Grady Booch Quotes

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

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.

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

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.

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.

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:

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

#The availability of high-quality Model Compilers and Virtual Execution Environments (VEEs) that provide "out of the box" platforms upon which Executable UML models can execute. These VEEs, which exist today in a somewhat incipient stage, will someday soon reduce low-level system architectures to near-commodity status.

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

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

[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 physician, a civil engineer, and a computer scientist were arguing about what was the oldest profession in the world. The physician remarked, "Well, in the Bible, it says that God created Eve from a rib taken out of Adam. This clearly required surgery, and so I can rightly claim that mine is the oldest profession in the world." The civil engineer interrupted, and said, "But even earlier in the book of Genesis, it states that God created the order of the heavens and the earth from out of the chaos. This was the first and certainly the most spectacular application of civil engineering. Therefore, fair doctor, you are wrong: mine is the oldest profession in the world." The computer scientist leaned back in her chair, smiled, and then said confidently, "Ah, but who do you think created the chaos?"

Perhaps the greatest strength of an object-oriented approach to development is that it offers a mechanism that captures a model of the real world.

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."