Learn Abstract Class and Abstract Method with examples

Learn  Abstract Class and Abstract Method with examples 

Abstract Class:

When we declare a class as abstract, this class cannot initiate in X++ code. To use this class or its method we have to first extend this class than only we are able to use this class or its method. To understand the abstract class consider following example

We have three classes

     1.      absClass  (it’s an abstract class)

     2.      normalClass (an another class which will use the absClass methods)

     3.      extendAbsClass (this class will extends the absClass)

    1.      abstract class absClass

     {

     }

    void printName()

   {

    ;    info("AbsClass... Deepak"); 

   }

    2.      class extendAbsClass extends absClass

{

}

    3.      class normalClass

{

}

  void accessAbsClass()

{

    absClass        absClass;

    extendAbsClass  extendAbsClass;

    ;

 //   absClass = new absClass();    // this declaration will throw error “Object could not be created because class absClass is abstract” so first we extend absClass into extendsAbsClass and further use extendsAbsClass to access absClass methods.

    extendAbsClass  = new extendAbsClass();

    extendAbsClass.printName();

}

Abstract Method:

When we declare a method as abstract , this method should be overload in child class or we can say , this method  should be declare/initiate in child class, than only we can use this class or its method.

Note:

a.      Abstract methods may only be declared in abstract classes.

b.      No code or declarations are allowed in abstract methods.

We have three classes

i.                    absMethodClass

ii.                  extendAbsClass

iii.                NormalClass

1.      abstract class absMethodClass

{

}

abstract void absPrintName()

{

                        // we cannot declare any code in abstract method

}

2.      class extendAbsClass extends absMethodClass

{

}

void absPrintName()

{

    ; // we have to initiate abstract method here as this class extends the abstract class.

    info("abstract method declaration in derived class");

}

3.      class childClass_1

{

}

void accessAbsClass()

{

    extendAbsClass  extendAbsClass;

    ;

    extendAbsClass  = new extendAbsClass();

    extendAbsClass.absPrintName();

}