Format |
|
|
|
Design Patterns: Format
What is the Format? Previous Page: Design Patterns Next Page: Creational Category What is the Format?
"At the moment when a person is faced with an act of design, he does not have time
to think about it from scratch"
The quote by Alexander above illustrates two points about design patterns - firstly it outlines one of the foundational principles upon which they exist. They enable designers to solve problems without having to think about them from scratch every time. Secondly, for this to be possible there must be an agreed upon manner in which this can be communicated between designers. So we need a formal specification, or a Format that allows this to be communicated. The GoF has for a long time been the standard reference for representing design patterns, since their book was the first book to present design patterns for software. Thus this website uses their work as the basis for representing patterns, however it uses a slightly modified format, this will be outlined where appropriate. The format consists of the following: Pattern name and classification - presents the common name of the pattern and its classification (Creational, Behavioral, Structural). Intent - is not used Also known as - is not used Motivation - this is a story or "scenario" [4] that frames a design problem and describes how the object-oriented constructs of the pattern aid in resolving the design problem. "The scenario will help you understand the more abstract description of the pattern..." [4] Applicability - presents poor design solutions that may benefit from the pattern Participants - describes textually all the classes and objects that participate in realizing the design pattern Collaborations - is not used Consequences - details the trade-offs incurred by using this pattern. On this website the focus will explicitly and more heavily focus on the non-functional requirements since these are considered more important in the context of mobile information systems Implementation - presents any language or technology specific limitations. This website will not describe these as all implementation will be done in either Java or Java ME - however where differences exist between the two aforementioned languages this will be duly presented. Sample Code - self-explanatory. All code will be presented in the font of "Courier New" Known Uses - will not normally be used - although some referencing to GoF or other books that provide real applications of the patterns may be provided Related Patterns - presents any patterns that resolve the same or similar functional requirements. Naturally the non-functional trade-offs will then differentiate the various patterns References
[1]Alexander, Christopher:
Notes on the Synthesis of Form,
[2]Alexander, Christopher: A Pattern
Language
[3]Alexander, Christopher:
The Timeless Way of Building
[4]Gamma, Erich., Helm, Richard., Johnson, Ralph. and Vlissides,
John:
Design Patterns: Elements |
copyright Paul Austrem (c) 2007