WEBDEV Concepts

Part 4: Advanced concepts 123 For example: • the Customer actor can be of two types: Individual customer or Company customer . • there are two ways to verify the user’s identity: a password or a fingerprint. • Package : divides and organizes the diagram representation (in the same way that directories organize files). Each package can contain actors and use cases. 2.3 Object diagram An object diagram represents a set of objects and how they relate to each other at a certain moment in time. An object diagram is used to show a context (before or after an interaction between objects, for example). For example, the diagram below presents a section of the general structure of motorcycles: An object diagram includes the following elements: • object : represents a class instance. Remark: If a class diagram is opened, you can create an object from a class in this diagram (Drag and drop it from the "UML analysis" pane). • composite object : visually represents an object made of other objects. For example: a window that contains scrollbars, buttons, etc. • link : represents the relationship between different objects. 2.4 Component diagram A component diagram describes the physical and static architecture of a software application. For example: source files, libraries, executables, etc. For example, the diagram below presents the steps of a program that allows users to log in in text mode in Unix. A component diagram includes the following elements: • module : represents the different physical elements that make up a software application. For example: a file, a library, etc. A module can be represented: • by a specification that shows the module interface. This specification can be generic for classes that can be configured. • by its body that presents the module implementation. • task : represents a component that has its own control flow (thread). • main programs of the software application. • subprograms : groups the procedures and functions that do not belong to any class.