FCC/Extension/WayneClassicFdcClient/WayneLogFacade/EventLogStorage/VolatileStorage.cs

#region  --------------- Copyright Dresser Wayne Pignone -------------
/*
 * $Log: /Wrk/WayneLibraries/Wrk/Log/EventLogStorage/VolatileStorage.cs $
 * 
 * 2     08-02-18 7:58 Mattias.larsson
 * Optimized use of Dictionaries.
 */
#endregion

using System.Collections.Generic;

namespace Wayne.Lib.Log
{
    /// <summary>
    /// The VolatileStorage event storage class keeps events only in memory which means that
    /// the unhandled events will vanish when the application is restarted.
    /// </summary>
    internal class VolatileStorage : ISubscriptionStorage
    {
        #region Fields

        private Dictionary<string, List<EventLogEntry>> db = new Dictionary<string, List<EventLogEntry>>();
        private object dbLock = new object();

        #endregion

        #region Methods

        public void Remove(string eventSubscriberId, EventLogEntry logEntry)
        {
            lock (dbLock)
            {
                List<EventLogEntry> pendingEventLogs;
                if (db.TryGetValue(eventSubscriberId, out pendingEventLogs))
                    pendingEventLogs.Remove(logEntry);
            }
        }

        public EventLogEntry[] GetStoredEvents(string eventSubscriberId)
        {
            lock (dbLock)
            {
                List<EventLogEntry> pendingEventLogs;
                if (db.TryGetValue(eventSubscriberId, out pendingEventLogs))
                    return pendingEventLogs.ToArray();
                else
                    return new EventLogEntry[0];
            }
        }

        public void Add(string eventSubscriberId, EventLogEntry logEntry)
        {
            lock (dbLock)
            {
                List<EventLogEntry> pendingEventLogs;
                if (!db.TryGetValue(eventSubscriberId, out pendingEventLogs))
                {
                    pendingEventLogs = new List<EventLogEntry>();
                    db.Add(eventSubscriberId, pendingEventLogs);
                }
                pendingEventLogs.Add(logEntry);
            }
        }

        #endregion
    }
}