Some Background on Design Patterns The term “design patterns” sounds a bit formal to the uninitiated and can besomewhat off-putting when you first encounter it. But, in fact, design patternsare just convenient ways of reusing object-oriented code between projects andbetween programmers. The idea behind design patterns is simple-- writedown and catalog common interactions between objects that programmershave frequently found useful. The field of design patterns goes back at least to the early 1980s. At that time,Smalltalk was the most common OO language and C++ was still in itsinfancy. At that time, structured programming was a commonly-used phrasedand OO programming was not yet as widely supported. The idea ofprogramming frameworks was popular however, and as frameworksdeveloped, some of what we now called design patterns began to emerge.