Join Jungwoo Ryoo for an in-depth discussion in this video Visitor, part of Python: Design Patterns.
- The Visitor design pattern allows adding new features to an existing class hierarchy without changing it. It is sometimes necessary to add new operations dynamically to existing classes with minimal changes. For our scenario, we present a House class. Visitors in this scenario include HVAC specialist and Electrician. HVAC specialist in our scenario is Visitor type 1 and Electrician is Visitor type 2.
The visitor pattern represents new operations to be performed on the various elements of an existing class hierarchy. Visitors can also provide operations on a composite object.
- Understanding design patterns
- Best design practices: consistency, completeness, and correctness
- Working with creational patterns
- Working with structural patterns
- Working with behavioral patterns
Skill Level Intermediate
Q: In the strategy pattern example, why does the code keep executing the default function rather than the alternate?
A: The programming demonstration skips the step of defining what the strategy pattern should be when an alternate function name is provided
as an argument as shown below.
Programming Foundations: Design Patternswith Elisabeth Robson2h 19m Intermediate
1. Understanding Design Patterns
2. Creational Patterns
3. Structural Patterns
4. Behavioral Patterns
5. Design Best Practices
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