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);
  24
  25                 eventAddedListener = new ArrayList<>();
  26         }
  27
  28         public boolean hasNext()
  29         {
  30                 return !events.isEmpty();
  31         }
  32
  33         public void executeNext()
  34         {
  35                 InnerEvent first = events.peek();
  36                 if (first != null)
  37                         executeUpTo(first.getTiming(), -1);
  38         }
  39
  40         public void executeAll()
  41         {
  42                 while (hasNext())
  43                         executeNext();
  44         }
  45
  46         /**
  47          * Executes all events up to a given simulation timestamp. The simulation process can be constrained by a real world timestamp.
  48          *
  49          * @param timestamp  the simulation timestamp up to which the events will be processed
  50          * @param stopMillis the System.currentTimeMillis() when simulation definitely needs to stop. A value of -1 means no timeout.
  51          * @return if it was possible to fulfil the goal in the given real world time.
  52          * @author Christian Femers
  53          */
  54         public ExecutionResult executeUpTo(long timestamp, long stopMillis)
  55         {
  56                 if (events.isEmpty())
  57                 {
  58                         currentTime = timestamp;
  59                         return ExecutionResult.NOTHING_DONE;
  60                 }
  61                 int checkStop = 0;
  62                 InnerEvent first = events.peek();
  63                 while (first != null && first.getTiming() <= timestamp)
  64                 {
  65                         events.remove();
  66                         currentTime = first.getTiming();
  67                         first.run();
  68                         // Don't check after every run
  69                         checkStop = (checkStop + 1) % 10;
  70                         if (checkStop == 0 && System.currentTimeMillis() >= stopMillis)
  71                                 return ExecutionResult.RAN_OUT_OF_TIME;
  72                         first = events.peek();
  73                 }
  74                 currentTime = timestamp;
  75                 return ExecutionResult.DONE_IN_TIME;
  76         }
  77
  78         public long getSimulationTime()
  79         {
  80                 return currentTime;
  81         }
  82
  83         public long nextEventTime()
  84         {
  85                 if (!hasNext())
  86                         return -1;
  87                 return events.peek().getTiming();
  88         }
  89
  90         public void reset()
  91         {
  92                 events.clear();
  93                 currentTime = 0;
  94         }
  95
  96         public void addEventAddedListener(Consumer<TimelineEvent> listener)
  97         {
  98                 eventAddedListener.add(listener);
  99         }
 100
 101         public void removeEventAddedListener(Consumer<TimelineEvent> listener)
 102         {
 103                 eventAddedListener.remove(listener);
 104         }
 105
 106         /**
 107          * Adds an Event to the {@link Timeline}
 108          *
 109          * @param function       The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
 110          * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
 111          */
 112         public void addEvent(TimelineEventHandler function, int relativeTiming)
 113         {
 114                 long timing = currentTime + relativeTiming;
 115                 TimelineEvent event = new TimelineEvent(timing);
 116                 events.add(new InnerEvent(function, event));
 117                 eventAddedListener.forEach(l -> l.accept(event));
 118         }
 119
 120         private class InnerEvent implements Comparable<InnerEvent>
 121         {
 122                 private final TimelineEventHandler function;
 123                 private final TimelineEvent event;
 124
 125                 /**
 126                  * Creates an {@link InnerEvent}
 127                  *
 128                  * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
 129                  * @param timing   Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
 130                  */
 131                 InnerEvent(TimelineEventHandler function, TimelineEvent event)
 132                 {
 133                         this.function = function;
 134                         this.event = event;
 135                 }
 136
 137                 public long getTiming()
 138                 {
 139                         return event.getTiming();
 140                 }
 141
 142                 public void run()
 143                 {
 144                         function.handle(event);
 145                 }
 146
 147                 @Override
 148                 public String toString()
 149                 {
 150                         return event.toString();
 151                 }
 152
 153                 @Override
 154                 public int compareTo(InnerEvent o)
 155                 {
 156                         long difference = getTiming() - o.getTiming();
 157                         if (difference == 0)
 158                                 return 0;
 159                         return difference < 0 ? -1 : 1;
 160                 }
 161         }
 162
 163         @Override
 164         public String toString()
 165         {
 166                 return "simulation time: " + currentTime + ", " + events.toString();
 167         }
 168
 169         public static long toNanoseconds(long ticks)
 170         {
 171                 return ticks; // TODO: Alter this when it has been determined how ticks should relate to real time.
 172         }
 173
 174         public enum ExecutionResult
 175         {
 176                 NOTHING_DONE, DONE_IN_TIME, RAN_OUT_OF_TIME
 177         }
 178 }