public static IProjectionAttribute ValList(this IProjection projection, Func <IProjectionAttribute, IProjectionAttribute> itemFactory)
{
if (projection.Data == null)
{
throw ProjectionException.ValueNotFound(projection.Metadata);
}
IProjectionMetadata itemMetadata = projection.Metadata?.Item ?? projection.Metadata;
using ProjectionReader reader = new ProjectionReader(projection.Data.Source, new[] { itemMetadata });
IProjectionAttribute attribute = new ProjectionAttribute(projection.Identity, projection.Context, itemMetadata, data: null);
if (reader.Read())
{
IProjectionData data = reader.GetData().First();
attribute = itemFactory(attribute.With(data: data));
}
while (reader.Read())
{
IProjectionData data = reader.GetData().First();
attribute = attribute.Append(", ");
attribute = itemFactory(attribute.With(data: data));
}
return(attribute);
}
public static IProjectionValues <TModel> Vals <TModel>(this IProjection <TModel> projection, int batchIndex = -1)
{
if (projection.Data == null)
{
throw ProjectionException.ValueNotFound(projection.Metadata);
}
else if (projection.Data.Source.Snapshot == null)
{
IEnumerable <IProjection <TModel> > emptyItems = Array.Empty <IProjection <TModel> >();
return(new ProjectionValues <TModel>(projection.Context, projection.Identity, emptyItems, batchIndex));
}
IProjectionMetadata[] header = new[] { projection.Metadata }.Concat(projection.Header.Select(a => a.Metadata)).ToArray();
IProjectionAttribute[] attributes = header.Skip(1).Select(m => new ProjectionAttribute(projection.Identity, projection.Context, m, data: null)).ToArray();
return(new ProjectionValues <TModel>(projection.Context, projection.Identity, innerReader(), batchIndex));
IEnumerable <IProjection <TModel> > innerReader()
{
using ProjectionReader reader = new ProjectionReader(projection.Data.Source, header);
while (reader.Read())
{
IProjectionData[] dataSet = reader.GetData().ToArray();
if (dataSet[0].Source.Snapshot != null)
{
IEnumerable <IProjectionAttribute> valueHeader = attributes.Zip(dataSet.Skip(1)).Select(t => t.First.With(data: t.Second));
yield return(projection.With(data: dataSet[0], header: valueHeader));
}
}
}
}
