Unified Modelling Language (UML) is a standard graphical language for modelling object oriented software. The Unified Modelling Language was originally developed at Rational Software but is now administered by the Object Management Group. It was developed by Grady Booch, Jim Rumbaugh and Ivar Jacobon at Rational Software.
Types of UML Diagrams:
Use Case Diagram - shows an outside-in view of the procedures available in the use of the system. These are summary diagrams and between them should contain all use cases available in the system and so all the available functionality of the system, represented at a high level.
Static Structure Diagram - includes object and class diagrams. Most methods use class diagrams to describe the properties of the objects in the system and their relationships. Object diagrams are rarely used, except for examples of the way in which object interact, and these are normally shown on sequence or collaboration diagrams
Interaction Diagrams - these include collaboration and sequence diagrams, both of which show the way in which objects interact in order to fulfil the functionality of the use case.
Use Case Diagram shows an outside-in view of the procedures available in the use of the system. It includes use case, actor, association and stereo types.
- Actors are anything outside the system that interacts with the system.Actors are anything outside the system that interacts with the system.
Class diagram is used to describe the properties of the objects in the system and their relationships and shows the static structure of the systems. It includes class name, attribute, operation and association.
- Attributes - The data properties of the classes including type, default value and constraints
- Operations - The signature of the functionality that can be applied to the objects of the classes including parameters, parameter types, parameter constraints, return types and the semantics.
- Associations - The references contained within the objects of the classes to other objects enabling interaction with those objects.
Sequence diagram show the way in which objects interact in order to fulfil the functionality of the use case. It includes objects, lifeline, activation and message. Normally these are specified as part of a use case or use case flow and show how the use case will be implemented in the system. They include:
- Objects - Oblong boxes at the top or actors, named or just shown as belonging to a class from or to which messages are sent to other objects.
- Messages - Solid lines for calls and dotted lines to data returns, showing the messages that are sending between objects. This includes the order of the messages which is from top of the diagram to the bottom.
- Object lifelines - Dotted vertical lines showing the lifetime of the objects.
- Activation - The vertical oblong boxes on the object lifelines showing the thread of control in a synchronous system.
UML also includes diagrams like Collaboration Diagram, Statechart Diagram, Activity Diagram, Component Diagram and Deployment Diagram. These diagrams are described as follows:
- Collaboration diagrams also show interaction between objects,but emphasise the structure required to support them.
- Statechart's are a class-centric view of system functionality.
- An activity diagram is as general purpose flowchart.
- Component diagrams show the types of software components in the system, their interfaces and dependencies
- Deployment diagrams show the computing nodes in the system, their communication links, the components that run on them and their dependencies.
Use Case Diagram
A use case diagram captures the functional requirements of the system. For our course work we have designed High level use case diagram and second level use case diagrams which are explained briefly in the next section.
HIGH LEVEL USE CASE DIAGRAM FOR DVD RENTAL SYSTEM
Our high level use case diagram explains about the events that occur in the DVD Rental System. Below is the High Level Use Case Diagram for DVD Rental System.
In this case study, a detailed UML documentation for DVD Rental Shop is given. The UML diagrams used in this case study are Use case diagram, 2nd level Use case diagram, Class diagram and Sequence diagram. Successfully completion of use case diagram helps in making class diagram and sequence diagram. The simplicity of this project adds the beauty to its accessibility. Any new user can easily access this software which makes this software user-friendly and reusable. DVD Rental Shop is an organization, the modelling of DVD Rental Shop is shown by using unified modelling language because UML provides a wide variety of notations for representing many aspects of software development.
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