getting and setting enums in java

Question

I can't seem to figure this out: I want to have an attribute of a class to be settable and gettable as an enumeration. The attribute in question is an objects shape, which can be either CONCAVE, CONVEX, or UNDEFINED. So I thought an enum would be good to use:

    private enum Shape {CONCAVE, CONVEX, UNDEFINED}

this is my constructor:

Vertex()
{
    point = new int[] {0, 0};
    Shape shape = Shape.UNDEFINED;
}

and here is its setter:

 public void setShape(Shape shape)
{
   Shape = shape;
}

and the corresponding accessor:

public Shape getShape()
{
    return  Shape;
}

and here is the compiler errors:

./Vertex.java:27: cannot find symbol symbol : variable Shape location: class Vertex Shape = shape; ^ ./Vertex.java:56: cannot find symbol symbol : variable Shape location: class Vertex return Shape; ^

I've tried all sorts of syntactical combinations and this is the closest I've come to. I also need to know how to properly pass the enumeration value via the setter method in the 'calling' class...

Answer 1

I don't quite understand what you have now, but I think you need:

public class Vertex {

    private enum Shape {CONCAVE, CONVEX, UNDEFINED}

    private Shape shape;

    private int[] point;

    public Vertex() {
        point = new int[] {0, 0};
        shape = Shape.UNDEFINED;
    }

    public Shape getShape() {
        return shape;
    }

    public void setShape(Shape shape) {
        this.shape = shape;
    }
}

Answer 2

Your getter and setter methods are wrong because you've made a typo: you are referencing enumeration instead of class fields. It should be:

public void setShape(Shape shape)
{
   this.shape = shape;
}

public Shape getShape()
{
    return shape;
}

shape should be a class field:

Shape shape;

Answer 3

Seems like you're missing an instance variable for the shape. Also, when allowing the Shape to be read and set, the enum type must be accessible (public, or package protected):

public class Vertex {

    public static enum Shape {
        CONCAVE, CONVEX, UNDEFINED
    }

    private Shape shape; // the instance variable
    private int[] point;

    public Vertex () {
        point = new int[] {0, 0};
        shape = Shape.UNDEFINED;
    }

    public Shape getShape () {
        return shape;
    }

    public void setShape (Shape shape) {
        this.shape = shape;
    }
}

Answer 4

public class Vertex {
private enum Shape {CONCAVE, CONVEX, UNDEFINED};
Shape shape;

Vertex(){
  this.shape = Shape.UNDEFINED;}

public void setShape(Shape shape){
  this.shape = shape;}

public Shape getShape(){
  return  this.shape;}

You have no variable for Shape. A variable would resolve errors.