23-02-2013, 10:11 AM
UNIFIED MODELING LANGUAGE
UNIFIED MODELING.pptx (Size: 655.6 KB / Downloads: 33)
Class Diagram
Class diagrams show the classes of the system, their interrelationships (including inheritance, aggregation, and association), and the operations and attributes of the classes.
Relationships between Classes
Association -- a relationship between instances of the two classes. There is an association between two classes if an instance of one class must know about the other in order to perform its work. In a diagram, an association is a link connecting two classes.
Aggregation -- an association in which one class belongs to a collection. An aggregation has a diamond end pointing to the part containing the whole.
Generalization -- an inheritance link indicating one class is a superclass of the other. A generalization has a triangle pointing to the superclass.
Interaction Diagrams
There is one (or more) Interaction diagram per use case
Represent a sequence of interactions
Made up of objects, links, and messages
Sequence diagrams
Models flow of control by time ordering
Emphasizes passing messages with respect to time
Shows simple iteration and branching
Collaboration diagrams
Models flow of control by organization
Structural relationships among instances in the interaction
Shows complex iteration and branching
Sequence Diagrams
X-axis is objects
Object that initiates interaction is left most
Object to the right are increasingly more subordinate
Y-axis is time
Messages sent and received are ordered by time
Object life lines represent the existence over a period of time
Activation (double line) is the execution of the procedure.
Collaboration Diagrams
Represents :
collaboration , which is a set of objects related in a particular context
interaction ,which is a set of messages exchanged among the objects within the collaboration to achieve desired outcome
Summary (Interaction Diagrams)
Well structured interaction diagrams:
Is focused on communicating one aspect of a system’s dynamics
Contains only those elements that are essential to understanding
Is not so minimal that it misinforms the reader about the semantics that are important
Diagrams should have meaningful names
Layout diagram to minimize line crossings
Use branching sparingly (leave for activity diagram)
Component Diagrams
A component is a physical thing that conforms to and realizes a set of interfaces
Bridge between logical and physical models
Can represent object libraries, COM components, Java Beans, etc.
Classes represent logical abstractions, components represent physical things that reside on a node (machine).
Components are reachable only through interface