/// <summary>
/// Constructs a new <see cref="PrimitiveExtractionStep"/>.
/// </summary>
/// <param name="extractor">
/// The <see cref="IFieldExtractor"/> defining how the primitive value is to be obtained.
/// </param>
/// <param name="converter">
/// A <see cref="DataConverter"/> defining how to transform the primitive value extracted according to
/// <paramref name="extractor"/>. If no transformation is desired, an
/// <see cref="DataConverter.Identity{T}">identity conversion</see> should be provided.
/// </param>
/// <pre>
/// The <see cref="DataConverter.SourceType">SourceType</see> of <paramref name="converter"/> is the same as
/// the <see cref="IFieldExtractor.FieldType">FieldType</see> of <paramref name="extractor"/>, or is a base
/// class or interface thereof
/// --and--
/// The <see cref="IFieldExtractor.FieldType">FieldType</see> of <paramref name="extractor"/> is a data type
/// supported by the Framework.
/// </pre>
public PrimitiveExtractionStep(IFieldExtractor extractor, DataConverter converter)
{
Guard.Against.Null(extractor, nameof(extractor));
Guard.Against.Null(converter, nameof(converter));
Debug.Assert(extractor.FieldType.IsInstanceOf(converter.SourceType));
Debug.Assert(DBType.IsSupported(converter.SourceType));
extractor_ = extractor;
converter_ = converter;
ExpectedSource = extractor_.ExpectedSource;
}
/// <summary>
/// Constructs a new <see cref="DecomposingExtractionStep"/>.
/// </summary>
/// <param name="extractor">
/// The <see cref="IFieldExtractor"/> defining how the primitive value is to be obtained.
/// </param>
/// <param name="decomposition">
/// The steps defining how to decompose the value produced by <paramref name="extractor"/>.
/// </param>
/// <pre>
/// <paramref name="decomposition"/> is not empty
/// --and--
/// The <see cref="IExtractionStep.ExpectedSource">ExpectedSource</see> of each element of
/// <paramref name="decomposition"/> is the same as the <see cref="IFieldExtractor.FieldType">FieldType</see>
/// of <paramref name="extractor"/>, or is a base class or interface thereof
/// --and--
/// The <see cref="IFieldExtractor.FieldType">FieldType</see> of <paramref name="extractor"/> is a data type
/// not supported by the Framework.
/// </pre>
public DecomposingExtractionStep(IFieldExtractor extractor, IEnumerable <IExtractionStep> decomposition)
{
Guard.Against.Null(extractor, nameof(extractor));
Guard.Against.Null(decomposition, nameof(decomposition));
Debug.Assert(!decomposition.IsEmpty());
Debug.Assert(decomposition.All(d => extractor.FieldType.IsInstanceOf(d.ExpectedSource)));
Debug.Assert(!DBType.IsSupported(extractor.FieldType)); // otherwise decomposition is unnecessary
extractor_ = extractor;
decomposition_ = decomposition;
ExpectedSource = extractor_.ExpectedSource;
}
/// <summary>
/// Protected default constructor that defines <see cref="PassThroughFieldExtractor"/> as the default field extractor.
/// </summary>
protected ExtractorLineAggregator()
{
FieldExtractor = new PassThroughFieldExtractor();
}
public FieldProcessor(IFieldExtractor extractor, IFieldAggregator[] aggregators)
{
this.extractor = extractor ?? throw new ArgumentNullException(nameof(extractor));
this.aggregators = aggregators ?? throw new ArgumentNullException(nameof(aggregators));
}
