@@ -41,12 +41,14 @@ public class SimulationEngine {
private final PriorityQueue < Event > eventQueue ; private final PriorityQueue < Event > eventQueue ;
/** /**
* A map storing all intersections in the simulation, keyed by their ID (e.g., "Cr1"). * A map storing all intersections in the simulation, keyed by their ID (e.g.,
* "Cr1").
*/ */
private final Map < String , Intersection > intersections ; private final Map < String , Intersection > intersections ;
/** /**
* Responsible for creating new vehicles according to the configured arrival model. * Responsible for creating new vehicles according to the configured arrival
* model.
*/ */
private final VehicleGenerator vehicleGenerator ; private final VehicleGenerator vehicleGenerator ;
@@ -70,7 +72,7 @@ public class SimulationEngine {
* Constructs a new SimulationEngine. * Constructs a new SimulationEngine.
* *
* @param config The {@link SimulationConfig} object containing all * @param config The {@link SimulationConfig} object containing all
* simulation parameters. * simulation parameters.
*/ */
public SimulationEngine ( SimulationConfig config ) { public SimulationEngine ( SimulationConfig config ) {
this . config = config ; this . config = config ;
@@ -82,6 +84,26 @@ public class SimulationEngine {
this . vehicleCounter = 0 ; this . vehicleCounter = 0 ;
} }
/**
* Calculates the travel time between intersections based on vehicle type.
*
* @param vehicleType The type of the vehicle.
* @return The travel time in seconds.
*/
private double calculateTravelTime ( VehicleType vehicleType ) {
double baseTime = config . getBaseTravelTime ( ) ;
switch ( vehicleType ) {
case BIKE :
return baseTime * config . getBikeTravelTimeMultiplier ( ) ;
case HEAVY :
return baseTime * config . getHeavyTravelTimeMultiplier ( ) ;
case LIGHT :
default :
return baseTime ;
}
}
/** /**
* Initializes the simulation. This involves: * Initializes the simulation. This involves:
* 1. Creating all {@link Intersection} and {@link TrafficLight} objects. * 1. Creating all {@link Intersection} and {@link TrafficLight} objects.
@@ -108,9 +130,9 @@ public class SimulationEngine {
* and adds their corresponding traffic lights. * and adds their corresponding traffic lights.
*/ */
private void setupIntersections ( ) { private void setupIntersections ( ) {
String [ ] intersectionIds = { " Cr1 " , " Cr2 " , " Cr3 " , " Cr4 " , " Cr5 " } ; String [ ] intersectionIds = { " Cr1 " , " Cr2 " , " Cr3 " , " Cr4 " , " Cr5 " } ;
// Note: "North" is commented out, so it won't be created. // Note: "North" is commented out, so it won't be created.
String [ ] directions = { /*"North",*/ " South " , " East " , " West " } ; String [ ] directions = { /* "North", */ " South " , " East " , " West " } ;
for ( String id : intersectionIds ) { for ( String id : intersectionIds ) {
Intersection intersection = new Intersection ( id ) ; Intersection intersection = new Intersection ( id ) ;
@@ -121,11 +143,10 @@ public class SimulationEngine {
double redTime = config . getTrafficLightRedTime ( id , direction ) ; double redTime = config . getTrafficLightRedTime ( id , direction ) ;
TrafficLight light = new TrafficLight ( TrafficLight light = new TrafficLight (
id + " - " + direction , id + " - " + direction ,
direction , direction ,
greenTime , greenTime ,
redTime redTime ) ;
) ;
intersection . addTrafficLight ( light ) ; intersection . addTrafficLight ( light ) ;
} }
@@ -137,7 +158,8 @@ public class SimulationEngine {
/** /**
* Configures how vehicles should be routed between intersections. * Configures how vehicles should be routed between intersections.
* This hardcoded logic defines the "map" of the city. * This hardcoded logic defines the "map" of the city.
