Senin, 28 Oktober 2013

Class Diagram

Class diagrams are diagrams used to show some class and packages that exist in the system / software we're using .
Class diagram gives us a picture ( static diagram ) of the system / software and relas - relationships that exist therein .


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 .

The Elements of UML class diagrams in modeling 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
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 ..

Senin, 07 Oktober 2013

Usecase Diagram


Use-case diagram is a UML diagram that models used to describe requirementfungsional expected from a system . Use-case diagram emphasizes on "who " did " what " within the software system to be built . Actual use-case diagram consists of two major parts , the first is the use case diagram ( use case dependencies including images ) and use case description .
Use-case diagram is a graphical depiction of some or all of the actors , use-case , and the interactions between these components are introducing a system to be built . Use-case diagrams to explain the benefits of a system when viewed in the eyes of people who are outside the system . This diagram shows the functionality of a system or class and how the system interacts with the outside world .
● Use case classes are used to model and express unit functions / services provided by the system (or parts of systems: subsystems or class) to the user.
● Use case can be covered with restrictions systems that are labeled name system.
● Use case is something that provides measurable results to the user or external system.
characteristics:
- Use cases are interaction or dialogue between the system and actors, including the exchange of messages and actions performed by the system.
- Use cases initiated by the actor and may involve the role of other actors. Use cases should provide a minimum value to the actor.
- Use cases can have an extension that defines specific actions in interactions or other use case may be inserted.
- Use case class has an object called a use case scenario. Scenarios expressed sequences and single action message.
Forming Component Use Case Diagram :
1 . Actor
Basically the actor is not a part of the use case diagram , but to be able to create a use case diagram needed some actor . The actors present someone or something ( such as devices , other systems ) that interact with the system . An actor may only provide information input to the system , only receive information from the system or both receiving and giving information on the system . Actors only interact with the use case , but does not have control over the use case . Actordigambarkan with a stick man . Actor can be described in general or specific , which we can use to distinguish relationship .

2 . Use Case
Use case is a description of the functionality of a system , so that the customer or system users know and understand about the usefulness of the system to be built .
Note : Use case diagram is a depiction of the system from the viewpoint of the system user ( user ) , thus making the use case is more focused on the functionality that exists on the system , not based on the flow or sequence of events .
How to determine a Use Case in the system :
a. Behavior patterns of software applications .
b . Job description of an actor .
c . Systems or " objects " which gives something of value to the actor .
d . What is done by the software ( * not how to do it ) .


 Sample images Interaction Between Actors and Systems (Use-case) on the blog:

 
This is an example usecase for the blog . Actors associated with the user profile usecase , usecase following other blogs , posting usecase . Usecase profile in which there are other elements such as edit profile , new profile , and delete profiles . On edit profile element , the user can change their self - change of data , such as account name , account password , account display picture . In the new profile element , the user can create a new profile you want to display on their blogs . On delete profile elements , users can delete the existing profile .
Usecase following other blogs in which there are other elements such as the following and unfollow . On the following elements , the user can follow the blog to see the latest posts from the blog . Users can participate in more than one blog . At unfollow element , the user can not follow a blog . Users can unfollow more than one blog .
Usecase posts in which there are other elements such as edit posts , new posts , and delete posts . In the post edit elements , the user can change the article that had their previous posts . At post new element , the user can post a new article on his blog . In the post delete elements , users can delete existing posts .
Admin on actors , there is a login usecase . At the login usecase there are elements of the password and username . If the username and password entered by the admin is correct, then the admin can relate to usecase profile , usecase following other blogs , posting usecase .

Senin, 16 September 2013

Korea