The open-closed principle sounds contradictory. In this video, explore how accommodating change is needed, but that you should limit the impact of change in a design.
- [Instructor] So where do we go from here? … Let's begin by getting some insight … from our next design principle, the open-closed principle. … This principle says that classes should be open … for extension but closed for modification. … What does that mean? … Well, think about our current design for the coffee shop. … We know in the future we'll need to support new … beverage types and new condiments but that means … we'll have to modify existing code, … and that's exactly what we don't want. … We want to leave our design open for new … beverage types and condiments but closed … in the sense that we don't want to touch existing code. … Let's look at this principle in a little more detail. … Again, the open-closed principle says that code … should be open for extension but closed for modification. … If we can do that, we have flexibility … and maintainability because we can add … new behavior but without the risk of introducing … new bugs into the code we've already written. … So our goal is to have designs …
- What are design patterns?
- Encapsulating code that varies with the Strategy pattern
- The limitations of inheritance
- Using the Adapter pattern
- Implementing the Observer pattern
- Extending behavior with composition and the Decorator pattern
- Encapsulating iteration with the Iterator pattern
- Object creation with the Factory Method pattern
- Using design principles to guide your object-oriented design
Skill Level Intermediate
1. Design Patterns
2. The Strategy Pattern
3. The Adapter Pattern
4. The Observer Pattern
Using the Observer pattern2m 23s
5. The Decorator Pattern
6. The Iterator Pattern
7. The Factory Patterns
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