Systems Analysis and Design Chapter 6

Systems Analysis and Design Chapter 6 object-oriented analysis ️an analysis of an information system by identifying things called objects. object ️a representation of a real person, place, event, or transaction. object model ️the end product of object-oriented analysis. This represents the information system in terms of objects and object-oriented concepts. Unified Modeling Language ️a widely used method of visualizing and documenting an information system. attributes ️characteristics that describe the object. methods ️tasks or functions that the object performs when it receives a message, or command, to do so. class ️a group of similar objects. instance ️a specific member of a class. state ️a specific attribute that describes the object's current status. polymorphism ️the concept that a message gives different meanings to different objects. black box ️an object whose message triggers changes within the object without specifying how the changes must be carried out. encapsulation ️the fact that all data and methods are self-contained. subclasses ️more specific categories within a class. superclass ️a general category to which a class can belong. relationships ️those which enable objects to communicate and interact as they perform business functions and transactions required by the system. inheritance ️the strongest relationship, which enables an object (called a CHILD) to derive one or more of its attributes from another object (called a PARENT). use case ️a representation of the steps in a specific business function or process. actor ️an external entity that initiates a use case by requesting the system to perform a function or process. use case description ️a description that documents the name of the use case, the actor, a description of the use case, a step-by-step list of the tasks and actions required for successful completion, a description of alternative courses of action, preconditions, postconditions, and assumptions. use case diagram ️a visual summary of several related use cases within a system or subsystem. system boundary ️a boundary that shows what is included in the system (inside the rectangle) and what is not included in the system (outside the rectangle). class diagram ️a diagram that shows the object classes and relationships involved in a use case. cardinality ️a concept included in the class diagram that describes how instances of one class relate to instances of another class. sequence diagram ️a dynamic model of a use case, showing the interaction among classes during a specified time period. lifeline ️a representation of the time during which the object above it is able to interact with the other objects in the use case. An X marks its end. focus ️that which indicates when an objects sends or receives a message. state transition diagram ️a diagram that shows how an object changes from one state to another, depending on events that affect the object. activity diagram ️a diagram that resembles a horizontal flowchart that shows the actions and events as they occur. business process modeling ️a form of modeling that can be used to represent people, events, and interaction in a system. pool ️the outside rectangle in a typical business process modeling dia