JD

Java Programming - Object-Oriented Design

Object-Oriented Design

Method Design

  • High-level design issues:
    • Identifying primary classes and objects.
    • Assigning responsibilities.
  • Low-level issue: Design of methods for efficiency and elegance.

Method Decomposition

  • Methods should be small and understandable.
  • Large methods can be decomposed into smaller methods for clarity.
  • Example: Translating English to Pig Latin involves multiple decompositions:
    • Translating each word.
    • Handling words by categories (e.g., starting with vowels, consonants, blends).

Visibility in UML Class Diagrams

  • Public members: +
  • Private members: -

Example: Pig Latin

  • Implementation shows method decomposition in action.
  • Involves main method for reading input and translating sentences.

Objects as Parameters

  • Java passes parameters by value (copies).
  • When objects are passed, the actual and formal parameters are aliases.

Method Overloading

  • Single method name can have multiple definitions based on parameters.
  • Signature must be unique (number, type, order of parameters) to determine the method invoked.
  • Examples:
    • println(String s), println(int i).

Testing

  • Various definitions: executing programs, human evaluations, finding errors.
  • Reviews enhance design or code quality via outside perspectives.
  • Test cases involve sets of inputs with expected results; organized into suites.
  • Types of testing:
    • Defect Testing: Executing to find errors.
    • Black-Box Testing: Based on inputs and expected outputs without logic consideration.
    • White-Box Testing: Focuses on internal code structure to test all paths.

Conclusion

  • Effective design involves method decomposition, parameter handling, and thoughtful testing strategies for quality assurance.