This is the The Gang of Four's template.
View and save this page's source from your web browser. It includes examples of
useful HTML formatting commands.
Pattern Name (Scope, Purpose)
The pattern's name conveys the essence of the pattern succinctly.
A good name is vital, because it will become part of your design
A short statement that answers the following questions:
What does the design pattern do? What is its rationale and intent?
What particular design issue or problem does it address?
Also Known As
Other well-known names for the pattern, if any.
A scenario that illustrates a design problem and how the class and
object structures in the pattern solve the problem. The scenario
will help you understand the more abstract description of the
pattern that follows.
What are the situations in which the design pattern can be applied?
What are examples of poor designs that the pattern can address? How
can you recognize these situations?
The classes and/or objects participating in the design pattern and
How the participants collaborate to carry out their
How does the pattern support its objectives? What are the
trade-offs and results of using the pattern? What aspect of
system structure does it let you vary independently?
- A consequence bullet.
Description of consequence
What pitfalls, hints, or techniques should you be aware of when
implementing the pattern? Are there language-specific issues?
- An implementation Bullet. Description of Bullet
Sample Code and Usage
Code fragments that illustrate how you might implement the pattern
in C++ or Smalltalk.
Examples of the pattern found in real systems. We include at least
two examples from different domains.
What design patterns are closely related to this one? What are the
important differences? With which other patterns should this one be
Your Name (firstname.lastname@example.org).
Last updated on Todays Date