The Unified Modeling Language (UML) is a standard visual language for describing and modelling software blueprints. The UML is more than just a graphical language. Stated formally, the UML is for: Visualizing, Specifying, Constructing, and Documenting.
The artifacts of a software-intensive system (particularly systems built using the object-oriented style).
Three Aspects of UML:
Figure – Three Aspects of UML
Note – Language, Model, and Unified are the important aspect of UML as described in the map above.
- It enables us to communicate about a subject which includes the requirements and the system.
- It is difficult to communicate and collaborate for a team to successfully develop a system without a language.
- It is a representation of a subject.
- It captures a set of ideas (known as abstractions) about its subject.
- It is to bring together the information systems and technology industry’s best engineering practices.
- These practices involve applying techniques that allow us to successfully develop systems.
A Conceptual Model:
A conceptual model of the language underlines the three major elements:
• The Building Blocks • The Rules • Some Common Mechanisms
Once you understand these elements, you will be able to read and recognize the models as well as create some of them.
Figure – A Conceptual Model of the UML
The vocabulary of the UML encompasses three kinds of building blocks:
Things are the abstractions that are first-class citizens in a model; relationships tie these things together; diagrams group interesting collections of things.
There are 4 kinds of things in the UML:
1. Structural things 2. Behavioral things 3. Grouping things 4. Annotational things
These things are the basic object-oriented building blocks of the UML. You use them to write well-formed models.
There are 4 kinds of relationships in the UML:
1. Dependency 2. Association 3. Generalization 4. Realization
These relationships are the basic relational building blocks of the UML.
It is the graphical presentation of a set of elements. It is rendered as a connected graph of vertices (things) and arcs (relationships).
1. Class diagram 2. Object diagram 3. Use case diagram 4. Sequence diagram 5. Collaboration diagram 6. Statechart diagram 7. Activity diagram 8. Component diagram 9. Deployment diagram
The UML has a number of rules that specify what a well-formed model should look like. A well-formed model is one that is semantically self-consistent and in harmony with all its related models.
The UML has semantic rules for:
- Names – What you can call things, relationships, and diagrams.
- Scope – The context that gives specific meaning to a name.
- Visibility – How those names can be seen and used by others.
- Integrity – How things properly and consistently relate to one another.
- Execution – What it means to run or simulate a dynamic model.
The UML is made simpler by the four common mechanisms. They are as follows:
1. Specifications 2. Adornments 3. Common divisions 4. Extensibility mechanisms