fixed minor bugs

src/TrafficController.java

@@ -55,30 +55,40 @@ public class TrafficController {
             if (!currentVehicle.hasRun) {
                 return 0;
             } else {
+                System.out.println(currentVehicle.getType() + " " + currentVehicle.id + " crosses the bridge.");
+                int t = currentVehicle.getCrossingTime();
                 queue.remove(currentVehicle);
                 currentVehicle.leave(this);
                 currentVehicle = null;
                 bridge.release();
                 crossings++;
+                return t;
             }
         }
-        
-        for (Vehicle vehicle : queue) {
-            if (vehicle instanceof EmergencyVehicle) {
-                currentVehicle = vehicle;
-                break;
-            // North is ZERO so look for South going car
-            } else if (vehicle.direction == 1 && (northLast || northSemaphore.availablePermits() == 10)) {
-                currentVehicle = vehicle;
-                northLast = false;
-                break;
-            } else if (vehicle.direction == 0 && (!northLast || southSemaphore.availablePermits() == 10)) {
-                currentVehicle = vehicle;
-                northLast = true;
-                break;
+
+        if (emergencySemaphore.availablePermits() != 10) {
+            for (Vehicle v : queue) {
+                if (v instanceof EmergencyVehicle) {
+                    currentVehicle = v;
+                    break;
+                }
+            }
+        } else {
+            for (Vehicle vehicle : queue) {
+                // North is ZERO so look for South going car
+                if (vehicle.direction == 1 && (northLast || northSemaphore.availablePermits() == 10)) {
+                    currentVehicle = vehicle;
+                    northLast = false;
+                    break;
+                } else if (vehicle.direction == 0 && (!northLast || southSemaphore.availablePermits() == 10)) {
+                    currentVehicle = vehicle;
+                    northLast = true;
+                    break;
+                }
             }
         }
 
+
         if (currentVehicle == null) {
             if (!queue.isEmpty()) {
                 System.out.println("Queue is NOT empty");
@@ -89,18 +99,15 @@ public class TrafficController {
             return 0;
         }
 
-        try {
-            bridge.acquire();
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-            System.out.println(currentVehicle.getType() + " " + currentVehicle.id + " could not cross.");
+        if (!bridge.tryAcquire()) {
+            return 0;
         }
 
         System.out.println(currentVehicle.getType() + " " + currentVehicle.id + " starts crossing the bridge.");
         runningVehicle = new Thread(currentVehicle);
         runningVehicle.start();
 
-        return currentVehicle.getCrossingTime();
+        return 0;
     }
 
     public Semaphore getNorthSemaphore() {

src/Vehicle.java

@@ -57,7 +57,6 @@ public abstract class Vehicle implements Runnable {
     public void run() {
         try {
             Thread.sleep(this.crossingTime);
-            System.out.println(this.getType() + " " + id + " crosses the bridge.");
             hasRun = true;
         } catch (InterruptedException e) {
             e.printStackTrace();