Software Architecture Lecture Slides PDF

Lecture 4 SENG 401 - SOFTWARE ARCHITECTURE ARCHITECTURE ABSTRACTION Dr. Ronnie de Souza Santos https://www.drdesouzasantos.ca/ ABSTRACTION SOLUTION REAL WORLD ARCHITECTURE ABSTRACTION...

Lecture 4 SENG 401 - SOFTWARE ARCHITECTURE ARCHITECTURE ABSTRACTION Dr. Ronnie de Souza Santos https://www.drdesouzasantos.ca/ ABSTRACTION SOLUTION REAL WORLD ARCHITECTURE ABSTRACTION SIMPLIFYING COMPLEX PROBLEMS BY REPRESENTING ESSENTIAL FEATURES WHILE HIDING UNNECESSARY DETAILS. OBSERVATION PERCEPTION MOTIVATION Abstraction is a crucial tool in software development that simplifies complexity and promotes effective problem-solving DEFINITION ABSTRACTION ARCHITECTURE ABSTRACTION HIGH-LEVEL REPRESENTATION OR SIMPLIFICATION OF COMPLEX SYSTEMS, DESIGNS, OR STRUCTURES. FUNCTIONAL HIERARCHICAL MOTIVATION Focus on particular aspects of a system without getting bogged down by the intricacies of every component. BEHAVIORAL  ARCHITECTURE ABSTRACTION User Story 1: Add a New Customer As a customer service representative, I want to add new customer details to the system, so that the customer can place an order and their information is stored for future use. ARCHITECTURE ABSTRACTION DECOMPOSITION COUPLING COHESION AGILE-DRIVEN DECOMPOSITION DECOMPOSITION IS THE IDEA OF BREAKING DOWN LARGE ENTITIES INTO SMALLER AND MORE SPECIALIZED ONES. MOTIVATION Create more modular, Model decomposition maintainable, and flexible provides multiple software designs. levels of granularity. POOR DECOMPOSITION NO MODULARIZATION 1. Customer class is responsible for all entities. 2. Customer class is responsible for all operations. POOR DECOMPOSITION MANY RESPONSABILITIES PER CLASS IMPROVED DECOMPOSITION MODULARIZATION 1. Customer class is responsible for representing customer to access information. 2. Order class is responsible for dealing with order elements. IMPROVED DECOMPOSITION DID YOU KNOW? PROGRAMMING LANGUAGES! CHRISTOPHER STRACHEY, AN LGBTQ+ SOFTWARE ENGINEERING SCIENTIST, REVOLUTIONIZED PROGRAMMING LANGUAGES IN THE 1960S BY CREATING DENOTATIONAL SEMANTICS. THIS METHOD USES MATH TO DESCRIBE HOW PROGRAMS WORK, MAKING IT EASIER TO DESIGN AND UNDERSTAND LANGUAGES. HIS IDEAS CONTINUE TO INFLUENCE MODERN OBJECT-ORIENTED LANGUAGES LIKE PYTHON. COUPLING COUPLING IS THE DENSITY OF DEPENDENCIES AMONG CLASSES. MOTIVATION If a class changes and there is high coupling, 1. High coupling means there are many other classes will many dependencies. need to change as well. 2. Low coupling means there are few dependencies. TIGHT COUPLING TIGHT 1. Customer class creates an Order object directly within its method. 2. Order class maintains a direct reference to the Customer object (customer attribute). TIGHT COUPLING ORDER DEPENDS ON CUSTOMER TO BE CREATED LOOSE COUPLING LOOSE 1. Order class no longer directly references the Customer class. 2. Customer information (name and email) referred as parameters with methos get() and set(). LOOSE COUPLING MAIN CLASS COHESION COHESION IS THE DEGREE OF UNITY OR CLOSENESS AMONG THE ELEMENTS WITHIN A CLASS. MOTIVATION Each class should represent a single Classes that are multi-concept or have concept. All methods of unrelated methods the class should be reduce effectiveness directly applicable to the and indicate need for improvements. concept. LOW COHESION LOW Customer mixing responsibilities with Order. LOW COHESION HIGH COHESION HIGH 1. Order class no longer deal with other elements. 2. Customer information restricted to the class. HIGH COHESION COUPLING VERSUS COHESION QUESTIONS? TRY IT! WHAT IS YOUR ANALYSIS? class handles most Multiple interactions Mixed processes of creating and instance responsabilities, e.g., instances, registering creations among Professor students, and so on. classes