feat: add Lab4

Lab1/Simulator.java

@@ -0,0 +1,51 @@
+import java.util.PriorityQueue;
+
+/**
+ * This class implements a discrete event simulator.
+ * The simulator maintains a priority queue of events.
+ * It runs through the events and simulates each one until
+ * the queue is empty.
+ *
+ * @author Yadunand Prem
+ * @version CS2030S AY22/23 Semester 2
+ */
+public class Simulator {
+  /** The event queue. */
+  private final PriorityQueue<Event> events;
+
+  /**
+   * The constructor for a simulator. It takes in
+   * a simulation as an argument, and calls the
+   * getInitialEvents method of that simulation to
+   * initialize the event queue.
+   *
+   * @param simulation The simulation to simulate.
+   */
+  public Simulator(Simulation simulation) {
+    this.events = new PriorityQueue<Event>();
+    for (Event e : simulation.getInitialEvents()) {
+      this.events.add(e);
+    }
+  }
+
+  /**
+   * Run the simulation until no more events is in
+   * the queue. For each event in the queue (in
+   * increasing order of time), print out its string
+   * representation, then simulate it. If the
+   * simulation returns one or more events, add them
+   * to the queue, and repeat.
+   */
+  public void run() {
+    Event event = this.events.poll();
+    while (event != null) {
+      System.out.println(event);
+      Event[] newEvents = event.simulate();
+      for (Event e : newEvents) {
+        this.events.add(e);
+      }
+      event = this.events.poll();
+    }
+    return;
+  }
+}