package net.jcip.examples;import java.util.*;import net.jcip.annotations.*;/** * CooperatingDeadlock * <p/> * Lock-ordering deadlock between cooperating objects * * @author Brian Goetz and Tim Peierls */public class CooperatingDeadlock {    // Warning: deadlock-prone!    class Taxi {        @GuardedBy("this") private Point location, destination;        private final Dispatcher dispatcher;        public Taxi(Dispatcher dispatcher) {            this.dispatcher = dispatcher;        }        public synchronized Point getLocation() {            return location;        }        public synchronized void setLocation(Point location) {            this.location = location;            if (location.equals(destination))                dispatcher.notifyAvailable(this);        }        public synchronized Point getDestination() {            return destination;        }        public synchronized void setDestination(Point destination) {            this.destination = destination;        }    }    class Dispatcher {        @GuardedBy("this") private final Set<Taxi> taxis;        @GuardedBy("this") private final Set<Taxi> availableTaxis;        public Dispatcher() {            taxis = new HashSet<Taxi>();            availableTaxis = new HashSet<Taxi>();        }        public synchronized void notifyAvailable(Taxi taxi) {            availableTaxis.add(taxi);        }        public synchronized Image getImage() {            Image image = new Image();            for (Taxi t : taxis)                image.drawMarker(t.getLocation());            return image;        }    }    class Image {        public void drawMarker(Point p) {        }    }}