feat: update structure

cs2030s/labs/Lab1/Event.java

@@ -0,0 +1,72 @@
+/**
+ * The Event class is an abstract class that encapsulates a
+ * discrete event to be simulated. An event encapsulates the
+ * time the event occurs. A subclass of event _must_ override
+ * the simulate() method to implement the logic of the
+ * simulation when this event is simulated. The simulate method
+ * returns an array of events, which the simulator will then
+ * add to the event queue. Note that an event also implements
+ * the Comparable interface so that a PriorityQueue can
+ * arrange the events in the order of event time.
+ * 
+ * @author Yadunand Prem
+ * @version CS2030S AY22/23 Semester 2
+ */
+abstract class Event implements Comparable<Event> {
+  /** The time this event occurs in the simulation. */
+  private final double time;
+
+  /**
+   * Creates an event that occurs at the given time.
+   *
+   * @param time The time the event occurs.
+   */
+  public Event(double time) {
+    this.time = time;
+  }
+
+  /**
+   * Getter to return the time of this event.
+   *
+   * @return The time this event occurs.
+   */
+  public double getTime() {
+    return this.time;
+  }
+
+  /**
+   * Compare this event with a given event e.
+   *
+   * @param e The other event to compare to.
+   * @return 1 if this event occurs later than e;
+   *         0 if they occur the same time;
+   *         -1 if this event occurs earlier.
+   */
+  @Override
+  public int compareTo(Event e) {
+    if (this.time > e.time) {
+      return 1;
+    } else if (this.time == e.time) {
+      return 0;
+    } else {
+      return -1;
+    }
+  }
+
+  /**
+   * Return the string representation this event.
+   *
+   * @return A string consists of the time this event occurs.
+   */
+  @Override
+  public String toString() {
+    return String.format("%.3f", this.time);
+  }
+
+  /**
+   * Simulate this event.
+   *
+   * @return An array of new events to be scheduled by the simulator.
+   */
+  public abstract Event[] simulate();
+}