Intermediate commit: works partially, but sometimes cars go over each other (Crossing.isAllowed() is not synchronized)

1 files changed, 79 insertions, 6 deletions

diff --git a/Week14 Route 66/src/OO14route66/Model.java b/Week14 Route 66/src/OO14route66/Model.java
index c79aa4e..f4e725f 100644
--- a/Week14 Route 66/src/OO14route66/Model.java
+++ b/Week14 Route 66/src/OO14route66/Model.java
@@ -1,7 +1,10 @@
 package OO14route66;
 
+import com.camilstaps.route66.Crossing;
 import java.util.ArrayList;
 import java.util.Observable;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import javax.swing.JFrame;
 
 /**
@@ -12,13 +15,13 @@ import javax.swing.JFrame;
  */
 public class Model extends Observable
 {
-	private final Car [] cars;
-	public static final int
-        DIRECTIONS = 2,
+    private final Car [] cars;
+    public static final int
+        DIRECTIONS = 4,
         NUMBEROFCARS = 5 * DIRECTIONS;   // total number of cars in system
         
-        private final ArrayList<JFrame> views;
-
+    private final ArrayList<JFrame> views;
+    private final Crossing crossing = new Crossing(this, Direction.North);
 
     /**
      * Constructor: create all cars
@@ -55,9 +58,79 @@ public class Model extends Observable
     /**
      * repaint all views
      */
-    public void update() {
+    public synchronized void update() {
         for (JFrame view: views) {
             view.repaint();
         }
+        notifyAll();
+    }
+    
+    /**
+     * Check if a location is safe for a car to go to. This should always be 
+     * checked by a driver before actually driving.
+     * @param car
+     * @param requested_location
+     * @return 
+     */
+    public synchronized boolean isSafeLocation(Car car, int requested_location) {
+        Car that_car = cars[car.getNumber() < DIRECTIONS ? car.getNumber() + NUMBEROFCARS - DIRECTIONS : car.getNumber() - DIRECTIONS];
+        
+        boolean ok;
+        
+        System.err.println("Car " + car.getNumber() + " requests safety.");
+        
+        do {
+            ok = !(that_car.getLocation() > requested_location &&
+                    that_car.getLocation() < requested_location + Car.CARLENGTH + Car.MINCARSPACE);
+
+//            if (!ok && that_car.getDriver().getWaitingToCross()) {
+//                crossing.doRequest();
+//            }
+            
+            if (car.isInFrontOfCrossing() && !crossing.isAllowed(car.getDirection())) {
+                System.err.println("Requesting switch for car " + car.getNumber());
+                ok = false;
+                //if (!car.getDriver().getWaitingToCross()) {
+                    //car.getDriver().setWaitingToCross(true);
+                    ok = crossing.doRequest();
+                    //car.getDriver().setWaitingToCross(!ok);
+                //}
+            }
+            
+            if (!ok) {
+                System.err.println("Car " + car.getNumber() + " waiting.");
+                try {
+                    wait();
+                } catch (InterruptedException ex) {
+                }
+                System.err.println("Car " + car.getNumber() + " acquired lock.");
+            }
+        } while (!ok);
+        
+        System.err.println("Car " + car.getNumber() + " has safe location.");
+        
+        return ok;
+    }
+    
+    public synchronized boolean isNoCarsOnCrossing() {
+        boolean ok = false;
+        while (!ok) {
+            ok = true;
+            for (Car car : cars) {
+                if (car.isOnCrossing()) {
+                    System.err.println("Car " + car.getNumber() + " is on crossing.");
+                    ok = false;
+                }
+            }
+            if (!ok) {
+                System.err.println("Checking crossing waiting");
+                try {
+                    wait();
+                } catch (InterruptedException ex) {
+                }
+                System.err.println("Checking crossing");
+            }
+        }
+        return true;
     }
 }