文档介绍：Object-Oriented Software EngineeringPractical Software Development using UML and JavaChapter 5: Modelling with Classes? Lethbridge/Laganière 2001Chapter 5: Modelling with What is UML?The Unified Modelling Language is a standard graphical language for modelling object oriented software?At the end of the 1980s and the beginning of 1990s, the first object-oriented development processes appeared?The proliferation of methods and notations tended to cause considerable confusion?Two important methodologists Rumbaugh and Booch decided to merge their approaches in 1994.—They worked together at the Rational Software Corporation?In 1995, another methodologist, Jacobson, joined the team—His work focused on use cases ?In 1997 the Object Management Group (OMG) started the process of UML standardization? Lethbridge/Laganière 2001Chapter 5: Modelling with classes3UML diagrams?Class diagrams—describe classes and their relationships?Interaction diagrams—show the behaviour of systems in terms of how objects interact with each other?State diagrams and activity diagrams—show how systems behave ponent and deployment diagrams—show how the ponents of systems are arranged logically and physically? Lethbridge/Laganière 2001Chapter 5: Modelling with classes4UML features?It has detailed semantics?It has extension mechanisms?It has an associated textual language—Object Constraint Language (OCL)The objective of UML is to assist in software development—It is not a methodology? Lethbridge/Laganière 2001Chapter 5: Modelling with classes5What constitutes a good model?A model should?use a standard notation ?be understandable by clients and users ?lead software engineers to have insights about the system?provide abstractionModels are used:?to help create designs?to permit analysis and review of those designs. ?as the core documentation describing the system. ? Lethbridge/Laganière 2001Chapter 5: Modelling with Essentials of UML Class DiagramsThe main symbols shown on class dia