plugins/net.mograsim.logic.core/src/net/mograsim/logic/core/timeline/Timeline.java

   1 package net.mograsim.logic.core.timeline;
   2
   3 import java.util.ArrayList;
   4 import java.util.List;
   5 import java.util.PriorityQueue;
   6 import java.util.function.BooleanSupplier;
   7 import java.util.function.Consumer;
   8
   9 /**
  10  * Orders Events by the time they are due to be executed. Can execute Events individually.
  11  *
  12  * @author Fabian Stemmler
  13  *
  14  */
  15 public class Timeline
  16 {
  17         private PriorityQueue<InnerEvent> events;
  18         private TimeFunction time;
  19         private long lastTimeUpdated = 0;
  20         private long eventCounter = 0;
  21
  22         private final List<Consumer<TimelineEvent>> eventAddedListener;
  23
  24         public final TimeFunction stepByStepExec = new TimeFunction()
  25         {
  26
  27                 @Override
  28                 public void setTime(long time)
  29                 {
  30                         lastTimeUpdated = time;
  31                 }
  32
  33                 @Override
  34                 public long getTime()
  35                 {
  36                         return lastTimeUpdated;
  37                 }
  38         };
  39         public final TimeFunction realTimeExec = new TimeFunction()
  40         {
  41                 private long offset = 0;
  42
  43                 @Override
  44                 public void setTime(long time)
  45                 {
  46                         offset = time;
  47                 }
  48
  49                 @Override
  50                 public long getTime()
  51                 {
  52                         return System.currentTimeMillis() - offset;
  53                 }
  54         };
  55         private boolean isWorking;
  56
  57         /**
  58          * Constructs a Timeline object. Per default the time function is set to step by step execution.
  59          *
  60          * @param initCapacity The initial capacity of the event queue.
  61          */
  62         public Timeline(int initCapacity)
  63         {
  64                 events = new PriorityQueue<>(initCapacity);
  65                 eventAddedListener = new ArrayList<>();
  66                 time = stepByStepExec;
  67         }
  68
  69         /**
  70          * @param timestamp exclusive
  71          * @return <code>true</code> if the first event in queue is later than the given timestamp
  72          */
  73         public BooleanSupplier laterThan(long timestamp)
  74         {
  75                 return () -> timeCmp(events.peek().getTiming(), timestamp) > 0;
  76         }
  77
  78         /**
  79          * @return <code>true</code> if there is at least one event enqueued. <code>false</code> otherwise
  80          */
  81         public boolean hasNext()
  82         {
  83                 return !events.isEmpty();
  84         }
  85
  86         /**
  87          * Executes all events at the next timestamp, at which there are any
  88          */
  89         public void executeNext()
  90         {
  91                 InnerEvent first = events.peek();
  92                 if (first != null)
  93                         executeUntil(laterThan(first.getTiming()), -1);
  94         }
  95
  96         /**
  97          * Executes all events enqueued in the {@link Timeline}. Use very carefully! Events may generate new events, causing an infinite loop.
  98          */
  99         public void executeAll()
 100         {
 101                 while (hasNext())
 102                         executeNext();
 103         }
 104
 105         /**
 106          * Executes all events until a given condition is met. The simulation process can be constrained by a real world timestamp.
 107          *
 108          * @param condition  the condition until which the events are be processed
 109          * @param stopMillis the System.currentTimeMillis() when simulation definitely needs to stop. A value of -1 means no timeout.
 110          * @return State of the event execution
 111          * @formatter:off
 112          * <code>NOTHING_DONE</code> if the {@link Timeline} was already empty
 113          * <code>EXEC_OUT_OF_TIME</code> if the given maximum time was reached
 114          * <code>EXEC_UNTIL_CONDITION</code> if the condition was met
 115          * <code>EXEC_UNTIL_EMPTY</code> if events were executed until the {@link Timeline} was empty
 116          * @formatter:on
 117          */
 118         public ExecutionResult executeUntil(BooleanSupplier condition, long stopMillis)
 119         {
 120                 if (events.isEmpty())
 121                 {
 122                         lastTimeUpdated = getSimulationTime();
 123                         return ExecutionResult.NOTHING_DONE;
 124                 }
 125                 working();
 126                 int checkStop = 0;
 127                 while (hasNext() && !condition.getAsBoolean())
 128                 {
 129                         InnerEvent event;
 130                         synchronized (events)
 131                         {
 132                                 event = events.remove();
 133                         }
 134                         lastTimeUpdated = event.getTiming();
 135                         event.run();
 136                         // Don't check after every run
 137                         checkStop = (checkStop + 1) % 10;
 138                         if (checkStop == 0 && System.currentTimeMillis() >= stopMillis)
 139                         {
 140                                 notWorking();
 141                                 lastTimeUpdated = getSimulationTime();
 142                                 return ExecutionResult.EXEC_OUT_OF_TIME;
 143                         }
 144                 }
 145                 notWorking();
 146                 lastTimeUpdated = getSimulationTime();
 147                 return hasNext() ? ExecutionResult.EXEC_UNTIL_EMPTY : ExecutionResult.EXEC_UNTIL_CONDITION;
 148         }
 149
 150         /**
 151          * Sets the function, which defines the current simulation time at any time.
