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
015package 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 */
022public 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    
034    /**
035     * Initializes this service. <em>Never call this method direclty. It's intended
036     * for internal Tapestry-IoC usage only</em>.
037     */
038    public void init();
039}