**Course Title:** Software Design Principles: Foundations and Best Practices **Section Title:** Introduction to Software Design Principles **Topic:** Analyze a poorly designed software system and identify design flaws. **Lab Topic Overview:** In this lab topic, we will analyze a poorly designed software system and identify the design flaws that contribute to its ineffectiveness. This exercise will help you understand how to apply software design principles in a real-world scenario and appreciate the importance of good design in software development. Please note that this exercise is meant to be a learning experience, and the goal is not to criticize existing software systems but rather to learn from their design flaws. **The Case Study:** For this lab, we will use a simplified example of an e-commerce application, which we will refer to as "E-Tail." E-Tail is designed to manage customer orders, inventory, and shipping. Unfortunately, the design of E-Tail is plagued with design flaws that lead to issues such as frequent crashes, slow performance, and frustrating user experiences. **System Design Overview:** The E-Tail e-commerce application consists of three main components: 1. **Order Management Module (OMM):** Handles customer order processing, including calculating totals and applying discounts. 2. **Inventory Management Module (IMM):** Manages product inventory levels and tracks product availability. 3. **Shipping Module (SM):** Handles order shipping and calculates shipping costs. **Identified Design Flaws:** Upon analyzing the E-Tail system, we have identified several design flaws: 1. **Tight Coupling:** The OMM, IMM, and SM are tightly coupled, meaning that changes to one module can affect the behavior of the other modules. 2. **Monolithic Architecture:** The entire system is built as a single, monolithic application, making it difficult to update or maintain individual components. 3. **Lack of Abstraction:** The system's design does not consider abstracting out interfaces or defined data access layers. 4. **Circular Dependencies:** Some modules have circular dependencies, which can lead to problems with initialization and crashes. **Task 1: Identify and Analyze** * Read through the provided system design document and identify the components and their responsibilities. * Using the provided system documentation, identify where the design flaws are present. * Document the effects these design flaws are likely to have on the overall system performance and user experience. **Task 2: Redesign (Design Restructure)** * Consider addressing the identified design flaws by: + Loosening coupling between components + Implementing abstraction layers + Using interfaces to enable polymorphism * Restructure the system design by creating new or updating existing module interfaces and responsibilities. * Document your proposed changes and identify how they will improve the system's performance and maintainability. **Additional Resources:** For a deeper understanding of software design principles, refer to the reading materials below: * "Clean Architecture: A Craftsman's Guide to Software Structure and Design" by Robert C. Martin ( Also known as Uncle Bob) [1] * "Design Principles and Design Patterns" by University of Colorado Boulder [2] **Conclusion:** Analyzing a poorly designed software system can be a valuable learning experience, helping you identify common design flaws and understand how to apply software design principles to mitigate these issues. By completing this lab, you should have gained practical experience identifying design flaws and designing potential solutions to improve the system's maintainability, scalability, and performance. **Leave a Comment/Ask for Help:** We would appreciate it if you leave a comment detailing your experience in this lab and any questions you have about the design flaws identified or potential solutions you've proposed. This will help us improve this lab topic and address any concerns you may have. In our next topic, we will delve into the Single Responsibility Principle (SRP) from the SOLID principles of object-oriented design. References: [1] https://cleancoders.com [2] https://www.coursera.org/learn/design-patterns