Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
SCXMLExecutor |
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| 1.4848484848484849;1.485 |
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. |
|
14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
|
16 | */ |
|
17 | package org.apache.commons.scxml; |
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18 | ||
19 | import java.io.Serializable; |
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20 | import java.util.ArrayList; |
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21 | import java.util.Arrays; |
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22 | import java.util.HashMap; |
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23 | import java.util.Iterator; |
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24 | import java.util.List; |
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25 | import java.util.Map; |
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26 | ||
27 | import org.apache.commons.logging.Log; |
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28 | import org.apache.commons.logging.LogFactory; |
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29 | import org.apache.commons.scxml.model.Datamodel; |
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30 | import org.apache.commons.scxml.model.History; |
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31 | import org.apache.commons.scxml.model.ModelException; |
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32 | import org.apache.commons.scxml.model.SCXML; |
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33 | import org.apache.commons.scxml.model.State; |
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34 | import org.apache.commons.scxml.model.Transition; |
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35 | import org.apache.commons.scxml.model.TransitionTarget; |
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36 | import org.apache.commons.scxml.semantics.SCXMLSemanticsImpl; |
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37 | ||
38 | /** |
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39 | * <p>The SCXML "engine" that executes SCXML documents. The |
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40 | * particular semantics used by this engine for executing the SCXML are |
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41 | * encapsulated in the SCXMLSemantics implementation that it uses.</p> |
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42 | * |
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43 | * <p>The default implementation is |
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44 | * <code>org.apache.commons.scxml.semantics.SCXMLSemanticsImpl</code></p> |
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45 | * |
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46 | * @see SCXMLSemantics |
|
47 | */ |
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48 | public class SCXMLExecutor implements Serializable { |
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49 | ||
50 | /** |
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51 | * Serial version UID. |
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52 | */ |
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53 | private static final long serialVersionUID = 1L; |
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54 | ||
55 | /** |
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56 | * The Logger for the SCXMLExecutor. |
|
57 | */ |
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58 | 54 | private Log log = LogFactory.getLog(SCXMLExecutor.class); |
59 | ||
60 | /** |
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61 | * The stateMachine being executed. |
|
62 | */ |
|
63 | private SCXML stateMachine; |
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64 | ||
65 | /** |
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66 | * The current status of the stateMachine. |
|
67 | */ |
|
68 | private Status currentStatus; |
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69 | ||
70 | /** |
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71 | * The event dispatcher to interface with external documents etc. |
|
72 | */ |
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73 | private EventDispatcher eventdispatcher; |
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74 | ||
75 | /** |
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76 | * The environment specific error reporter. |
|
77 | */ |
