Strategy Design Pattern
1 like1,471 views
The document explains the strategy pattern, a design pattern in software that allows for the selection of an algorithm's behavior at runtime. It encapsulates a family of algorithms, making them interchangeable and suggesting their use in scenarios like calculating discounts in a shopping mall. Additionally, it emphasizes the open-closed principle, advocating for separable logic to enhance reusability and maintainability.
Strategy Design Pattern
- 1. http://jy aasa.comCopyright 2016. Jyaasa Technologies. Strategy Pattern
- 2. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Ganesh Kunwar Sr. Software Engineer Jyaasa Technologies
- 3. Copyright 2016. Jyaasa Technologies. http://jy aasa.com What is Strategy Pattern?
- 4. Copyright 2016. Jyaasa Technologies. http://jy aasa.com
- 5. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Ktm Butwal Taxi Plan Taxi Ktm. Airport Bhairahawa Airport Ktm Butwal Taxi Bus Kalanki Ktm Butwal Taxi Bus BusKalanki Chitwan Strategy 1 Strategy 2 Strategy 3
- 6. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Wikipedia Definition the strategy pattern (also known as the policy pattern) is a software design pattern that enables an algorithm's behavior to be selected at runtime. The strategy pattern ● defines a family of algorithms, ● encapsulates each algorithm, and ● makes the algorithms interchangeable within that family.
- 7. Copyright 2016. Jyaasa Technologies. http://jy aasa.com When to Use? Shopping Mall Example - Accept customer detail - Calculate bill amount - Apply discount based on the day of week - Monday - High discount (10%) - Friday - Low discount (5%)
- 8. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Where does the discount logic reside? Inside ShoppingMall class Or Outside ShoppingMall class
- 9. Copyright 2016. Jyaasa Technologies. http://jy aasa.com
- 10. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Open closed principle - software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification - New discount logic may be applied in future - Not reusable - Same discount strategy can be use in other shopping mall
- 11. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Separate discount logic from ShoppingMall class
- 12. Copyright 2016. Jyaasa Technologies. http://jy aasa.com Context Strategy
- 13. Copyright 2016. Jyaasa Technologies. http://jy aasa.com
- 14. Copyright 2016. Jyaasa Technologies. http://jy aasa.com => grill = Grill.new(HotDog.new) => grill.grilling # => "Grilling the hot dogs!" => grill.food = Hamburger.new => grill.grilling # => "Grilling the hamburgers!" => grill.food = VeggiePatty.new => grill.grilling # => "Grilling the veggie patties!"
- 15. Copyright 2016. Jyaasa Technologies. http://jy aasa.com References - https://dockyard.com/blog/2013/07/25/design-patterns-strategy-pattern - https://en.wikipedia.org/wiki/Strategy_pattern - https://sourcemaking.com/design_patterns/strategy
- 16. Thank you! Lets Discuss github.com/glunwar @gkunwar1 Copyright 2015. Jyaasa Technologies.Copyright 2016. Jyaasa Technologies. http://jyaasa.com