Factory Sample: Defining a Specific Instance of a Factory Class?

Question

I am trying to learn patterns, and I am stuck in determining how and where the Factory pattern determines which class should initiate. If I have an application that calls Factory and sends it, say, an xml configuration file to determine what action to take, where does this logic to interpret the configuration file take place?

THE FACTORY

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace myNamespace
{
    public abstract class SourceFactory
    {
        abstract public UploadSource getUploadSource();
    }
    public class TextSourceFactory : SourceFactory
    {
        public override UploadSource getUploadSource()
        {
            return new TextUploadSource();
        }
    }
    public class XmlSourceFacotry : SourceFactory
    {
        public override UploadSource getUploadSource()
        {
            return new XmlUploadSource();
        }
    }
    public class SqlSourceFactory : SourceFactory
    {
        public override UploadSource getUploadSource()
        {
            return new SqlUploadSource();
        }
    }
}

CLASSES

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace myNamespace
{
    public abstract class UploadSource
    {
        abstract public void Execute();
    }
    public class TextUploadSource : UploadSource
    {
        public override void Execute()
        {
            Console.WriteLine("You executed a text upload source");
        }
    }
    public class XmlUploadSource : UploadSource
    {
        public override void Execute()
        {
            Console.WriteLine("You executed an XML upload source");
        }
    }
    public class SqlUploadSource : UploadSource
    {
        public override void Execute()
        {
            Console.WriteLine("You executed a SQL upload source");
        }
    }
}

Answer 1

factory , factory. , . xml factory .

; factory . , factory , () . , , , .

. / XML , factory, , / .