* * For example, `intersections.get("Cr1").configureRoute("Cr2", "East");` means * * For example, `intersections.get("Cr1").configureRoute("Cr2", "East");`
* means
* "at intersection Cr1, any vehicle whose *next* destination is Cr2 * "at intersection Cr1, any vehicle whose *next* destination is Cr2
* should be sent to the 'East' traffic light queue." * should be sent to the 'East' traffic light queue."
*/ */
@@ -156,12 +178,12 @@ public class SimulationEngine {
intersections . get ( " Cr3 " ) . configureRoute ( " S " , " South " ) ; // "S" is the exit intersections . get ( " Cr3 " ) . configureRoute ( " S " , " South " ) ; // "S" is the exit
// Cr4 routing // Cr4 routing
//intersections.get("Cr4").configureRoute("Cr1", "North"); // intersections.get("Cr4").configureRoute("Cr1", "North");
intersections . get ( " Cr4 " ) . configureRoute ( " Cr5 " , " East " ) ; intersections . get ( " Cr4 " ) . configureRoute ( " Cr5 " , " East " ) ;
// Cr5 routing // Cr5 routing
//intersections.get("Cr5").configureRoute("Cr2", "North"); // intersections.get("Cr5").configureRoute("Cr2", "North");
//intersections.get("Cr5").configureRoute("Cr4", "West"); // intersections.get("Cr5").configureRoute("Cr4", "West");
intersections . get ( " Cr5 " ) . configureRoute ( " S " , " East " ) ; // "S" is the exit intersections . get ( " Cr5 " ) . configureRoute ( " S " , " East " ) ; // "S" is the exit
} }
@@ -186,9 +208,10 @@ public class SimulationEngine {
* Creates and schedules a new {@link EventType#TRAFFIC_LIGHT_CHANGE} event. * Creates and schedules a new {@link EventType#TRAFFIC_LIGHT_CHANGE} event.
* The event is scheduled to occur at {@code currentTime + delay}. * The event is scheduled to occur at {@code currentTime + delay}.
* *
* @param light The {@link TrafficLight} that will change state. * @param light The {@link TrafficLight} that will change state.
* @param intersectionId The ID of the intersection where the light is located. * @param intersectionId The ID of the intersection where the light is located.
* @param delay The time (in seconds) from {@code currentTime} when the change should occur. * @param delay The time (in seconds) from {@code currentTime} when the
* change should occur.
*/ */
private void scheduleTrafficLightChange ( TrafficLight light , String intersectionId , double delay ) { private void scheduleTrafficLightChange ( TrafficLight light , String intersectionId , double delay ) {
double changeTime = currentTime + delay ; double changeTime = currentTime + delay ;
@@ -200,7 +223,8 @@ public class SimulationEngine {
* Schedules the next {@link EventType#VEHICLE_GENERATION} event. * Schedules the next {@link EventType#VEHICLE_GENERATION} event.
* The time of the next arrival is determined by the {@link VehicleGenerator}. * The time of the next arrival is determined by the {@link VehicleGenerator}.
* *
* @param baseTime The time from which to calculate the next arrival (usually {@code currentTime}). * @param baseTime The time from which to calculate the next arrival (usually
* {@code currentTime}).
*/ */
private void scheduleNextVehicleGeneration ( double baseTime ) { private void scheduleNextVehicleGeneration ( double baseTime ) {
// Get the absolute time for the next arrival. // Get the absolute time for the next arrival.
@@ -258,7 +282,8 @@ public class SimulationEngine {
/** /**
* Main event processing logic. * Main event processing logic.
* Delegates the event to the appropriate handler method based on its {@link EventType}. * Delegates the event to the appropriate handler method based on its
* {@link EventType}.
* *
* @param event The {@link Event} to be processed. * @param event The {@link Event} to be processed.
*/ */
@@ -288,13 +313,14 @@ public class SimulationEngine {
* at its first destination intersection. * at its first destination intersection.
