Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||
Invoker |
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| 1.0;1 |
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.commons.scxml.invoke; |
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18 | ||
19 | import java.util.Map; |
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20 | ||
21 | import org.apache.commons.scxml.SCInstance; |
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22 | import org.apache.commons.scxml.TriggerEvent; |
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23 | ||
24 | /** |
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25 | * <p>The Invoker interface is used to define the possible interactions |
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26 | * between the parent state machine (executor) and the types of invocable |
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27 | * activities.</p> |
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28 | * |
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29 | * <p>Invocable activities must first register an Invoker implementation class |
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30 | * for the appropriate "targettype" (attribute of <invoke>) with the |
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31 | * parent <code>SCXMLExecutor</code>.</p> |
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32 | * |
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33 | * <p>The communication link between the parent state machine executor and |
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34 | * the invoked activity is a bi-directional events pipe.</p> |
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35 | * |
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36 | * <p>All events triggered on the parent state machine get forwarded to the |
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37 | * invoked activity. The processing semantics for these events depend |
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38 | * upon the "targettype", and thereby vary per concrete implementation of |
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39 | * this interface.</p> |
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40 | * |
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41 | * <p>The invoked activity in turn must fire a special "done" event |
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42 | * when it concludes. It may fire additional events before the "done" |
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43 | * event. The semantics of any additional events depend upon the |
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44 | * "targettype". The invoked activity must not fire any events after the |
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45 | * "done" event. The name of the special "done" event must be |
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46 | * the ID of the parent state wherein the corresponding <invoke> |
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47 | * resides, with the String ".invoke.done" appended.</p> |
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48 | * |
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49 | * <p>The Invoker "lifecycle" is outlined below: |
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50 | * <ol> |
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51 | * <li>Instantiation via {@link Class#newInstance()} |
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52 | * (Invoker implementation requires accessible constructor).</li> |
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53 | * <li>Configuration (setters for parent state ID and |
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54 | * {@link SCInstance}).</li> |
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55 | * <li>Initiation of invoked activity via invoke() method, passing |
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56 | * the source URI and the map of params.</li> |
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57 | * <li>Zero or more bi-directional event triggering.</li> |
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58 | * <li>Either completion or cancellation.</li> |
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59 | * </ol> |
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60 | * </p> |
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61 | */ |
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62 | public interface Invoker { |
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63 | ||
64 | /** |
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65 | * Set the state ID of the owning state for the <invoke>. |
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66 | * Implementations must use this ID for constructing the event name for |
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67 | * the special "done" event (and optionally, for other event names |
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68 | * as well). |
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69 | * |
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70 | * @param parentStateId The ID of the parent state. |
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71 | */ |
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72 | void setParentStateId(String parentStateId); |
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73 | ||
74 | /** |
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75 | * Set the "context" of the parent state machine, which provides the |
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76 | * channel. |
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77 | * |
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78 | * @param scInstance The "context" of the parent state machine. |
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79 | */ |
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80 | void setSCInstance(SCInstance scInstance); |
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81 | ||
82 | /** |
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83 | * Begin this invocation. |
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84 | * |
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85 | * @param source The source URI of the activity being invoked. |
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86 | * @param params The <param> values |
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87 | * @throws InvokerException In case there is a fatal problem with |
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88 | * invoking the source. |
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89 | */ |
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90 | void invoke(String source, Map params) |
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91 | throws InvokerException; |
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92 | ||
93 | /** |
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94 | * Forwards the events triggered on the parent state machine |
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95 | * on to the invoked activity. |
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96 | * |
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97 | * @param evts |
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98 | * an array of external events which triggered during the last |
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99 | * time quantum |
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100 | * |
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101 | * @throws InvokerException In case there is a fatal problem with |
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102 | * processing the events forwarded by the |
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103 | * parent state machine. |
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104 | */ |
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105 | void parentEvents(TriggerEvent[] evts) |
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106 | throws InvokerException; |
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107 | ||
108 | /** |
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109 | * Cancel this invocation. |
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110 | * |
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111 | * @throws InvokerException In case there is a fatal problem with |
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112 | * canceling this invoke. |
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113 | */ |
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114 | void cancel() |
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115 | throws InvokerException; |
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116 | ||
117 | } |
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118 |