sharee.bike-App/TINKLib/Model/Connector/Filter/GroupFilterFactory.cs

using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace TINK.Model.Connector.Filter
{
    public static class GroupFilterFactory
    {
        /// <summary>
        /// Creates filter object.
        /// </summary>
        /// <param name="group">if value consists
        /// - list of strings entries are used to filter (intersect) with or if value is
        /// - null or an empty list null filter is applied, i.e. filtering is off.</param>
        /// <returns>Filtering object.</returns>
        /// <remarks>
        /// Tread group values of null and empty lists as marker to turn filtering off to handle COPRI responses maximal flexible.
        /// </remarks>
        public static IGroupFilter Create(IEnumerable<string> group)
        {
            return group != null && group.Count() > 0 
                ? (IGroupFilter) new IntersectGroupFilter(group) : 
                new NullGroupFilter();
        }
    }
}