Encapsulation

• Object Integrity

  • immutable identity (be careful with lexicalized objects)
  • obeys its behavior specification (e.g., no arbitrary state change)

• Interface Specification

  • implicit or explicit declaration of services
  • tradeoffs for query processing

• Implementation Independence

  • separates specification from implementation
  • view one way, but implement in another (more efficient) way
  • overriding and late binding for polymorphic variations

We should observe these principles even if not language supported.

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