| 1 | package de.uka.ipd.sdq.reliability.solver.pcm2markov; |
| 2 | |
| 3 | import java.util.ArrayList; |
| 4 | import java.util.Iterator; |
| 5 | import java.util.List; |
| 6 | |
| 7 | import org.apache.log4j.Logger; |
| 8 | import org.eclipse.emf.common.util.EList; |
| 9 | |
| 10 | import de.uka.ipd.sdq.markov.MarkovChain; |
| 11 | import de.uka.ipd.sdq.markov.State; |
| 12 | import de.uka.ipd.sdq.markov.StateType; |
| 13 | import de.uka.ipd.sdq.pcm.reliability.ExternalFailureOccurrenceDescription; |
| 14 | import de.uka.ipd.sdq.pcm.reliability.FailureType; |
| 15 | import de.uka.ipd.sdq.pcm.reliability.HardwareInducedFailureType; |
| 16 | import de.uka.ipd.sdq.pcm.reliability.InternalFailureOccurrenceDescription; |
| 17 | import de.uka.ipd.sdq.pcm.reliability.NetworkInducedFailureType; |
| 18 | import de.uka.ipd.sdq.pcm.reliability.SoftwareInducedFailureType; |
| 19 | import de.uka.ipd.sdq.pcm.repository.Role; |
| 20 | import de.uka.ipd.sdq.pcm.repository.Signature; |
| 21 | import de.uka.ipd.sdq.pcm.resourceenvironment.CommunicationLinkResourceSpecification; |
| 22 | import de.uka.ipd.sdq.pcm.resourceenvironment.ProcessingResourceSpecification; |
| 23 | import de.uka.ipd.sdq.pcm.resourceenvironment.ResourceContainer; |
| 24 | import de.uka.ipd.sdq.pcm.seff.AbstractAction; |
| 25 | import de.uka.ipd.sdq.pcm.seff.AbstractBranchTransition; |
| 26 | import de.uka.ipd.sdq.pcm.seff.AbstractInternalControlFlowAction; |
| 27 | import de.uka.ipd.sdq.pcm.seff.AcquireAction; |
| 28 | import de.uka.ipd.sdq.pcm.seff.BranchAction; |
| 29 | import de.uka.ipd.sdq.pcm.seff.CollectionIteratorAction; |
| 30 | import de.uka.ipd.sdq.pcm.seff.ExternalCallAction; |
| 31 | import de.uka.ipd.sdq.pcm.seff.ForkAction; |
| 32 | import de.uka.ipd.sdq.pcm.seff.ForkedBehaviour; |
| 33 | import de.uka.ipd.sdq.pcm.seff.InternalAction; |
| 34 | import de.uka.ipd.sdq.pcm.seff.LoopAction; |
| 35 | import de.uka.ipd.sdq.pcm.seff.ReleaseAction; |
| 36 | import de.uka.ipd.sdq.pcm.seff.ResourceDemandingBehaviour; |
| 37 | import de.uka.ipd.sdq.pcm.seff.ResourceDemandingSEFF; |
| 38 | import de.uka.ipd.sdq.pcm.seff.ServiceEffectSpecification; |
| 39 | import de.uka.ipd.sdq.pcm.seff.SetVariableAction; |
| 40 | import de.uka.ipd.sdq.pcm.seff.StartAction; |
| 41 | import de.uka.ipd.sdq.pcm.seff.StopAction; |
| 42 | import de.uka.ipd.sdq.pcm.seff.SynchronisationPoint; |
| 43 | import de.uka.ipd.sdq.pcm.seff.seff_performance.ParametricResourceDemand; |
| 44 | import de.uka.ipd.sdq.pcm.seff.seff_reliability.FailureHandlingEntity; |
| 45 | import de.uka.ipd.sdq.pcm.seff.seff_reliability.RecoveryAction; |
| 46 | import de.uka.ipd.sdq.pcm.seff.seff_reliability.RecoveryActionBehaviour; |
| 47 | import de.uka.ipd.sdq.pcm.seff.util.SeffSwitch; |
| 48 | import de.uka.ipd.sdq.pcmsolver.transformations.ContextWrapper; |
| 49 | import de.uka.ipd.sdq.pcmsolver.visitors.EMFQueryHelper; |
| 50 | import de.uka.ipd.sdq.probfunction.math.ManagedPMF; |
| 51 | import de.uka.ipd.sdq.reliability.core.MarkovEvaluationType; |
| 52 | import de.uka.ipd.sdq.reliability.core.MarkovHardwareInducedFailureType; |
| 53 | import de.uka.ipd.sdq.reliability.core.MarkovNetworkInducedFailureType; |
| 54 | import de.uka.ipd.sdq.reliability.core.MarkovSoftwareInducedFailureType; |
| 55 | |
| 56 | /** |
| 57 | * This class represents a visitor for an RDSEFF within a PCM instance. The |
| 58 | * visitor is used in the transformation from PCM with solved dependencies into |
| 59 | * a Markov Chain Model for reliability prediction. |
| 60 | * |
| 61 | * @author brosch |
| 62 | */ |
| 63 | public class MarkovSeffVisitor extends SeffSwitch<MarkovChain> { |
| 64 | |
| 65 | /** |
