MVP Dependency Chaining Framework

using System;
using System.Collections.Generic;
using System.Text;

/************************************************************************************
*
* Copyright � 2007 Rohit Gadagkar
*
* This software is provided 'as-is', without any explicit or implied warranty. 
*
* Permission is granted to anyone to use this software for any purpose, including
* commercial applications, and to alter it and redistribute it freely, subject to the
* following restrictions:
*
* 1. The origin of this software must not be misrepresented. You must not claim that
* you wrote the original software. If you use this software in a product, 
* the following acknowledgement in the product documentation is required.
*
* "Portions Copyright � 2007 Rohit Gadagkar"
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
************************************************************************************/

namespace MVPChainingFactory.Factory
{
    /// <summary>
    /// Derived implementations of Presenter may be marked with this attribute.
    /// The head and tail of the chain of presenters can be defined using this attribute.
    /// </summary>
    /// <remarks>
    /// Note that there can be only one derived type each that can be marked as Head or Tail.
    /// This attribute cannot be inherited. So the developer specifies if a subclass of a 
    /// concrete implementer is head or tail. 
    /// </remarks>
    [AttributeUsage(AttributeTargets.Class)]
    public class PresenterPositionAttribute : Attribute
    {
        private Position _presenterChainPosition;
        private Type _comesAfter;

        public Type ComesAfter
        {
            get { return _comesAfter; }
            set { _comesAfter = value; }
        }

        public Position PresenterChainPosition
        {
            get { return _presenterChainPosition; }
            set { _presenterChainPosition = value; }
        }

        public PresenterPositionAttribute(Position presenterChainPosition, Type comesAfter)
        {
            _presenterChainPosition = presenterChainPosition; _comesAfter = comesAfter;
        }

        public PresenterPositionAttribute(Position presenterChainPosition)
            : this(presenterChainPosition, null)
        {}

        public PresenterPositionAttribute()
            : this(Position.Middle) { }
    }

    /// <summary>
    /// Defines the position of a presenter in the presenters linked list.
    /// Head indicates the presenter with highest preference. Tail indicates the 
    /// default presenter that handles a request in the fallback case.
    /// </summary>
    public enum Position
    {
        Middle,
        Head,
        Tail
    }
}