GOF Design pattern with java
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This document discusses various object-oriented design patterns including creational, structural, and behavioral patterns. It provides examples of common design patterns like singleton, factory, abstract factory, builder, prototype, adapter, decorator, proxy, facade, iterator, strategy, chain of responsibility, observer, and template patterns. It also discusses pillars of object-oriented programming like abstraction, encapsulation, modularity, and hierarchy.
GOF Design pattern with java
- 1. Deep Dive Design pattern Rajeev Gupta [email protected] Java Trainer & consultant @rajeev_gupta76
- 8. Pillors of OO ● Abstraction ● Encapsulation ● Modularity ● Hierarchy
- 9. Abstraction
- 10. Encapsulation ● Changing data in organized way, by using data hiding and appying business constraints ● Encapsulation= data hiding + constraints
- 12. Modularity
- 13. Hierarchy
- 14. UML 101
- 16. We write code that is ...
- 18. So WHY SOLID?
- 19. It helps us to write code that is ... ● Loosely coupled ● Highly cohesive ● Easily composable ● Reusable
- 20. SOLID
- 21. SOLID
- 29. Design pattern • Proven way of doing things • Gang of 4 design patterns ??? • total 23 patterns • Classification patterns 1. Creational 2. Structural 3. Behavioral
- 32. Patterns classification • Creational patterns? What is the best way to create object as per requirment • Structural patterns? Structural Patterns describe how objects and classes can be combined to form larger structures • Behavioral Patterns? Behavioral patterns are those which are concerned with interactions between the objects ( talking to each other still loosely coupled)
- 35. Singleton Design Consideration # Eager initialization # Static block initialization # Lazy Initialization # Thread Safe Singleton # Serialization issue # Cloning issue # Using Reflection to destroy Singleton Pattern # Enum Singleton # Best programming practices
- 37. Abstract Factory
- 38. Builder Pattern The Builder pattern can be used to ease the construction of a complex object from simple objects. java.lang.StringBuilder#append() (unsynchronized) java.lang.StringBuffer#append() (synchronized)
- 39. Prototype Pattern Cloning of an object to avoid creation. If the cost of creating a new object is large and creation is resource intensive, we clone the object.
- 41. Adapter Pattern The Adapter pattern is used so that two unrelated interfaces can work together.
- 42. Decorator design pattern Series of wrapper class that define functionality, In the Decorator pattern, a decorator object is wrapped around the original object.
- 44. Facade pattern
- 47. Strategy pattern /policy pattern
- 48. Chain of Responsibility Chain of responsibility pattern is used to achieve loose coupling in software design where a request from client is passed to a chain of objects to process them.
- 49. Observer Design pattern Observer design pattern is useful when you are interested in the state of an object and want to get notified whenever there is any change.