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