CSCE 315 Lecture 10

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Information Hiding

1. Identify areas that are likely to change
2. Create clasess for each of those items
3. Limit connections to that class and/or create an interface that's unlikely to change

Keep Coupling Loose

• Relations to other classes/routines
• Small size (fewer parameters and methods)
• Avoid global variables
• Keep it flexible

Types of Coupling

• Data-Parameter (good)
  • Data passed as parameter lists
  • Primitive data types
• Simple-object (good)
  • Module instantiates that object
• Object-parameter (meh)
  • Object 1 requires Object 2 to pass an Object 3
• Semantic (bad)
  • One object makes use of other modules or knowledge about other modules
  • ex: Module 1 passes a control flag to Module 2,Module 2 uses global data that Module 1 modifies

DESIGN PATTERNS

Common software patterns to outline design