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78 | 48 | private ErrorReporter errorReporter = null; |
79 | ||
80 | /** |
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81 | * Run-to-completion. |
|
82 | */ |
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83 | 48 | private boolean superStep = true; |
84 | ||
85 | /** |
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86 | * Interpretation semantics. |
|
87 | */ |
|
88 | private SCXMLSemantics semantics; |
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89 | ||
90 | /** |
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91 | * The SCInstance. |
|
92 | */ |
|
93 | private SCInstance scInstance; |
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94 | ||
95 | /** |
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96 | * The worker method. |
|
97 | * Re-evaluates current status whenever any events are triggered. |
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98 | * |
|
99 | * @param evts |
|
100 | * an array of external events which triggered during the last |
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101 | * time quantum |
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102 | * @throws ModelException in case there is a fatal SCXML object |
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103 | * model problem. |
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104 | */ |
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105 | public synchronized void triggerEvents(final TriggerEvent[] evts) |
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106 | throws ModelException { |
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107 | // Set event data, saving old values |
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108 | 151 | Object[] oldData = setEventData(evts); |
109 | ||
110 | // Forward events (external only) to any existing invokes, |
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111 | // and finalize processing |
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112 | 151 | semantics.processInvokes(evts, errorReporter, scInstance); |
113 | ||
114 | 151 | List evs = new ArrayList(Arrays.asList(evts)); |
115 | 151 | Step step = null; |
116 | ||
117 | do { |
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118 | // CreateStep |
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119 | 266 | step = new Step(evs, currentStatus); |
120 | // EnumerateReachableTransitions |
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121 | 266 | semantics.enumerateReachableTransitions(stateMachine, step, |
122 | errorReporter); |
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123 | // FilterTransitionSet |
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124 | 266 | semantics.filterTransitionsSet(step, eventdispatcher, |
125 | errorReporter, scInstance); |
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126 | // FollowTransitions |
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127 | 266 | semantics.followTransitions(step, errorReporter, scInstance); |
128 | // UpdateHistoryStates |
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129 | 266 | semantics.updateHistoryStates(step, errorReporter, scInstance); |
130 | // ExecuteActions |
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131 | 266 | semantics.executeActions(step, stateMachine, eventdispatcher, |
132 | errorReporter, scInstance); |
|
133 | // AssignCurrentStatus |
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134 | 266 | updateStatus(step); |
135 | // ***Cleanup external events if superStep |
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136 | 266 | if (superStep) { |
137 | 266 | evs.clear(); |
138 | } |
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139 | 266 | } while (superStep && currentStatus.getEvents().size() > 0); |
140 | ||
141 | // InitiateInvokes only after state machine has stabilized |
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142 | 151 | semantics.initiateInvokes(step, errorReporter, scInstance); |
143 | ||
144 | // Restore event data |
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145 | 151 | restoreEventData(oldData); |
146 | 151 | logState(); |
147 | 151 | } |
148 | ||
149 | /** |
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150 | * Convenience method when only one event needs to be triggered. |
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151 | * |
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152 | * @param evt |
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153 | * the external events which triggered during the last |
