Object-Oriented Concepts in AB Suite презентация

concepts
Implement object-oriented concepts in AB Suite application development

Suite Framework

the 1970s
Developed to make software development simpler
Developed to simplify applications and improve maintainability

a car
Conceptual, like a bank transaction


An object is a software bundle of related state and behavior
State is the current condition an object is in and it might change
Behavior is how an object responds to operations

a group of objects that are the same.
An instance is an individual object of a class at runtime.

item of data, such as a customer name or age. For example, strings, numbers, and so on.
Complex class — Is a composition of other classes.

Belongs to the Customer class, a Complex class

Name: Jenny (String)
Gender: Female (String)
Age: 42 (Number)

Primitive classes

object that holds the state of a class
Variable - Temporary storage for information
Parameter - Special variable used to pass data into and/or out of a method call
You can define an instance of a class by setting its Multiplicity property to > 0.
For example, to create an instance of class Customer, set the Multiplicity property of the Customer element to 1.

invoked.
Current instance qualifiers in System Modeler:
This—Refers to the current instance in which the method is running, this can a framework instance or a user-defined instance
Super—Refers to the superclass of the current instance
Owner—Refers to the owner of the current instance
Component—Refers to the current segment
Current instance qualifiers help to reduce programming logic.

contains logic that refers fields from the CUST table.



Consider an instance of CUST ispec, MyCUST in the SALE event.
When MyMethod() is invoked from MyCUST, the logic is:

Referring the instance using the current instance qualifier

Referring the instance by name

interface to the class using:
Parameters
Return variables
AB Suite methods:

Framework Methods

User Defined Method

method call.
Values passed back to the calling method can prompt the calling method to take a particular action.
You can set the return value of a method using the Return command

Return CUSTOMER

calling method from internal changes.
You can write method logic using current instances by:
Explicitly specifying the current instance qualifier
Implicitly specifying the attribute name of the instance

of visibility and ownership of members

It is a means of managing access to an object’s members
Private ( ), visible only within the class
Protected ( ), visible within its class and any class inheriting from it
Public ( ), visible outside the class
It reduces maintenance cost by minimizing scope of change.

than zero

Stock balance = STOCKBAL – Quantity
(STOCKBAL) 1000 – 1500
= -500

STOCKBAL updated, but STOCKBAL is < 0, which is against business rule

Sale Event

Without Encapsulation

With Encapsulation

Stock balance = STOCKBAL – Quantity
(STOCKBAL)

STOCKBAL is not updated, as STOCKBAL is < 0

Sale Event

UpdateStockbal()

Returns False

STOCKBAL is Public

STOCKBAL is Private

This avoids redundancy and helps in reuse of code.
Set the class members that represent the object as Private.
Set the class members that service the external needs of other classes (typically methods) as Public.
Hide implementation by setting the members protected or private.
Expose only interfaces by use of public methods.
Use parameters to pass information from one class to another and into or out of methods.
Do not use global variables for encapsulation.
Set variables that are used only within a method as local variables.

new and more complex objects.
For example, a Customer object is a composition of Name, Address, Credit limit, and so on
It models a relationship between two objects where one object owns, or is made up of, other objects.
It uses attributes that can have special characteristic such as:
Persistence
Presentation

ispec

Customer Number field appears as a drop-down list in the CASH event presentation

Customer Number field appears as a drop-down list in the SALE event presentation

CUST ispec presentation

the model
Can be used more than once in an class

SalesOrder

orderNum
custID
billAddress
delivAddress

Address

streetNum
streetName
streetType
town

billAddress

delivAddress

SalesOrder object owns two instances of Address class

them into another class.
An inheritance hierarchy is formed between the objects
The generalized object is referred to as the superclass
The specializing object is referred to as the subclass
It promotes reuse, reducing complexity among similar objects.

(subclass) inherits attributes, methods, and relationship of another class (superclass).




It allows the reuse of members of a class, reducing the complexity amongst similar objects.
In System Modeler, the Inherits property enables a “subclass” to acquire all the behavior of its “superclass”.

this process subclass members with the same name as the superclass members are overridden.
You cannot override a member if its IsFinal property is set to True.

of the inner class have access to the attributes and methods of its owner.
In System Modeler, the inner class behavior is implemented using the IsInnerClass property.

IsInner is a concept that allows classes to interact through the structural ownership relationship.
IsInner relationship is a simplified interface to private members and the cost of weakened encapsulation.

ability to refer to the instance of a subclass through a common interface defined in the superclass.
In System Modeler, Inherits property is used to associate the objects that are polymorphic.
Overriding the superclass method enhances the capabilities of polymorphism.

are inherited implicitly in every user defined class.
Properties of a class control the level of inheritance.
Members inherited from the framework object depend on the primitive type and stereotype.

processing cycle.
For example, ispecs and segments are both classes, but they have different stereotypes.
A stereotyped class or object inherits a set of built-in attributes and methods.
For example, the built-in attributes and methods inherited by a segment class include:
An attribute called GLB.
A built-in method called Startup().

Stereotypes in AB Suite

Segment
Ispec
Report
Frame
Group
Insertable
Event
CopyIspec
CopyEvent
SQL Script
Presentation Interface
Serializable Interface

do not contain any logic.
To add logic to framework methods invoked during the runtime cycle, you need to override the methods.

in AB Suite application development