| 66 | * A logger to give detailed information about the PCM instance traversal. |
| 67 | */ |
| 68 | private static Logger logger = Logger.getLogger(MarkovSeffVisitor.class |
| 69 | .getName()); |
| 70 | |
| 71 | /** |
| 72 | * The ContextWrapper provides easy access to the decorations of the solved |
| 73 | * PCM instance. |
| 74 | */ |
| 75 | private ContextWrapper contextWrapper; |
| 76 | |
| 77 | /** |
| 78 | * The degree of distinction between failure types. |
| 79 | */ |
| 80 | private MarkovEvaluationType evaluationType; |
| 81 | |
| 82 | /** |
| 83 | * The Markov Builder is used to create Markov Chain instances. |
| 84 | */ |
| 85 | private MarkovBuilder markovBuilder; |
| 86 | |
| 87 | /** |
| 88 | * Indicates if the Markov Chain reduction is performed during the |
| 89 | * transformation. If so, then the chain as a whole never exists, because |
| 90 | * during construction, it is already reduced again. |
| 91 | */ |
| 92 | private boolean optimize; |
| 93 | |
| 94 | /** |
| 95 | * The prefix list enables unique naming of all Markov states, which in turn |
| 96 | * allows to search for differences between two chains. |
| 97 | */ |
| 98 | private List<String> prefixes; |
| 99 | |
| 100 | /** |
| 101 | * Indicates if the resulting Makov model shall be augmented with tracing |
| 102 | * information for diagnostic purposes. |
| 103 | */ |
| 104 | private boolean recordTraces; |
| 105 | |
| 106 | /** |
| 107 | * Indicates if resource states are handled according to the simpler |
| 108 | * "always ask" strategy, which may yield less accurate results, but avoids |
| 109 | * iterating over all possible state combinations. |
| 110 | */ |
| 111 | private boolean simplifiedStateHandling; |
| 112 | |
| 113 | /** |
| 114 | * A provider of information about the PCM instance and the corresponding |
| 115 | * resource descriptors. |
| 116 | */ |
| 117 | private MarkovTransformationSource transformationState; |
| 118 | |
| 119 | /** |
| 120 | * The constructor. |
| 121 | * |
| 122 | * @param transformationState |
| 123 | * the Markov transformation state |
| 124 | * @param wrapper |
| 125 | * the ContextWrapper provides easy access to the decorations of |
| 126 | * the solved PCM instance |
| 127 | * @param prefixes |
| 128 | * the list of prefixes for state names |
| 129 | * @param evaluationType |
| 130 | * the degree of differentiation between failure types |
| 131 | * @param simplifiedStateHandling |
| 132 | * controls the handling of physical resource states |
| 133 | * @param optimize |
| 134 | * controls if Markov Chain reduction is performed during |
| 135 | * transformation |
| 136 | * @param recordTraces |
| 137 | * controls if traces shall be recorded during transformation |
| 138 | */ |
| 139 | public MarkovSeffVisitor( |
| 140 | final MarkovTransformationSource transformationState, |
| 141 | final ContextWrapper wrapper, final List<String> prefixes, |
| 142 | final MarkovEvaluationType evaluationType, |
| 143 | final boolean simplifiedStateHandling, final boolean optimize, |
| 144 | final boolean recordTraces) { |
| 145 | this.transformationState = transformationState; |
| 146 | this.contextWrapper = wrapper; |
| 147 | this.prefixes = prefixes; |
| 148 | this.evaluationType = evaluationType; |
| 149 | this.optimize = optimize; |
| 150 | this.recordTraces = recordTraces; |
| 151 | this.simplifiedStateHandling = simplifiedStateHandling; |
| 152 | this.markovBuilder = new MarkovBuilder(recordTraces); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Adds a new failure description to a list of existing descriptions. |
| 157 | * |
| 158 | * @param failureDescriptions |
| 159 | * the list of descriptions |
| 160 | * @param newFailureDescription |
