A design pattern is a general and reusable idea for recurring design problems; it is not readily coded solution, but rather provides proven templates and best practices for how to solve a specific problem and can be used recurrently. Design patterns are practical implementations that adhere to SOLID Design Principles and GRASP Design Principles. The sub-nodes of design pattern involves UML Diagrams for illustrating concepts.

Composition of a pattern node

Pattern name
- e.g. Creational Patterns - Factory Method Pattern
Applicability
- What the pattern is designed to solve (i.e. when to apply the pattern)
Approach
- The process of how to apply and implement the pattern
Components
- The components of the pattern to achieve its purpose
Example
- A concrete example to demonstrate the concepts of a pattern

Classification of patterns base on purpose

Creational Patterns
- Abstract the instantiation process
- Make a system independent of how its objects are created, composed and represented
Structural Patterns
- How classes and objects are composed to form larger structures, while keeping the structures flexible and efficient
Behavioural Patterns
- Concerns of algorithms and the assignment of responsibilities between objects

Classification of patterns based on relationships

Patterns often used together
- e.g. Composite often used with Iterator or Visitor
Alternative patterns
- e.g. Prototype often alternative to Abstract Factory
Patterns results in similar design
- e.g. structure diagram of composite and Decorator are similar