Abstract keyword

Monkey Forums/Monkey Beginners/Abstract keyword

Captain Sullivan

(Posted 2014) [#1]

I am very sorry if it has been asked before, but i have not found it anywhere.

The question is: How do abstract methods in interfaces, and abstract classes work? I have a little knowledge about how they work in Java but I have not programmed in a while and, trying to do so again, i have had many problems making it work in xmonkey.

Thank you to everyone.

Sincerelly, Sullivan.

Gerry Quinn

(Posted 2014) [#2]

An abstract class is a class with one or more abstract methods. You can't instantiate such a class, only extended classes that implement all the abstract methods,

' You can't instantiate this class
Class MyAbstractClass

	Method NormalMethod:Int()
		Return 10
	End
	
	Method AbstractMethod:Int() Abstract

End


' This class is fine, and has two working methods
Class RealClass Extends AbstractClass

	' This has to be defined
	Method AbstractMethod:Int()
		Return 20
	End

End

An interface has only abstract methods, so you don't need the Abstract keyword when declaring them. A class can only extend one class, but it can implement as many interfaces as it wants.

Interface AnInterface
	Method AMethod:Int()
End

Class AClass Implements AnInterface
	Method AMethod:Int()
		Return 30
	End
End

It's quite similar to Java, really.

Captain Sullivan

(Posted 2014) [#3]

Thank you very much.