* 4. Schedules the *next* {@link EventType#VEHICLE_GENERATION} event. * 4. Schedules the *next* {@link EventType#VEHICLE_GENERATION} event.
* (Note: This line is commented out in the original, which might be a bug, * (Note: This line is commented out in the original, which might be a bug,
* as it implies only one vehicle is ever generated. It should likely be active.) * as it implies only one vehicle is ever generated. It should likely be
* active.)
*/ */
private void handleVehicleGeneration ( ) { private void handleVehicleGeneration ( ) {
Vehicle vehicle = vehicleGenerator . generateVehicle ( " V " + ( + + vehicleCounter ) , currentTime ) ; Vehicle vehicle = vehicleGenerator . generateVehicle ( " V " + ( + + vehicleCounter ) , currentTime ) ;
System . out . printf ( " [t=%.2f] Vehicle %s generated (type=%s, route=%s)%n " , System . out . printf ( " [t=%.2f] Vehicle %s generated (type=%s, route=%s)%n " ,
currentTime , vehicle . getId ( ) , vehicle . getType ( ) , vehicle . getRoute ( ) ) ; currentTime , vehicle . getId ( ) , vehicle . getType ( ) , vehicle . getRoute ( ) ) ;
// Register with statistics collector // Register with statistics collector
statisticsCollector . recordVehicleGeneration ( vehicle , currentTime ) ; statisticsCollector . recordVehicleGeneration ( vehicle , currentTime ) ;
@@ -302,8 +328,8 @@ public class SimulationEngine {
// Schedule arrival at first intersection // Schedule arrival at first intersection
String firstIntersection = vehicle . getCurrentDestination ( ) ; String firstIntersection = vehicle . getCurrentDestination ( ) ;
if ( firstIntersection ! = null & & ! firstIntersection . equals ( " S " ) ) { if ( firstIntersection ! = null & & ! firstIntersection . equals ( " S " ) ) {
// Assume minimal travel t ime to first intersection (e.g., 1-3 seconds) double T ime = calculateTravelTime ( vehicle . getType ( ) ) ;
double arrivalTime = currentTime + 1 . 0 + Math . random ( ) * 2 . 0 ; double arrivalTime = currentTime + travelTime ;
Event arrivalEvent = new Event ( arrivalTime , EventType . VEHICLE_ARRIVAL , vehicle , firstIntersection ) ; Event arrivalEvent = new Event ( arrivalTime , EventType . VEHICLE_ARRIVAL , vehicle , firstIntersection ) ;
eventQueue . offer ( arrivalEvent ) ; eventQueue . offer ( arrivalEvent ) ;
} }
@@ -324,7 +350,8 @@ public class SimulationEngine {
* current intersection using {@link Intersection#receiveVehicle(Vehicle)}. * current intersection using {@link Intersection#receiveVehicle(Vehicle)}.
* 5. Attempts to process the vehicle immediately if its light is green. * 5. Attempts to process the vehicle immediately if its light is green.
* *
* @param event The arrival event, containing the {@link Vehicle} and intersection ID. * @param event The arrival event, containing the {@link Vehicle} and
* intersection ID.
*/ */
private void handleVehicleArrival ( Event event ) { private void handleVehicleArrival ( Event event ) {
Vehicle vehicle = ( Vehicle ) event . getData ( ) ; Vehicle vehicle = ( Vehicle ) event . getData ( ) ;
@@ -337,7 +364,7 @@ public class SimulationEngine {
} }
System . out . printf ( " [t=%.2f] Vehicle %s arrived at %s%n " , System . out . printf ( " [t=%.2f] Vehicle %s arrived at %s%n " ,
currentTime , vehicle . getId ( ) , intersectionId ) ; currentTime , vehicle . getId ( ) , intersectionId ) ;
// Record arrival time (used to calculate waiting time later) // Record arrival time (used to calculate waiting time later)
statisticsCollector . recordVehicleArrival ( vehicle , intersectionId , currentTime ) ; statisticsCollector . recordVehicleArrival ( vehicle , intersectionId , currentTime ) ;
@@ -359,7 +386,8 @@ public class SimulationEngine {
return ; return ;
} }
// Add vehicle to the appropriate traffic light queue based on its next destination // Add vehicle to the appropriate traffic light queue based on its next
// destination
intersection . receiveVehicle ( vehicle ) ; intersection . receiveVehicle ( vehicle ) ;
// Try to process the vehicle immediately if its light is already green // Try to process the vehicle immediately if its light is already green
@@ -370,18 +398,18 @@ public class SimulationEngine {
* Checks if a newly arrived vehicle (or a vehicle in a queue * Checks if a newly arrived vehicle (or a vehicle in a queue
* that just turned green) can start crossing. * that just turned green) can start crossing.
