com.almende.eve.scheduling.clock.RunnableClock.java Source code

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Here is the source code for com.almende.eve.scheduling.clock.RunnableClock.java

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/*
 * Copyright: Almende B.V. (2014), Rotterdam, The Netherlands
 * License: The Apache Software License, Version 2.0
 */
package com.almende.eve.scheduling.clock;

import java.util.ArrayList;
import java.util.List;
import java.util.NavigableMap;
import java.util.TreeMap;
import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;

import org.joda.time.DateTime;
import org.joda.time.Interval;

import com.almende.util.threads.ThreadPool;
import com.fasterxml.jackson.annotation.JsonIgnore;

/**
 * The Class RunnableClock.
 */
public class RunnableClock implements Runnable, Clock {
    private static final Logger LOG = Logger.getLogger(RunnableClock.class.getName());
    private final NavigableMap<ClockEntry, ClockEntry> TIMELINE = new TreeMap<ClockEntry, ClockEntry>();
    private static final ScheduledExecutorService SCHEDULER = ThreadPool.getScheduledPool();
    private static final Executor RUNNER = ThreadPool.getPool();
    private ScheduledFuture<?> future = null;

    /*
     * (non-Javadoc)
     * @see java.lang.Runnable#run()
     */
    @Override
    public void run() {
        final List<Runnable> toRun = new ArrayList<Runnable>();
        synchronized (TIMELINE) {
            while (!TIMELINE.isEmpty()) {
                final ClockEntry ce = TIMELINE.firstEntry().getValue();
                final DateTime now = DateTime.now();
                if (ce.getDue().isEqual(now) || ce.getDue().isBefore(now)) {
                    TIMELINE.remove(ce);
                    toRun.add(ce.getCallback());
                    continue;
                }
                final long interval = new Interval(now, ce.getDue()).toDurationMillis();
                if (interval <= 0) {
                    continue;
                }
                if (future == null || future.getDelay(TimeUnit.MILLISECONDS) != interval) {
                    if (future != null) {
                        future.cancel(false);
                    }
                    future = SCHEDULER.schedule(this, interval, TimeUnit.MILLISECONDS);
                }
                break;
            }
            if (future == null && !TIMELINE.isEmpty()) {
                LOG.warning("Lost trigger, should never happen!");
            }
        }
        for (Runnable run : toRun) {
            RUNNER.execute(run);
        }
    }

    /*
     * (non-Javadoc)
     * @see
     * com.almende.eve.scheduler.clock.Clock#requestTrigger(java.lang.String,
     * org.joda.time.DateTime, java.lang.Runnable)
     */
    @Override
    public void requestTrigger(final String triggerId, final DateTime due, final Runnable callback) {
        synchronized (TIMELINE) {
            final ClockEntry ce = new ClockEntry(triggerId, due, callback);
            final ClockEntry oldVal = TIMELINE.get(ce);
            if (oldVal == null || oldVal.getDue().isAfter(due)) {
                TIMELINE.put(ce, ce);
            } else {
                LOG.warning(ce.getTriggerId() + ": Skip adding ce, because has old value earlier than current. "
                        + oldVal.getTriggerId());
            }
        }
        RUNNER.execute(this);
    }

    /*
     * (non-Javadoc)
     * @see com.almende.eve.scheduling.clock.Clock#cancel(java.lang.String)
     */
    @Override
    public void cancel(final String triggerId) {
        synchronized (TIMELINE) {
            final ClockEntry ce = new ClockEntry(triggerId, null, null);
            TIMELINE.remove(ce);
        }
    }

    /*
     * (non-Javadoc)
     * @see com.almende.eve.scheduling.clock.Clock#clear()
     */
    @Override
    public void clear() {
        synchronized (TIMELINE) {
            TIMELINE.clear();
            if (future != null) {
                future.cancel(false);
                future = null;
            }
        }
    }
}

/**
 * @author Almende
 */
class ClockEntry implements Comparable<ClockEntry> {
    private String triggerId;
    private DateTime due;
    private Runnable callback;

    public ClockEntry() {
    };

    /**
     * Instantiates a new clock entry.
     *
     * @param triggerId
     *            the trigger id
     * @param due
     *            the due
     * @param callback
     *            the callback
     */
    public ClockEntry(final String triggerId, final DateTime due, final Runnable callback) {
        this.triggerId = triggerId;
        this.due = due;
        this.callback = callback;
    }

    /**
     * @return TriggerId
     */
    public String getTriggerId() {
        return triggerId;
    }

    /**
     * Sets the trigger id.
     *
     * @param triggerId
     *            the new trigger id
     */
    public void setTriggerId(final String triggerId) {
        this.triggerId = triggerId;
    }

    /**
     * @return Due date
     */
    public DateTime getDue() {
        return due;
    }

    /**
     * Sets the due.
     *
     * @param due
     *            the new due
     */
    public void setDue(final DateTime due) {
        this.due = due;
    }

    /**
     * @return This tasks callback.
     */
    @JsonIgnore
    public Runnable getCallback() {
        return callback;
    }

    /**
     * Sets the callback.
     *
     * @param callback
     *            the new callback
     */
    public void setCallback(final Runnable callback) {
        this.callback = callback;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (!(o instanceof ClockEntry)) {
            return false;
        }
        final ClockEntry other = (ClockEntry) o;
        return triggerId.equals(other.triggerId);
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return triggerId.hashCode();
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    @Override
    public int compareTo(final ClockEntry o) {
        if (due == null || o.due == null) {
            // Become consistent with equals:
            if (equals(o)) {
                return 0;
            } else {
                return -1;
            }
        }
        if (due.equals(o.due)) {
            // Become consistent with equals:
            if (equals(o)) {
                return 0;
            } else {
                return -1;
            }
        }
        return due.compareTo(o.due);
    }
}