libraries/scheduler/src/main/java/org/qi4j/library/scheduler/schedule/cron/CronSchedule.java

/*
 * Copyright (c) 2010-2012, Paul Merlin. All Rights Reserved.
 * Copyright (c) 2012, Niclas Hedhman. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 *
 *     You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.qi4j.library.scheduler.schedule.cron;

import org.qi4j.api.mixin.Mixins;
import org.qi4j.api.property.Immutable;
import org.qi4j.api.property.Property;
import org.qi4j.library.scheduler.schedule.Schedule;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Mixins( CronSchedule.CronScheduleMixin.class )
public interface CronSchedule
    extends Schedule
{
    /**
     * The Cron expression indicating when the Schedule is to be run.
     * The Schedule can NOT be changed once it is set. If this is needed, delete this Schedule and attach the Task
     * to a new Schedule.
     *
     * @return The cron expression that will be used on {@link org.qi4j.api.unitofwork.UnitOfWork} completion to compute next run
     */
    @CronExpression
    @Immutable
    Property<String> cronExpression();

    abstract class CronScheduleMixin
        implements CronSchedule
    {
        private static final Logger LOGGER = LoggerFactory.getLogger( Schedule.class );
        private boolean running;

        @Override
        public void taskStarting()
        {
            running = true;
        }

        @Override
        public void taskCompletedSuccessfully()
        {
            running = false;
        }

        @Override
        public void taskCompletedWithException( RuntimeException ex )
        {
            running = false;
        }

        @Override
        public String presentationString()
        {
            return cronExpression().get();
        }

        @Override
        public boolean isTaskRunning()
        {
            // See SchedulerMixin.ScheduleRunner::run
            return false;
        }

        @Override
        public long nextRun( long from )
        {
            long actualFrom = from;
            long firstRun = start().get().getMillis();
            if( firstRun > from )
            {
                actualFrom = firstRun;
            }
            Long nextRun = new org.codeartisans.sked.cron.CronSchedule( cronExpression().get() )
                .firstRunAfter( actualFrom );
            LOGGER.info( "CronSchedule::nextRun({}) is {}", from, firstRun );
            return nextRun;
        }
    }

}