1 // -----------------------------------------------------------------------
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2 // <copyright file="CollectionExtensions.cs" company="GRNET">
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3 // Copyright 2011-2012 GRNET S.A. All rights reserved.
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5 // Redistribution and use in source and binary forms, with or
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6 // without modification, are permitted provided that the following
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7 // conditions are met:
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9 // 1. Redistributions of source code must retain the above
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10 // copyright notice, this list of conditions and the following
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13 // 2. Redistributions in binary form must reproduce the above
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14 // copyright notice, this list of conditions and the following
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15 // disclaimer in the documentation and/or other materials
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16 // provided with the distribution.
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18 // THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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19 // OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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20 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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21 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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22 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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25 // USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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26 // AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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27 // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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28 // ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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29 // POSSIBILITY OF SUCH DAMAGE.
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31 // The views and conclusions contained in the software and
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32 // documentation are those of the authors and should not be
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33 // interpreted as representing official policies, either expressed
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34 // or implied, of GRNET S.A.
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36 // -----------------------------------------------------------------------
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38 using System.Collections.Concurrent;
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40 namespace Pithos.Core.Agents
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43 using System.Collections.Generic;
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48 /// Extension methods for collections
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50 public static class CollectionExtensions
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53 /// Remove the first message in a queue that matches the predicate
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55 /// <param name="predicate">The condition to match</param>
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56 /// <remarks>Removes the first message that matches the predicate by dequeing all
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57 /// messages and re-enqueing all except the first matching message</remarks>
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58 public static void RemoveFirst<TMessage>(this ConcurrentQueue<TMessage> queue, Func<TMessage, bool> predicate)
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60 //Can this work? Dequeue all items
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61 //and then enqueue everything except the filtered items
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63 //Possible problems:
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64 //* A matching item may be dequeued between one TryDequeue and the next
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65 var temp = new Queue<TMessage>();
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67 var alreadyFound = false;
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68 while (queue.TryDequeue(out message))
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70 if (!predicate(message) || alreadyFound)
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71 temp.Enqueue(message);
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74 alreadyFound = true;
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78 queue.AddFromEnumerable(temp);
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