Macro Management Framework

using System;
using System.Collections;
using System.Reflection;
using System.Diagnostics;

namespace MacMan
{
   /// <summary>
   /// Creates Macros from a class attributed with macro attributes.
   /// </summary>
   sealed class MacroSuiteBuilder
   {
      MacroSuiteBuilder() {}

      internal static int Build(object obj, Hashtable macromap)
      {
         Type T; CheckArgs(obj, macromap, out T);

         MacroSuiteAttribute msa = MacroSuiteAttribute.OnType(T);

         MethodInfo[] methods = GetMethodsOf(T);
         int n = 0;
         foreach (MethodInfo method in methods)
         {
            MacroAttribute ma = MacroAttribute.OnMethod(method);
            if (ma == null) continue;
            if (macromap.ContainsKey(method.Name))
            {
               Trace.WriteLine(string.Format("Macro allready defined: {0}, skipping", method.Name), "Macro Suite Builder");
               continue;
            }
            if (!IsMethodSignatureOK(method))
            {
               Trace.WriteLine(string.Format("Method signature mismatch: {0}, skipping", method.Name), "Macro Suite Builder");
               continue;
            }

            macromap.Add( method.Name, new Macro(obj, method, ma, msa) );
            ++n;
         }

         return n;
      }

      internal static int Strip(object obj, Hashtable macromap)
      {
         Type T; CheckArgs(obj, macromap, out T);

         MethodInfo[] methods = GetMethodsOf(T);
         int n = 0;
         foreach (MethodInfo method in methods)
         {
            if (!macromap.ContainsKey(method.Name)) continue;
            macromap.Remove( method.Name );
            ++n;
         }

         return n;
      }

      static bool IsMethodSignatureOK(MethodInfo method)
      {
         if (method.ReturnType != typeof(string)) return false;
         ParameterInfo[] pars = method.GetParameters();
         if (pars.Length != 1 || pars[0].ParameterType != typeof(string)) return false;

         return true;
      }

      [System.Diagnostics.DebuggerHidden]
      static void CheckArgs(object obj, Hashtable macromap, out Type T)
      {
         if (obj == null)
            throw new ArgumentNullException("obj");
         if (macromap == null)
            throw new ArgumentNullException("macromap");
         T = obj.GetType();
         if ( !MacroSuiteAttribute.IsDefined(T) )
            throw new ArgumentException("Not a macro resolution suite", "obj");
      }

      static MethodInfo[] GetMethodsOf(Type T)
      {
         return T.GetMethods(BindingFlags.Instance|BindingFlags.Public);
      }
   }
}