ContextExtensions.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

using System;

namespace Deveel.Data.Diagnostics {
    public static class ContextExtensions {
        public static void RegisterEvent(this IContext context, IEvent @event) {
            var currentContext = context;
            while (currentContext != null) {
                if (currentContext is IEventScope) {
                    var scope = (IEventScope) currentContext;
                    scope.EventRegistry.RegisterEvent(@event);
                }

                currentContext = currentContext.Parent;
            }
        }

        public static void AttachRouter(this IContext context, IEventRouter router) {
            var currentContext = context;
            while (currentContext != null) {
                if (currentContext is IEventScope) {
                    currentContext.RegisterInstance(router);
                    break;
                }

                currentContext = currentContext.Parent;
            }
        }

        public static void Route<TEvent>(this IContext context, Action<TEvent> router)
            where TEvent : class, IEvent {
            context.Route(router, null);
        }

        public static void Route<TEvent>(this IContext context, Action<TEvent> router, Func<TEvent, bool> condition)
            where TEvent : class, IEvent {
            context.AttachRouter(new DelegateRouter<TEvent>(router, condition));
        }

        #region DelegatedRouter

        class DelegateRouter<TEvent> : ThreadedQueue<TEvent>, IEventRouter where TEvent : class, IEvent {
            private Func<TEvent, bool> condition;
            private Action<TEvent> route;

            public DelegateRouter(Action<TEvent> route, Func<TEvent, bool> condition) {
                this.route = route;
                this.condition = condition;
            }

            protected override void Consume(TEvent message) {
                route(message);
            }

            public bool CanRoute(IEvent @event) {
                if (!(@event is TEvent))
                    return false;

                if (condition == null)
                    return true;

                return condition((TEvent)@event);
            }

            public void RouteEvent(IEvent e) {
                Enqueue((TEvent)e);
            }
        }

        #endregion
    }
}