paho.mqtt.m2mqtt/M2Mqtt/Utility/QueueExtension.cs

/*
Copyright (c) 2013, 2014 Paolo Patierno

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License v1.0
and Eclipse Distribution License v1.0 which accompany this distribution. 

The Eclipse Public License is available at 
   http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at 
   http://www.eclipse.org/org/documents/edl-v10.php.

Contributors:
   Paolo Patierno - initial API and implementation and/or initial documentation
*/

using System;
using System.Collections;

namespace uPLibrary.Networking.M2Mqtt.Utility
{
    /// <summary>
    /// Extension class for a Queue
    /// </summary>
    internal static class QueueExtension
    {
        /// <summary>
        /// Predicate for searching inside a queue
        /// </summary>
        /// <param name="item">Item of the queue</param>
        /// <returns>Result of predicate</returns>
        internal delegate bool QueuePredicate(object item);

        /// <summary>
        /// Get (without removing) an item from queue based on predicate
        /// </summary>
        /// <param name="queue">Queue in which to search</param>
        /// <param name="predicate">Predicate to verify to get item</param>
        /// <returns>Item matches the predicate</returns>
        internal static object Get(this Queue queue, QueuePredicate predicate)
        {
            foreach (var item in queue)
            {
                if (predicate(item))
                    return item;
            }
            return null;
        }
    }
}