Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
Pipeline |
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| 0.0;0 |
1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with |
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4 | * this work for additional information regarding copyright ownership. |
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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6 | * (the "License"); you may not use this file except in compliance with |
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7 | * the License. You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | */ |
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17 | package org.apache.camel.processor; |
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18 | ||
19 | import java.util.Collection; |
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20 | import java.util.List; |
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21 | ||
22 | import org.apache.camel.Exchange; |
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23 | import org.apache.camel.Processor; |
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24 | import org.apache.camel.Message; |
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25 | import org.apache.commons.logging.Log; |
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26 | import org.apache.commons.logging.LogFactory; |
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27 | ||
28 | /** |
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29 | * Creates a Pipeline pattern where the output of the previous step is sent as |
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30 | * input to the next step, reusing the same message exchanges |
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31 | * |
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32 | * @version $Revision: 563931 $ |
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33 | */ |
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34 | public class Pipeline extends MulticastProcessor implements Processor { |
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35 | 3 | private static final transient Log LOG = LogFactory.getLog(Pipeline.class); |
36 | ||
37 | public Pipeline(Collection<Processor> processors) { |
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38 | 45 | super(processors); |
39 | 45 | } |
40 | ||
41 | public static Processor newInstance(List<Processor> processors) { |
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42 | 258 | if (processors.isEmpty()) { |
43 | 0 | return null; |
44 | 258 | } else if (processors.size() == 1) { |
45 | 228 | return processors.get(0); |
46 | } |
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47 | 30 | return new Pipeline(processors); |
48 | } |
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49 | ||
50 | public void process(Exchange exchange) throws Exception { |
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51 | 39 | Exchange nextExchange = exchange; |
52 | 39 | boolean first = true; |
53 | 39 | for (Processor producer : getProcessors()) { |
54 | 78 | if (first) { |
55 | 39 | first = false; |
56 | 39 | } else { |
57 | 39 | nextExchange = createNextExchange(producer, nextExchange); |
58 | } |
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59 | 78 | producer.process(nextExchange); |
60 | 75 | } |
61 | 36 | } |
62 | ||
63 | /** |
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64 | * Strategy method to create the next exchange from the |
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65 | * |
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66 | * @param producer the producer used to send to the endpoint |
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67 | * @param previousExchange the previous exchange |
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68 | * @return a new exchange |
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69 | */ |
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70 | protected Exchange createNextExchange(Processor producer, Exchange previousExchange) { |
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71 | 39 | Exchange answer = copyExchangeStrategy(previousExchange); |
72 | ||
73 | // now lets set the input of the next exchange to the output of the |
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74 | // previous message if it is not null |
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75 | 39 | Object output = previousExchange.getOut().getBody(); |
76 | 39 | Message in = answer.getIn(); |
77 | 39 | if (output != null) { |
78 | 9 | in.setBody(output); |
79 | 9 | } |
80 | else { |
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81 | 30 | Object previousInBody = previousExchange.getIn().getBody(); |
82 | 30 | if (in.getBody() == null && previousInBody != null) { |
83 | 0 | LOG.warn("Bad exchange implementation; the copy() method did not copy across the in body: " + previousExchange |
84 | + " of type: " + previousExchange.getClass()); |
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85 | 0 | in.setBody(previousInBody); |
86 | } |
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87 | } |
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88 | 39 | return answer; |
89 | } |
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90 | ||
91 | /** |
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92 | * Strategy method to copy the exchange before sending to another endpoint. |
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93 | * Derived classes such as the {@link Pipeline} will not clone the exchange |
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94 | * |
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95 | * @param exchange |
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96 | * @return the current exchange if no copying is required such as for a |
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97 | * pipeline otherwise a new copy of the exchange is returned. |
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98 | */ |
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99 | protected Exchange copyExchangeStrategy(Exchange exchange) { |
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100 | 39 | return exchange.copy(); |
101 | } |
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102 | ||
103 | @Override |
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104 | public String toString() { |
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105 | 42 | return "Pipeline" + getProcessors(); |
106 | } |
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107 | } |