era.mi/src/era/mi/logic/timeline/Timeline.java

   1 package era.mi.logic.timeline;
   2
   3 import java.util.ArrayList;
   4 import java.util.List;
   5 import java.util.PriorityQueue;
   6 import java.util.function.Consumer;
   7
   8 /**
   9  * Orders Events by the time they are due to be executed. Can execute Events individually.
  10  *
  11  * @author Fabian Stemmler
  12  *
  13  */
  14 public class Timeline
  15 {
  16         private PriorityQueue<InnerEvent> events;
  17         private long currentTime = 0;
  18
  19         private final List<Consumer<TimelineEvent>> eventAddedListener;
  20
  21         public Timeline(int initCapacity)
  22         {
  23                 events = new PriorityQueue<InnerEvent>(initCapacity, (a, b) ->
  24                 {
  25                         long difference = a.getTiming() - b.getTiming();
  26                         if (difference == 0)
  27                                 return 0;
  28                         return difference < 0 ? -1 : 1;
  29                 });
  30
  31                 eventAddedListener = new ArrayList<>();
  32         }
  33
  34         public boolean hasNext()
  35         {
  36                 return !events.isEmpty();
  37         }
  38
  39         public void executeNext()
  40         {
  41                 InnerEvent first = events.poll();
  42                 currentTime = first.getTiming();
  43                 first.run();
  44         }
  45
  46         public void executeAll()
  47         {
  48                 while (hasNext())
  49                         executeNext();
  50         }
  51
  52         /**
  53          * Executes all events up to a given simulation timestamp. The simulation process can be constrained by a real world timestamp.
  54          *
  55          * @param timestamp  the simulation timestamp up to which the events will be processed
  56          * @param stopMillis the System.currentTimeMillis() when simulation definitely needs to stop.
  57          * @return if it was possible to fulfil the goal in the given real world time.
  58          * @author Christian Femers
  59          */
  60         public ExecutionResult executeUpTo(long timestamp, long stopMillis)
  61         {
  62                 if (events.isEmpty())
  63                 {
  64                         currentTime = timestamp;
  65                         return ExecutionResult.NOTHING_DONE;
  66                 }
  67                 int checkStop = 0;
  68                 InnerEvent first = events.peek();
  69                 while (first != null && first.getTiming() <= timestamp)
  70                 {
  71                         events.remove();
  72                         currentTime = first.getTiming();
  73                         first.run();
  74                         // Don't check after every run
  75                         checkStop = (checkStop + 1) % 10;
  76                         if (checkStop == 0 && System.currentTimeMillis() >= stopMillis)
  77                                 return ExecutionResult.RAN_OUT_OF_TIME;
  78                         first = events.peek();
  79                 }
  80                 currentTime = timestamp;
  81                 return ExecutionResult.DONE_IN_TIME;
  82         }
  83
  84         public long getSimulationTime()
  85         {
  86                 return currentTime;
  87         }
  88
  89         public long nextEventTime()
  90         {
  91                 if (!hasNext())
  92                         return -1;
  93                 else
  94                         return events.peek().timing;
  95         }
  96
  97         public void reset()
  98         {
  99                 events.clear();
 100                 currentTime = 0;
 101         }
 102
 103         public void addEventAddedListener(Consumer<TimelineEvent> listener)
 104         {
 105                 eventAddedListener.add(listener);
 106         }
 107
 108         public void removeEventAddedListener(Consumer<TimelineEvent> listener)
 109         {
 110                 eventAddedListener.remove(listener);
 111         }
 112
 113         /**
 114          * Adds an Event to the {@link Timeline}
 115          *
 116          * @param function       The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
 117          * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
 118          */
 119         public void addEvent(TimelineEventHandler function, int relativeTiming)
 120         {
 121                 long timing = currentTime + relativeTiming;
 122                 TimelineEvent event = new TimelineEvent(timing);
 123                 events.add(new InnerEvent(function, event, timing));
 124                 eventAddedListener.forEach(l -> l.accept(event));
 125         }
 126
 127         private class InnerEvent
 128         {
 129
 130                 private final long timing;
 131                 private final TimelineEventHandler function;
 132                 private final TimelineEvent event;
 133
 134                 /**
 135                  * Creates an {@link InnerEvent}
 136                  *
 137                  * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
 138                  * @param timing   Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
 139                  */
 140                 InnerEvent(TimelineEventHandler function, TimelineEvent event, long timing)
 141                 {
 142                         this.function = function;
 143                         this.event = event;
 144                         this.timing = timing;
 145                 }
 146
 147                 public long getTiming()
 148                 {
 149                         return timing;
 150                 }
 151
 152                 public void run()
 153                 {
 154                         function.handle(event);
 155                 }
 156
 157                 @Override
 158                 public String toString()
 159                 {
 160                         return event.toString();
 161                 }
 162         }
 163
 164         @Override
 165         public String toString()
 166         {
 167                 return "simulation time: " + currentTime + ", " + events.toString();
 168         }
 169
 170         public static long toNanoseconds(long ticks)
 171         {
 172                 return ticks; // TODO: Alter this when it has been determined how ticks should relate to real time.
 173         }
 174
 175         public enum ExecutionResult
 176         {
 177                 NOTHING_DONE, DONE_IN_TIME, RAN_OUT_OF_TIME
 178         }
 179 }