1 | #region License Information |
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2 | /* |
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3 | * This file is part of SimSharp which is licensed under the MIT license. |
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4 | * See the LICENSE file in the project root for more information. |
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5 | */ |
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6 | #endregion |
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7 | |
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8 | using System; |
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9 | using System.Collections.Generic; |
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10 | |
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11 | namespace SimSharp { |
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12 | /// <summary> |
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13 | /// The base class for all events in SimSharp. |
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14 | /// An event can be in one of three states at any time: |
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15 | /// - Alive: The event object exists, but is neither scheduled to |
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16 | /// be executed, nor is it already executed. |
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17 | /// - Triggered: The event has been put in the event queue and is |
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18 | /// going to be executed. |
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19 | /// - Processed: The event has been executed. |
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20 | /// |
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21 | /// Usually, the event is alive until its Trigger, Succeed, or Fail |
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22 | /// method have been called. Then it becomes triggered. When the |
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23 | /// Environment progresses to the event and executes its callbacks |
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24 | /// the event becomes processed. |
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25 | /// </summary> |
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26 | public class Event { |
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27 | protected internal Simulation Environment { get; private set; } |
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28 | protected List<Action<Event>> CallbackList { get; set; } |
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29 | |
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30 | /// <summary> |
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31 | /// The value property can be used to return arbitrary data from a |
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32 | /// process or an event. It also represents the interrupt cause to |
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33 | /// a process. |
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34 | /// </summary> |
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35 | public object Value { get; protected set; } |
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36 | |
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37 | /// <summary> |
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38 | /// The IsOk flag indicates if the event succeeded or failed. An event |
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39 | /// that failed indicates to a waiting process that the action could |
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40 | /// not be performed and that the faulting situation must be handled. |
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41 | /// Typically, interrupting a process sets the IsOk flag to false. |
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42 | /// </summary> |
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43 | public bool IsOk { get; protected set; } |
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44 | /// <summary> |
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45 | /// An event is alive when it is not triggered and not processed. That |
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46 | /// is, when it exists in memory without being scheduled. Typically, |
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47 | /// a Process is alive until its last event has been processed and the |
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48 | /// process event itself is to be processed. |
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49 | /// </summary> |
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50 | public bool IsAlive { get { return !IsTriggered && !IsProcessed; } } |
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51 | /// <summary> |
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52 | /// An event becomes processed when its callbacks have been executed. |
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53 | /// Events may only be processed once and an exception will be thrown |
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54 | /// if they are to be processed multiple times. |
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55 | /// </summary> |
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56 | public bool IsProcessed { get; protected set; } |
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57 | /// <summary> |
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58 | /// An event becomes triggered when it is placed into the event queue. |
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59 | /// That is, when its callbacks are going to be executed. |
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60 | /// An even that is triggered may later not be failed or retriggered. |
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61 | /// </summary> |
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62 | public bool IsTriggered { get; protected set; } |
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63 | |
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64 | public Event(Simulation environment) { |
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65 | Environment = environment; |
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66 | CallbackList = new List<Action<Event>>(); |
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67 | } |
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68 | |
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69 | /// <summary> |
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70 | /// This method schedules the event right now. It takes the IsOk state |
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71 | /// and uses the <see cref="Value"/> of the given <paramref name="@event"/>. |
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72 | /// Thus if the given event fails, this event will also be triggered as |
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73 | /// failing. |
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74 | /// </summary> |
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75 | /// <exception cref="InvalidOperationException"> |
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76 | /// Thrown when the event has already been triggered. |
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77 | /// </exception> |
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78 | /// <remarks> |
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79 | /// The signature of this method allows it to be used as a callback. |
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80 | /// </remarks> |
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81 | /// <param name="event">The event that triggers this event.</param> |
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82 | /// <param name="priority">The priority to rank events at the same time (smaller value = higher priority).</param> |
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83 | public virtual void Trigger(Event @event, int priority = 0) { |
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84 | if (IsTriggered) |
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85 | throw new InvalidOperationException("Event has already been triggered."); |
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86 | IsOk = @event.IsOk; |
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87 | Value = @event.Value; |
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88 | IsTriggered = true; |
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89 | Environment.Schedule(this, priority); |
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90 | } |
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91 | |
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92 | /// <summary> |
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93 | /// This method schedules the event right now. It sets IsOk state to true |
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94 | /// and optionally uses also the value. If urgent is given, the event may |
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95 | /// be scheduled as urgent. Urgent events are placed in a separate event |
