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     */
017    package 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     *
028     * @version $Revision: 980370 $
029     */
030    public interface SuspendableService extends Service {
031    
032        /**
033         * Suspends the service.
034         *
035         * @throws Exception is thrown if suspending failed
036         */
037        void suspend() throws Exception;
038    
039        /**
040         * Resumes the service.
041         *
042         * @throws Exception is thrown if resuming failed
043         */
044        void resume() throws Exception;
045    
046        /**
047         * Tests whether the service is suspended or not.
048         *
049         * @return <tt>true</tt> if suspended
050         */
051        boolean isSuspended();
052    }