| 161 | * the failure description to add |
| 162 | */ |
| 163 | private void addFailureDescription( |
| 164 | List<FailureDescription> failureDescriptions, |
| 165 | FailureDescription newFailureDescription) { |
| 166 | FailureDescription existingFailureDescription = null; |
| 167 | Iterator<FailureDescription> iterator = failureDescriptions.iterator(); |
| 168 | while (iterator.hasNext()) { |
| 169 | FailureDescription comparator = iterator.next(); |
| 170 | if (newFailureDescription.getFailureType().equals( |
| 171 | comparator.getFailureType())) { |
| 172 | existingFailureDescription = comparator; |
| 173 | break; |
| 174 | } |
| 175 | } |
| 176 | if (existingFailureDescription == null) { |
| 177 | failureDescriptions.add(newFailureDescription); |
| 178 | } else { |
| 179 | existingFailureDescription |
| 180 | .setFailureProbability(existingFailureDescription |
| 181 | .getFailureProbability() |
| 182 | + newFailureDescription.getFailureProbability()); |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Handles RecoveryActions. |
| 188 | * |
| 189 | * This is a workaround using the case for |
| 190 | * AbstractInternalControlFlowActions, because RecoveryActions are not |
| 191 | * directly contained in the SEFF package, and thus there is no case for |
| 192 | * them. |
| 193 | * |
| 194 | * First, for each RecoveryActionBehaviour a specific Markov chain is built. |
| 195 | * Then, specific chains are appended to each other according to the |
| 196 | * specification of handled failure types. |
| 197 | * |
| 198 | * @param controlFlowAction |
| 199 | * the control flow action |
| 200 | * @return the resulting Markov Chain. |
| 201 | */ |
| 202 | @Override |
| 203 | public MarkovChain caseAbstractInternalControlFlowAction( |
| 204 | final AbstractInternalControlFlowAction controlFlowAction) { |
| 205 | |
| 206 | // Only consider RecoveryBlockActions: |
| 207 | if (!(controlFlowAction instanceof RecoveryAction)) { |
| 208 | return null; |
| 209 | } |
| 210 | RecoveryAction action = (RecoveryAction) controlFlowAction; |
| 211 | |
| 212 | // Logging & naming: |
| 213 | String name = action.getEntityName() + "[" + action.getId() + "]"; |
| 214 | prefixes.add(name); |
| 215 | logger.debug("Visit RecoveryAction: " + name); |
| 216 | |
| 217 | // Retrieve the list of RecoveryBlockBehaviours: |
| 218 | List<RecoveryActionBehaviour> behaviours = action |
| 219 | .getRecoveryActionBehaviours__RecoveryAction(); |
| 220 | if (behaviours.size() == 0) { |
| 221 | throw new MarkovException("RecoveryAction '" |
| 222 | + action.getEntityName() |
| 223 | + "' does not specify any behaviours."); |
| 224 | } |
| 225 | |
| 226 | // Create the resulting Markov chain: |
| 227 | MarkovChain resultChain = processRecoveryActionBehaviour(action, action |
| 228 | .getPrimaryBehaviour__RecoveryAction()); |
| 229 | |
| 230 | // Naming: |
| 231 | prefixes.remove(prefixes.size() - 1); |
| 232 | |
| 233 | // Return the result: |
| 234 | return resultChain; |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * An Acquire Action returns a trivial Markov Chain. |
| 239 | * |
| 240 | * @param acquireAction |
| 241 | * the acquire action |
| 242 | * @return the resulting Markov Chain. |
| 243 | */ |
| 244 | @Override |
| 245 | public MarkovChain caseAcquireAction(final AcquireAction acquireAction) { |
| 246 | |
| 247 | // Logging & naming: |
| 248 | String name = acquireAction.getEntityName() + "[" |
| 249 | + acquireAction.getId() + "]"; |
| 250 | prefixes.add(name); |
| 251 | logger.debug("Visit AcquireAction: " + name); |
| 252 | |
| 253 | // Create a Markov chain for the Acquire action: |
| 254 | MarkovChain resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 255 | |