 152          *
 153          * @param time The return value of calling this function is the current simulation time.
 154          */
 155         public void setTimeFunction(TimeFunction time)
 156         {
 157                 time.setTime(this.time.getTime());
 158                 this.time = time;
 159         }
 160
 161         /**
 162          * Calculates the current simulation time.
 163          *
 164          * @return The simulation time as defined by the time function.
 165          */
 166         public long getSimulationTime()
 167         {
 168                 return isWorking() ? lastTimeUpdated : time.getTime();
 169         }
 170
 171         /**
 172          * Retrieves the timestamp of the next event.
 173          *
 174          * @return The timestamp of the next enqueued event, if the {@link Timeline} is not empty, -1 otherwise.
 175          */
 176         public long nextEventTime()
 177         {
 178                 if (!hasNext())
 179                         return -1;
 180                 return events.peek().getTiming();
 181         }
 182
 183         /**
 184          * Clears the {@link Timeline} of enqueued events.
 185          */
 186         public void reset()
 187         {
 188                 synchronized (events)
 189                 {
 190                         events.clear();
 191                 }
 192                 lastTimeUpdated = time.getTime();
 193         }
 194
 195         /**
 196          * Adds a listener, that is called when a {@link TimelineEvent} is added.
 197          */
 198         public void addEventAddedListener(Consumer<TimelineEvent> listener)
 199         {
 200                 eventAddedListener.add(listener);
 201         }
 202
 203         /**
 204          * Removes the listener, if possible. It will no longer be called when a {@link TimelineEvent} is added.
 205          */
 206         public void removeEventAddedListener(Consumer<TimelineEvent> listener)
 207         {
 208                 eventAddedListener.remove(listener);
 209         }
 210
 211         /**
 212          * Adds an Event to the {@link Timeline}
 213          *
 214          * @param function       The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
 215          * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
 216          */
 217         public void addEvent(TimelineEventHandler function, int relativeTiming)
 218         {
 219                 long timing = getSimulationTime() + relativeTiming;
 220                 TimelineEvent event = new TimelineEvent(timing);
 221                 synchronized (events)
 222                 {
 223                         events.add(new InnerEvent(function, event, eventCounter++));
 224                 }
 225                 eventAddedListener.forEach(l -> l.accept(event));
 226         }
 227
 228         //@formatter:off
 229         private void working() { isWorking = true; }
 230         private void notWorking() { isWorking = false; }
 231         private boolean isWorking() { return isWorking; }
 232         //@formatter:on
 233
 234         private class InnerEvent implements Runnable, Comparable<InnerEvent>
 235         {
 236                 private final TimelineEventHandler function;
 237                 private final TimelineEvent event;
 238                 private final long id;
 239
 240                 /**
 241                  * Creates an {@link InnerEvent}
 242                  *
 243                  * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
 244                  * @param timing   Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
 245                  */
 246                 InnerEvent(TimelineEventHandler function, TimelineEvent event, long id)
 247                 {
 248                         this.function = function;
 249                         this.event = event;
 250                         this.id = id;
 251                 }
 252
 253                 public long getTiming()
 254                 {
 255                         return event.getTiming();
 256                 }
 257
 258                 @Override
 259                 public void run()
 260                 {
 261                         function.handle(event);
 262                 }
 263
 264                 @Override
 265                 public String toString()
 266                 {
 267                         return event.toString();
 268                 }
 269
 270                 @Override
 271                 public int compareTo(InnerEvent o)
 272                 {
 273                         int c1;
 274                         return (c1 = timeCmp(getTiming(), o.getTiming())) == 0 ? timeCmp(id, o.id) : c1;
 275                 }
 276         }
 277
 278         public static int timeCmp(long a, long b)
 279         {
 280                 return Long.signum(a - b);
 281         }
 282
 283         @Override
 284         public String toString()
 285         {
 286                 String eventsString;
 287                 synchronized (events)
 288                 {
 289                         eventsString = events.toString();
 290                 }
 291                 return String.format("Simulation time: %s, Last update: %d, Events: %s", getSimulationTime(), lastTimeUpdated, eventsString);
 292         }
 293
 294         public static enum ExecutionResult
 295         {
 296                 NOTHING_DONE, EXEC_UNTIL_EMPTY, EXEC_UNTIL_CONDITION, EXEC_OUT_OF_TIME
 297         }
 298
 299         public static interface TimeFunction
 300         {
 301                 long getTime();
 302
 303                 void setTime(long time);
 304         }
 305 }