Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="MessageService.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   Singleton unity container to make it very easy to get instances services.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using Microsoft.Practices.Unity;

namespace Catel.IoC
{
    /// <summary>
    /// Singleton unity container to make it very easy to get instances services.
    /// </summary>
    public sealed class UnityContainer
    {
        #region Variables
        /// <summary>
        /// The instance of this singleton class.
        /// </summary>
        private static readonly UnityContainer _instance = new UnityContainer();

        /// <summary>
        /// The <see cref="IUnityContainer"/> managed by this class.
        /// </summary>
        private static IUnityContainer _unityContainer;

        /// <summary>
        /// Lock object for the <see cref="_unityContainer"/> field.
        /// </summary>
        private static readonly object _unityContainerLock = new object();
        #endregion

        #region Constructor & destructor
        #endregion

        #region Properties
        /// <summary>
        /// Gets the instance of this singleton class.
        /// </summary>
        /// <value>The instance of this singleton class.</value>
        public static UnityContainer Instance { get { return _instance; } }

        /// <summary>
        /// Gets the <see cref="IUnityContainer"/> maanged by this class.
        /// </summary>
        /// <value>The unity container.</value>
        public IUnityContainer Container
        {
            get
            {
                if (_unityContainer == null)
                {
                    lock (_unityContainerLock)
                    {
                        if (_unityContainer == null)
                        {
                            _unityContainer = new Microsoft.Practices.Unity.UnityContainer();
                        }
                    }
                }

                return _unityContainer;
            }
        }
        #endregion

        #region Methods
        #endregion
    }
}