Unified Modeling Language Part One

--Originally published at Newbie Programmer

We talked about this modeling language before when we defined some examples of the modeling in computer science, UML can be used for stablishing a standard way to visualize the design of a system. UML was created by Grady Booch, Ivar Jacobson and James Rumbaugh at Rational Software in 1994, at 1997 UML was adopted as a standard of Object Management Group (OMG) and in 2005 published by International Organization for Standardization (ISO). We use UML because it’s a standard and it’s easy to use, because have a lot of useful tools for modeling that can be applied to code implementation. To explain a little the tools of UML I choose in this part one sequence diagrams, class diagrams and object diagrams.

Sequence Diagrams (event diagrams)

As the name says this type of diagrams describe the sequence of messages and interaction between the actors and objects, this can be active when they are needed for the communication, these diagrams are used in software development to represent the architecture of the system.

Class Diagrams

This is a diagram that is based in the object-oriented programming paradigm because this shows the common-sense relationship between the classes, the methods and attributes. This diagram consists in three parts, where the first one is the name of the class, second the attributes of the class and third the methods of the class, to represent the relationship between classes we use arrows with direction that represents the way of the association, and in each part of the arrows we have numbers that show cardinality.

Object Diagrams

Object diagrams are quite like class diagrams, this can be considered as a screenshot of the instances in the program and the relationships between the classes in a certain moment simulating a real-world scenario.