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96 | /// queue. The callbacks of urgent events are executed before normal events. |
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97 | /// </summary> |
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98 | /// <exception cref="InvalidOperationException"> |
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99 | /// Thrown when the event has already been triggered. |
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100 | /// </exception> |
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101 | /// <param name="value">The value that the event should use.</param> |
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102 | /// <param name="priority">The priority to rank events at the same time (smaller value = higher priority).</param> |
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103 | public virtual void Succeed(object value = null, int priority = 0) { |
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104 | if (IsTriggered) |
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105 | throw new InvalidOperationException("Event has already been triggered."); |
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106 | IsOk = true; |
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107 | Value = value; |
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108 | IsTriggered = true; |
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109 | Environment.Schedule(this, priority); |
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110 | } |
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111 | |
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112 | /// <summary> |
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113 | /// This method schedules the event right now. It sets IsOk state to false |
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114 | /// and optionally uses also the value. If urgent is given, the event may |
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115 | /// be scheduled as urgent. Urgent events are placed in a separate event |
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116 | /// queue. The callbacks of urgent events are executed before normal events. |
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117 | /// </summary> |
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118 | /// <exception cref="InvalidOperationException"> |
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119 | /// Thrown when the event has already been triggered. |
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120 | /// </exception> |
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121 | /// <param name="value">The value that the event should use.</param> |
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122 | /// <param name="priority">The priority to rank events at the same time (smaller value = higher priority).</param> |
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123 | public virtual void Fail(object value = null, int priority = 0) { |
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124 | if (IsTriggered) |
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125 | throw new InvalidOperationException("Event has already been triggered."); |
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126 | IsOk = false; |
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127 | Value = value; |
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128 | IsTriggered = true; |
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129 | Environment.Schedule(this, priority); |
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130 | } |
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131 | |
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132 | /// <summary> |
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133 | /// This method adds a callback to the list of callbacks. Callbacks will be |
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134 | /// executed in the order they have been added. |
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135 | /// </summary> |
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136 | /// <param name="callback">The callback to execute when the event is being |
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137 | /// processed.</param> |
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138 | public virtual void AddCallback(Action<Event> callback) { |
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139 | if (IsProcessed) throw new InvalidOperationException("Event is already processed."); |
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140 | CallbackList.Add(callback); |
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141 | } |
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142 | |
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143 | /// <summary> |
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144 | /// This method adds a range of callbacks to the list of callbacks. Callbacks |
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145 | /// will be executed in the order they have been added. |
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146 | /// </summary> |
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147 | /// <param name="callbacks">The callbacks to execute when the event is being |
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148 | /// processed.</param> |
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149 | public virtual void AddCallbacks(IEnumerable<Action<Event>> callbacks) { |
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150 | if (IsProcessed) throw new InvalidOperationException("Event is already processed."); |
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151 | CallbackList.AddRange(callbacks); |
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152 | } |
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153 | |
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154 | /// <summary> |
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155 | /// This method removes a callback to the list of callbacks. |
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156 | /// </summary> |
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157 | /// <remarks> |
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158 | /// It is not checked if the callback has actually been added before and |
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159 | /// no exception will be thrown if it had not been present. |
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160 | /// </remarks> |
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161 | /// <param name="callback">The callback to remove.</param> |
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162 | public virtual void RemoveCallback(Action<Event> callback) { |
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163 | if (IsProcessed) throw new InvalidOperationException("Event is already processed."); |
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164 | CallbackList.Remove(callback); |
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165 | } |
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166 | |
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167 | /// <summary> |
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168 | /// This method processes the event, that is, it calls all the callbacks. |
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169 | /// When it finishes it will be marked IsProcessed and cannot be processed |
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170 | /// again. |
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171 | /// </summary> |
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172 | /// <exception cref="InvalidOperationException">When the event has already |
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173 | /// been processed.</exception> |
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174 | public virtual void Process() { |
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175 | if (IsProcessed) throw new InvalidOperationException("Event has already been processed."); |
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176 | IsProcessed = true; |
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177 | for (var i = 0; i < CallbackList.Count; i++) |
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178 | CallbackList[i](this); |
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179 | CallbackList = null; |
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180 | } |
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181 | |
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182 | public static Condition operator &(Event event1, Event event2) { |
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183 | return new AllOf(event1.Environment, event1, event2); |
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184 | } |
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185 | public static Condition operator |(Event event1, Event event2) { |
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186 | return new AnyOf(event1.Environment, event1, event2); |
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187 | } |
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188 | } |
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189 | } |
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