CSC 423 Chapter 00, Fall 2011

Introduction to UML Adopted from several internet resources  What is Modeling?  What is UML?  A brief history of UML  Understanding the basics of UML  UML diagrams  UML Modeling tools Overview  Describing a system at a high level of abstraction ◦ A model of the system ◦ Used for requirements and specifications  Is it necessary to model software systems? Modeling  UML stands for “Unified Modeling Language”  It is a industry-standard graphical language for specifying, visualizing, constructing, and documenting the artifacts of software systems  The UML uses mostly graphical notations to express the OO analysis and design of software projects.  Simplifies the complex process of software design What is UML?  Use graphical notation to communicate more clearly than natural language (imprecise) and code(too detailed).  Help acquire an overall view of a system.  UML is not dependent on any one language or technology.  UML moves us from fragmentation to standardization. Why UML for Modeling  Activity Diagrams  Use Case Diagram  Class Diagram  Sequence Diagram  Collaboration Diagram  State Diagram This is only a subset of diagrams … but are most widely used Types of UML Diagrams  describe dynamic aspects of the system.  Activity diagram is basically a flow chart to represent the flow form one activity to another activity (or an operation of the system).  This flow can be sequential, branched or concurrent. Activity diagrams deals with all type of flow control by using different elements like fork, join etc. Activity Diagrams Before drawing an activity diagram we should identify the following elements:  Activities  Association  Conditions  Constraints How to draw them:  rounded rectangles represent activities;  diamonds represent decisions;  bars represent the start (split) or end (join) of concurrent activities;  a black circle represents the start (initial state) of the workflow;  an encircled black circle represents the end (final state). An example of business flow activity to process order. Requested order is input parameter of activity. After order is accepted and info is filled, payment processing and shipment is done in parallel An example of formal Document Management Process activity Partitions are shown here as horizontal swimlanes and represent different roles participating in the activity - Author, Reviewer, Approver, and Owner. Document is created, reviewed, updated, approved, and at some point archived. This activity diagram shows responsibilities of different roles and flow or sequence of document changes.  Used for describing a set of user scenarios  Mainly used for capturing user requirements  Work like a contract between end user and software developers Use Case Diagram Use Case Diagram (core components) Actors: A role that a user plays with respect to the system,including human users and other systems. e.g.,inanimate physical objects (e.g. robot); an external system that needs some information from the current system. Use case: A set of scenarios that describing an interaction between a user and a system, including alternatives. System boundary: rectangle diagram representing the boundary between the actors and the system. Use Case Diagram(core relationship) Association: communication between an actor and a use case; Represented by a solid line. Generalization: relationship between one general use case and a special use case (used for defining special alternatives) Represented by a line with a triangular arrow head toward the parent use case. Use Case Diagram(core relationship) Extend: a dotted line labeled <<extend>> with an arrow toward the base case. The extending use case may add behavior to the base use case. The base class declares “extension points”. <<extend>> Include: a dotted line labeled <<include>> beginning at base use case and ending with an arrows pointing to the include use case. The include relationship occurs when a chunk of behavior is similar across more than one use case. Use “include” in stead of copying the description of that behavior. <<include>> Use Case Diagrams Library System Borrow Order Title Fine Remittance Client Employee Supervisor •  A generalized description of how a system will be used. •  Provides an overview of the intended functionality of the system Boundary Actor Use Case Use Case Diagrams(cont.) (TogetherSoft, Inc) Use Case Diagrams(cont.) • Pay Bill is a parent use case and Bill Insurance is the child use case. (generalization) • Both Make Appointment and Request Medication include Check Patient Record as a subtask.(include) • The extension point is written inside the base case Pay bill; the extending class Defer payment adds the behavior of this extension point. (extend)  Used for describing structure and behavior in the use cases  Provide a conceptual model of the system in terms of entities and their relationships  Used for requirement capture, end-user interaction  Detailed class diagrams are used for developers Class diagram  Each class is represented by a rectangle subdivided into three compartments ◦ Name ◦ Attributes ◦ Operations  Modifiers are used to indicate visibility of attributes and operations. ◦ ‘+’ is used to denote Public visibility (everyone) ◦ ‘#’ is used to denote Protected visibility (friends and derived) ◦ ‘-’ is used to denote Private visibility (no one)  By default, attributes are hidden and operations are visible. Class representation An example of Class Account_Name - Customer_Name - Balance +addFunds( ) +withDraw( ) +transfer( ) Name Attributes Operations  There are two kinds of Relationships ◦ Generalization (parent-child relationship) ◦ Association (student enrolls in course)  Associations can be further classified as ◦ Aggregation ◦ Composition OO Relationships Subtype2 Supertype Subtype1 OO Relationships: Generalization - Generalization expresses a parent/child relationship among related classes. - Used for abstracting details in several layers Regular Customer Loyalty Customer Customer Example: Regular Customer Loyalty Customer Customer or:  Represent relationship between instances of classes ◦ Student enrolls in a course ◦ Courses have students ◦ Courses have exams ◦ Etc.  Association has two ends ◦ Role names (e.g. enrolls) ◦ Multiplicity (e.g. One course can have many students) ◦ Navigability (unidirectional, bidirectional) OO Relationships: Association Association: Multiplicity and Roles University Person 1 0..1 * * Multiplicity Symbol Meaning 1 One and only one 0..1 Zero or one M..N From M to N (natural language) * From zero to any positive integer 0..