TimerSchedulerBean.java

/*
 * Copyright (c) 2016 Red Hat, Inc. and/or its affiliates.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Cheng Fang - Initial API and implementation
 */

package org.jberet.schedule;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import javax.annotation.Resource;
import javax.batch.operations.BatchRuntimeException;
import javax.ejb.Singleton;
import javax.ejb.Timeout;
import javax.ejb.Timer;
import javax.ejb.TimerConfig;
import javax.ejb.TimerService;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;

import org.jberet.schedule._private.ScheduleExecutorMessages;

/**
 * EJB-Timer-based job scheduler, as a singleton session bean.
 * This job scheduler class supports single action, repeatable, and
 * calendar-based job schedule. Persistent job schedule is also supported.
 *
 * @since 1.3.0
 * @see JobScheduler
 */
@Singleton()
@TransactionAttribute(TransactionAttributeType.SUPPORTS)
public class TimerSchedulerBean extends JobScheduler {
    @Resource
    private TimerService timerService;

    @Override
    public JobSchedule schedule(final JobScheduleConfig scheduleConfig) {
        final Timer timer;
        final JobSchedule jobSchedule = new JobSchedule(null, scheduleConfig);
        if (scheduleConfig.initialDelay > 0) {
            if (scheduleConfig.interval > 0) {
                timer = timerService.createIntervalTimer(toMillis(scheduleConfig.initialDelay),
                        toMillis(scheduleConfig.interval),
                        new TimerConfig(jobSchedule, scheduleConfig.isPersistent()));
            } else if (scheduleConfig.afterDelay > 0) {
                timer = timerService.createIntervalTimer(toMillis(scheduleConfig.initialDelay),
                        toMillis(scheduleConfig.afterDelay),
                        new TimerConfig(jobSchedule, scheduleConfig.isPersistent()));
            } else {
                timer = timerService.createSingleActionTimer(toMillis(scheduleConfig.initialDelay),
                        new TimerConfig(jobSchedule, scheduleConfig.isPersistent()));
            }
        } else if (scheduleConfig.scheduleExpression != null) {
            timer = timerService.createCalendarTimer(scheduleConfig.scheduleExpression,
                    new TimerConfig(jobSchedule, scheduleConfig.isPersistent()));
        } else {
            throw ScheduleExecutorMessages.MESSAGES.invalidJobScheduleConfig(scheduleConfig);
        }

        jobSchedule.setId(getTimerId(timer));
        return jobSchedule;
    }

    @Override
    public List<JobSchedule> getJobSchedules() {
        final List<JobSchedule> result = new ArrayList<JobSchedule>();
        final Collection<Timer> timers = timerService.getTimers();
        for (final Timer t : timers) {
            Serializable info = t.getInfo();
            if (info instanceof JobSchedule) {
                final JobSchedule jobSchedule = (JobSchedule) info;
                if (jobSchedule.getId() == null) {
                    jobSchedule.setId(getTimerId(t));
                }
                result.add(jobSchedule);
            }
        }
        Collections.sort(result, Collections.<JobSchedule>reverseOrder());
        return result;
    }

    @Override
    public boolean cancel(final String scheduleId) {
        final Collection<Timer> timers = timerService.getTimers();
        for (final Timer t : timers) {
            if (scheduleId.equals(getTimerId(t))) {
                t.cancel();
                return true;
            }
        }
        return false;
    }

    @Override
    public JobSchedule getJobSchedule(final String scheduleId) {
        final Collection<Timer> timers = timerService.getTimers();
        for (final Timer e : timers) {
            final JobSchedule js = (JobSchedule) e.getInfo();
            if (scheduleId.equals(js.getId())) {
                return js;
            }
        }
        return null;
    }

    @Override
    public String[] getFeatures() {
        return new String[]{PERSISTENT, CALENDAR};
    }

    /**
     * Timeout method, which starts the job, or restarts the job execution, and
     * saves the new job execution id to {@link JobSchedule}.
     *
     * @param timer the current timer which has just expired
     */
    @Timeout
    protected void timeout(final Timer timer) {
        final JobSchedule jobSchedule = (JobSchedule) timer.getInfo();
        final JobScheduleConfig scheduleConfig = jobSchedule.getJobScheduleConfig();
        if (scheduleConfig.getJobExecutionId() > 0) {
            jobSchedule.addJobExecutionIds(
            JobScheduler.getJobOperator().restart(scheduleConfig.jobExecutionId, scheduleConfig.jobParameters));
        } else {
            jobSchedule.addJobExecutionIds(
            JobScheduler.getJobOperator().start(scheduleConfig.jobName, scheduleConfig.jobParameters));
        }
    }

    private static long toMillis(final long t) {
        return JobScheduler.timeUnit.toMillis(t);
    }

    /**
     * Gets timer id from its string representation, e.g.,
     * <p/>
     * [id=ea4f6ae1-4a73-4480-bf89-d1f361c7d56a timedObjectId=...]
     * <p/>
     * Improve it when appropriate timer API is available.
     *
     * @param timer the timer
     * @return timer id
     */
    private static String getTimerId(final Timer timer) {
        final String s = timer.toString();
        int start = s.indexOf("id=");
        if (start < 0) {
            throw new BatchRuntimeException("Failed to get timer id: " + timer);
        }
        start += 3;
        final int end = s.indexOf(' ', start);
        return end > 0 ? s.substring(start, end) : s.substring(start);
    }
}