A class is a set of objects that share a common structure and a common behavior

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.

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

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 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.

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.

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.