Message.cs

/* Message.cs
 * part of Daniel's XL Toolbox NG
 * 
 * Copyright 2014-2018 Daniel Kraus
 * 
 * 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;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Bovender.Mvvm.Messaging
{
    public class Message<T> : IMessage<T> where T : MessageContent, new() 
    {
        #region IViewModelMessage interface

        public event EventHandler<MessageArgs<T>> Sent;

        #endregion

        #region Protected methods

        public virtual void Send(
            T messageContent,
            Action<T> respond)
        {
            EventHandler<MessageArgs<T>> h = Sent;
            if (h != null)
            {
                Logger.Info("Sending message to {0} subscriber(s)", h.GetInvocationList().Length);
                Logger.Debug("Message content is a {0}",
                    messageContent == null ? "null reference" : messageContent.GetType().FullName);
                h(this,
                    new MessageArgs<T>(
                        messageContent,
                        () =>
                        { 
                            if (respond != null) respond(messageContent);
                        }
                    )
                );
            };
        }

        public virtual void Send(T messageContent)
        {
            Send(messageContent, null);
        }

        public virtual void Send()
        {
            Send(new T(), null);
        }

        #endregion

        #region Class logger

        private static NLog.Logger Logger { get { return _logger.Value; } }

        private static readonly Lazy<NLog.Logger> _logger = new Lazy<NLog.Logger>(() => NLog.LogManager.GetCurrentClassLogger());

        #endregion
    }
}