CODEWITHSUNDEEP
javaswingoopjava-2d
B-Mac
B-Mac

Reputation: 567

Common interface for these shapes

I need to read input from a file and draw the appropriate shape. The shape can be a rectangle, ellipse, circle or a line. I know how to work with all these. However, I was wondering if I could use a common interface and work with each of them.

I mean, I wish I could have something defined as:

Shape currentShape;

and then I can do:

currentShape = new Rectangle(-);
currentShape = new Ellipse2D.Double(-);

and so on.

However, I cannot access the exclusive methods of the objects using the currentShape.

What is the alternative?
PS: I'm using the swing class.

Upvotes: 0

Views: 57

Answers (1)

CMPS
CMPS

Reputation: 7769

Well, you cannot access the methods for the dynamic type (Rectangle, Double etc..) because the static type is a parent (Shape). But here's how you can cast it:

Shape currentShape;
currentShape = new Ellipse2D.Double();

if(currentShape instanceof Ellipse2D.Double){
    Ellipse2D.Double tmpShape = (Ellipse2D.Double) currentShape;

    // Code goes here
} // else if (same for Rectangle, or any other child of Shape)

Upvotes: 1

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