001/* 002 * Copyright 2002-2018 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.context; 018 019/** 020 * A common interface defining methods for start/stop lifecycle control. 021 * The typical use case for this is to control asynchronous processing. 022 * <b>NOTE: This interface does not imply specific auto-startup semantics. 023 * Consider implementing {@link SmartLifecycle} for that purpose.</b> 024 * 025 * <p>Can be implemented by both components (typically a Spring bean defined in a 026 * Spring context) and containers (typically a Spring {@link ApplicationContext} 027 * itself). Containers will propagate start/stop signals to all components that 028 * apply within each container, e.g. for a stop/restart scenario at runtime. 029 * 030 * <p>Can be used for direct invocations or for management operations via JMX. 031 * In the latter case, the {@link org.springframework.jmx.export.MBeanExporter} 032 * will typically be defined with an 033 * {@link org.springframework.jmx.export.assembler.InterfaceBasedMBeanInfoAssembler}, 034 * restricting the visibility of activity-controlled components to the Lifecycle 035 * interface. 036 * 037 * <p>Note that the present {@code Lifecycle} interface is only supported on 038 * <b>top-level singleton beans</b>. On any other component, the {@code Lifecycle} 039 * interface will remain undetected and hence ignored. Also, note that the extended 040 * {@link SmartLifecycle} interface provides sophisticated integration with the 041 * application context's startup and shutdown phases. 042 * 043 * @author Juergen Hoeller 044 * @since 2.0 045 * @see SmartLifecycle 046 * @see ConfigurableApplicationContext 047 * @see org.springframework.jms.listener.AbstractMessageListenerContainer 048 * @see org.springframework.scheduling.quartz.SchedulerFactoryBean 049 */ 050public interface Lifecycle { 051 052 /** 053 * Start this component. 054 * <p>Should not throw an exception if the component is already running. 055 * <p>In the case of a container, this will propagate the start signal to all 056 * components that apply. 057 * @see SmartLifecycle#isAutoStartup() 058 */ 059 void start(); 060 061 /** 062 * Stop this component, typically in a synchronous fashion, such that the component is 063 * fully stopped upon return of this method. Consider implementing {@link SmartLifecycle} 064 * and its {@code stop(Runnable)} variant when asynchronous stop behavior is necessary. 065 * <p>Note that this stop notification is not guaranteed to come before destruction: 066 * On regular shutdown, {@code Lifecycle} beans will first receive a stop notification 067 * before the general destruction callbacks are being propagated; however, on hot 068 * refresh during a context's lifetime or on aborted refresh attempts, a given bean's 069 * destroy method will be called without any consideration of stop signals upfront. 070 * <p>Should not throw an exception if the component is not running (not started yet). 071 * <p>In the case of a container, this will propagate the stop signal to all components 072 * that apply. 073 * @see SmartLifecycle#stop(Runnable) 074 * @see org.springframework.beans.factory.DisposableBean#destroy() 075 */ 076 void stop(); 077 078 /** 079 * Check whether this component is currently running. 080 * <p>In the case of a container, this will return {@code true} only if <i>all</i> 081 * components that apply are currently running. 082 * @return whether the component is currently running 083 */ 084 boolean isRunning(); 085 086}