source: src/main/java/geniusweb/partiesserver/RunningPartiesUpdater.java@ 8

package geniusweb.partiesserver;

import java.util.logging.Level;

import geniusweb.partiesserver.repository.RunningPartiesRepo;
import geniusweb.partiesserver.repository.RunningParty;
import geniusweb.party.Party;
import tudelft.utilities.logging.ReportToLogger;
import tudelft.utilities.logging.Reporter;

/**
 * 
 * This object keeps the {@link RunningPartiesRepo} up to date. Main job is to
 * remove parties that have been timed out. When a party times out,
 * it calls {@link Party#terminate()} but that might fail to stop a party. 
 * In the end, the protocol should close the connection after the deadline. Start and run only once.
 */
public class RunningPartiesUpdater implements Runnable {
        private final long period;
        private final Reporter log = new ReportToLogger("partiesserver");
        private final RunningPartiesRepo running;
        /**
         * when a negotiation runs out of time, the protocol may want to inform all
         * parties about the failed session. If the parties are all killed at that
         * moment, this is impossible. Therefore we wait KILL_DELAY extra time before
         * really killing the parties.
         */
        private static final long KILL_DELAY = 2000;

        /**
         * @param repo   the {@link RunningPartiesRepo} that must be updated
         *               automatically
         * @param period the period with which to check time-out (ms). Recommended 1000.
         *               After constructing you can run this in separate thread or just
         *               call {@link #run()}
         * 
         */
        public RunningPartiesUpdater(RunningPartiesRepo repo, final long period) {
                this.running = repo;
                this.period = period;
        }

        /**
         * 
         * run the updater. Please run only one of this to avoid neeedless CPU load.
         */
        @Override
        public void run() {
                try {
                        while (true) {
                                Thread.sleep(period);
                                update();
                        }
                } catch (InterruptedException e) {
                        System.err.println("ERROR:  RunningPartiesUpdater was interrupted!");
                }
        }

        /**
         * Called when some file that may be relevant has changed. Synchronized to avoid
         * weird states if filesystem changes rapidly. We ignore everything but jar
         * files.
         */
        void update() {
                for (RunningParty party : running.list()) {
                        long now = System.currentTimeMillis();
                        if (now >= party.getEndDate().getTime() + KILL_DELAY) {
                                running.remove(party.getID());
                                log.log(Level.WARNING, "party " + party.getID() + " still running 2s after deadline. Removed now.");
                        }
                }
        }

}