| 256 | // Naming: |
| 257 | prefixes.remove(prefixes.size() - 1); |
| 258 | |
| 259 | // Return the result: |
| 260 | return resultChain; |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * For a BranchAction, first the Markov Chain of each of the transition |
| 265 | * behaviours is built. The results are then inserted into a new Markov |
| 266 | * Chain that has one State for each of the possible branches. |
| 267 | * |
| 268 | * @param branchAction |
| 269 | * the BranchAction |
| 270 | * @return the resulting Markov Chain |
| 271 | */ |
| 272 | @Override |
| 273 | public MarkovChain caseBranchAction(final BranchAction branchAction) { |
| 274 | |
| 275 | // Logging & naming: |
| 276 | String name = branchAction.getEntityName() + "[" + branchAction.getId() |
| 277 | + "]"; |
| 278 | prefixes.add(name); |
| 279 | logger.debug("Visit BranchAction: " + name); |
| 280 | |
| 281 | // Determine the inner Markov Chains associated with the branch |
| 282 | // behaviors: |
| 283 | EList<AbstractBranchTransition> transitions = branchAction |
| 284 | .getBranches_Branch(); |
| 285 | ArrayList<MarkovChain> specificMarkovChains = new ArrayList<MarkovChain>(); |
| 286 | ArrayList<Double> branchProbabilities = new ArrayList<Double>(); |
| 287 | double branchProbabilitySum = 0.0; |
| 288 | for (int i = 0; i < transitions.size(); i++) { |
| 289 | Double branchProbability = contextWrapper |
| 290 | .getBranchProbability(transitions.get(i)); |
| 291 | branchProbabilitySum += branchProbability; |
| 292 | if (branchProbability > 1.0) { |
| 293 | throw new MarkovException( |
| 294 | "Error in solved parametric dependencies detected: " |
| 295 | + "BranchAction \"" |
| 296 | + branchAction.getEntityName() |
| 297 | + "\" has probability " + branchProbability |
| 298 | + ", which is greater than 1.0"); |
| 299 | } |
| 300 | if (branchProbabilitySum > 1.0) { |
| 301 | throw new MarkovException( |
| 302 | "Error in solved parametric dependencies detected: " |
| 303 | + "Branch probabilities of BranchAction \"" |
| 304 | + branchAction.getEntityName() |
| 305 | + "\" sum up to more than 1.0"); |
| 306 | } |
| 307 | branchProbabilities.add(branchProbability); |
| 308 | |
| 309 | // Handle only branches with positive branch probabilities; other |
| 310 | // branches don't influence the reliability. Furthermore, branches |
| 311 | // with zero probability could not be handled anyway, because the |
| 312 | // dependency solver omits them and leaves their parametric |
| 313 | // dependencies unsolved (see also Bug 615). |
| 314 | if (branchProbability > 0.0) { |
| 315 | prefixes.add(transitions.get(i).getEntityName() + "[" |
| 316 | + transitions.get(i).getId() + "]"); |
| 317 | specificMarkovChains.add((MarkovChain) doSwitch(transitions |
| 318 | .get(i).getBranchBehaviour_BranchTransition())); |
| 319 | prefixes.remove(prefixes.size() - 1); |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | // Initialize the aggregate Markov Chain representing the loop: |
| 324 | MarkovChain aggregateMarkovChain = markovBuilder.initBranchMarkovChain( |
| 325 | prefixes, branchProbabilities); |
| 326 | |
| 327 | // Incorporate the specific MarkovChain into the aggregate one: |
| 328 | ArrayList<State> statesToReplace = new ArrayList<State>(); |
| 329 | for (int i = 0; i < aggregateMarkovChain.getStates().size(); i++) { |
| 330 | if (aggregateMarkovChain.getStates().get(i).getType().equals( |
| 331 | StateType.DEFAULT)) { |
| 332 | statesToReplace.add(aggregateMarkovChain.getStates().get(i)); |
| 333 | } |
| 334 | } |
| 335 | for (int i = 0; i < statesToReplace.size(); i++) { |
