+visitElementA(in a : ConcreteElementA) +visitElementB(in b : ConcreteElementB) «interface» Visitor +visitElementA(in a : ConcreteElementA) +visitElementB(in b : ConcreteElementB) ConcreteVisitor +accept(in v : Visitor) «interface» Element +accept(in v : Visitor) ConcreteElementA +accept(in v : Visitor) ConcreteElementB Client Visitor Type: Behavioral What it is: Represent an operation to be perfo