* *
* @param vehicle The vehicle to process. * @param vehicle The vehicle to process.
* @param intersection The intersection where the vehicle is. * @param intersection The intersection where the vehicle is.
*/ */
private void tryProcessVehicle ( Vehicle vehicle , Intersection intersection ) { //FIXME private void tryProcessVehicle ( Vehicle vehicle , Intersection intersection ) { // FIXME
// Find the direction (and light) this vehicle is queued at // Find the direction (and light) this vehicle is queued at
// This logic is a bit flawed: it just finds the *first* non-empty queue // This logic is a bit flawed: it just finds the *first* non-empty queue
// A better approach would be to get the light from the vehicle's route // A better approach would be to get the light from the vehicle's route
String direction = intersection . getTrafficLights ( ) . stream ( ) String direction = intersection . getTrafficLights ( ) . stream ( )
. filter ( tl - > tl . getQueueSize ( ) > 0 ) . filter ( tl - > tl . getQueueSize ( ) > 0 )
. map ( TrafficLight : : getDirection ) . map ( TrafficLight : : getDirection )
. findFirst ( ) . findFirst ( )
. orElse ( null ) ; . orElse ( null ) ;
if ( direction ! = null ) { if ( direction ! = null ) {
TrafficLight light = intersection . getTrafficLight ( direction ) ; TrafficLight light = intersection . getTrafficLight ( direction ) ;
@@ -403,7 +431,7 @@ public class SimulationEngine {
* 1. Calculates and records the vehicle's waiting time. * 1. Calculates and records the vehicle's waiting time.
* 2. Schedules an immediate {@link EventType#CROSSING_START} event. * 2. Schedules an immediate {@link EventType#CROSSING_START} event.
* *
* @param vehicle The {@link Vehicle} that is crossing. * @param vehicle The {@link Vehicle} that is crossing.
* @param intersection The {@link Intersection} it is crossing. * @param intersection The {@link Intersection} it is crossing.
*/ */
private void scheduleCrossing ( Vehicle vehicle , Intersection intersection ) { private void scheduleCrossing ( Vehicle vehicle , Intersection intersection ) {
@@ -431,7 +459,7 @@ public class SimulationEngine {
double crossingTime = getCrossingTime ( vehicle . getType ( ) ) ; double crossingTime = getCrossingTime ( vehicle . getType ( ) ) ;
System . out . printf ( " [t=%.2f] Vehicle %s started crossing at %s (duration=%.2fs)%n " , System . out . printf ( " [t=%.2f] Vehicle %s started crossing at %s (duration=%.2fs)%n " ,
currentTime , vehicle . getId ( ) , intersectionId , crossingTime ) ; currentTime , vehicle . getId ( ) , intersectionId , crossingTime ) ;
// Schedule the *end* of the crossing // Schedule the *end* of the crossing
double endTime = currentTime + crossingTime ; double endTime = currentTime + crossingTime ;
@@ -443,7 +471,8 @@ public class SimulationEngine {
* Handles {@link EventType#CROSSING_END}. * Handles {@link EventType#CROSSING_END}.
* 1. Updates intersection and vehicle statistics. * 1. Updates intersection and vehicle statistics.
