/mcs/class/System.Data.Linq/src/DbLinq/Data/Linq/Identity/Implementation/IdentityReader.cs

#region MIT license

// 

// MIT license

//

// Copyright (c) 2007-2008 Jiri Moudry, Pascal Craponne

// 

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

// 

// The above copyright notice and this permission notice shall be included in

// all copies or substantial portions of the Software.

// 

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

// THE SOFTWARE.

// 

#endregion



using System;

using System.Reflection;

using System.Collections.Generic;

using DbLinq.Data.Linq.Identity;

using DbLinq.Util;



#if MONO_STRICT

using System.Data.Linq;

#else

using DbLinq.Data.Linq;

#endif



namespace DbLinq.Data.Linq.Identity.Implementation

{

    /// <summary>

    /// IIdentityReader default implementation

    /// Currently uses reflection

    /// TODO: use compilation

    /// </summary>

    internal class IdentityReader : IIdentityReader

    {

        private readonly Type type;

        private readonly IList<MemberInfo> keyMembers = new List<MemberInfo>();



        /// <summary>

        /// Gets an object identity

        /// </summary>

        /// <param name="entity"></param>

        /// <returns></returns>

        public IdentityKey GetIdentityKey(object entity)

        {

            // no PK? --> null as identity (==we can not collect it)

            if (keyMembers.Count == 0)

                return null;

            var keys = new List<object>();

            foreach (var keyMember in keyMembers)

            {

                var key = keyMember.GetMemberValue(entity);

                if(key != null)

                    keys.Add(key);

            }

            return new IdentityKey(type, keys);

        }



        /// <summary>

        /// Initializes a new instance of the <see cref="IdentityReader"/> class.

        /// </summary>

        /// <param name="t">The t.</param>

        /// <param name="dataContext">The data context.</param>

        public IdentityReader(Type t, DataContext dataContext)

        {

            foreach (var member in dataContext.Mapping.GetTable(t).RowType.IdentityMembers)

                keyMembers.Add(member.Member);

            type = t;

        }

    }

}