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Summary. What is a Design Pattern?. A Design Pattern is a solution to a problem in a context, where The context is the situation in which the pattern is applied, where such situations are encountered repeatedly
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Summary SE-2811 Dr. Mark L. Hornick
What is a Design Pattern? A Design Pattern is a solution to a problem in a context, where • The context is the situation in which the pattern is applied, where such situations are encountered repeatedly • The solution is a general design that can be applied with small modifications to similar contexts SE-2811 Dr. Mark L. Hornick
Design Patterns emerge from the software development community There is no central organization that invents Design Patterns • Patterns are “discovered” by software developers that recognize similarities in solutions applied in different contexts • experience helps • Patterns are “popularized” by software developers cataloging these solutions • Creating a common language that can be used in the development community SE-2811 Dr. Mark L. Hornick
Design Patterns are categorized by formally describing their characteristics The “Pattern Community” has evolved a de-facto template outlining a Pattern’s • Intent • Motivation • Applicability • Structure • Consequences • Sample usage • …. SE-2811 Dr. Mark L. Hornick
You can “discover” patterns too Practical experience is vital • Learn all you can about existing patterns • Write lots of applications • Reflect on your experiences • If you have a big idea, contribute it • See if your idea becomes accepted SE-2811 Dr. Mark L. Hornick
Not all “Patterns” are beneficial Anti-Patterns tell you what to avoid in creating a solution to a problem • More negative consequences than positive benefits • Particular bad practices • Alternate, better approaches are suggested along with the description of the bad pattern’s aspects SE-2811 Dr. Mark L. Hornick