// SNMP application factory class.// Copyright (C) 2009-2010 Lex Li// // Permission is hereby granted, free of charge, to any person obtaining a copy of this// software and associated documentation files (the "Software"), to deal in the Software// without restriction, including without limitation the rights to use, copy, modify, merge,// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons// to whom the Software is furnished to do so, subject to the following conditions://// The above copyright notice and this permission notice shall be included in all copies or// substantial portions of the Software.//// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER// DEALINGS IN THE SOFTWARE. using System.Collections.Generic; namespace GSF.Net.Snmp.Pipeline{    /// <summary>    /// SNMP application factory, who holds all pipeline instances.    /// </summary>    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]    public sealed class SnmpApplicationFactory    {        private readonly ILogger _logger;        private readonly ObjectStore _store;        private readonly IMembershipProvider _membershipProvider;        private readonly MessageHandlerFactory _factory;        private readonly object _root = new object();        private readonly Queue<SnmpApplication> _queue = new Queue<SnmpApplication>();         /// <summary>        /// Initializes a new instance of the <see cref="SnmpApplicationFactory"/> class.        /// </summary>        /// <param name="logger">The logger.</param>        /// <param name="store">The store.</param>        /// <param name="membershipProvider">The membership provider.</param>        /// <param name="factory">The factory.</param>        public SnmpApplicationFactory(ILogger logger, ObjectStore store, IMembershipProvider membershipProvider, MessageHandlerFactory factory)        {            _logger = logger;            _membershipProvider = membershipProvider;            _store = store;            _factory = factory;        }         /// <summary>        /// Initializes a new instance of the <see cref="SnmpApplicationFactory"/> class.        /// </summary>        /// <param name="store">The store.</param>        /// <param name="membershipProvider">The membership provider.</param>        /// <param name="factory">The factory.</param>        public SnmpApplicationFactory(ObjectStore store, IMembershipProvider membershipProvider, MessageHandlerFactory factory)            : this(null, store, membershipProvider, factory) // TODO: handle the null case in the future.        {        }         /// <summary>        /// Creates a pipeline for the specified context.        /// </summary>        /// <param name="context">The context.</param>        /// <returns></returns>        public SnmpApplication Create(ISnmpContext context)        {            SnmpApplication result = null;            lock (_root)            {                if (_queue.Count > 0)                {                    result = _queue.Dequeue();                }            }             if (result == null)            {                result = new SnmpApplication(this, _logger, _store, _membershipProvider, _factory);                          }             result.Init(context);            return result;        }         /// <summary>        /// Reuses the specified pipeline.        /// </summary>        /// <param name="application">The application.</param>        internal void Reuse(SnmpApplication application)        {            lock (_root)            {                _queue.Enqueue(application);            }        }    }}