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/*
* The MIT License (MIT)
*
* Copyright (c) 2015 Camil Staps <info@camilstaps.nl>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.camilstaps.route66;
import java.util.ArrayList;
import java.util.Observable;
import javax.swing.JFrame;
/**
* Route 66 model with crossing
*
* The class model holds all cars in the simulation.
*
* @author Pieter Koopman, Camil Staps
*/
public class Model extends Observable {
private final Car [] cars;
public static final int
DIRECTIONS = 4,
NUMBEROFCARS = 5 * DIRECTIONS; // total number of cars in system
private final ArrayList<JFrame> views;
/**
* Crossing attributes:
*
* allowed - which direction is currently allowed; if East is allowed, West
* is also allowed, etc.
* crossingWaiting - whether or not the crossing is waiting for cars to
* leave the crossing to switch (i.e. orange)
* lastCrossingChange - when the crossing switched the last time
* MIN_CROSS_TIME - the minimum time the crossing should wait before
* switching again after the last switch
*/
private Direction allowed = Direction.East;
private boolean crossingWaiting = false;
private long lastCrossingChange = 0;
private static final int MIN_CROSS_TIME = 1000;
/**
* Constructor: create all cars
*/
public Model() {
views = new ArrayList<>();
cars = new Car [NUMBEROFCARS];
for (int c = 0; c < NUMBEROFCARS; c += 1) {
cars[c] = new Car(c, this);
}
}
/**
* add the view to this model. It will be repainted upon an update
* @param view
*/
public void addView(JFrame view) {
views.add(view);
}
public Car[] getCars() {
return cars;
}
/**
* Get a car from the model
* @param i numbers of required car
* @return the car itself (not a copy)
*/
public Car getCar(int i) {
return cars[i];
}
/**
* Repaint all views, and notify all drivers to reconsider driving
*/
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) {
// Check that we don't collide with the car in front of us
Car that_car = cars[car.getNumber() < DIRECTIONS ? car.getNumber() + NUMBEROFCARS - DIRECTIONS : car.getNumber() - DIRECTIONS];
boolean ok = !(that_car.getLocation() > requested_location &&
that_car.getLocation() < requested_location + Car.CARLENGTH + Car.MINCARSPACE);
// If we have to wait for the crossing... well, do that.
if (car.isInFrontOfCrossing() && !isCrossingAllowed(car.getDirection())) {
ok = doCrossingRequest();
}
if (!ok) {
try {
wait();
} catch (InterruptedException ex) {}
}
return ok;
}
/**
* Check if there are any cars on the crossing
* @return
*/
public synchronized boolean isCarsOnCrossing() {
for (Car car : cars) {
if (car.isOnCrossing()) {
return true;
}
}
return false;
}
/**
* Switch the crossing
*/
public synchronized void doSwitchCrossing() {
crossingWaiting = true;
while (isCarsOnCrossing()) {
try {
wait();
} catch (InterruptedException ex) {
}
}
if (allowed == Direction.East || allowed == Direction.West) {
allowed = Direction.North;
} else {
allowed = Direction.East;
}
crossingWaiting = false;
lastCrossingChange = System.currentTimeMillis();
}
/**
* Check if crossing in some direction is allowed
* @param direction
* @return
*/
public synchronized boolean isCrossingAllowed(Direction direction) {
return !crossingWaiting && (direction == allowed || Direction.opposite(direction) == allowed);
}
/**
* Try to switch the crossing
* This may return false without even trying to switch, if it's too early to
* ask (see {@link Model#MIN_CROSS_TIME}) or if a request has been made already.
* @return
*/
public synchronized boolean doCrossingRequest() {
if (crossingWaiting || System.currentTimeMillis() - lastCrossingChange < MIN_CROSS_TIME) {
return false;
}
doSwitchCrossing();
return true;
}
}
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