EntityModeToTuplizerMapping.cs

using System;
using System.Collections;
using NHibernate.Util;

namespace NHibernate.Tuple
{
	/// <summary> Centralizes handling of <see cref="EntityMode"/> to <see cref="ITuplizer"/> mappings. </summary>
	[Serializable]
	public abstract class EntityModeToTuplizerMapping
	{
		// map of EntityMode -> Tuplizer
		private readonly IDictionary tuplizers = new SequencedHashMap();

		protected internal void AddTuplizer(EntityMode entityMode, ITuplizer tuplizer)
		{
			tuplizers[entityMode] = tuplizer;
		}

		/// <summary> Given a supposed instance of an entity/component, guess its entity mode. </summary>
		/// <param name="obj">The supposed instance of the entity/component.</param>
		/// <returns> The guessed entity mode. </returns>
		public virtual EntityMode? GuessEntityMode(object obj)
		{
			foreach (DictionaryEntry entry in tuplizers)
			{
				ITuplizer tuplizer = (ITuplizer)entry.Value;
				if (tuplizer.IsInstance(obj))
				{
					return (EntityMode)entry.Key;
				}
			}
			return null;
		}

		/// <summary> 
		/// Locate the contained tuplizer responsible for the given entity-mode.  If
		/// no such tuplizer is defined on this mapping, then return null. 
		/// </summary>
		/// <param name="entityMode">The entity-mode for which the caller wants a tuplizer.
		/// </param>
		/// <returns> The tuplizer, or null if not found.
		/// </returns>
		public virtual ITuplizer GetTuplizerOrNull(EntityMode entityMode)
		{
			return (ITuplizer)tuplizers[entityMode];
		}

		/// <summary> Locate the tuplizer contained within this mapping which is responsible
		/// for the given entity-mode.  If no such tuplizer is defined on this
		/// mapping, then an exception is thrown.
		/// 
		/// </summary>
		/// <param name="entityMode">The entity-mode for which the caller wants a tuplizer.
		/// </param>
		/// <returns> The tuplizer.
		/// </returns>
		/// <throws>  HibernateException Unable to locate the requested tuplizer. </throws>
		public virtual ITuplizer GetTuplizer(EntityMode entityMode)
		{
			ITuplizer tuplizer = GetTuplizerOrNull(entityMode);
			if (tuplizer == null)
			{
				throw new HibernateException("No tuplizer found for entity-mode [" + entityMode + "]");
			}
			return tuplizer;
		}
	}
}