JNTU B.Tech III DESIGN PATTERNS Previous Question Paper (February/March - 2022 - R16)

Redesign is often necessary when software requirements evolve or initial designs prove inflexible. Common causes include:

• Tight coupling: Dependencies between classes make it difficult to modify one part of the system without affecting others.
• Lack of abstraction: Failing to anticipate future changes leads to code that is hard to extend or reuse.
• Hard-coded dependencies: Directly instantiating objects prevents the use of different implementations or configurations.
• Inability to subclass: Designing classes that are not intended to be extended limits the system's adaptability.
• Platform or environment changes: Shifts in hardware, operating systems, or external libraries may require significant structural adjustments.

To effectively use a design pattern, follow these systematic steps:

1. Identify the problem: Analyze the current design constraints, such as inflexibility, tight coupling, or redundant code, to determine if a pattern is applicable.
2. Study the pattern: Understand the intent, structure, participants, and consequences of the pattern to ensure it addresses the specific problem.
3. Examine the consequences: Evaluate the trade-offs, such as increased complexity or performance overhead, to ensure the pattern is the right fit.
4. Adapt the design: Modify the existing code structure to incorporate the pattern's participants (classes and interfaces) while maintaining the original functionality.
5. Implement and Refine: Write the code, ensuring that the pattern's collaborations are correctly realized, and refactor as necessary to improve clarity and maintainability.