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         private PriorityQueue<InnerEvent> events;
  16         private long currentTime = 0;
  17
  18         private final List<Consumer<TimelineEvent>> eventAddedListener;
  19
  20         public Timeline(int initCapacity) {
  21                 events = new PriorityQueue<InnerEvent>(initCapacity, (a, b) -> {
  22                         long difference = a.getTiming() - b.getTiming();
  23                         if (difference == 0)
  24                                 return 0;
  25                         return difference < 0 ? -1 : 1;
  26                 });
  27
  28                 eventAddedListener = new ArrayList<>();
  29         }
  30
  31         public boolean hasNext() {
  32                 return !events.isEmpty();
  33         }
  34
  35         public void executeNext() {
  36                 InnerEvent first = events.poll();
  37                 currentTime = first.getTiming();
  38                 first.run();
  39         }
  40
  41         public void executeAll() {
  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.
  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                 if (events.isEmpty()) {
  56                         currentTime = timestamp;
  57                         return ExecutionResult.NOTHING_DONE;
  58                 }
  59                 int checkStop = 0;
  60                 InnerEvent first = events.peek();
  61                 while (first != null && first.getTiming() <= timestamp) {
  62                         events.remove();
  63                         currentTime = first.getTiming();
  64                         first.run();
  65                         // Don't check after every run
  66                         checkStop = (checkStop + 1) % 10;
  67                         if (checkStop == 0 && System.currentTimeMillis() >= stopMillis)
  68                                 return ExecutionResult.RAN_OUT_OF_TIME;
  69                         first = events.peek();
  70                 }
  71                 currentTime = timestamp;
  72                 return ExecutionResult.DONE_IN_TIME;
  73         }
  74
  75         public long getSimulationTime() {
  76                 return currentTime;
  77         }
  78
  79         public long nextEventTime() {
  80                 if (!hasNext())
  81                         return -1;
  82                 else
  83                         return events.peek().timing;
  84         }
  85
  86         public void reset() {
  87                 events.clear();
  88                 currentTime = 0;
  89         }
  90
  91         public void addEventAddedListener(Consumer<TimelineEvent> listener) {
  92                 eventAddedListener.add(listener);
  93         }
  94
  95         public void removeEventAddedListener(Consumer<TimelineEvent> listener) {
  96                 eventAddedListener.remove(listener);
  97         }
  98
  99         /**
 100          * Adds an Event to the {@link Timeline}
 101          *
 102          * @param function       The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
 103          * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
 104          */
 105         public void addEvent(TimelineEventHandler function, int relativeTiming) {
 106                 long timing = currentTime + relativeTiming;
 107                 TimelineEvent event = new TimelineEvent(timing);
 108                 events.add(new InnerEvent(function, event, timing));
 109                 eventAddedListener.forEach(l -> l.accept(event));
 110         }
 111
 112         private class InnerEvent {
 113
 114                 private final long timing;
 115                 private final TimelineEventHandler function;
 116                 private final TimelineEvent event;
 117
 118                 /**
 119                  * Creates an {@link InnerEvent}
 120                  *
 121                  * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
 122                  * @param timing   Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
 123                  */
 124                 InnerEvent(TimelineEventHandler function, TimelineEvent event, long timing) {
 125                         this.function = function;
 126                         this.event = event;
 127                         this.timing = timing;
 128                 }
 129
 130                 public long getTiming() {
 131                         return timing;
 132                 }
 133
 134                 public void run() {
 135                         function.handle(event);
 136                 }
 137
 138                 @Override
 139                 public String toString() {
 140                         return event.toString();
 141                 }
 142         }
 143
 144         @Override
 145         public String toString() {
 146                 return "simulation time: " + currentTime + ", " + events.toString();
 147         }
 148
 149         public static long toNanoseconds(long ticks) {
 150                 return ticks; // TODO: Alter this when it has been determined how ticks should relate to real time.
 151         }
 152
 153         public enum ExecutionResult {
 154                 NOTHING_DONE, DONE_IN_TIME, RAN_OUT_OF_TIME
 155         }
 156 }