Class Definition Diagram
Class is a collection of objects with and that have a common structure , common behavior , common relationships , and semantic / general word . Classes determined / discovered by examining objects in sequence diagrams and collaboration diagrams . A class is described as a square with three parts of the room . Class should be named using a noun according to domain / section / group ( Jeffery L. Whitten et al , 2004) .
Class Diagram is a diagram that shows the existing classes
of a system and its relationship with logic. Class diagrams describe the static
structure of a system . Because the class diagram is the backbone or basic
strength of almost any object -oriented method including UML ( Henderi , 2008)
. While according to ( Jeffery L. Whitten et al 2004:432 ) class diagram is a
graphic image of the static object structure of a system , showing object
classes that make up a system and also the relationship between the object
class .
Class
diagrams are the most popular UML diagrams used for construction of software
applications. So it is very important to learn the drawing procedure of class
diagram. Class diagrams have lot of properties to consider while drawing but
here the diagram will be considered from a top level view. Class diagram is
basically a graphical representation of the static view of the system and
represents different aspects of the application. So a collection of class
diagrams represent the whole system.
Class
A
class represents an entity of a given system that provides an encapsulated
implementation of certain functionality of a given entity. These are exposed by
the class to other classes as methods. Apart from business functionality, a class
also has properties that reflect unique features of a class. The properties of
a class are called as attributes. The UML representation of a class is a
rectangle containing three compartments stacked vertically
Association
An
association represents a relationship between two classes. An association
indicates that objects of one class have a relationship with objects of another
class, in which this connection has a specifically defined meaning.
Diagram Class Diagram or hump is to describe the structure of the system
in terms of the week was made to build ndefisian classes that will be created
to build the system .
class has what is called
attributes and methods or operations .
a. Attributes are the
variables owned by a class .
b . Operations or methods
are functions that belong to a class
Classes that exist in the structure of the system must be able to perform these functions in accordance with the needs of the system . The composition of both the class structure diagram keleas should have these kinds of classes as follows :
1 . Main class
Is the class that has the initial function is executed when the system starts up
2 . Class that handles the display system
Classes that define and set the display to the user
3 . Classes are taken from defining use case
Class - handling function is a function that should be taken from the definition usecase
4 . Classes are taken from the data defining
Class used to hold or wrap the data into a unit that will be taken and saved to the database
so the purpose of the class diagram can be summarized as :
- Analysis and design of the static view of an application.
- Describe responsibilities of a system.
- Base for component and deployment diagrams.
- Forward and reverse engineering.
so the purpose of the class diagram can be summarized as :
- Analysis and design of the static view of an application.
- Describe responsibilities of a system.
- Base for component and deployment diagrams.
- Forward and reverse engineering.
Elements-elements relevant in modeling UML class diagram consists of: classes, class structure, the nature of class (class behavior), association / union (association), collection / unity (aggregation), dependency (dependency), derivatives relations, diversity and navigation indicators, and role name (role / task name).
Class diagram symbols
1. Class: Class is a block - the building blocks of object-oriented programming. A class is described as a box that is divided into 3 parts. The upper part is a part of the class name. Defines the center of the property / class attribute. The final section defines methodmethod of a class.
2. Association: An association is a relationship between the 2 most common class and is represented by a line connecting the two classes. This line could symbolize the types of relationship and also can display the multiplicity of laws in a relationship. (Example: One-to- one, one-to-many, many-to-many).
3. Composition: If a class can not stand alone and must be part of another class, then the class has a Composition relation to the class in which he relies. A composition relationship is described as a line with a parallelogram-shaped tip contains.
4. Dependency: Sometimes a class uses another class. This is called a dependency. Generally use the dependency is used to indicate operation in a class that uses another class. A dependency is represented as a dotted arrow.
5. Aggregation: Aggregation indicates a whole part relationship and is usually referred to as relations.
Class also has 3 main areas (main) ie: name, attributes, and operations. Serves for the member name identity on a class, an attribute function is for members only on the characteristics of the data owned by an object in the classroom, while the operations function is to provide a function to an object. In defining the existing methods in the classroom should be noted that his name Cohesion and Coupling, Cohesion is a measure of relevance instruction in a method, Coupling is a measure of the relationship between methods. In the class diagram there is a relationship between conceptual classes, called Relation between Class, in UML provided a variety of inter-class relationships, including: Association (static relationship between classes), aggregation (the relationship of the whole object), generalizations (some subclass relation to the super class), Dependency (connectedness of each class).
One object diagram is designing a system that is used to describe object names, attributes and methods. An object diagram is a picture of the objects in a system at one time. This diagram is often also referred to as the command diagram, because the diagram of his commands more highlighted than class.
This is the example of class diagram about blog system:
Mengelola Profil(setNewProfil, editProfil)Attribute : userID,username,bio,email
Operation : setid_Profil, s setuser_name,getuser_name,createpost,comment,share,updateprofile,uploadpic,removep ost,deletecomment,addfriend,deletefriend,subscribe,login.logout,editpost,editcomment
Mengelola Post(inputNewPost, editPost, removePost)Attribute : isi_posting, tgl_isi_posting, panjang_isiPosting,link
Operation : set_isiPost, get_isiPost, set_tglPost, get_tglPost
Mengelola Category(addCategory,editcategory,deletecategory)Attribute : categoryID,categoryname
Operation : set_category,get_category
Mengelola Comment(inputnewComment, deleteComment, editComment)Attribute : isi_comment, tgl_sendcomment,email,penerima,panjang_isiComment
Operation : setisi_Comment, getisi_Comment, settgl_send_Comment, gettgl_send_Comment
