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PATTERNS-STRUCTURAL

PATTERNS

WATTANAPONG SUTTAPAKSoftware Engineering, School of Information Communication Technology,University of PHAYAO

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STRUCTURAL PATTERNS• These patterns concern class and object composition

•Concept of inheritance is used to compose interfaces and define ways to compose objects to obtain new functionalities 1. Adapter2. Bridge3. Filter(new)4. Composite

5. Decorator6. Façade7. Flyweight8. Proxy

ADAPTER PATTERN• works as a bridge between two incompatible interfaces.

• A real life example, card reader(adapter) read memory(object) to laptop(object)

ADAPTER PATTERN

ADAPTER PATTERN Interface class

ADAPTER PATTERN Implements AdvanceMediaPlayer

ADAPTER PATTERN Implements MediaPlayer

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ADAPTER PATTERN demo adapter pattern

Result

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BRIDGE PATTERN•decouple an abstraction from its implementation

•the two can vary independently.

•decouples implementation class and abstract class by providing a bridge structure between them.

•This pattern involves an interface as a bridge

•functionality of concrete classes independent from interface implementer classes.

•demonstrating use of Bridge pattern via following example in which a circle can be drawn in different colors using same abstract class method but different bridge implementer classes.

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BRIDGE PATTERN• Shape Square ,Triangle, …

• check duplicate pattern

• Color Red, Blue, …

• Shape and Color

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BRIDGE PATTERN

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BRIDGE PATTERN

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BRIDGE PATTERN

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BRIDGE PATTERN

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BRIDGE PATTERN

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BRIDGE PATTERN

Result

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FILTER PATTERN•filter a set of objects

•using different criteria

•combining multiple criteria to obtain single criteria.

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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FILTER PATTERN

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COMPOSITE PATTERN group of objects in similar way as a single object

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COMPOSITE PATTERN

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COMPOSITE PATTERN Result

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DECORATOR PATTERN add new properties to existing object without altering structure

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DECORATOR PATTERN

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DECORATOR PATTERN Result

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FACADE PATTERN hiding the complexities of the system

the client can access the system via interface

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FACADE PATTERN

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FACADE PATTERN

Result

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FLYWEIGHT PATTERN primary pattern for reduce the number of objects created

decrease memory footprint and increase performance

demonstrate this pattern by drawing 20 circle of different locations but we'll creating only 5 objects. Only 5 colors are available so color property is used to check already existing Circle objects.

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FLYWEIGHT PATTERN

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FLYWEIGHT PATTERN

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FLYWEIGHT PATTERN

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FLYWEIGHT PATTERNResult

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PROXY PATTERN a class represents functionality of another class

In Proxy pattern, we create object having original object to interface its functionality to outer world.

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PROXY PATTERNResult

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PROXY PATTERNResult