using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.Text;
 
namespace Web.DataAccess
{
    public sealed class AccessHelperParameterCache
    {
        private AccessHelperParameterCache() { }
 
        private static OleDbParameter[] CloneParameters(OleDbParameter[] originalParameters)
        {
            OleDbParameter[] cloneParameters = new OleDbParameter[originalParameters.Length];
            for (int i = 0; i < cloneParameters.Length; i++)
            {
                cloneParameters[i] = (OleDbParameter)(((ICloneable)originalParameters[i]).Clone());
            }
 
            return cloneParameters;
        }
 
        private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
 
        public static void CacheParameterSet(string connectionString, string commandText, params OleDbParameter[] commandParameters)
        {
            if (null == connectionString || string.Empty == connectionString) throw new ArgumentNullException("connectionString");
            if (null == commandText || string.Empty == commandText) throw new ArgumentNullException("commandText");
            if (null == commandParameters || 0 == commandParameters.Length) throw new ArgumentNullException("commandParameters");
 
            paramCache[connectionString + ":" + commandText] = CloneParameters(commandParameters);
        }
 
        public static OleDbParameter[] GetCacheParameterSet(string connectionString, string commandText)
        {
            if (null == connectionString || string.Empty == connectionString) throw new ArgumentNullException("connectionString");
            if (null == commandText || string.Empty == commandText) throw new ArgumentNullException("commandText");
 
            OleDbParameter[] cachedParameters = paramCache[connectionString + commandText] as OleDbParameter[];
            if (null != cachedParameters)
            {
                CloneParameters(cachedParameters);
            }
            return null;
        }
    }
}