2.2 KiB
2.2 KiB
- #CT2106 - Object-Oriented Programming
- Previous Topic: First Java Code
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- Relevant Slides:
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Composition & Inheritance
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Composition
- What is Composition? #card
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- Composition is a type of "has-a" relationship. One object is composed of another and relies upon its services for its own functionality.
- It is one of the fundamental relationships between classes in OOP.
- For example:
- The class
RacingBikehas-aWheel- Composition.
- The class
- How do you represent Composition in OOP class diagrams? #card
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- In OOP class diagrams, a diamond shape indicates composition or a "has-a" relationship.
- This class diagram tells us that a
Vehicleobject is composed of a singleEngineobject.
- This class diagram tells us that a
- How do you realise Composition in Java? #card
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- To realise a "has-a" relationship in Java, you must ^^create a link between the participant classes using a reference type variable.^^
- The reference declaration is in the owner class.
- To realise a "has-a" relationship in Java, you must ^^create a link between the participant classes using a reference type variable.^^
- What is Composition? #card
card-last-interval:: 28.3
card-repeats:: 4
card-ease-factor:: 2.66
card-next-schedule:: 2022-12-09T18:41:43.657Z
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card-last-score:: 5
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Inheritance
- What is Inheritance? #card
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card-last-score:: 5
- Inheritance is a type of "is-a" relationship.
- It is one of the fundamental relationships between classes in OOP.
- For example:
- A
RacingBikeis-a type ofBicycle- Inheritance.
- A
- What is Inheritance? #card
card-last-interval:: 21.53
card-repeats:: 4
card-ease-factor:: 2.32
card-next-schedule:: 2022-12-06T08:00:59.616Z
card-last-reviewed:: 2022-11-14T20:00:59.616Z
card-last-score:: 5
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