GenericDataLink.cs :  » Persistence-Frameworks » FileHelpers-Library » FileHelpers » DataLink » C# / CSharp Open Source

#region "   Copyright 2005-07 to Marcos Meli - http://www.marcosmeli.com.ar" 

// Errors, suggestions, contributions, send a mail to: marcos@filehelpers.com.

#endregion

using System;
using System.Reflection;

namespace FileHelpers.DataLink{
  /// <summary>
  /// This class has the responsability to enable the two directional
  /// transformation.
  /// <list type="bullet">
  /// <item> DataStorage &lt;-> DataStorage </item>
  /// </list>
  /// </summary>
  /// <remarks>
  /// <para>Uses two <see cref="DataStorage"/> to accomplish this task.</para>
  /// </remarks>
  /// <seealso href="quick_start.html">Quick Start Guide</seealso>
  /// <seealso href="class_diagram.html">Class Diagram</seealso>
  /// <seealso href="examples.html">Examples of Use</seealso>
  /// <seealso href="example_datalink.html">Example of the DataLink</seealso>
  /// <seealso href="attributes.html">Attributes List</seealso>
  public sealed class GenericDataLink
  {
    #region "  Constructor  "

    /// <summary>Create a new instance of the class.</summary>
    /// <param name="provider1">The First <see cref="DataStorage"/> used to insert/extract records .</param>
    /// <param name="provider2">The Second <see cref="DataStorage"/> used to insert/extract records .</param>
    public GenericDataLink(DataStorage provider1, DataStorage provider2)
    {
      if (provider1 == null)
        throw new ArgumentException("provider1 cant be null", "provider1");
      else
        mDataStorage1 = provider1;

      if (provider2 == null)
        throw new ArgumentException("provider2 cant be null", "provider2");
      else
        mDataStorage2 = provider2;

      ValidateRecordTypes();
    }

    #endregion

    private DataStorage mDataStorage1;
    private DataStorage mDataStorage2;

    /// <summary>Extract the records from DataStorage1 and Insert them to the DataStorage2.</summary>
    /// <returns>The Copied records.</returns>
    public object[] CopyDataFrom1To2()
    {
      object[] res = DataStorage1.ExtractRecords();
      DataStorage2.InsertRecords(res);
      return res;
    }

    /// <summary>Extract the records from DataStorage2 and Insert them to the DataStorage1.</summary>
    /// <returns>The Copied records.</returns>
    public object[] CopyDataFrom2To1()
    {
      object[] res = DataStorage2.ExtractRecords();
      DataStorage1.InsertRecords(res);
      return res;
    }

    MethodInfo mConvert1to2 = null;
    MethodInfo mConvert2to1 = null;


    /// <summary>The fisrt <see cref="DataStorage"/> of the <see cref="GenericDataLink"/>.</summary>
    public DataStorage DataStorage1
    {
      get { return mDataStorage1; }
    }

    /// <summary>The second <see cref="DataStorage"/> of the <see cref="GenericDataLink"/>.</summary>
    public DataStorage DataStorage2
    {
      get { return mDataStorage2; }
    }

    private void ValidateRecordTypes()
    {
      if (DataStorage1.RecordType == null)
        throw new BadUsageException("DataLink1 cant have a null RecordType.");

      if (DataStorage2.RecordType == null)
        throw new BadUsageException("DataLink2 cant have a null RecordType.");

      if (DataStorage1.RecordType != DataStorage2.RecordType)
      {
        mConvert1to2 = GetTransformMethod(DataStorage1.RecordType, DataStorage2.RecordType);
        if (mConvert1to2 == null)
          throw new BadUsageException("You must to define a method in the class " + DataStorage1.RecordType.Name + " with the attribute [TransfortToRecord(typeof(" + DataStorage2.RecordType.Name + "))]");

        mConvert2to1 = GetTransformMethod(DataStorage2.RecordType, DataStorage1.RecordType);
        if (mConvert2to1 == null)
          throw new BadUsageException("You must to define a method in the class " + DataStorage2.RecordType.Name + " with the attribute [TransfortToRecord(typeof(" + DataStorage1.RecordType.Name + "))]");
      }
    }

    private MethodInfo GetTransformMethod(Type sourceType, Type destType)
    {
      MethodInfo[] methods = sourceType.GetMethods(BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance | BindingFlags.NonPublic);
//      foreach (MethodInfo m in methods)
//      {
//        if (m.IsDefined(typeof (TransformToRecordAttribute), false))
//        {
//          TransformToRecordAttribute ta = (TransformToRecordAttribute) m.GetCustomAttributes(typeof (TransformToRecordAttribute), false)[0];
//          if (ta.TargetType == destType)
//          {
//            return m;
//          }
//        }
//      }

      return null;
    }

  }
}