shutdown and teardown fixes + incoming connection handler

main/src/main/java/sd/IntersectionProcess.java

@@ -12,10 +12,10 @@ import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
 import sd.config.SimulationConfig;
+import sd.engine.TrafficLightThread;
 import sd.model.Intersection;
 import sd.model.MessageType;
 import sd.model.TrafficLight;
-import sd.model.TrafficLightState;
 import sd.model.Vehicle;
 import sd.protocol.MessageProtocol;
 import sd.protocol.SocketConnection;
@@ -178,128 +178,15 @@ public class IntersectionProcess {
         System.out.println("\n[" + intersectionId + "] Starting traffic light threads...");
 
         for (TrafficLight light : intersection.getTrafficLights()) {
-            trafficLightPool.submit(() -> runTrafficLightCycle(light));
+
+            TrafficLightThread lightTask = new TrafficLightThread(light, this, config);
+
+            trafficLightPool.submit(lightTask);
+
             System.out.println("  Started thread for: " + light.getDirection());
         }
     }
 
-    /**
-     * The main loop for a traffic light thread.
-     * Continuously cycles between green and red states.
-     * 
-     * only one traffic light can be green at any given time in this intersection.
-     *
-     * @param light The traffic light to control.
-     */
-    private void runTrafficLightCycle(TrafficLight light) {
-        System.out.println("[" + light.getId() + "] Traffic light thread started.");
-
-        while (running) {
-            try {
-                // Acquire coordination lock to become green
-                trafficCoordinationLock.lock();
-                try {
-                    // Wait until no other direction is green
-                    while (currentGreenDirection != null && running) {
-                        trafficCoordinationLock.unlock();
-                        Thread.sleep(100); // Brief wait before retrying
-                        trafficCoordinationLock.lock();
-                    }
-
-                    if (!running) {
-                        break; // Exit if shutting down
-                    }
-
-                    // Mark this direction as the current green light
-                    currentGreenDirection = light.getDirection();
-                    light.changeState(TrafficLightState.GREEN);
-                    System.out.println("[" + light.getId() + "] State: GREEN");
-
-                } finally {
-                    trafficCoordinationLock.unlock();
-                }
-
-                // Process vehicles while green
-                processGreenLight(light);
-
-                // Wait for green duration
-                Thread.sleep((long) (light.getGreenTime() * 1000));
-
-                // Release coordination lock (turn red)
-                trafficCoordinationLock.lock();
-                try {
-                    light.changeState(TrafficLightState.RED);
-                    currentGreenDirection = null; // Release exclusive access
-                    System.out.println("[" + light.getId() + "] State: RED (RELEASED ACCESS)");
-                } finally {
-                    trafficCoordinationLock.unlock();
-                }
-
-                // Wait for red duration
-                Thread.sleep((long) (light.getRedTime() * 1000));
-
-            } catch (InterruptedException e) {
-                System.out.println("[" + light.getId() + "] Traffic light thread interrupted.");
-                break;
-            }
-        }
-
-        System.out.println("[" + light.getId() + "] Traffic light thread stopped.");
-    }
-
-    /**
-     * Processes vehicles when a traffic light is GREEN.
-     * Dequeues vehicles and sends them to their next destination.
-     *
-     * @param light The traffic light that is currently green.
-     */
-    private void processGreenLight(TrafficLight light) {
-        while (light.getState() == TrafficLightState.GREEN && light.getQueueSize() > 0) {
-            Vehicle vehicle = light.removeVehicle();
-
-            if (vehicle != null) {
-                // Get crossing time based on vehicle type
-                double crossingTime = getCrossingTimeForVehicle(vehicle);
-
-                // Simulate crossing time
-                try {
-                    Thread.sleep((long) (crossingTime * 1000));
-                } catch (InterruptedException e) {
-                    Thread.currentThread().interrupt();
-                    break;
-                }
-
-                // Update vehicle statistics
-                vehicle.addCrossingTime(crossingTime);
-
-                // Update intersection statistics
-                intersection.incrementVehiclesSent();
-
-                // Send vehicle to next destination
-                sendVehicleToNextDestination(vehicle);
-            }
-        }
-    }
-
-    /**
-     * Gets the crossing time for a vehicle based on its type.
-     *
-     * @param vehicle The vehicle.
-     * @return The crossing time in seconds.
-     */
-    private double getCrossingTimeForVehicle(Vehicle vehicle) {
-        switch (vehicle.getType()) {
-            case BIKE:
-                return config.getBikeVehicleCrossingTime();
-            case LIGHT:
-                return config.getLightVehicleCrossingTime();
-            case HEAVY:
-                return config.getHeavyVehicleCrossingTime();
-            default:
-                return config.getLightVehicleCrossingTime();
-        }
-    }
-
     /**
      * Sends a vehicle to its next destination via socket connection.
      *
@@ -410,12 +297,21 @@ public class IntersectionProcess {
                 System.out.println("[" + intersectionId + "] New connection accepted from " +
                         clientSocket.getInetAddress().getHostAddress());
 
