<< Chapter < Page Chapter >> Page >
A short tutorial on using UML diagrams, particularly class diagrams, in object-oriented design.

Unified Modeling Language ("UML") is the industry standard"language"for describing, visualizing, and documenting object-oriented (OO) systems. UML is a collection of a variety of diagrams for differing purposes. Each type of diagram models a particular aspect of OO design in an easy to understand, visual manner. The UML standard specifies exactly how the diagrams are to be drawn and what each component in the diagram means. UML is not dependent on any particular programming language, instead it focuses one the fundamental concepts and ideas that model a system. Using UML enables anyone familiar with its specifications to instantly read and understand diagrams drawn by other people. There are UML diagram for modeling static class relationships, dynamic temporal interactions between objects, the usages of objects, the particulars of an implementation, and the state transitions of systems

In general, a UML diagram consists of the following features:

  • Entities : These may be classes, objects, users or systems behaviors.
  • Relationship Lines that model the relationships between entities in the system.
    • Generalization -- a solid line with an arrow that points to a higher abstraction of the present item.
    • Association -- a solid line that represents that one entity uses another entity as part of its behavior.
    • Dependency -- a dotted line with an arrowhead that shows one entity depends on the behavior of another entity.

Class diagrams

UML class diagrams model static class relationships that represent the fundamental architecture of the system. Note that these diagrams describe the relationships between classes , not those between specific objects instantiated from those classes. Thus the diagram applies to all the objects in the system.

A class diagram consists of the following features:

  • Classes : These titled boxes represent the classes in the system and contain information about the name of the class, fields, methods and access specifiers. Abstract roles of the class in the system can also be indicated.
  • Interfaces : These titled boxes represent interfaces in the system and contain information about the name of the interface and its methods.
  • Relationship Lines that model the relationships between classes and interfaces in the system.
    • Generalization
      • Inheritance : a solid line with a solid arrowhead that points from a sub-class to a superclass or from a sub-interface to its super-interface.
      • Implementation : a dotted line with a solid arrowhead that points from a class to the interface that it implement
    • Association -- a solid line with an open arrowhead that represents a"has a"relationship. The arrow points from the containing to the contained class. Associations can be one of the following two types or not specified.
      • Composition : Represented by an association line with a solid diamond at the tail end. A composition models the notion of one object"owning"another and thus being responsible for the creation and destruction of another object.
      • Aggregation : Represented by an association line with a hollow diamond at the tail end. An aggregation models the notion that one object uses another object without"owning"it and thus is not responsible for its creation or destruction.
    • Dependency -- a dotted line with an open arrowhead that shows one entity depends on the behavior of another entity. Typical usages are to represent that one class instantiates another or that it uses the other as an input parameter.
  • Notes that are used to provide further details or explanations of particular parts of the diagram. Notes are boxes with a little"dog-ear"on one corner.

Here is an example of a UML class diagram that holds most of the more common features:

Uml class diagram

The above diagram contains classes, interfaces, inheritance and implementation lines, aggregation lines, dependency lines and notes.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 1

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Principles of object-oriented programming. OpenStax CNX. May 10, 2013 Download for free at http://legacy.cnx.org/content/col10213/1.37
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Principles of object-oriented programming' conversation and receive update notifications?