001/*
002 * Copyright 2002-2012 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.scheduling;
018
019import java.util.Date;
020
021import org.springframework.lang.Nullable;
022
023/**
024 * Common interface for trigger objects that determine the next execution time
025 * of a task that they get associated with.
026 *
027 * @author Juergen Hoeller
028 * @since 3.0
029 * @see TaskScheduler#schedule(Runnable, Trigger)
030 * @see org.springframework.scheduling.support.CronTrigger
031 */
032public interface Trigger {
033
034        /**
035         * Determine the next execution time according to the given trigger context.
036         * @param triggerContext context object encapsulating last execution times
037         * and last completion time
038         * @return the next execution time as defined by the trigger,
039         * or {@code null} if the trigger won't fire anymore
040         */
041        @Nullable
042        Date nextExecutionTime(TriggerContext triggerContext);
043
044}