A design pattern is a formally documented solution to a design problem.

Patterns are used to communicate architectural knowledge, teach new design paradigms, and convey design experience

They are normally modeled in natural languages and visual notations (UML)

Each design pattern typically contains several participants.

When the pattern is applied names are changed to suit the application domain

This means pattern information represented by the role names is lost.

When this happens it becomes difficult to identify the patterns used in the system.

Several approaches have been suggested.

-Venn diagram-style annotation -UML collaboration annotation -Pattern:role annotation

COMPOSITION OF PATTERNS VENN DIAGRAM-STYLE

UML COLLABORATION PATTERN:ROLE

Static notations attached to UML diagrams

Cannot distinguish between two instantiations of the same pattern

Only applied in class diagrams not in sequence or behavioral diagrams

Do not cover the roles of operations or attributes.

Design pattern modeling language (DPML) Adds new symbols to UML

Design recovery frameworksLogic based languagesSpecialized version of UML meta-

model

An extension to the existing UML specification through stereotypes

Tagged Values for each stereotype role@name [instance]

Multiple tags per class are allowed.

On-demand visualization techniques based on coloring and mouse movement

VisDP – tool that can hide/show design pattern information on demand.

Mouse-over a class in a pattern, and all classes in that pattern turn a different color.

Pattern information overlaid over diagram