Restructure

app/src/main/java/simulation/Event.java

@@ -1,16 +1,21 @@
 package simulation;
 
 class Event {
-	// Constructor, creates an event of a certain type that should be put in the event list at a certain time.
-	Event(int type, double timeOfEvent) {
+	// Constructor, creates an event of a certain type that should be put in the
+	// event list at a certain time.
+	Event(int type, double eventTimeStamp) throws IllegalArgumentException {
+		if (type > 3 || type < 1)
+			throw new IllegalArgumentException("Event type must be one of ARRIVAL, READY or MEASURE");
+
 		eventType = type;
-		eventTime = timeOfEvent;
+		eventTime = eventTimeStamp;
 	}
 
 	// Empty constructor (used by the event list constructor)
-	Event() { }
+	// Event() {
+	// }
 
 	public double eventTime;
 	public int eventType;
-	public Event next = null;
+	public Event next = null; // Explicitly initialize to null
 }

app/src/main/java/simulation/EventList.java

@@ -1,43 +1,72 @@
 package simulation;
 
+import java.util.LinkedList;
+
+// Essentially a linked list of a non-template node type
 public class EventList {
-	private Event head, tail;
+	private Event head = null;
+	private Integer size = 0;
 
 	EventList() {
-		head = new Event();
-		tail = new Event();
-		head.next = tail;
 	}
 
-	public void InsertEvent(int type, double TimeOfEvent) {
-		Event temp, pretemp;
+	// Yes
+	public Event getHead() {
+		return head;
+	}
 
-		pretemp = this.head;
-		temp = this.head.next;
+	public Integer length() {
+		return size;
+	}
 
-		Event newEvent = new Event(type, TimeOfEvent);
-
-		// Find the right place in the list using a sliding window
-		while ((temp.eventTime < newEvent.eventTime) && (temp != tail)) {
-			pretemp = temp;
-			temp = temp.next;
+	public void insertEvent(Event newEvent) {
+		if (this.head == null) {
+			this.head = newEvent;
+			size += 1;
+			return;
 		}
 
-		pretemp.next = newEvent;
-		newEvent.next = temp;
+		Event cursor = this.head;
+		// int tries = 0;
+		// Find the right place in the list using a sliding window
+		while ((cursor.next != null) && (cursor.eventTime < newEvent.eventTime)) {
+			cursor = cursor.next;
+			// tries++;
+		}
+
+		if (cursor.eventTime > newEvent.eventTime) {
+			newEvent.next = this.head;
+			this.head = newEvent;
+		} else {
+			newEvent.next = cursor.next;
+			cursor.next = newEvent;
+		}
+
+		// System.out.println("Tries: " + tries);
+		size += 1;
 	}
 
-	public Event FetchEvent() {
-		Event temp = head.next;
-		head.next = temp.next;
+	public Event popEvent() {
+		if (head == null)
+			return null;
+		Event temp = head;
+		head = head.next;
 		temp.next = null;
+		size -= 1;
 		return temp;
 	}
 
-	public Event popFront() {
+	public Event fetchEvent() {
 		Event temp = head.next;
 		head.next = temp.next;
 		temp.next = null;
+		size -= 1;
 		return temp;
 	}
+
+	// public Event popFront() {
+	// Event front = this.head;
+	// this.head = this.head.next;
+	// return front;
+	// }
 }

app/src/main/java/simulation/GlobalSimulation.java

@@ -1,7 +1,10 @@
 package simulation;
 
+import java.util.Random;
+
 // This class is only created to be able to store the global time.
-public class GlobalSimulation{
+public class GlobalSimulation {
 	public static final int ARRIVAL = 1, READY = 2, MEASURE = 3;
 	public static double time = 0;
+	public static Random rand = new Random();
 }

app/src/main/java/simulation/MainSimulation.java

@@ -5,16 +5,15 @@ import java.io.*;
 public class MainSimulation extends GlobalSimulation {
 
 	public static void main(String[] args) throws IOException {
-		Event actEvent;
 		EventList myEventList = new EventList();
-
+		Event actEvent;
 		State actState = new State(myEventList);
 
-		myEventList.InsertEvent(ARRIVAL, 0);
-		myEventList.InsertEvent(MEASURE, 5);
+		myEventList.insertEvent(new Event(ARRIVAL, 0));
+		myEventList.insertEvent(new Event(MEASURE, 5));
 
 		while (MainSimulation.time < 50000) {
-			actEvent = myEventList.FetchEvent();
+			actEvent = myEventList.popEvent();
 			MainSimulation.time = actEvent.eventTime;
 			actState.TreatEvent(actEvent);
 		}

app/src/main/java/simulation/State.java

@@ -3,55 +3,44 @@ package simulation;
 import java.util.*;
 
 class State extends GlobalSimulation {
-
 	public int numberInQueue = 0, accumulated = 0, noMeasurements = 0;
+	private EventList eventList;
 
