using System;
using System.Collections;
namespace DoFactory.GangOfFour.Visitor.Structural
{
// MainApp test application
class MainApp
{
staticvoid Main()
{
// Setup structure
ObjectStructure o = new ObjectStructure();
o.Attach(new ConcreteElementA());
o.Attach(new ConcreteElementB());
// Create visitor objects
ConcreteVisitor1 v1 = new ConcreteVisitor1();
ConcreteVisitor2 v2 = new ConcreteVisitor2();
// Structure accepting visitors
o.Accept(v1);
o.Accept(v2);
// Wait for user
Console.Read();
}
}
// "Visitor"
abstractclass Visitor
{
publicabstractvoid VisitConcreteElementA(
ConcreteElementA concreteElementA);
publicabstractvoid VisitConcreteElementB(
ConcreteElementB concreteElementB);
}
// "ConcreteVisitor1"
class ConcreteVisitor1 : Visitor
{
publicoverridevoid VisitConcreteElementA(
ConcreteElementA concreteElementA)
{
Console.WriteLine("{0} visited by {1}",
concreteElementA.GetType().Name, this.GetType().Name);
}
publicoverridevoid VisitConcreteElementB(
ConcreteElementB concreteElementB)
{
Console.WriteLine("{0} visited by {1}",
concreteElementB.GetType().Name, this.GetType().Name);
}
}
// "ConcreteVisitor2"
class ConcreteVisitor2 : Visitor
{
publicoverridevoid VisitConcreteElementA(
ConcreteElementA concreteElementA)
{
Console.WriteLine("{0} visited by {1}",
concreteElementA.GetType().Name, this.GetType().Name);
}
publicoverridevoid VisitConcreteElementB(
ConcreteElementB concreteElementB)
{
Console.WriteLine("{0} visited by {1}",
concreteElementB.GetType().Name, this.GetType().Name);
}
}
// "Element"
abstractclass Element
{
publicabstractvoid Accept(Visitor visitor);
}
// "ConcreteElementA"
class ConcreteElementA : Element
{
publicoverridevoid Accept(Visitor visitor)
{
visitor.VisitConcreteElementA(this);
}
publicvoid OperationA()
{
}
}
// "ConcreteElementB"
class ConcreteElementB : Element
{
publicoverridevoid Accept(Visitor visitor)
{
visitor.VisitConcreteElementB(this);
}
publicvoid OperationB()
{
}
}
// "ObjectStructure"
class ObjectStructure
{
private ArrayList elements = new ArrayList();
publicvoid Attach(Element element)
{
elements.Add(element);
}
publicvoid Detach(Element element)
{
elements.Remove(element);
}
publicvoid Accept(Visitor visitor)
{
foreach (Element e in elements)
{
e.Accept(visitor);
}
}
}
}
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