Implementation of Class Factories in C#

//=========================================================================
//
// HashSwitchFactory.cs
//
// Sample implementation of a class factory using a hash table &
// switch statement.
//
// Sean Winstead, 1/17/2003
//
//=========================================================================
using System;
using System.Collections;

namespace ClassFactory
{
  public class HashSwitchFactory : BaseClassFactory
  {
    // The following hash table maps an XSLT element name to an
    // integer index. The Create method uses the index to identify
    // the class to be instantiated.
    private Hashtable _ElementHash;

    public HashSwitchFactory()
    {
      // Populate the hash table.
      _ElementHash = new Hashtable(50, (float)0.5);
      _ElementHash.Add(Globals.ElementNames[0], 0);
      _ElementHash.Add(Globals.ElementNames[1], 1);
      _ElementHash.Add(Globals.ElementNames[2], 2);
      _ElementHash.Add(Globals.ElementNames[3], 3);
      _ElementHash.Add(Globals.ElementNames[4], 4);
      _ElementHash.Add(Globals.ElementNames[5], 5);
      _ElementHash.Add(Globals.ElementNames[6], 6);
      _ElementHash.Add(Globals.ElementNames[7], 7);
      _ElementHash.Add(Globals.ElementNames[8], 8);
      _ElementHash.Add(Globals.ElementNames[9], 9);
      _ElementHash.Add(Globals.ElementNames[10], 10);
      _ElementHash.Add(Globals.ElementNames[11], 11);
      _ElementHash.Add(Globals.ElementNames[12], 12);
      _ElementHash.Add(Globals.ElementNames[13], 13);
      _ElementHash.Add(Globals.ElementNames[14], 14);
      _ElementHash.Add(Globals.ElementNames[15], 15);
      _ElementHash.Add(Globals.ElementNames[16], 16);
      _ElementHash.Add(Globals.ElementNames[17], 17);
      _ElementHash.Add(Globals.ElementNames[18], 18);
      _ElementHash.Add(Globals.ElementNames[19], 19);
      _ElementHash.Add(Globals.ElementNames[20], 20);
      _ElementHash.Add(Globals.ElementNames[21], 21);
      _ElementHash.Add(Globals.ElementNames[22], 22);
      _ElementHash.Add(Globals.ElementNames[23], 23);
    }

    public override BaseElement Create(string name)
    {
      switch ((int) _ElementHash[name])
      {
        case 0:
          return new XslApplyImports();
        case 1:
          return new XslApplyTemplates();
        case 2:
          return new XslAttribute();
        case 3:
          return new XslAttributeSet();
        case 4:
          return new XslCallTemplate();
        case 5:
          return new XslChoose();
        case 6:
          return new XslComment();
        case 7:
          return new XslCopy();
        case 8:
          return new XslCopyOf();
        case 9:
          return new XslDecimalFormat();
        case 10:
          return new XslDocument();
        case 11:
          return new XslElement();
        case 12:
          return new XslFallback();
        case 13:
          return new XslForEach();
        case 14:
          return new XslIf();
        case 15:
          return new XslImport();
        case 16:
          return new XslInclude();
        case 17:
          return new XslKey();
        case 18:
          return new XslMessage();
        case 19:
          return new XslNamespaceAlias();
        case 20:
          return new XslNumber();
        case 21:
          return new XslOtherwise();
        case 22:
          return new XslOutput();
        case 23:
          return new XslParam();
        default:
          return null;
      }
    }

  }
}