class1.cs

来自DoFactory的设计模式, 由于是本人根据已有代码创建,没有NETOptimized项

// Visitor pattern -- Real World example  

using System;
using System.Collections;

namespace DoFactory.GangOfFour.Visitor.RealWorld
{

    // MainApp startup application 

    class MainApp
    {
        static void Main()
        {
            // Setup employee collection 
            Employees e = new Employees();
            e.Attach(new Clerk());
            e.Attach(new Director());
            e.Attach(new President());

            // Employees are 'visited' 
            e.Accept(new IncomeVisitor());
            e.Accept(new VacationVisitor());

            // Wait for user 
            Console.Read();
        }
    }

    // "Visitor" 

    interface IVisitor
    {
        void Visit(Element element);
    }

    // "ConcreteVisitor1" 

    class IncomeVisitor : IVisitor
    {
        public void Visit(Element element)
        {
            Employee employee = element as Employee;

            // Provide 10% pay raise 
            employee.Income *= 1.10;
            Console.WriteLine("{0} {1}'s new income: {2:C}",
              employee.GetType().Name, employee.Name,
              employee.Income);
        }
    }

    // "ConcreteVisitor2" 

    class VacationVisitor : IVisitor
    {
        public void Visit(Element element)
        {
            Employee employee = element as Employee;

            // Provide 3 extra vacation days 
            Console.WriteLine("{0} {1}'s new vacation days: {2}",
              employee.GetType().Name, employee.Name,
              employee.VacationDays);
        }
    }

    class Clerk : Employee
    {
        // Constructor 
        public Clerk()
            : base("Hank", 25000.0, 14)
        {
        }
    }

    class Director : Employee
    {
        // Constructor 
        public Director()
            : base("Elly", 35000.0, 16)
        {
        }
    }

    class President : Employee
    {
        // Constructor 
        public President()
            : base("Dick", 45000.0, 21)
        {
        }
    }

    // "Element" 

    abstract class Element
    {
        public abstract void Accept(IVisitor visitor);
    }

    // "ConcreteElement" 

    class Employee : Element
    {
        string name;
        double income;
        int vacationDays;

        // Constructor 
        public Employee(string name, double income,
          int vacationDays)
        {
            this.name = name;
            this.income = income;
            this.vacationDays = vacationDays;
        }

        // Properties 
        public string Name
        {
            get { return name; }
            set { name = value; }
        }

        public double Income
        {
            get { return income; }
            set { income = value; }
        }

        public int VacationDays
        {
            get { return vacationDays; }
            set { vacationDays = value; }
        }

        public override void Accept(IVisitor visitor)
        {
            visitor.Visit(this);
        }
    }

    // "ObjectStructure" 

    class Employees
    {
        private ArrayList employees = new ArrayList();

        public void Attach(Employee employee)
        {
            employees.Add(employee);
        }

        public void Detach(Employee employee)
        {
            employees.Remove(employee);
        }

        public void Accept(IVisitor visitor)
        {
            foreach (Employee e in employees)
            {
                e.Accept(visitor);
            }
            Console.WriteLine();
        }
    }
}