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154 | * time quantum |
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155 | * @throws ModelException in case there is a fatal SCXML object |
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156 | * model problem. |
|
157 | */ |
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158 | public void triggerEvent(final TriggerEvent evt) |
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159 | throws ModelException { |
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160 | 0 | triggerEvents(new TriggerEvent[] {evt}); |
161 | 0 | } |
162 | ||
163 | /** |
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164 | * Constructor. |
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165 | * |
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166 | * @param expEvaluator The expression evaluator |
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167 | * @param evtDisp The event dispatcher |
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168 | * @param errRep The error reporter |
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169 | */ |
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170 | public SCXMLExecutor(final Evaluator expEvaluator, |
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171 | final EventDispatcher evtDisp, final ErrorReporter errRep) { |
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172 | 48 | this(expEvaluator, evtDisp, errRep, null); |
173 | 48 | } |
174 | ||
175 | /** |
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176 | * Convenience constructor. |
|
177 | */ |
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178 | public SCXMLExecutor() { |
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179 | 0 | this(null, null, null, null); |
180 | 0 | } |
181 | ||
182 | /** |
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183 | * Constructor. |
|
184 | * |
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185 | * @param expEvaluator The expression evaluator |
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186 | * @param evtDisp The event dispatcher |
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187 | * @param errRep The error reporter |
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188 | * @param semantics The SCXML semantics |
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189 | */ |
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190 | public SCXMLExecutor(final Evaluator expEvaluator, |
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191 | final EventDispatcher evtDisp, final ErrorReporter errRep, |
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192 | 48 | final SCXMLSemantics semantics) { |
193 | 48 | this.eventdispatcher = evtDisp; |
194 | 48 | this.errorReporter = errRep; |
195 | 48 | this.currentStatus = new Status(); |
196 | 48 | this.stateMachine = null; |
197 | 48 | if (semantics == null) { |
198 | // Use default semantics, if none provided |
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199 | 48 | this.semantics = new SCXMLSemanticsImpl(); |
200 | } else { |
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201 | 0 | this.semantics = semantics; |
202 | } |
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203 | 48 | this.scInstance = new SCInstance(this); |
204 | 48 | this.scInstance.setEvaluator(expEvaluator); |
205 | 48 | } |
206 | ||
207 | /** |
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208 | * Clear all state and begin from "initialstate" indicated |
|
209 | * on root SCXML element. |
|
210 | * |
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211 | * @throws ModelException in case there is a fatal SCXML object |
|
212 | * model problem. |
|
213 | */ |
|
214 | public synchronized void reset() throws ModelException { |
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215 | // Reset all variable contexts |
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216 | 50 | Context rootCtx = scInstance.getRootContext(); |
217 | // Clone root datamodel |
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218 | 50 | if (stateMachine == null) { |
219 | 0 | log.error(ERR_NO_STATE_MACHINE); |
220 | 0 | throw new ModelException(ERR_NO_STATE_MACHINE); |
221 | } else { |
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222 | 50 | Datamodel rootdm = stateMachine.getDatamodel(); |
223 | 50 | SCXMLHelper.cloneDatamodel(rootdm, rootCtx, |
224 | scInstance.getEvaluator(), log); |
|
225 | } |
|
