overview

Use case viewActivity viewStructure viewInteraction viewState machine viewImplementation view

Kinds of UML (logical) models

State model static view of the system models data requirements and operations on dataoperations obtain from behavioral model class diagram Behavior model operational view of the system models function requirements diagrams use caseactivitycommunication State change model dynamic view of the system models object evolution over time state machine diagram

Summary

The use case model is the main UML representative and the focal point of behavior modeling.

The activity model can graphically represent the flow of events of a use case.

Class modeling integrates and embodies all other modeling activities.

Interaction modeling captures the interactions between objects needed to execute a use case or part of it.

A state machine model specifies dynamic changes in a class.

UML provides component diagrams and deployment diagrams as two tools for architectural/structural modeling of physical implementation of the system.

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1.use case

overview

用例驱动整个软件开发的生命周期用例：参与者外部可见，且可单独测试，不应该有孤立用例，不是所有用例都需要和角色关联用例间不要泛化

Documenting use cases

Brief DescriptionActors involvedPreconditions necessary for the use case to startDetailed Description of flow of events that includes: Main Flow of events, that can be broken down to show:Subflows of events (subflows can be further divided into smaller subflows to improve document readability)Alternative Flows to define exceptional situations Postconditions that define the state of the system after the use case ends

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2. The activity view

overview

Can graphically represent the flow of events of a use caseCan also be used: to understand a business process at a high-level of abstraction before use cases are producedat a much lower level of abstraction to design complex sequential algorithms or to design concurrency in multithreaded applications Activity Diagram shows transitions between actionsstart of an activity： A solid filled circle represents theThe end of an activity is shown using a bull’s eye symbolTransitions can branch and merge (diamond) –alternative computation threadsTransitions can fork and re-join (bar line) – concurrent (parallel) computation threadsActivity diagram without concurrent processes resembles a conventional flowchart

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3. The structure view (class diagram)

it represents data structures and their relationshipsit identifies operations that act on these data不应该有孤立的类class entity classes : loaded to memory from persistent databasepresentation (boundary) classes (view classes) : classes that define GUI objects (such as forms or webpages)control classes: classes that control the program’s logic and process use eventsresource classes: classes responsible for communication with external data sources (DAO)mediator classes: classes responsible for managing entity objects in memory cache and for conducting business transactions (JDBC)

4. The interaction view

Two kinds of interaction diagrams Sequence diagram – concentrate on time sequencesCommunication diagram (called collaboration diagram prior to UML 2.0) – emphasize object relationships

Sequence Diagram

Roles - horizontal dimension (与类图中保持一致)Message sequence - top to bottom on vertical dimensionEach vertical line - the object’s lifeline （过程中生成的对象，要有始有终）Activation (execution specification) – a method activated on a lifeline（多次调用，要分开；一个激活内有自调用时，产生新的激活）Arrow - message from a calling object (sender) to an operation (method) in the called object (target)Showing the return of control from the target to the sender is not necessary(不显示返回结果)Iteration marker – an asterisk in front of the message label – indicates iterating over a collection

Communication diagram

message/function

通过交互图确定类图中的方法

5.state diagram

specifies dynamic changes in a classNormally attached to a class, but can be attached to other modeling concepts, e.g. a use caseWhen attached to a class, the diagram determines how objects of that class react to events Determines – for each object state – what action the object will perform when it receives an eventThe same object may perform a different action for the same event depending on the object’s stateThe action’s execution will typically cause a state change The complete description of a transition consists of three parts event (parameters) [guard] / action 状态可嵌套，下图中1为嵌套状态，状态转出嵌套状态时，可到任意转态

6.The implementation view

architectural/structural modeling of the physical implementation of a system

provides a connection between the logical and physical structure of the system

Component - modular, deployable, and replaceable part of a system that encapsulates implementation and exposes a set of interfaces

component diagram

Node - physical object that represents a processing resource, generally, having at least a memory and often processing capability as well

includes computing devices but also human resources or mechanical processing resourcesdeployment diagram

Subsystems and packages

Subsystem • encapsulates some part of system behavior • its services are the result of the services provided by its classes • its services are defined using interfacesPackage • grouping of modeling elements • like subsystem, its services are the result of the services provided by its classes • unlike subsystem, its services are not exposed using interfaces“The difference between a subsystem and a package is that, for a package, a client asks some element inside the package to fulfill a behavior; for a subsystem, a client asks the subsystem itself to fulfill the behavior.” from Ferm (2003, p.2)