net.sf.jrtps.udds.ParticipantLeaseManager Maven / Gradle / Ivy

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package net.sf.jrtps.udds;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import net.sf.jrtps.builtin.ParticipantData;
import net.sf.jrtps.types.GuidPrefix;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * ParticipantLeaseManager tracks leaseTime of remote participants. If leaseTime
 * is expired, Local endpoints will be notified of this.
 * 
 * @author mcr70
 */
class ParticipantLeaseManager implements Runnable {
    private static final Logger log = LoggerFactory.getLogger(ParticipantLeaseManager.class);
    private final Participant participant;
    private final Map discoveredParticipants;

    ParticipantLeaseManager(Participant participant, Map discoveredParticipants) {
        this.participant = participant;
        this.discoveredParticipants = discoveredParticipants;
    }

    @Override
    public void run() {
        boolean running = true;
        while (running) {
            if (discoveredParticipants.size() > 0) {
                log.debug("Checking lease of {} remote participants", discoveredParticipants.size());
            }

            List expiryList = new LinkedList<>();
            for (ParticipantData pd : discoveredParticipants.values()) {
                if (pd.isLeaseExpired()) {
                    Date current = new Date();
                    Date expiration = new Date(pd.getLeaseExpirationTime());

                    SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS");

                    log.debug("Lease has expired for {}, currentTime is {}, expirationTime is {}", pd.getGuidPrefix(),
                            sdf.format(current), sdf.format(expiration));
                    expiryList.add(pd.getGuidPrefix());
                }
            }

            for (GuidPrefix prefix : expiryList) {
                participant.handleParticipantLeaseExpiration(prefix);
            }

            long sleepTime = getNextSleepTime();
            // log.debug("Next sleep time is " + sleepTime);
            running = participant.waitFor(sleepTime);
        }

        log.debug("ParticipantLeaseManager is exiting.");
    }

    /**
     * Gets the next LeaseTime. If there is no Participants detected, next
     * sleepTime is 1 second. Otherwise, next sleepTime is smallest sleepTime of
     * detected participants.
     * 
     * @return next sleepTime
     */
    private long getNextSleepTime() {
        if (discoveredParticipants.size() == 0) {
            return 1000; // TODO: configurable?
        }

        long smallest_expireTime = Long.MAX_VALUE;

        for (ParticipantData pd : discoveredParticipants.values()) {
            if (pd.getLeaseExpirationTime() < smallest_expireTime) {
                smallest_expireTime = pd.getLeaseExpirationTime();
            }
        }

        long nextSleeptime = smallest_expireTime - System.currentTimeMillis();
        nextSleeptime = nextSleeptime + 1000; // Grace period. Check lease one
                                              // sec after expiration

        if (nextSleeptime <= 0) {
            nextSleeptime = 1000; // TODO: configurable?
        }

        return nextSleeptime;
    }
}