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.processor.loadbalancer;
018    
019    import java.util.ArrayList;
020    import java.util.List;
021    import java.util.concurrent.CopyOnWriteArrayList;
022    
023    import org.apache.camel.Navigate;
024    import org.apache.camel.Processor;
025    import org.apache.camel.impl.ServiceSupport;
026    import org.apache.camel.util.ServiceHelper;
027    
028    /**
029     * A default base class for a {@link LoadBalancer} implementation
030     *
031     * @version $Revision: 769303 $
032     */
033    public abstract class LoadBalancerSupport extends ServiceSupport implements LoadBalancer, Navigate<Processor> {
034    
035        private final List<Processor> processors = new CopyOnWriteArrayList<Processor>();
036    
037        public void addProcessor(Processor processor) {
038            processors.add(processor);
039        }
040    
041        public void removeProcessor(Processor processor) {
042            processors.remove(processor);
043        }
044    
045        public List<Processor> getProcessors() {
046            return processors;
047        }
048    
049        public List<Processor> next() {
050            if (!hasNext()) {
051                return null;
052            }
053            return new ArrayList<Processor>(processors);
054        }
055    
056        public boolean hasNext() {
057            return processors.size() > 0;
058        }
059    
060        protected void doStart() throws Exception {
061            ServiceHelper.startServices(processors);        
062        }
063    
064        protected void doStop() throws Exception {
065            ServiceHelper.stopServices(processors);       
066        }
067    }