Class Definition Diagram
Class diagrams are used to show classes and packages in the system .
Class diagram gives an overview of the system and the static relationships
between them . Typically , dibua some class diagrams for a single system . Some
diagrams will show a subset of the classes and their relationships . Can be
made a few diagrams as desired to get a complete picture of the system is
built .
Class diagram is the best tool for the design of the development team .
The diagram helps developers get the system structure before the code is
written , and help to ensure that the system is the best design .
- Class
Class is something that wraps and behavioral information . Traditionally
, the system is built with the basic idea that will save the information on the
data lines and pengolahnya behavioral data on the application side . One of the
differences structured object-oriented approach is
in combining object-oriented and information -processing behavior and
hide all the information into something called class . In UML , classes are
expressed using the following notation .
The top of the Class notation is used as a class name , and optionally
also used his stereotype . The middle section is used to store attributes , and
the bottom is used to save the operation .
- Define the class
A good way to find classes were started from watching the flow of events
( flow of events ) of a use case . Note the noun in the flow of events , may be
one of the following four points .
1 . Actor
2 . class
3 . Attributes of the class
4 . Expression , not the actor , not a class , and not attributes .
By selecting the object in the flow of events , classes can be found in
the system . Other alternatives , can test objects in sequence diagrams and
collaboration diagrams .
There are two common ways of defining sequence of inter -related classes
in the class diagram and sequence diagrams or collaboration diagram.Yang first
, by creating a sequence diagram or a collaboration diagram first . Then
proceeded to create the class diagram . In contrast , the second , is to find
classes and create class diagrams first, then use a stretcher classes as "
Dictionary " objects and their relationships to create a sequence diagram
or a collaboration diagram .
- Stereotype in class
Stereotype is a mechanism used to categorize classes . For example , can
be made stereotypical form first , and then determine the classes in step
further . This feature helps to better understand the responsibilities of each
class in the model . The classes with the stereotype of ' form ' responsibility
to show and receive information from the user .
Stereotypes also assist in the process of code generation . When the
code generation process , stereotype class that will determine the type of
class diabawa kebahasa programming .
Some Stereotypes can be used since at this stage of the analysis process
, at the time not yet determined teretentu programming language to generate
code . Stereotypes can also depend on the programming language chosen and used
at this stage of the design process .
When analysis , classes can be categorized according to the function
they perform . There are 3 types of classes in the UML stereotypes are used in
the analysis , namely : delimiter ( boundry ) , entity ( entity ) and control .
a. Limiting classes
Limiting classes are classes that are located between the system with
the world around him . All forms , reports , interfaces ( interfaces ) such as
soft keperangkat Printer or scanner , and interfaces ( interfaces ) to other
systems are included in this category . UML presented
class barrier as follows .
To locate and identify the limiting classes can be done by testing the
use case diagram . At a minimum there should be a barrier to class setiapa
interaction between actors - use case . Class limit is what allows the actors
interact with the system .
No need to make the grade boundary for each pair of actor - use case .
For example , if two actors have equally initialize the same use case to
communicate with the system .
b . Entity classes
Entity classes to handle the information stored in persistent storage .
Entity classes are usually found in the incident flow ( flow of events ) on the
interaction diagram . They are classes that are most meaningful to the wearer
and are typically given a domain name using the technology business.
Note the noun in the flow of
events . Some nouns will be the entity classes in the system . Another way is
to consider the structure of the data base . If the design of the database has
been created , note the names of the table . The tables deal with some
permanent information record , while the entity class , handle information in
computer memory when the computer is turned on . In UML , the class notation
entity described as follows .
Of database design , can trace back some of the fields in the database
system needs . System needs to determine the flow of events ( flow of events )
, and the flow of events to determine the objects , classes , and attributes -
attributes in the class . Each of these attributes in the entity class may be
fields in the database .
c . Control classes
Control class is responsible for coordinating the activities of the
other classes . This class is optional , but if the class of this control is
used , then tropical one control class for such a use case . There are classes
that control is shared by several use cases . In UML , the class notation entity
described as follows .
naming class
Each class must have a unique name . Most organizations have their own
naming convention for naming classes are made . Classes are generally named
using singular noun .
Do not use the class name spaces . This is done for practical reasons ,
where some programming languages do not allow any space . Another thing to
note is that the class name should be short enough to explain what the class
will do .
So it really depends on the class naming our organization . If we have a
class that is used within the organization , but it is clear that it should be
consistently used for whole classes were made .
- Visibility class
Visibility option determines whether a class can be seen from the
outside of the package . There are 3 options for the visibility of a class is:
1 . Public
2 . States that a class can be seen from the other classes in the system
.
3 . Protected or private
4 . States that a class can be seen from multiple classes ( nested ) ,
friends , or of the class itself .
5 . Package or implementation .
6 . States that a class can be seen only by other classes in the same
package .
multiplicity class
Multiplicity provide instant overview ebuah to be accommodated in the
classroom . For example , in a class of employees , we may have some instant ,
one for Ani , one for Ina , one for Nana and so on . So Multiplicity for n set
class employees . In the control class , Multiplicity is set 1 , because at the
time the application runs only one class .
Several types of Multiplicity class .
Table Multiplicity for class :
Multiplicity
|
Arti
|
n (default)
|
Banyak
|
0..0
|
Nol
|
0..1
|
Nol atau Satu
|
0..n
|
Nol atau Banyak
|
1..1
|
Tepat satu
|
1. .n
|
Satu atau banyak
|
Multiplicity Notation table using the customization
Format
|
Arti
|
Tepat
|
|
..
|
Antara
|
..
|
Atau nol
|
,
|
|
, ..
|
Tepat atau antara dan
|
.. ,
..
|
Antara dan atau antara dan
|
Package used unruk group classes have in common . In UML , described as
follows :
There are several ways to group classes in the package , but somehow ,
these classes can be grouped in the same package depends on our own desires .
One approach that can be used is based on the stereotype . With this approach ,
a package can be created for entity classes , and one class for the control
classes .
Other approaches that can be used is with functionality. For example ,
we have a security package for the classes that are used to handle the security
system .
Finally , it can be used a combination of the above two approaches .
Package can be nested , in which a packet containing other packages . At the
highest level , can be grouped based on functionality , then followed with
another sub functionality or with his stereotype .
