Design Pattern Course Expectations

Expect to spend more time explaining decisions than copying implementations. A pattern is learned when you can recognize its design pressure, construct a small implementation, and defend its trade-offs. Merely reproducing the class names from a diagram is not enough.

A Repeatable Decision Process

1. Describe the change pressure. Identify what varies today or is likely to vary, such as signal timing, object creation, or notification rules.
2. Assign responsibilities. Decide which object should own each decision and which information it requires.
3. Sketch the simplest design. Establish a baseline before introducing pattern participants.
4. Compare a candidate pattern. State what coupling it removes and which new abstractions it creates.
5. Test a likely change. Add a new vehicle, signal policy, or intersection rule and observe which design changes in fewer places.
6. Document the consequences. Record both the benefit and the cost so another developer can revisit the decision.

• short analyses that identify objects, responsibilities, and collaborations;
• Java or C++ examples that demonstrate a pattern in a narrow context;
• tests or executable drivers that show the intended behavior;
• comparisons between a pattern-based solution and a simpler alternative; and
• an evolving design for the traffic-flow simulation.

Code quality matters, but the primary deliverable is a reasoned design. A correct explanation of why a pattern should not be used is as valuable as a correct implementation.

The course combines pattern descriptions with diagrams, quizzes, and hands-on exercises. Diagrams show structure, while the text explains runtime collaboration and consequences.

The Gang of Four catalog focuses on object-oriented design at the class and object level. It does not provide a complete architecture for distributed systems, concurrency, persistence, security, user-interface design, or real-time scheduling. Modern applications often combine GoF patterns with architectural, integration, and domain-specific patterns.

Examples in this course deliberately stay small so the collaboration is visible. Before transferring a solution to production, evaluate threading, failure handling, resource ownership, observability, and framework behavior in the target environment.

Quizzes check terminology and pattern recognition. Exercises ask you to write or explain a design and therefore may have more than one defensible answer. Compare your response with the reference analysis, then identify which assumptions caused the designs to differ.

• Image galleries: show alternative structures or implementation stages.
• Descriptive diagrams: identify participants and provide tooltips for important relationships.
• Course Glossary: Review unfamiliar terms in the Design Patterns Glossary.