using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using Bowin.Common.Utility;

namespace Bowin.Common
{
    [AttributeUsage( AttributeTargets.Property, AllowMultiple = false)]
    public class DataPropertyAttribute: Attribute
    {
        private static Dictionary<Type, PropertyInfo[]> dataProperties = new Dictionary<Type, PropertyInfo[]>();
        public static PropertyInfo[] GetDataProperties(Type entityType)
        {
            Guard.ArgumentNotNullOrEmpty(entityType, "entityType");
            if (dataProperties.ContainsKey(entityType))
            {
                return dataProperties[entityType];
            }
            lock (typeof(DataPropertyAttribute))
            {
                if (dataProperties.ContainsKey(entityType))
                {
                    return dataProperties[entityType];
                }
                var properties = (from property in entityType.GetProperties()
                                  where property.GetCustomAttributes(typeof(DataPropertyAttribute), true).Any()
                                  select property).ToArray();
                dataProperties[entityType] = properties;
                return properties;
            }
        }
    }
}