| 336 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 337 | specificMarkovChains.get(i), statesToReplace.get(i), |
| 338 | optimize, false); |
| 339 | } |
| 340 | |
| 341 | // Naming: |
| 342 | prefixes.remove(prefixes.size() - 1); |
| 343 | |
| 344 | // Return the result: |
| 345 | return aggregateMarkovChain; |
| 346 | } |
| 347 | |
| 348 | /** |
| 349 | * A collection iterator action is handled the same way as an ordinary loop. |
| 350 | * |
| 351 | * @param collectionIteratorAction |
| 352 | * the CollectionIteratoraction |
| 353 | * @return the resulting Markov Chain |
| 354 | */ |
| 355 | @Override |
| 356 | public MarkovChain caseCollectionIteratorAction( |
| 357 | final CollectionIteratorAction collectionIteratorAction) { |
| 358 | |
| 359 | // Logging & naming: |
| 360 | String name = collectionIteratorAction.getEntityName() + "[" |
| 361 | + collectionIteratorAction.getId() + "]"; |
| 362 | prefixes.add(name); |
| 363 | logger.debug("Visit CollectionIteratorAction: " + name); |
| 364 | |
| 365 | // Determine the inner Markov Chain associated with the loop behaviour: |
| 366 | ArrayList<String> prefixesCopy = new ArrayList<String>(); |
| 367 | prefixesCopy.addAll(prefixes); |
| 368 | prefixes.clear(); |
| 369 | MarkovChain specificMarkovChain = (MarkovChain) doSwitch(collectionIteratorAction |
| 370 | .getBodyBehaviour_Loop()); |
| 371 | prefixes.addAll(prefixesCopy); |
| 372 | |
| 373 | // Get the solved loop probability mass function: |
| 374 | ManagedPMF pmf = contextWrapper |
| 375 | .getLoopIterations(collectionIteratorAction); |
| 376 | |
| 377 | // Initialize the aggregate Markov Chain representing the loop: |
| 378 | MarkovChain aggregateMarkovChain = markovBuilder.initLoopMarkovChain( |
| 379 | prefixes, pmf); |
| 380 | |
| 381 | // Incorporate the specific MarkovChain into the aggregate one: |
| 382 | ArrayList<State> statesToReplace = new ArrayList<State>(); |
| 383 | for (int i = 0; i < aggregateMarkovChain.getStates().size(); i++) { |
| 384 | if (aggregateMarkovChain.getStates().get(i).getType().equals( |
| 385 | StateType.DEFAULT)) { |
| 386 | statesToReplace.add(aggregateMarkovChain.getStates().get(i)); |
| 387 | } |
| 388 | } |
| 389 | for (int i = 0; i < statesToReplace.size(); i++) { |
| 390 | markovBuilder |
| 391 | .incorporateMarkovChain(aggregateMarkovChain, |
| 392 | specificMarkovChain, statesToReplace.get(i), |
| 393 | optimize, true); |
| 394 | } |
| 395 | |
| 396 | // Naming: |
| 397 | prefixes.remove(prefixes.size() - 1); |
| 398 | |
| 399 | // Return the result: |
| 400 | return aggregateMarkovChain; |
| 401 | } |
| 402 | |
| 403 | /** |
| 404 | * Evaluates the availability of a resource container. Returns a |
| 405 | * corresponding Markov chain. |
| 406 | * |
| 407 | * @param descriptors |
| 408 | * the list of required resources and their states |
| 409 | * @return the resulting Markov chain |
| 410 | */ |
| 411 | private MarkovChain caseContainerAvailability( |
| 412 | final ResourceContainer container) { |
| 413 | |
| 414 | // Check for the requested type of analysis: |
| 415 | MarkovChain resultChain = null; |
| 416 | if (simplifiedStateHandling) { |
| 417 | // Simplified state handling; iterate over all resource states like |
| 418 | // a branch: |
| 419 | resultChain = caseContainerAvailabilityForIteratedResourceStates(container); |
| 420 | } else { |
| 421 | // Full state handling; container availability is evaluated |
| 422 | // only once (for the current resource state): |
| 423 | resultChain = caseContainerAvailabilityForResourceState(container); |
| 424 | } |
| 425 | |
| 426 | // Return the result: |
| 427 | return resultChain; |
| 428 | } |
| 429 | |
| 430 | /** |
| 431 | * Evaluates the availability of a resource container through iteration over |