226 | // all states and parallels, only states have variable contexts |
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227 | 50 | for (Iterator i = stateMachine.getTargets().values().iterator(); |
228 | 294 | i.hasNext();) { |
229 | 244 | TransitionTarget tt = (TransitionTarget) i.next(); |
230 | 244 | if (tt instanceof State) { |
231 | 234 | Context context = scInstance.lookupContext(tt); |
232 | 234 | if (context != null) { |
233 | 11 | context.reset(); |
234 | 11 | Datamodel dm = tt.getDatamodel(); |
235 | 11 | if (dm != null) { |
236 | 0 | SCXMLHelper.cloneDatamodel(dm, context, |
237 | scInstance.getEvaluator(), log); |
|
238 | } |
|
239 | } |
|
240 | 10 | } else if (tt instanceof History) { |
241 | 7 | scInstance.reset((History) tt); |
242 | } |
|
243 | } |
|
244 | // CreateEmptyStatus |
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245 | 50 | currentStatus = new Status(); |
246 | 50 | Step step = new Step(null, currentStatus); |
247 | // DetermineInitialStates |
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248 | 50 | semantics.determineInitialStates(stateMachine, |
249 | step.getAfterStatus().getStates(), |
|
250 | step.getEntryList(), errorReporter, scInstance); |
|
251 | // ExecuteActions |
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252 | 50 | semantics.executeActions(step, stateMachine, eventdispatcher, |
253 | errorReporter, scInstance); |
|
254 | // AssignCurrentStatus |
|
255 | 50 | updateStatus(step); |
256 | // Execute Immediate Transitions |
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257 | 50 | if (superStep && currentStatus.getEvents().size() > 0) { |
258 | 50 | this.triggerEvents(new TriggerEvent[0]); |
259 | } else { |
|
260 | // InitiateInvokes only after state machine has stabilized |
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261 | 0 | semantics.initiateInvokes(step, errorReporter, scInstance); |
262 | 0 | logState(); |
263 | } |
|
264 | 50 | } |
265 | ||
266 | /** |
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267 | * Get the current status. |
|
268 | * |
|
269 | * @return The current Status |
|
270 | */ |
|
271 | public synchronized Status getCurrentStatus() { |
|
272 | 152 | return currentStatus; |
273 | } |
|
274 | ||
275 | /** |
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276 | * Set the expression evaluator. |
|
277 | * |
|
278 | * @param evaluator The evaluator to set. |
|
279 | */ |
|
280 | public void setEvaluator(final Evaluator evaluator) { |
|
281 | 0 | this.scInstance.setEvaluator(evaluator); |
282 | 0 | } |
283 | ||
284 | /** |
|
285 | * Get the expression evaluator in use. |
|
286 | * |
|
287 | * @return Evaluator The evaluator in use. |
|
288 | */ |
|
289 | public Evaluator getEvaluator() { |
|
290 | 0 | return scInstance.getEvaluator(); |
291 | } |
|
292 | ||
293 | /** |
|
294 | * Set the root context for this execution. |
|
295 | * |
|
296 | * @param rootContext The Context that ties to the host environment. |
|
297 | */ |
|
298 | public void setRootContext(final Context rootContext) { |
|
299 | 48 | this.scInstance.setRootContext(rootContext); |
300 | 48 | } |
301 | ||
302 | /** |
|
303 | * Get the root context for this execution. |
|
304 | * |
|
305 | * @return Context The root context. |
|
306 | */ |
|
307 | public Context getRootContext() { |
|
308 | 4 | return scInstance.getRootContext(); |
309 | } |
|
310 | ||
311 | /** |
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312 | * Get the state machine that is being executed. |
|
313 | * |
|
314 | * @return Returns the stateMachine. |
|
315 | */ |
|
316 | public SCXML getStateMachine() { |
|
317 | 2 | return stateMachine; |
318 | } |
|
319 | ||
320 | /** |
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321 | * Set the state machine to be executed. |
|
322 | * |
|
323 | * @param stateMachine The stateMachine to set. |
|
324 | */ |
|
325 | public void setStateMachine(final SCXML stateMachine) { |
|
326 | // NormalizeStateMachine |
|
327 | 48 | SCXML sm = semantics.normalizeStateMachine(stateMachine, |
328 | errorReporter); |
|
329 | // StoreStateMachine |
|
330 | 48 | this.stateMachine = sm; |
331 | 48 | } |
332 | ||
333 | /** |
|
334 | * Initiate state machine execution. |
|
335 | * |
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336 | * @throws ModelException in case there is a fatal SCXML object |
|
337 | * model problem. |
|
338 | */ |
|
339 | public void go() throws ModelException { |
|
340 | // same as reset |
|
341 | 48 | this.reset(); |
342 | 48 | } |
343 | ||
344 | /** |
|
345 | * Get the environment specific error reporter. |
