FieldFactory.cs :  » Persistence-Frameworks » FileHelpers-Library » FileHelpers » 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.Reflection;

namespace FileHelpers{
  internal sealed class FieldFactory
  {
    #region "  Avoid Creation  "

    private FieldFactory()
    {
    }

    #endregion

    public static FieldBase CreateField(FieldInfo fi, TypedRecordAttribute recordAttribute, bool someOptional)
    {
      // If ignored, return null
      if (fi.IsDefined(typeof (FieldIgnoredAttribute), true))
        return null;

      FieldBase res = null;

      FieldAttribute[] attributes;
      FieldAttribute fieldAttb;

      attributes = (FieldAttribute[]) fi.GetCustomAttributes(typeof (FieldAttribute), true);

      // CHECK USAGE ERRORS !!!

      if (attributes.Length > 1)
        throw new BadUsageException("The field: " + fi.Name + " has more than one FieldAttribute (left only one or none)");

      if (attributes.Length == 0 && recordAttribute is FixedLengthRecordAttribute)
        throw new BadUsageException("The record class marked with the FixedLengthRecord attribute must include a FixedLength attribute in each field.");

      if (recordAttribute is DelimitedRecordAttribute && fi.IsDefined(typeof (FieldAlignAttribute), true))
        throw new BadUsageException("The AlignAttribute is only valid for fixed length records and are used only for write purpouse.");


      // PROCESS IN NORMAL CONDITIONS

      if (attributes.Length > 0)
      {
        fieldAttb = attributes[0];

        if (fieldAttb is FieldFixedLengthAttribute)
        {
          if (recordAttribute is DelimitedRecordAttribute)
            throw new BadUsageException("The FieldFixedLengthAttribute is only for the FixedLengthRecords not for the delimited ones.");

          FieldFixedLengthAttribute attb = ((FieldFixedLengthAttribute) fieldAttb);

          FieldAlignAttribute[] alignAttbs = (FieldAlignAttribute[]) fi.GetCustomAttributes(typeof (FieldAlignAttribute), true);
          FieldAlignAttribute align = null;

          if (alignAttbs.Length > 0)
            align = alignAttbs[0];

          res = new FixedLengthField(fi, attb.Length, align);
          ((FixedLengthField) res).mFixedMode = ((FixedLengthRecordAttribute)recordAttribute).mFixedMode;
        }
        else if (fieldAttb is FieldDelimiterAttribute)
        {
          if (recordAttribute is FixedLengthRecordAttribute)
            throw new BadUsageException("The DelimitedAttribute is only for DelimitedRecords not for the fixed ones.");

          res = new DelimitedField(fi, ((FieldDelimiterAttribute) fieldAttb).mSeparator);

        }
        else
          throw new BadUsageException("Custom TypedRecords not currently supported.");
      }
      else // attributes.Length == 0
      {
        if (recordAttribute is DelimitedRecordAttribute)
          res = new DelimitedField(fi, ((DelimitedRecordAttribute) recordAttribute).Separator);
      }

      //-----  TRIMMING

      if (res != null)
      {
        FieldTrimAttribute[] trim = (FieldTrimAttribute[]) fi.GetCustomAttributes(typeof (FieldTrimAttribute), true);
        if (trim.Length > 0)
        {
          res.mTrimMode = trim[0].TrimMode;
          res.mTrimChars = trim[0].TrimChars;
        }

        FieldQuotedAttribute[] quotedAttributes = (FieldQuotedAttribute[]) fi.GetCustomAttributes(typeof (FieldQuotedAttribute), true);
        if (quotedAttributes.Length > 0)
        {
          if (res is FixedLengthField)
            throw new BadUsageException("The QuotedAttribute can't be used in FixedLength fields.");

          ((DelimitedField) res).mQuoteChar = quotedAttributes[0].QuoteChar;
          ((DelimitedField) res).mQuoteMode = quotedAttributes[0].QuoteMode;
          ((DelimitedField) res).mQuoteMultiline = quotedAttributes[0].QuoteMultiline;
        }

        FieldOptionalAttribute[] optionalAttribs = (FieldOptionalAttribute[]) fi.GetCustomAttributes(typeof (FieldOptionalAttribute), true);

        if (optionalAttribs.Length > 0)
          res.mIsOptional  = true;
        else if (someOptional)
          throw new BadUsageException("When you define a field as FieldOptional, the next fields must be marked with the same attribute. ( Try adding [FieldOptional] to " + res.mFieldInfo.Name + " )");

        
        res.mInNewLine = fi.IsDefined(typeof(FieldInNewLineAttribute), true);
      }


      return res;
    }
  }
}