* 2. Checks the vehicle's *next* destination. * 2. Checks the vehicle's *next* destination.
* 3. If the next destination is the exit ("S"), call {@link #handleVehicleExit(Vehicle)}. * 3. If the next destination is the exit ("S"), call
* {@link #handleVehicleExit(Vehicle)}.
* 4. Otherwise, schedule a {@link EventType#VEHICLE_ARRIVAL} event at the * 4. Otherwise, schedule a {@link EventType#VEHICLE_ARRIVAL} event at the
* *next* intersection, after some travel time. * *next* intersection, after some travel time.
* *
@@ -463,14 +492,15 @@ public class SimulationEngine {
vehicle . addCrossingTime ( crossingTime ) ; vehicle . addCrossingTime ( crossingTime ) ;
System . out . printf ( " [t=%.2f] Vehicle %s finished crossing at %s%n " , System . out . printf ( " [t=%.2f] Vehicle %s finished crossing at %s%n " ,
currentTime , vehicle . getId ( ) , intersectionId ) ; currentTime , vehicle . getId ( ) , intersectionId ) ;
// Decide what to do next // Decide what to do next
String nextDest = vehicle . getCurrentDestination ( ) ; String nextDest = vehicle . getCurrentDestination ( ) ;
if ( nextDest ! = null & & ! nextDest . equals ( " S " ) ) { if ( nextDest ! = null & & ! nextDest . equals ( " S " ) ) {
// Route to the *next* intersection // Route to the *next* intersection
// Assume 5-10 seconds travel time between intersections // Travel time varies by vehicle type: tmoto = 0.5 × ×
double travelTime = 5 . 0 + Math . random ( ) * 5 . 0 ; // tmoto
double travelTime = calculateTravelTime ( vehicle . getType ( ) ) ;
double arrivalTime = currentTime + travelTime ; double arrivalTime = currentTime + travelTime ;
Event arrivalEvent = new Event ( arrivalTime , EventType . VEHICLE_ARRIVAL , vehicle , nextDest ) ; Event arrivalEvent = new Event ( arrivalTime , EventType . VEHICLE_ARRIVAL , vehicle , nextDest ) ;
eventQueue . offer ( arrivalEvent ) ; eventQueue . offer ( arrivalEvent ) ;
@@ -488,9 +518,9 @@ public class SimulationEngine {
*/ */
private void handleVehicleExit ( Vehicle vehicle ) { private void handleVehicleExit ( Vehicle vehicle ) {
System . out . printf ( " [t=%.2f] Vehicle %s exited the system (wait=%.2fs, travel=%.2fs)%n " , System . out . printf ( " [t=%.2f] Vehicle %s exited the system (wait=%.2fs, travel=%.2fs)%n " ,
currentTime , vehicle . getId ( ) , currentTime , vehicle . getId ( ) ,
vehicle . getTotalWaitingTime ( ) , vehicle . getTotalWaitingTime ( ) ,
vehicle . getTotalTravelTime ( currentTime ) ) ; vehicle . getTotalTravelTime ( currentTime ) ) ;
// Record the exit for final statistics calculation // Record the exit for final statistics calculation
statisticsCollector . recordVehicleExit ( vehicle , currentTime ) ; statisticsCollector . recordVehicleExit ( vehicle , currentTime ) ;
@@ -499,7 +529,8 @@ public class SimulationEngine {
/** /**
* Handles {@link EventType#TRAFFIC_LIGHT_CHANGE}. * Handles {@link EventType#TRAFFIC_LIGHT_CHANGE}.
* 1. Toggles the light's state (RED to GREEN or GREEN to RED). * 1. Toggles the light's state (RED to GREEN or GREEN to RED).
* 2. If the light just turned GREEN, call {@link #processGreenLight(TrafficLight, Intersection)} * 2. If the light just turned GREEN, call
* {@link #processGreenLight(TrafficLight, Intersection)}
* to process any waiting vehicles. * to process any waiting vehicles.
