001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel;
018
019/**
020 * A {@link Service} which is also capable of suspending and resuming.
021 * <p/>
022 * This is useable for services which needs more fine grained control at runtime supporting suspension.
023 * Other services may select to mimic suspending by just stopping the service.
024 * <p/>
025 * For example this is use by the JmsConsumer which suspends the Spring JMS listener instead of stopping
026 * the consumer totally.
027 * <p/>
028 * <b>Important:</b> The service should also implement the {@link Suspendable} marker interface to indicate
029 * the service supports suspension using custom code logic.
030 *
031 * @see Suspendable
032 */
033public interface SuspendableService extends Service {
034
035    /**
036     * Suspends the service.
037     *
038     * @throws Exception is thrown if suspending failed
039     */
040    void suspend() throws Exception;
041
042    /**
043     * Resumes the service.
044     *
045     * @throws Exception is thrown if resuming failed
046     */
047    void resume() throws Exception;
048
049    /**
050     * Tests whether the service is suspended or not.
051     *
052     * @return <tt>true</tt> if suspended
053     */
054    boolean isSuspended();
055}