| 432 | * the possible states of its required resources. Returns a corresponding |
| 433 | * Markov chain. |
| 434 | * |
| 435 | * @param container |
| 436 | * the resource container |
| 437 | * @return the resulting Markov chain |
| 438 | */ |
| 439 | private MarkovChain caseContainerAvailabilityForIteratedResourceStates( |
| 440 | final ResourceContainer container) { |
| 441 | |
| 442 | // Create the result chain: |
| 443 | MarkovChain resultChain; |
| 444 | |
| 445 | // Retrieve descriptors for the resources required by the container: |
| 446 | List<ProcessingResourceDescriptor> descriptors = getResourceDescriptors( |
| 447 | container, true); |
| 448 | |
| 449 | // Create the state probabilities and specific state chains: |
| 450 | ArrayList<Double> stateProbabilities = new ArrayList<Double>(); |
| 451 | ArrayList<MarkovChain> stateChains = new ArrayList<MarkovChain>(); |
| 452 | ArrayList<String> prefixesCopy = new ArrayList<String>(); |
| 453 | prefixesCopy.addAll(prefixes); |
| 454 | prefixes.clear(); |
| 455 | for (long i = 0; i < Math.pow(2, descriptors.size()); i++) { |
| 456 | setResourceState(descriptors, i); |
| 457 | stateProbabilities.add(getResourceStateProbability(descriptors)); |
| 458 | stateChains |
| 459 | .add(caseContainerAvailabilityForResourceState(container)); |
| 460 | } |
| 461 | prefixes.addAll(prefixesCopy); |
| 462 | |
| 463 | // Initialize the aggregate Markov chain representing the branch: |
| 464 | resultChain = markovBuilder.initBranchMarkovChain(prefixes, |
| 465 | stateProbabilities); |
| 466 | |
| 467 | // Incorporate the specific Markov chains into the aggregate one: |
| 468 | ArrayList<State> statesToReplace = new ArrayList<State>(); |
| 469 | for (int i = 0; i < resultChain.getStates().size(); i++) { |
| 470 | if (resultChain.getStates().get(i).getType().equals( |
| 471 | StateType.DEFAULT)) { |
| 472 | statesToReplace.add(resultChain.getStates().get(i)); |
| 473 | } |
| 474 | } |
| 475 | for (int i = 0; i < statesToReplace.size(); i++) { |
| 476 | markovBuilder.incorporateMarkovChain(resultChain, stateChains |
| 477 | .get(i), statesToReplace.get(i), optimize, true); |
| 478 | } |
| 479 | |
| 480 | // Return the result: |
| 481 | return resultChain; |
| 482 | } |
| 483 | |
| 484 | /** |
| 485 | * Evaluates the availability of a resource container. Returns a |
| 486 | * corresponding Markov chain. |
| 487 | * |
| 488 | * @param descriptors |
| 489 | * the list of required resources and their states |
| 490 | * @return the resulting Markov chain |
| 491 | */ |
| 492 | private MarkovChain caseContainerAvailabilityForResourceState( |
| 493 | final ResourceContainer container) { |
| 494 | |
| 495 | // Retrieve the resource failure descriptions: |
| 496 | List<ProcessingResourceDescriptor> descriptors = getResourceDescriptors( |
| 497 | container, true); |
| 498 | List<FailureDescription> failureDescriptions = getFailureDescriptionsForResourceState(descriptors); |
| 499 | |
| 500 | MarkovChain resultChain = null; |
| 501 | if (failureDescriptions.isEmpty()) { |
| 502 | // All resource available: |
| 503 | resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 504 | } else { |
| 505 | // If there are unavailable resources, build a Markov chain |
| 506 | // that reflects each unavailable resource: |
| 507 | resultChain = markovBuilder.initResourceFailureMarkovChain( |
| 508 | prefixes, failureDescriptions); |
| 509 | } |
| 510 | |
| 511 | // Return the result: |
| 512 | return resultChain; |
| 513 | } |
| 514 | |
| 515 | /** |
| 516 | * Handles an ExternalCallAction. Generates a Markov Chain of the executing |
| 517 | * behavior. The Markov Chain is generated by |
