DNSTaskStarter.java

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package javax.jmdns.impl;

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicReference;

import javax.jmdns.impl.tasks.RecordReaper;
import javax.jmdns.impl.tasks.Responder;
import javax.jmdns.impl.tasks.resolver.ServiceInfoResolver;
import javax.jmdns.impl.tasks.resolver.ServiceResolver;
import javax.jmdns.impl.tasks.resolver.TypeResolver;
import javax.jmdns.impl.tasks.state.Announcer;
import javax.jmdns.impl.tasks.state.Canceler;
import javax.jmdns.impl.tasks.state.Prober;
import javax.jmdns.impl.tasks.state.Renewer;

public interface DNSTaskStarter {

    public static final class Factory {

        private static volatile Factory                        _instance;
        private final ConcurrentMap<JmDNSImpl, DNSTaskStarter> _instances;

        public static interface ClassDelegate {

            public DNSTaskStarter newDNSTaskStarter(JmDNSImpl jmDNSImpl);
        }

        private static final AtomicReference<Factory.ClassDelegate> _databaseClassDelegate = new AtomicReference<Factory.ClassDelegate>();

        private Factory() {
            super();
            _instances = new ConcurrentHashMap<JmDNSImpl, DNSTaskStarter>(20);
        }

        public static void setClassDelegate(Factory.ClassDelegate delegate) {
            _databaseClassDelegate.set(delegate);
        }

        public static Factory.ClassDelegate classDelegate() {
            return _databaseClassDelegate.get();
        }

        protected static DNSTaskStarter newDNSTaskStarter(JmDNSImpl jmDNSImpl) {
            DNSTaskStarter instance = null;
            Factory.ClassDelegate delegate = _databaseClassDelegate.get();
            if (delegate != null) {
                instance = delegate.newDNSTaskStarter(jmDNSImpl);
            }
            return (instance != null ? instance : new DNSTaskStarterImpl(jmDNSImpl));
        }

        public static Factory getInstance() {
            if (_instance == null) {
                synchronized (DNSTaskStarter.Factory.class) {
                    if (_instance == null) {
                        _instance = new Factory();
                    }
                }
            }
            return _instance;
        }

        public DNSTaskStarter getStarter(JmDNSImpl jmDNSImpl) {
            DNSTaskStarter starter = _instances.get(jmDNSImpl);
            if (starter == null) {
                _instances.putIfAbsent(jmDNSImpl, newDNSTaskStarter(jmDNSImpl));
                starter = _instances.get(jmDNSImpl);
            }
            return starter;
        }

    }

    public static final class DNSTaskStarterImpl implements DNSTaskStarter {

        private final JmDNSImpl _jmDNSImpl;

        private final Timer     _timer;

        private final Timer     _stateTimer;

        public static class StarterTimer extends Timer {

            // This is needed because in some case we cancel the timers before all the task have finished running and in some case they will try to reschedule
            private volatile boolean _cancelled;

            public StarterTimer() {
                super();
                _cancelled = false;
            }

            public StarterTimer(boolean isDaemon) {
                super(isDaemon);
                _cancelled = false;
            }

            public StarterTimer(String name, boolean isDaemon) {
                super(name, isDaemon);
                _cancelled = false;
            }

            public StarterTimer(String name) {
                super(name);
                _cancelled = false;
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#cancel()
             */
            @Override
            public synchronized void cancel() {
                if (_cancelled) return;
                _cancelled = true;
                super.cancel();
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#schedule(java.util.TimerTask, long)
             */
            @Override
            public synchronized void schedule(TimerTask task, long delay) {
                if (_cancelled) return;
                super.schedule(task, delay);
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#schedule(java.util.TimerTask, java.util.Date)
             */
            @Override
            public synchronized void schedule(TimerTask task, Date time) {
                if (_cancelled) return;
                super.schedule(task, time);
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#schedule(java.util.TimerTask, long, long)
             */
            @Override
            public synchronized void schedule(TimerTask task, long delay, long period) {
                if (_cancelled) return;
                super.schedule(task, delay, period);
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#schedule(java.util.TimerTask, java.util.Date, long)
             */
            @Override
            public synchronized void schedule(TimerTask task, Date firstTime, long period) {
                if (_cancelled) return;
                super.schedule(task, firstTime, period);
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long)
             */
            @Override
            public synchronized void scheduleAtFixedRate(TimerTask task, long delay, long period) {
                if (_cancelled) return;
                super.scheduleAtFixedRate(task, delay, period);
            }

            /*
             * (non-Javadoc)
             * @see java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, java.util.Date, long)
             */
            @Override
            public synchronized void scheduleAtFixedRate(TimerTask task, Date firstTime, long period) {
                if (_cancelled) return;
                super.scheduleAtFixedRate(task, firstTime, period);
            }

        }

        public DNSTaskStarterImpl(JmDNSImpl jmDNSImpl) {
            super();
            _jmDNSImpl = jmDNSImpl;
            _timer = new StarterTimer("JmDNS(" + _jmDNSImpl.getName() + ").Timer", true);
            _stateTimer = new StarterTimer("JmDNS(" + _jmDNSImpl.getName() + ").State.Timer", false);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#purgeTimer()
         */
        @Override
        public void purgeTimer() {
            _timer.purge();
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#purgeStateTimer()
         */
        @Override
        public void purgeStateTimer() {
            _stateTimer.purge();
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#cancelTimer()
         */
        @Override
        public void cancelTimer() {
            _timer.cancel();
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#cancelStateTimer()
         */
        @Override
        public void cancelStateTimer() {
            _stateTimer.cancel();
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startProber()
         */
        @Override
        public void startProber() {
            new Prober(_jmDNSImpl).start(_stateTimer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startAnnouncer()
         */
        @Override
        public void startAnnouncer() {
            new Announcer(_jmDNSImpl).start(_stateTimer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startRenewer()
         */
        @Override
        public void startRenewer() {
            new Renewer(_jmDNSImpl).start(_stateTimer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startCanceler()
         */
        @Override
        public void startCanceler() {
            new Canceler(_jmDNSImpl).start(_stateTimer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startReaper()
         */
        @Override
        public void startReaper() {
            new RecordReaper(_jmDNSImpl).start(_timer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startServiceInfoResolver(javax.jmdns.impl.ServiceInfoImpl)
         */
        @Override
        public void startServiceInfoResolver(ServiceInfoImpl info) {
            new ServiceInfoResolver(_jmDNSImpl, info).start(_timer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startTypeResolver()
         */
        @Override
        public void startTypeResolver() {
            new TypeResolver(_jmDNSImpl).start(_timer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startServiceResolver(java.lang.String)
         */
        @Override
        public void startServiceResolver(String type) {
            new ServiceResolver(_jmDNSImpl, type).start(_timer);
        }

        /*
         * (non-Javadoc)
         * @see javax.jmdns.impl.DNSTaskStarter#startResponder(javax.jmdns.impl.DNSIncoming, int)
         */
        @Override
        public void startResponder(DNSIncoming in, int port) {
            new Responder(_jmDNSImpl, in, port).start(_timer);
        }
    }

    public void purgeTimer();

    public void purgeStateTimer();

    public void cancelTimer();

    public void cancelStateTimer();

    public void startProber();

    public void startAnnouncer();

    public void startRenewer();

    public void startCanceler();

    public void startReaper();

    public void startServiceInfoResolver(ServiceInfoImpl info);

    public void startTypeResolver();

    public void startServiceResolver(String type);

    public void startResponder(DNSIncoming in, int port);

}