    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 very simple schedule, that simply executes the desired job at fixed intervals.
    019 *
    020 * @since 5.3
    021 */
    022public class IntervalSchedule implements Schedule
    023{
    024    private final long interval;
    025
    026    /**
    027     * Interval at which the schedule should execute jobs. The first execution is delayed from current time
    028     * by the interval as well.
    029     *
    030     * @param interval in milliseconds
    031     */
    032    public IntervalSchedule(long interval)
    033    {
    034        assert interval > 0;
    035
    036        this.interval = interval;
    037    }
    038
    039    @Override
    040    public long firstExecution()
    041    {
    042        return nextExecution(System.currentTimeMillis());
    043    }
    044
    045    @Override
    046    public long nextExecution(long previousExecution)
    047    {
    048        return previousExecution + interval;
    049    }
    050}