-                // Check running flag again before handling - prevents accepting during shutdown
+                // Check running flag again before handling
                 if (!running) {
                     clientSocket.close();
                     break;
                 }
 
+                // **Set timeout before submitting to handler**
+                try {
+                    clientSocket.setSoTimeout(1000);
+                } catch (java.net.SocketException e) {
+                    System.err.println("[" + intersectionId + "] Failed to set timeout: " + e.getMessage());
+                    clientSocket.close();
+                    continue;
+                }
+
                 // Handle each connection in a separate thread
                 connectionHandlerPool.submit(() -> handleIncomingConnection(clientSocket));
 
@@ -424,7 +320,6 @@ public class IntersectionProcess {
                 if (!running) {
                     break; // Normal shutdown
                 }
-                // Unexpected error during normal operation
                 System.err.println("[" + intersectionId + "] Error accepting connection: " +
                         e.getMessage());
             }
@@ -438,11 +333,16 @@ public class IntersectionProcess {
      * @param clientSocket The accepted socket connection.
      */
     private void handleIncomingConnection(Socket clientSocket) {
-        try (SocketConnection connection = new SocketConnection(clientSocket)) {
+        try {
-
-            // Set socket timeout so receiveMessage() won't block forever
             clientSocket.setSoTimeout(1000); // 1 second timeout
 
+        } catch (java.net.SocketException e) {
+            System.err.println("[" + intersectionId + "] Failed to set socket timeout: " + e.getMessage());
+            return;
+        }
+
+        try (SocketConnection connection = new SocketConnection(clientSocket)) {
+
             System.out.println("[" + intersectionId + "] New connection accepted from " +
                     clientSocket.getInetAddress().getHostAddress());
 
@@ -462,7 +362,7 @@ public class IntersectionProcess {
                     }
 
                 } catch (java.net.SocketTimeoutException e) {
-                    // Timeout is expected - just check running flag and continue
+                    // Timeout - check running flag and continue
                     if (!running) {
                         break;
                     }
@@ -487,46 +387,57 @@ public class IntersectionProcess {
      * Shuts down all threads and closes all connections.
      */
     public void shutdown() {
+        // Check if already shutdown
+        if (!running) {
+            return; // Already shutdown, do nothing
+        }
+
         System.out.println("\n[" + intersectionId + "] Shutting down...");
         running = false;
 
+        // 1. Close ServerSocket first
         if (serverSocket != null && !serverSocket.isClosed()) {
             try {
                 serverSocket.close();
             } catch (IOException e) {
-                System.err.println("[" + intersectionId + "] Error closing server socket: " +
+                // Expected
-                        e.getMessage());
             }
         }
+
+        // 2. Shutdown thread pools with force
+        if (trafficLightPool != null && !trafficLightPool.isShutdown()) {
+            trafficLightPool.shutdownNow();
+        }
+        if (connectionHandlerPool != null && !connectionHandlerPool.isShutdown()) {
+            connectionHandlerPool.shutdownNow();
+        }
+
+        // 3. Wait briefly for termination (don't block forever)
+        try {
+            if (trafficLightPool != null) {
+                trafficLightPool.awaitTermination(1, TimeUnit.SECONDS);
+            }
+            if (connectionHandlerPool != null) {
+                connectionHandlerPool.awaitTermination(1, TimeUnit.SECONDS);
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+
+        // 4. Close outgoing connections
         synchronized (outgoingConnections) {
             for (SocketConnection conn : outgoingConnections.values()) {
                 try {
                     conn.close();
                 } catch (Exception e) {
-                    // Ignore errors during shutdown
+                    // Ignore
                 }
             }
             outgoingConnections.clear();
         }
 
-        trafficLightPool.shutdown();
-        connectionHandlerPool.shutdownNow(); // Use shutdownNow() to interrupt running tasks
-
-        try {
-            if (!trafficLightPool.awaitTermination(2, TimeUnit.SECONDS)) {
-                trafficLightPool.shutdownNow();
-            }
-            if (!connectionHandlerPool.awaitTermination(2, TimeUnit.SECONDS)) {
-                connectionHandlerPool.shutdownNow();
-            }
-        } catch (InterruptedException e) {
-            trafficLightPool.shutdownNow();
-            connectionHandlerPool.shutdownNow();
-            Thread.currentThread().interrupt();
-        }
-
         System.out.println("[" + intersectionId + "] Shutdown complete.");
-        System.out.println("=".repeat(60) + "\n");
+        System.out.println("============================================================\n");
     }
 
     /**

main/src/test/java/IntersectionProcessTest.java

@@ -97,11 +97,17 @@ public class IntersectionProcessTest {
         Files.writeString(configFile, configContent);
     }
 
-    // cleanup after tests
     @AfterEach
     public void tearDown() {
         if (intersectionProcess != null) {
+            try {
+                // Only shutdown if still running
                 intersectionProcess.shutdown();
+            } catch (Exception e) {
+                System.err.println("Error in tearDown: " + e.getMessage());
+            } finally {
+                intersectionProcess = null;
+            }
         }
     }