//Visitor
public void Visitor()
{
ObjectGuard guard = new ObjectGuard();
AbstractVisitor visitor = new ConcreteVisitor();
guard.Attach(new ConcreteElement1());
guard.Attach(new ConcreteElement2());
guard.Notify(visitor);
}
public static void Run()
{
var elementA = new ConcreteElementA();
var elementB = new ConcreteElementB();
var visitor = new ConcreteVisitor();
elementA.Accept(visitor);
elementB.Accept(visitor);
}
public void TestVisitor()
{
var context = new VisitorContext();
var concreteElementOne = new ConcreteElementOne();
var visitor = new ConcreteVisitor();
context.AddElement(concreteElementOne);
context.Accept(visitor);
}
private static void GenericVisitor()
{
var list = new List <IVisitee>
{
new ConcreteVisitee1(),
new ConcreteVisitee2(),
new ConcreteVisitee1(),
};
var visitor = new ConcreteVisitor();
foreach (var visitee in list)
{
visitee.Accept(visitor);
}
}
public static void Main()
{
var elements = new Element[]
{
new ConcreteElementA("EA1"),
new ConcreteElementA("EA2"),
new ConcreteElementB("EB1"),
new ConcreteElementA("EA3"),
new ConcreteElementC("EC1"),
new ConcreteElementC("EC2"),
new ConcreteElementA("EA5"),
new ConcreteElementB("EB2"),
new ConcreteElementC("EC3")
};
ConcreteVisitor visitor = new ConcreteVisitor();
foreach (var element in elements)
{
element.Accept(visitor);
}
Console.ReadKey();
}
static void Main(string[] args)
{
var people = new List <Person>();
people.Add(new Employee()
{
Name = "Frank"
});
people.Add(new Employee()
{
Name = "Rob"
});
people.Add(new Employee()
{
Name = "Joe"
});
people.Add(new Director()
{
Name = "Andy"
});
people.Add(new Director()
{
Name = "Barry", GolfPartner = "Fabio"
});
people.Add(new Employee()
{
Name = "Stuart"
});
int employeeCountByVisitor = 0;
// Since ConcreteVisitor already implements IPersonVisitor, these statements should generate the same IL
var concreteVisitor = VisitorFactory <IPersonVisitor> .Create(new ConcreteVisitor());
concreteVisitor = new ConcreteVisitor();
// Anonymous classes provide their implementations by way of Action<> delegates
// The name of the properties is not important
var anonymousVisitor = VisitorFactory <IPersonVisitor> .Create(new
{
Employee = new Action <Employee>(e => employeeCountByVisitor++),
Director = new Action <Director>(d =>
{
d.PlayGolf();
})
}, ActionOnMissing.NoOp);
// Concrete classes can also provide implementations by way of Action<> delegates
// Use caution, as any properties of type Action<> that match a Visit method in the given interface will be wired up as implementation
var concreteDelegate = VisitorFactory <IPersonVisitor> .Create(new ConcreteDelegate()
{
Employee = new Action <Employee>(e => employeeCountByVisitor++)
});
// If for some reason you want to, you can use VisitorFactory to inject visitor interfaces into concrete classes with methods
// At the moment, this will take the first method that matches the required signature, regardless of name.
// This will probably change in future.
var concreteDuck = VisitorFactory <IPersonVisitor> .Create(new ConcreteDuck());
// In the case where a concrete class has a method and a Action<> delegate that both match, the method trumps the delegate
var delegateDuck = VisitorFactory <IPersonVisitor> .Create(new DelegateDuck()
{
Employee = new Action <Employee>(e => employeeCountByVisitor++),
Director = new Action <Director>(director =>
{
director.PlayGolf();
})
});
foreach (var person in people)
{
person.Accept(delegateDuck);
}
Console.WriteLine($"There are {employeeCountByVisitor} employees.");
Console.Read();
}
public void Accept(ConcreteVisitor visitor)
{
visitor.Visit(this);
}
public void Accept(ConcreteVisitor visitor)
{
visitor.Visit <ConcreteElementC>(this);
}
