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.processor;
018
019import java.util.ArrayList;
020import java.util.List;
021
022import org.apache.camel.Exchange;
023import org.apache.camel.Navigate;
024import org.apache.camel.Processor;
025import org.apache.camel.support.ServiceSupport;
026import org.apache.camel.util.ServiceHelper;
027
028/**
029 * A Delegate pattern which delegates processing to a nested {@link Processor} which can
030 * be useful for implementation inheritance when writing an {@link org.apache.camel.spi.Policy}
031 * <p/>
032 * <b>Important:</b> This implementation does <b>not</b> support the asynchronous routing engine.
033 * If you are implementing a EIP pattern please use the {@link org.apache.camel.processor.DelegateAsyncProcessor}
034 * instead.
035 * 
036 * @version 
037 * @see org.apache.camel.processor.DelegateAsyncProcessor
038 */
039public class DelegateProcessor extends ServiceSupport implements org.apache.camel.DelegateProcessor, Processor, Navigate<Processor> {
040    protected Processor processor;
041
042    public DelegateProcessor() {
043    }
044
045    public DelegateProcessor(Processor processor) {
046        if (processor == this) {
047            throw new IllegalArgumentException("Recursive DelegateProcessor!");
048        }
049        this.processor = processor;
050    }
051
052    public void process(Exchange exchange) throws Exception {
053        processNext(exchange);
054    }
055
056    protected void processNext(Exchange exchange) throws Exception {
057        if (processor != null) {
058            processor.process(exchange);
059        }
060    }
061
062    @Override
063    public String toString() {
064        return "Delegate[" + processor + "]";
065    }
066
067    public Processor getProcessor() {
068        return processor;
069    }
070
071    public void setProcessor(Processor processor) {
072        this.processor = processor;
073    }
074
075    protected void doStart() throws Exception {
076        ServiceHelper.startServices(processor);
077    }
078
079    protected void doStop() throws Exception {
080        ServiceHelper.stopServices(processor);
081    }
082
083    public boolean hasNext() {
084        return processor != null;
085    }
086
087    public List<Processor> next() {
088        if (!hasNext()) {
089            return null;
090        }
091        List<Processor> answer = new ArrayList<>(1);
092        answer.add(processor);
093        return answer;
094    }
095}