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.component.direct;
018    
019    import org.apache.camel.Endpoint;
020    import org.apache.camel.Processor;
021    import org.apache.camel.ShutdownRunningTask;
022    import org.apache.camel.SuspendableService;
023    import org.apache.camel.impl.DefaultConsumer;
024    import org.apache.camel.spi.ShutdownAware;
025    
026    /**
027     * The direct consumer.
028     *
029     * @version 
030     */
031    public class DirectConsumer extends DefaultConsumer implements ShutdownAware, SuspendableService {
032    
033        private DirectEndpoint endpoint;
034    
035        public DirectConsumer(Endpoint endpoint, Processor processor) {
036            super(endpoint, processor);
037            this.endpoint = (DirectEndpoint) endpoint;
038        }
039    
040        @Override
041        protected void doStart() throws Exception {
042            // add consumer to endpoint
043            boolean existing = this == endpoint.getConsumer();
044            if (!existing && endpoint.hasConsumer(this)) {
045                throw new IllegalArgumentException("Cannot add a 2nd consumer to the same endpoint. Endpoint " + endpoint + " only allows one consumer.");
046            }
047            if (!existing) {
048                endpoint.addConsumer(this);
049            }
050        }
051    
052        @Override
053        protected void doStop() throws Exception {
054            endpoint.removeConsumer(this);
055        }
056    
057        @Override
058        protected void doSuspend() throws Exception {
059            endpoint.removeConsumer(this);
060        }
061    
062        @Override
063        protected void doResume() throws Exception {
064            // resume by using the start logic
065            doStart();
066        }
067    
068        public boolean deferShutdown(ShutdownRunningTask shutdownRunningTask) {
069            // deny stopping on shutdown as we want direct consumers to run in case some other queues
070            // depend on this consumer to run, so it can complete its exchanges
071            return true;
072        }
073    
074        public int getPendingExchangesSize() {
075            // return 0 as we do not have an internal memory queue with a variable size
076            // of inflight messages. 
077            return 0;
078        }
079    
080        public void prepareShutdown(boolean forced) {
081            // noop
082        }
083    }