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.