|
346 | * |
|
347 | * @return Returns the errorReporter. |
|
348 | */ |
|
349 | public ErrorReporter getErrorReporter() { |
|
350 | 0 | return errorReporter; |
351 | } |
|
352 | ||
353 | /** |
|
354 | * Set the environment specific error reporter. |
|
355 | * |
|
356 | * @param errorReporter The errorReporter to set. |
|
357 | */ |
|
358 | public void setErrorReporter(final ErrorReporter errorReporter) { |
|
359 | 0 | this.errorReporter = errorReporter; |
360 | 0 | } |
361 | ||
362 | /** |
|
363 | * Get the event dispatcher. |
|
364 | * |
|
365 | * @return Returns the eventdispatcher. |
|
366 | */ |
|
367 | public EventDispatcher getEventdispatcher() { |
|
368 | 0 | return eventdispatcher; |
369 | } |
|
370 | ||
371 | /** |
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372 | * Set the event dispatcher. |
|
373 | * |
|
374 | * @param eventdispatcher The eventdispatcher to set. |
|
375 | */ |
|
376 | public void setEventdispatcher(final EventDispatcher eventdispatcher) { |
|
377 | 0 | this.eventdispatcher = eventdispatcher; |
378 | 0 | } |
379 | ||
380 | /** |
|
381 | * Use "super-step", default is <code>true</code> |
|
382 | * (that is, run-to-completion is default). |
|
383 | * |
|
384 | * @return Returns the superStep property. |
|
385 | * @see #setSuperStep(boolean) |
|
386 | */ |
|
387 | public boolean isSuperStep() { |
|
388 | 0 | return superStep; |
389 | } |
|
390 | ||
391 | /** |
|
392 | * Set the super step. |
|
393 | * |
|
394 | * @param superStep |
|
395 | * if true, the internal derived events are also processed |
|
396 | * (run-to-completion); |
|
397 | * if false, the internal derived events are stored in the |
|
398 | * CurrentStatus property and processed within the next |
|
399 | * triggerEvents() invocation, also the immediate (empty event) transitions |
|
400 | * are deferred until the next step |
|
401 | */ |
|
402 | public void setSuperStep(final boolean superStep) { |
|
403 | 46 | this.superStep = superStep; |
404 | 46 | } |
405 | ||
406 | /** |
|
407 | * Add a listener to the document root. |
|
408 | * |
|
409 | * @param scxml The document root to attach listener to. |
|
410 | * @param listener The SCXMLListener. |
|
411 | */ |
|
412 | public void addListener(final SCXML scxml, final SCXMLListener listener) { |
|
413 | 47 | Object observable = scxml; |
414 | 47 | scInstance.getNotificationRegistry().addListener(observable, listener); |
415 | 47 | } |
416 | ||
417 | /** |
|
418 | * Remove this listener from the document root. |
|
419 | * |
|
420 | * @param scxml The document root. |
|
421 | * @param listener The SCXMLListener to be removed. |
|
422 | */ |
|
423 | public void removeListener(final SCXML scxml, |
|
424 | final SCXMLListener listener) { |
|
425 | 0 | Object observable = scxml; |
426 | 0 | scInstance.getNotificationRegistry().removeListener(observable, |
427 | listener); |
|
428 | 0 | } |
429 | ||
430 | /** |
|
431 | * Add a listener to this transition target. |
|
432 | * |
|
433 | * @param transitionTarget The <code>TransitionTarget</code> to |
|
434 | * attach listener to. |
|
435 | * @param listener The SCXMLListener. |
|
436 | */ |
|
437 | public void addListener(final TransitionTarget transitionTarget, |
|
438 | final SCXMLListener listener) { |
|
439 | 0 | Object observable = transitionTarget; |
440 | 0 | scInstance.getNotificationRegistry().addListener(observable, listener); |
441 | 0 | } |
442 | ||
443 | /** |
|
444 | * Remove this listener for this transition target. |
|
445 | * |
|
446 | * @param transitionTarget The <code>TransitionTarget</code>. |
|
447 | * @param listener The SCXMLListener to be removed. |
|
448 | */ |
|
449 | public void removeListener(final TransitionTarget transitionTarget, |
|
450 | final SCXMLListener listener) { |
|
451 | 0 | Object observable = transitionTarget; |
452 | 0 | scInstance.getNotificationRegistry().removeListener(observable, |
453 | listener); |
|
454 | 0 | } |
455 | ||
456 | /** |
|
457 | * Add a listener to this transition. |
|
458 | * |
|
459 | * @param transition The <code>Transition</code> to attach listener to. |
|
460 | * @param listener The SCXMLListener. |
|
461 | */ |
|
462 | public void addListener(final Transition transition, |
|
463 | final SCXMLListener listener) { |
|
464 | 0 | Object observable = transition; |
465 | 0 | scInstance.getNotificationRegistry().addListener(observable, listener); |
466 | 0 | } |
467 | ||
468 | /** |
|
469 | * Remove this listener for this transition. |
|
470 | * |
|
471 | * @param transition The <code>Transition</code>. |
|
