Search IQuery Example 2

SeachIQuery2.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using NHibernate;
using NHibernate.Linq;

namespace Test.Core.Domain
{
    public class MyQuery : IQuery<IEnumerable<Scam>>
    {
        private readonly string _scamType;
        private readonly DateTime? _start;
        private readonly DateTime? _end;
        private readonly string _gender;

        public MyQuery (string scamType = "", DateTime? start = null, DateTime? end = null, string gender = "")
        {
            _scamType = scamType;
            _start = start;
            _end = end;
            _gender = gender;
        }

        public IEnumerable<Scam> Execute(ISession session)
        {
            var query = session.Query<Scam>()
                .Where(GetScamTypeFilter())
                .Where(GetDateRangeFilter())
                .Where(GetGenderFilter());

            return query.ToList();

        }

        private Expression<Func<Scam, bool>>  GetScamTypeFilter()
        {
            if (!String.IsNullOrEmpty(_scamType))
                return x => x.ScamType == _scamType;
            return x => true;
        }

        private Expression<Func<Scam, bool>> GetDateRangeFilter()
        {
            if (_start != null && _end != null)
                return x => x.ScameDate >= _start && x.ScameDate <= _end;
            return x => true;
        }

        private Expression<Func<Scam, bool>> GetGenderFilter()
        {
            if (!String.IsNullOrEmpty(_gender))
                return x => x.Gender == _gender;
            return x => true;
        }

    }

    public class Scam
    {
        public int Id { get; set; }
        public string ScamType { get; set; }
        public DateTime ScameDate { get; set; }
        public string Gender { get; set; }
    }
}