001    // Copyright 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.ioc.services.cron;
016    
017    /**
018     * A service that executes a job at intervals specified by a {@link Schedule}.
019     *
020     * @since 5.3
021     */
022    public interface PeriodicExecutor
023    {
024        /**
025         * Adds a job to be executed. The job is executed in a thread pool (via {@link org.apache.tapestry5.ioc.services.ParallelExecutor#invoke(org.apache.tapestry5.ioc.Invokable)}), as determined by the schedule.
026         *
027         * @param schedule defines when the job will next execute
028         * @param name     a name used in debugging output related to the job
029         * @param job      a Runnable object that represents the work to be done
030         * @return a PeriodicJob that can be used to query when the job executes, or to cancel its execution
031         */
032        PeriodicJob addJob(Schedule schedule, String name, Runnable job);
033    }