SelectStrategy.cs :  » Persistence-Frameworks » iBATIS.NET » IBatisNet » DataMapper » MappedStatements » ArgumentStrategy » C# / CSharp Open Source

#region Apache Notice
/*****************************************************************************
 * $Revision: 374175 $
 * $LastChangedDate: 2006-04-25 19:40:27 +0200 (mar., 25 avr. 2006) $
 * $LastChangedBy: gbayon $
 * 
 * iBATIS.NET Data Mapper
 * Copyright (C) 2006/2005 - The Apache Software Foundation
 *  
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 ********************************************************************************/
#endregion

using System;
using System.Collections;
#if dotnet2
using System.Collections.Generic;
#endif
using System.Data;
//using System.Reflection;
//using IBatisNet.Common;
//using IBatisNet.DataMapper.Commands;
using IBatisNet.DataMapper.Configuration.ResultMapping;
using IBatisNet.DataMapper.Exceptions;
using IBatisNet.DataMapper.Scope;

namespace IBatisNet.DataMapper.MappedStatements.ArgumentStrategy{
  /// <summary>
  /// <see cref="IArgumentStrategy"/> implementation when a 'select' attribute exists
  /// on a <see cref="ArgumentProperty"/>
  /// </summary>
  public class SelectStrategy : IArgumentStrategy
  {
        private IArgumentStrategy _selectStrategy = null;

        /// <summary>
        /// Initializes a new instance of the <see cref="SelectStrategy"/> class.
        /// </summary>
        /// <param name="mapping">The mapping.</param>
        /// <param name="selectArrayStrategy">The select array strategy.</param>
        /// <param name="selectGenericListStrategy">The select generic list strategy.</param>
        /// <param name="selectListStrategy">The select list strategy.</param>
        /// <param name="selectObjectStrategy">The select object strategy.</param>
    public SelectStrategy(ResultProperty mapping,
            IArgumentStrategy selectArrayStrategy,
            IArgumentStrategy selectGenericListStrategy,
            IArgumentStrategy selectListStrategy,
            IArgumentStrategy selectObjectStrategy)
    {
      // Collection object or .NET object      
      if (mapping.MemberType.BaseType == typeof(Array))
      {
                _selectStrategy = selectArrayStrategy;
      }
#if dotnet2
            else if (mapping.MemberType.IsGenericType &&
                 typeof(IList<>).IsAssignableFrom(mapping.MemberType.GetGenericTypeDefinition())) 
            {
                _selectStrategy = selectGenericListStrategy;
            }
#endif        
            // Check if the object to Map implement 'IList' or is IList type
      // If yes the ResultProperty is map to a IList object
      else if ( typeof(IList).IsAssignableFrom(mapping.MemberType) )
      {
                _selectStrategy = selectListStrategy;
      }

      else // The ResultProperty is map to a .Net object
      {
                _selectStrategy = selectObjectStrategy;
      }
    }

    #region IArgumentStrategy Members

    /// <summary>
    /// Gets the value of an argument constructor.
    /// </summary>
    /// <param name="request">The current <see cref="RequestScope"/>.</param>
    /// <param name="mapping">The <see cref="ResultProperty"/> with the argument infos.</param>
    /// <param name="reader">The current <see cref="IDataReader"/>.</param>
    /// <param name="selectKeys">The keys</param>
    /// <returns>The paremeter value.</returns>
    public object GetValue(RequestScope request, ResultProperty mapping, 
                           ref IDataReader reader, object selectKeys)
    {
      string paramString = mapping.ColumnName;
      object keys = null;
      bool wasNull = false;

      #region Finds the select keys.
      if (paramString.IndexOf(',')>0 || paramString.IndexOf('=')>0) // composite parameters key
      {
        IDictionary keyMap = new Hashtable();
        keys = keyMap;
        // define which character is seperating fields
        char[] splitter  = {'=',','};

        string[] paramTab = paramString.Split(splitter);
        if (paramTab.Length % 2 != 0) 
        {
          throw new DataMapperException("Invalid composite key string format in '"+mapping.PropertyName+". It must be: property1=column1,property2=column2,..."); 
        }
        IEnumerator enumerator = paramTab.GetEnumerator();
        while (!wasNull && enumerator.MoveNext()) 
        {
          string hashKey = ((string)enumerator.Current).Trim();
                    if (paramString.Contains("="))// old 1.x style multiple params
                    {
                        enumerator.MoveNext();
                    }
            object hashValue = reader.GetValue( reader.GetOrdinal(((string)enumerator.Current).Trim()) );

          keyMap.Add(hashKey, hashValue );
          wasNull = (hashValue == DBNull.Value);
        }
      } 
      else // single parameter key
      {
        keys = reader.GetValue(reader.GetOrdinal(paramString));
        wasNull = reader.IsDBNull(reader.GetOrdinal(paramString));
      }
      #endregion

      if (wasNull) 
      {
        return null;
      } 
      else // Collection object or .Net object
      {
        // lazyLoading is not permit for argument constructor
        return _selectStrategy.GetValue(request, mapping, ref reader, keys);
      }  
    }

    #endregion
  }
}