diagram.puml

@startuml
namespace vistor {
    class areaCalculator << (S,Aquamarine) >> {
        - area int

        - visitForSquare(s *square) 
        - visitForCircle(s *circle) 
        - visitForrectangle(s *rectangle) 

    }
    class circle << (S,Aquamarine) >> {
        - radius int

        - accept(v visitor) 
        - getType() string

    }
    class middleCoordinates << (S,Aquamarine) >> {
        - x int
        - y int

        - visitForSquare(s *square) 
        - visitForCircle(c *circle) 
        - visitForrectangle(t *rectangle) 

    }
    class rectangle << (S,Aquamarine) >> {
        - l int
        - b int

        - accept(v visitor) 
        - getType() string

    }
    interface shape  {
        - getType() string
        - accept( visitor) 

    }
    class square << (S,Aquamarine) >> {
        - side int

        - accept(v visitor) 
        - getType() string

    }
    interface visitor  {
        - visitForSquare( *square) 
        - visitForCircle( *circle) 
        - visitForrectangle( *rectangle) 

    }
}

"vistor.visitor" <|-- "vistor.areaCalculator"
"vistor.shape" <|-- "vistor.circle"
"vistor.visitor" <|-- "vistor.middleCoordinates"
"vistor.shape" <|-- "vistor.rectangle"
"vistor.shape" <|-- "vistor.square"

@enduml