Factory Pattern without a Switch or If/Then

Question

I\'m looking for a simple example of how to implement a factory class, but without the use of a Switch or an If-Then statement. All the examples I can find use one. F

Answer 1

Why overcomplicate things? Here is one simple solution:

using System;
using System.Collections.Generic;

class Program
{
    interface IPosition
    {
        string Title { get; }
    }

    class Manager : IPosition
    {
        public string Title
        {
            get { return "Manager"; }
        }
    }

    class Clerk : IPosition
    {
        public string Title
        {
            get { return "Clerk"; }
        }
    }

    class Programmer : IPosition
    {
        public string Title
        {
            get { return "Programmer"; }
        }
    }

    class Factory
    {
        private List positions = new List();
        public Factory()
        {
            positions.Add(new Manager());
            positions.Add(new Clerk());
            positions.Add(new Programmer());
            positions.Add(new Programmer());
        }

        public IPosition GetPositions(int id)
        {
            return positions[id];
        }
    }

    static void Main(string[] args)
    {
        Factory factory = new Factory();

        for (int i = 0; i <= 2; i++)
        {
            var position = factory.GetPositions(i);
            Console.WriteLine("Where id = {0}, position = {1} ", i, position.Title);
        }
        Console.ReadLine();
    }
}

Here is how to do this without using factory class at all:

using System;
using System.Collections.Generic;

class Program
{
    interface IPosition
    {
        string Title { get; }
    }

    class Manager : IPosition
    {
        public string Title
        {
            get { return "Manager"; }
        }
    }

    class Clerk : IPosition
    {
        public string Title
        {
            get { return "Clerk"; }
        }
    }

    class Programmer : IPosition
    {
        public string Title
        {
            get { return "Programmer"; }
        }
    }

    static void Main(string[] args)
    {
        List positions = new List { new Manager(), new Clerk(), new Programmer(), new Programmer() };

        for (int i = 0; i <= 2; i++)
        {
            var position = positions[i];
            Console.WriteLine("Where id = {0}, position = {1} ", i, position.Title);
        }
        Console.ReadLine();
    }
}