/src/BurnSystems/src/Scope/Extensions.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace BurnSystems.Scope

{

    /// <summary>

    /// Contains some extension methods for Context

    /// </summary>

    public static class Extensions

    {

        /// <summary>

        /// Tries to add the context source of the given object. 

        /// If the object implements IContextSource or IContextSourceFactory, the object

        /// can be added

        /// </summary>

        /// <param name="context">Context, where Context Source shall be added</param>

        /// <param name="value">Object perhaps containing a context source</param>

        /// <returns>true, if something could be added, otherwise false</returns>

        public static bool TryToAddContextSource(this IContext context, object value)

        {

            var contextSource = value as IContextSource;

            if (contextSource != null)

            {

                context.Add(contextSource);

                return true;

            }



            var contextSourceFactory = value as IContextSourceFactory;

            if (contextSourceFactory != null)

            {

                context.Add(contextSourceFactory.CreateContextSource());

                return true;

            }



            return false;

        }



        /// <summary>

        /// Adds a context object, if no object is already existing at the place. 

        /// This is done by check, if an instance can be created

        /// </summary>

        /// <typeparam name="T">Type of the context</typeparam>

        /// <param name="contextSource">Contextsource to whom the object shall be added</param>

        /// <param name="factory">Factory method</param>

        public static void AddIfNotExisting<T>(this IContextSource contextSource, Func<T> factory)

        {

            using (var testContext = new Context(contextSource, "TestContext"))

            {

                var value = testContext.Get<T>();

                if (value == null)

                {

                    contextSource.Add<T>(factory);

                }

            }

        }



        /// <summary>

        /// Adds a context object, if no object is already existing at the place. 

        /// This is done by check, if an instance can be created

        /// </summary>

        /// <typeparam name="T">Type of the context</typeparam>

        /// <param name="contextSource">Contextsource to whom the object shall be added</param>

        /// <param name="token">Token of the object</param>

        /// <param name="factory">Factory method</param>

        public static void AddIfNotExisting<T>(this IContextSource contextSource, string token, Func<T> factory)

        {

            using (var testContext = new Context(contextSource, "TestContext"))

            {

                var value = testContext.Get<T>(token);

                if (value == null)

                {

                    contextSource.Add<T>(token, factory);

                }

            }

        }

    }

}