* From zero to any positive integer 1..* From one to any positive integer teacher employer Role Role “A given university groups many people; some act as students, others as teachers. A given student belongs to a single university; a given teacher may or may not be working for the university at a particular time.” student Class Diagram Order -dateReceived -isPrepaid -number :String -price : Money +dispatch() +close() Customer -name -address +creditRating() : String() Corporate Customer -contactName -creditRating -creditLimit +remind() +billForMonth(Integer) Personal Customer -creditCard# OrderLine -quantity: Integer -price: Money -isSatisfied: Boolean Product * 1 1 * Employee * {if Order.customer.creditRating is "poor", then Order.isPrepaid must be true } * 1 Constraint (inside braces{}} Operations Attributes Name Association Multiplicity: mandatory Multiplicity: Many value Multiplicity: optional Generalization [from UML Distilled Third Edition] class 0..1 Class Student { Course enrolls[4]; } Class Course { Student have[]; } Association: Model to Implementation Student Course enrolls has * 4 OO Relationships: Composition Class W Class P1 Class P2 Composition: expresses a relationship among instances of related classes. It is a specific kind of Whole-Part relationship. It expresses a relationship where an instance of the Whole-class has the responsibility to create and initialize instances of each Part-class. It may also be used to express a relationship where instances of the Part-classes have privileged access or visibility to certain attributes and/or behaviors defined by the Whole-class. Composition should also be used to express relationship where instances of the Whole-class have exclusive access to and control of instances of the Part-classes. Composition should be used to express a relationship where the behavior of Part instances is undefined without being related to an instance of the Whole. And, conversely, the behavior of the Whole is ill-defined or incomplete if one or more of the Part instances are undefined. Whole Class Part Classes Automobile Engine Transmission Example [From Dr.David A. Workman] OO Relationships: Aggregation Class C Class E1 Class E2 AGGREGATION Aggregation: expresses a relationship among instances of related classes. It is a specific kind of Container- Containee relationship. It expresses a relationship where an instance of the Container-class has the responsibility to hold and maintain instances of each Containee-class that have been created outside the auspices of the Container-class. Aggregation should be used to express a more informal relationship than composition expresses. That is, it is an appropriate relationship where the Container and its Containees can be manipulated independently. Aggregation is appropriate when Container and Containees have no special access privileges to each other. Container Class Containee Classes Bag Apples Milk Example [From Dr.David A. Workman] Aggregation vs. Composition • Composition is really a strong form of aggregation • components have only one owner • components cannot exist independent of their owner • components live or die with their owner e.g. Each car has an engine that can not be shared with other cars. • Aggregations may form "part of" the aggregate, but may not be essential to it. They may also exist independent of the aggregate. e.g. Apples may exist independent of the bag.  The sequence diagram is used primarily to show the interactions between objects in the sequential order that those interactions occur.  One of the primary uses of sequence diagrams is in the transition from requirements expressed as use cases to the next and more formal level of refinement. Sequence Diagrams A sequence diagram that has incoming and outgoing messages Sequence Diagram(make a phone call) Caller Phone Recipient Picks up Dial tone Dial Ring notification Ring Picks up Hello  Creation ◦ Create message ◦ Object life starts at that point  Activation ◦ Symbolized by rectangular stripes ◦ Place on the lifeline where object is activated. ◦ Rectangle also denotes when object is deactivated.  Deletion ◦ Placing an ‘X’ on lifeline ◦ Object’s life ends at that point Sequence Diagrams – Object Life Spans Activation bar A B Create X Deletion Return Lifeline Sequence Diagram User Catalog Reservations 1: look up () 2: title data () 3: [not available] reserve title () 4 : title returned () 5: hold title () 5 : title available () 6 : borrow title () 6 : remove reservation () • Sequence diagrams demonstrate the behavior of objects in a use case by describing the objects and the messages they pass. • The horizontal dimension shows the objects participating in the interaction. • The vertical arrangement of messages indicates their order. • The labels may contain the seq. # to indicate concurrency. Message Interaction Diagrams: Collaboration diagrams User Catalog Reservations start 1: look up 2: title data 3 : [not available] reserve title 4 : title returned 5 : hold title 6 : borrow title 6: remove reservation 5: title available • Shows the relationship between objects and the order of messages passed between them. between them. • The objects are listed as rectangles and arrows indicate the messages being passed • The numbers next to the messages are called sequence numbers. They show the sequence of the messages as they are passed between the objects. • convey the same information as sequence diagrams, but focus on object roles instead of the time sequence. State Diagrams (Billing Example) State Diagrams show the sequences of states an object goes through during its life cycle in response to stimuli, together with its responses and actions; an abstraction of all possible behaviors. Unpaid Start End Paid Invoice created paying Invoice destroying State Diagrams (Traffic light example) Yellow Red Green Traffic Light State Transition Event Start  Rational Rose (www.rational.com) by IBM  TogetherSoft Control Center, Borland ( http://www.borland.com/together/index.html)  ArgoUML (free software) (http://argouml.tigris.org/ ) OpenSource; written in java  Others (http://www.objectsbydesign.com/tools/umltools_byCompany.html ) UML Modeling Tools 1. UML Distilled: A Brief Guide to the Standard Object Modeling Language Martin Fowler, Kendall Scott 2. IBM Rational http://www-306.ibm.com/software/rational/uml/ 3. Practical UML --- A Hands-On Introduction for Developers http://www.togethersoft.com/services/practical_guides/umlonlinecourse/ 4. Software Engineering Principles and Practice. Second Edition; Hans van Vliet. 5. http://www-inst.eecs.berkeley.edu/~cs169/ Reference