UUIDStringGenerator.cs

using System;
using System.Text;
using NHibernate.Engine;

namespace NHibernate.Id
{
	/// <summary>
	/// An <see cref="IIdentifierGenerator" /> that returns a string of length
	/// 16.  
	/// </summary>
	/// <remarks>
	/// <p>
	///	This id generation strategy is specified in the mapping file as 
	///	<code>&lt;generator class="uuid.string" /&gt;</code>
	/// </p>
	/// <para>
	/// The identifier string will NOT consist of only alphanumeric characters.  Use
	/// this only if you don't mind unreadable identifiers.
	/// </para>
	/// <para>
	/// This impelementation was known to be incompatible with Postgres.
	/// </para>
	/// </remarks>
	public partial class UUIDStringGenerator : IIdentifierGenerator
	{
		#region IIdentifierGenerator Members

		/// <summary>
		/// Generate a new <see cref="String"/> for the identifier using the "uuid.string" algorithm.
		/// </summary>
		/// <param name="session">The <see cref="ISessionImplementor"/> this id is being generated in.</param>
		/// <param name="obj">The entity for which the id is being generated.</param>
		/// <returns>The new identifier as a <see cref="String"/>.</returns>
		public object Generate(ISessionImplementor session, object obj)
		{
			StringBuilder guidBuilder = new StringBuilder(16, 16);

			byte[] guidInBytes = Guid.NewGuid().ToByteArray();

			// add each item in Byte[] to the string builder
			for (int i = 0; i < guidInBytes.Length; i++)
			{
				guidBuilder.Append((char) guidInBytes[i]);
			}

			return guidBuilder.ToString();
		}

		#endregion
	}
}