* 3. Schedules the *next* state change for this light based on its * 3. Schedules the *next* state change for this light based on its
* green/red time duration. * green/red time duration.
@@ -512,13 +543,13 @@ public class SimulationEngine {
// Toggle state // Toggle state
TrafficLightState newState = ( light . getState ( ) = = TrafficLightState . RED ) TrafficLightState newState = ( light . getState ( ) = = TrafficLightState . RED )
? TrafficLightState . GREEN ? TrafficLightState . GREEN
: TrafficLightState . RED ; : TrafficLightState . RED ;
light . changeState ( newState ) ; light . changeState ( newState ) ;
System . out . printf ( " [t=%.2f] Traffic light %s changed to %s%n " , System . out . printf ( " [t=%.2f] Traffic light %s changed to %s%n " ,
currentTime , light . getId ( ) , newState ) ; currentTime , light . getId ( ) , newState ) ;
// If changed to GREEN, process waiting vehicles // If changed to GREEN, process waiting vehicles
if ( newState = = TrafficLightState . GREEN ) { if ( newState = = TrafficLightState . GREEN ) {
@@ -530,8 +561,8 @@ public class SimulationEngine {
// Schedule the *next* state change for this same light // Schedule the *next* state change for this same light
double nextChangeDelay = ( newState = = TrafficLightState . GREEN ) double nextChangeDelay = ( newState = = TrafficLightState . GREEN )
? light . getGreenTime ( ) ? light . getGreenTime ( )
: light . getRedTime ( ) ; : light . getRedTime ( ) ;
scheduleTrafficLightChange ( light , intersectionId , nextChangeDelay ) ; scheduleTrafficLightChange ( light , intersectionId , nextChangeDelay ) ;
} }
@@ -546,7 +577,7 @@ public class SimulationEngine {
* processes the entire queue "instantaneously" at the moment * processes the entire queue "instantaneously" at the moment
* the light turns green. * the light turns green.
* *
* @param light The {@link TrafficLight} that just turned green. * @param light The {@link TrafficLight} that just turned green.
* @param intersection The {@link Intersection} where the light is. * @param intersection The {@link Intersection} where the light is.
*/ */
private void processGreenLight ( TrafficLight light , Intersection intersection ) { private void processGreenLight ( TrafficLight light , Intersection intersection ) {
@@ -572,7 +603,8 @@ public class SimulationEngine {
} }
/** /**
* Utility method to get the configured crossing time for a given {@link VehicleType}. * Utility method to get the configured crossing time for a given
* {@link VehicleType}.
* *
* @param type The type of vehicle. * @param type The type of vehicle.
* @return The crossing time in seconds. * @return The crossing time in seconds.
@@ -603,6 +635,7 @@ public class SimulationEngine {
/** /**
* Gets the current simulation time. * Gets the current simulation time.
*
* @return The time in virtual seconds. * @return The time in virtual seconds.
*/ */
public double getCurrentTime ( ) { public double getCurrentTime ( ) {
@@ -612,6 +645,7 @@ public class SimulationEngine {
/** /**
* Gets a map of all intersections in the simulation. * Gets a map of all intersections in the simulation.
* Returns a copy to prevent external modification. * Returns a copy to prevent external modification.
*
* @return A {@link Map} of intersection IDs to {@link Intersection} objects. * @return A {@link Map} of intersection IDs to {@link Intersection} objects.
*/ */
public Map < String , Intersection > getIntersections ( ) { public Map < String , Intersection > getIntersections ( ) {
@@ -620,6 +654,7 @@ public class SimulationEngine {
/** /**
* Gets the statistics collector instance. * Gets the statistics collector instance.
*
* @return The {@link StatisticsCollector}. * @return The {@link StatisticsCollector}.
*/ */
public StatisticsCollector getStatisticsCollector ( ) { public StatisticsCollector getStatisticsCollector ( ) {