472 | * @param listener The SCXMLListener to be removed. |
|
473 | */ |
|
474 | public void removeListener(final Transition transition, |
|
475 | final SCXMLListener listener) { |
|
476 | 0 | Object observable = transition; |
477 | 0 | scInstance.getNotificationRegistry().removeListener(observable, |
478 | listener); |
|
479 | 0 | } |
480 | ||
481 | /** |
|
482 | * Register an <code>Invoker</code> for this target type. |
|
483 | * |
|
484 | * @param targettype The target type (specified by "targettype" |
|
485 | * attribute of <invoke> tag). |
|
486 | * @param invokerClass The <code>Invoker</code> <code>Class</code>. |
|
487 | */ |
|
488 | public void registerInvokerClass(final String targettype, |
|
489 | final Class invokerClass) { |
|
490 | 1 | scInstance.registerInvokerClass(targettype, invokerClass); |
491 | 1 | } |
492 | ||
493 | /** |
|
494 | * Remove the <code>Invoker</code> registered for this target |
|
495 | * type (if there is one registered). |
|
496 | * |
|
497 | * @param targettype The target type (specified by "targettype" |
|
498 | * attribute of <invoke> tag). |
|
499 | */ |
|
500 | public void unregisterInvokerClass(final String targettype) { |
|
501 | 0 | scInstance.unregisterInvokerClass(targettype); |
502 | 0 | } |
503 | ||
504 | /** |
|
505 | * Get the state chart instance for this executor. |
|
506 | * |
|
507 | * @return The SCInstance for this executor. |
|
508 | */ |
|
509 | SCInstance getSCInstance() { |
|
510 | 2 | return scInstance; |
511 | } |
|
512 | ||
513 | /** |
|
514 | * Log the current set of active states. |
|
515 | */ |
|
516 | private void logState() { |
|
517 | 151 | if (log.isInfoEnabled()) { |
518 | 0 | Iterator si = currentStatus.getStates().iterator(); |
519 | 0 | StringBuffer sb = new StringBuffer("Current States: ["); |
520 | 0 | while (si.hasNext()) { |
521 | 0 | State s = (State) si.next(); |
522 | 0 | sb.append(s.getId()); |
523 | 0 | if (si.hasNext()) { |
524 | 0 | sb.append(", "); |
525 | } |
|
526 | } |
|
527 | 0 | sb.append(']'); |
528 | 0 | log.info(sb.toString()); |
529 | } |
|
530 | 151 | } |
531 | ||
532 | /** |
|
533 | * @param step The most recent Step |
|
534 | */ |
|
535 | private void updateStatus(final Step step) { |
|
536 | 316 | currentStatus = step.getAfterStatus(); |
537 | 316 | scInstance.getRootContext().setLocal("_ALL_STATES", |
538 | SCXMLHelper.getAncestorClosure(currentStatus.getStates(), null)); |
|
539 | 316 | } |
540 | ||
541 | /** |
|
542 | * @param evts The events being triggered. |
|
543 | * @return Object[] Previous values. |
|
544 | */ |
|
545 | private Object[] setEventData(final TriggerEvent[] evts) { |
|
546 | 151 | Context rootCtx = scInstance.getRootContext(); |
547 | 151 | Object[] oldData = {rootCtx.get(EVENT_DATA), |
548 | rootCtx.get(EVENT_DATA_MAP)}; |
|
549 | 151 | Object eventData = null; |
550 | 151 | Map payloadMap = new HashMap(); |
551 | 151 | int len = evts.length; |
552 | 253 | for (int i = 0; i < len; i++) { |
553 | 102 | TriggerEvent te = evts[i]; |
554 | 102 | payloadMap.put(te.getName(), te.getPayload()); |
555 | } |
|
556 | 151 | if (len == 1) { |
557 | // we have only one event |
|
558 | 100 | eventData = evts[0].getPayload(); |
559 | } |
|
560 | 151 | rootCtx.setLocal(EVENT_DATA, eventData); |
561 | 151 | rootCtx.setLocal(EVENT_DATA_MAP, payloadMap); |
562 | 151 | return oldData; |
563 | } |
|
564 | ||
565 | /** |
|
566 | * @param oldData The old values to restore to. |
|
567 | */ |
|
568 | private void restoreEventData(final Object[] oldData) { |
|
569 | 151 | scInstance.getRootContext().setLocal(EVENT_DATA, oldData[0]); |
570 | 151 | scInstance.getRootContext().setLocal(EVENT_DATA_MAP, oldData[1]); |
571 | 151 | } |
572 | ||
573 | /** |
|
574 | * The special variable for storing single event data / payload. |
|
575 | */ |
|
576 | private static final String EVENT_DATA = "_eventdata"; |
|
577 | ||
578 | /** |
|
579 | * The special variable for storing event data / payload, |
|
580 | * when multiple events are triggered, keyed by event name. |
|
581 | */ |
|
582 | private static final String EVENT_DATA_MAP = "_eventdatamap"; |
|
583 | ||
584 | /** |
|
585 | * SCXMLExecutor put into motion without setting a model (state machine). |
|
586 | */ |
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587 | private static final String ERR_NO_STATE_MACHINE = |
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588 | "SCXMLExecutor: State machine not set"; |
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589 | ||
590 | } |
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591 |