Decorator Pattern

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Decorator Pattern

• Lecture Oo29
• Artificial Life Simulation

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Teaching Points

• Decorator Pattern
• Artificial Life Simulation
• Lab 3

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Review

• What is a component
• How can you use components and interfaces to
  efficiently partition your systems physical
  architecture?
• In Java-style exception handling what is thrown?

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Decorator Pattern

• The Problem
• sometimes we want to add responsibilities to
  individual objects, not to an entire class.
• for responsibilities that can be add/withdrawn
  dynamically
• when extension by subclassing is impractical

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Decorator Pattern

• The solution
• Attach additional responsibilities to an object
  dynamically.
• A flexible approach is to enclose the component
  in another object that adds the responsibility.

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Decorator Pattern (structure)
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Decorator Pattern (example)
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Artificial Life Simulator

• A framework
• Pattern based
• Decorator
• Chain of responsibility
• Observer
• Iterator

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Use Case Diagram
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Architecture
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Run Simulation Use Case
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Update Creature State Use Case

• Interaction with the world

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Update Creature State Use Case

• Reproduction

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Teaching Points

• Decorator Pattern
• Artificial Life Simulation
• Lab 3