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

   1 package era.mi.logic.timeline;
   2
   3 import java.util.PriorityQueue;
   4
   5 /**
   6  * Orders Events by the time they are due to be executed. Can execute Events individually.
   7  * @author Fabian Stemmler
   8  *
   9  */
  10 public class Timeline
  11 {
  12         private PriorityQueue<InnerEvent> events;
  13         private long currentTime = 0;
  14
  15         public Timeline(int initCapacity)
  16         {
  17                 events = new PriorityQueue<InnerEvent>(initCapacity, (a, b) -> {
  18                         long difference = a.getTiming() - b.getTiming();
  19                         if(difference == 0)
  20                                 return 0;
  21                         return difference < 0 ? -1 : 1;
  22                 });
  23         }
  24
  25         public boolean hasNext()
  26         {
  27                 return !events.isEmpty();
  28         }
  29
  30         public void executeNext()
  31         {
  32                 InnerEvent first = events.poll();
  33                 currentTime = first.getTiming();
  34                 first.run();
  35         }
  36
  37         public void executeAll()
  38         {
  39                 while (hasNext())
  40                         executeNext();
  41         }
  42
  43         /**
  44          * Executes all events up to a given simulation timestamp. The simulation
  45          * process can be constrained by a real world timestamp.
  46          *
  47          * @param timestamp  the simulation timestamp up to which the events will be
  48          *                   processed
  49          * @param stopMillis the System.currentTimeMillis() when simulation definitely
  50          *                   needs to stop.
  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 void reset()
  84         {
  85                 events.clear();
  86                 currentTime = 0;
  87         }
  88
  89         /**
  90          * Adds an Event to the {@link Timeline}
  91          * @param function The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
  92          * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
  93          */
  94         public void addEvent(TimelineEventHandler function, int relativeTiming)
  95         {
  96                 long timing = currentTime + relativeTiming;
  97                 events.add(new InnerEvent(function, new TimelineEvent(timing), timing));
  98         }
  99
 100         private class InnerEvent
 101         {
 102
 103                 private final long timing;
 104                 private final TimelineEventHandler function;
 105                 private final TimelineEvent event;
 106
 107                 /**
 108                  * Creates an {@link InnerEvent}
 109                  * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
 110                  * @param timing Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
 111                  */
 112                 InnerEvent(TimelineEventHandler function, TimelineEvent event, long timing)
 113                 {
 114                         this.function = function;
 115                         this.event = event;
 116                         this.timing = timing;
 117                 }
 118
 119                 public long getTiming()
 120                 {
 121                         return timing;
 122                 }
 123
 124                 public void run()
 125                 {
 126                         function.handle(event);
 127                 }
 128
 129                 @Override
 130                 public String toString()
 131                 {
 132                         return event.toString();
 133                 }
 134         }
 135
 136         @Override
 137         public String toString()
 138         {
 139                 return "simulation time: " + currentTime + ", " + events.toString();
 140         }
 141
 142         public static long toNanoseconds(long ticks)
 143         {
 144                 return ticks; //TODO: Alter this when it has been determined how ticks should relate to real time.
 145         }
 146
 147         public enum ExecutionResult
 148         {
 149                 NOTHING_DONE, DONE_IN_TIME, RAN_OUT_OF_TIME
 150         }
 151 }