-	private EventList myEventList;
-
-	static Random slump = new Random();
-
-	State(EventList x) {
-		myEventList = x;
-	}
-
-	private void InsertEvent(int event, double timeOfEvent) {
-		myEventList.InsertEvent(event, timeOfEvent);
+	State(EventList eventList) {
+		this.eventList = eventList;
 	}
 
+	// Dispatches the events to the right handler
 	public void TreatEvent(Event x) {
-		switch (x.eventType) {
-			case ARRIVAL:
-				arrival();
-				break;
-			case READY:
-				ready();
-				break;
-			case MEASURE:
-				measure();
-				break;
-		}
+		if (x.eventType == ARRIVAL)
+			arrival();
+		else if (x.eventType == READY)
+			ready();
+		else if (x.eventType == MEASURE)
+			measure();
 	}
 
-	private double generateMean(double mean) {
-		return 2 * mean * slump.nextDouble();
+	// Helper to generate a random number with certain statistical properties
+	private static double generateMean(double mean) {
+		return 2 * mean * rand.nextDouble();
 	}
 
 	private void arrival() {
 		if (numberInQueue == 0)
-			InsertEvent(READY, time + generateMean(1));
+			eventList.insertEvent(new Event(READY, time + generateMean(1)));
 		numberInQueue++;
-		InsertEvent(ARRIVAL, time + generateMean(2));
+		eventList.insertEvent(new Event(ARRIVAL, time + generateMean(2)));
 	}
 
 	private void ready() {
 		numberInQueue--;
 		if (numberInQueue > 0)
-			InsertEvent(READY, time + generateMean(1));
+			eventList.insertEvent(new Event(READY, time + generateMean(1)));
 	}
 
 	private void measure() {
 		accumulated = accumulated + numberInQueue;
 		noMeasurements++;
-		InsertEvent(MEASURE, time + generateMean(5));
+		eventList.insertEvent(new Event(MEASURE, time + generateMean(5)));
 	}
 }

app/src/test/java/simulation/EventListTest.java

@@ -0,0 +1,63 @@
+package simulation;
+
+import java.util.Random;
+
+import org.junit.jupiter.api.Test;
+
+public class EventListTest {
+    @Test
+    void testEventListConstructor() {
+        EventList eventList = new EventList();
+        Event event = new Event(1, 0.0);
+        eventList.insertEvent(event);
+        assert eventList.getHead() == event;
+        assert eventList.getHead().next == null;
+    }
+
+    @Test
+    void testOrdering() {
+        EventList eventList = new EventList();
+        Event event1 = new Event(1, 0.0);
+        Event event2 = new Event(1, 1.0);
+        Event event3 = new Event(1, 2.0);
+        eventList.insertEvent(event3);
+        eventList.insertEvent(event2);
+        eventList.insertEvent(event1);
+        assert eventList.getHead() == event1;
+        assert eventList.getHead().next == event2;
+        assert eventList.getHead().next.next == event3;
+        assert eventList.getHead().next.next.next == null;
+    }
+
+    @Test
+    void testLength() {
+        Random rand = new Random();
+        EventList eventList = new EventList();
+        for(int i : rand.ints(0, 100).limit(100).toArray()) {
+            eventList.insertEvent(new Event(1, (double) i));
+        }
+        assert eventList.length() == 100;
+    }
+
+    @Test
+    void testPop() {
+        EventList eventList = new EventList();
+        Event event1 = new Event(1, 0.0);
+        eventList.insertEvent(event1);
+        assert eventList.popEvent() == event1;
+        assert eventList.popEvent() == null;
+    }
+
+    @Test 
+    void testOrderingRandomAmount() {
+        Random rand = new Random();
+        EventList eventList = new EventList();
+        for(int i : rand.ints(0, 100).limit(100).toArray()) {
+            eventList.insertEvent(new Event(1, (double) i));
+        }
+        for(Event e = eventList.getHead(); e != null; e = eventList.popEvent()) {
+            if(e.next == null) break;
+            assert e.eventTime < e.next.eventTime;
+        }
+    }
+}

app/src/test/java/simulation/EventTest.java

@@ -0,0 +1,17 @@
+package simulation;
+
+import org.junit.jupiter.api.Test;
+
+public class EventTest {
+    @Test void testConstructor() {
+        Event event = new Event(1, 0.0);
+        assert event.eventType == 1;
+        assert event.eventTime == 0.0;
+    }
+
+    // @Test void testEmptyConstructor() {
+    //     Event event = new Event();
+    //     assert event.eventType == 0;
+    //     assert event.eventTime == 0.0;
+    // }
+}