| 518 | * {@link MarkovSeffVisitor.createExternalCallActionChain}. If an retry |
| 519 | * count is set in the internal action, the chain is repeatedly appended to |
| 520 | * the main chains failure state. |
| 521 | * |
| 522 | * @param externalCallAction |
| 523 | * the ExternalCallAction |
| 524 | * @return the resulting Markov Chain. |
| 525 | */ |
| 526 | @Override |
| 527 | public MarkovChain caseExternalCallAction( |
| 528 | final ExternalCallAction externalCallAction) { |
| 529 | |
| 530 | // Logging & naming: |
| 531 | String name = externalCallAction.getEntityName() + "[" |
| 532 | + externalCallAction.getId() + "]"; |
| 533 | prefixes.add(name); |
| 534 | logger.debug("Visit ExternalCallAction: " + name); |
| 535 | |
| 536 | // Get a reference to the executing SEFF: |
| 537 | ServiceEffectSpecification seff = contextWrapper |
| 538 | .getNextSEFF(externalCallAction); |
| 539 | |
| 540 | // Build a specific Markov Chain depending on the type of call: |
| 541 | MarkovChain resultChain = null; |
| 542 | if (seff == null) { |
| 543 | |
| 544 | // A system external call might fail according to |
| 545 | // FailureOccurrenceDescriptions given as |
| 546 | // SpecifiedReliabilityAnnotations to the system: |
| 547 | resultChain = caseExternalCallActionOutsideSystem(externalCallAction); |
| 548 | |
| 549 | } else { |
| 550 | |
| 551 | // If the call is not system external, build a Markov chain that |
| 552 | // reflects the service-providing behaviour of the call: |
| 553 | resultChain = caseExternalCallActionInsideSystem(externalCallAction); |
| 554 | } |
| 555 | |
| 556 | // If a retry policy has been specified for this external call, |
| 557 | // and if the differentiation of failure types is fine-grained enough, |
| 558 | // then reflect the failure handling behaviour accordingly: |
| 559 | if ((evaluationType != MarkovEvaluationType.SINGLE) |
| 560 | && (evaluationType != MarkovEvaluationType.CLASSES)) { |
| 561 | int retryCount = externalCallAction.getRetryCount(); |
| 562 | if (retryCount < 0) { |
| 563 | logger.warn("Retry count of ExternalCallAction \"" |
| 564 | + externalCallAction.getEntityName() |
| 565 | + "\" is negative. Assuming 0."); |
| 566 | retryCount = 0; |
| 567 | } |
| 568 | List<String> failureTypeIds = getFailureTypeIds(externalCallAction); |
| 569 | MarkovChain handlingChain = markovBuilder |
| 570 | .copyMarkovChain(resultChain); |
| 571 | for (int i = 0; i < retryCount; ++i) { |
| 572 | markovBuilder.appendFailureHandlingMarkovChain(resultChain, |
| 573 | handlingChain, failureTypeIds, optimize); |
| 574 | } |
| 575 | } |
| 576 | |
| 577 | // Naming: |
| 578 | prefixes.remove(prefixes.size() - 1); |
| 579 | |
| 580 | // Return the result: |
| 581 | return resultChain; |
| 582 | } |
| 583 | |
| 584 | /** |
| 585 | * Evaluates an external call action that does not leave the system |
| 586 | * boundaries. Returns a corresponding Markov chain. |
| 587 | * |
| 588 | * @param call |
| 589 | * the ExternalCallAction |
| 590 | * @return the resulting Markov Chain. |
| 591 | */ |
| 592 | private MarkovChain caseExternalCallActionInsideSystem( |
| 593 | final ExternalCallAction call) { |
| 594 | |
| 595 | // Get a reference to the executing SEFF: |
| 596 | ServiceEffectSpecification seff = contextWrapper.getNextSEFF(call); |
| 597 | |
| 598 | // For the new SEFF, we need a new ContextWrapper. As during the |
| 599 | // creation of the new ContextWrapper, the old one is altered (which |
| 600 | // is certainly bad programming style!), we need to save a copy of |
| 601 | // the old one and restore it after generating the new one: |
| 602 | ContextWrapper originalContextWrapper = (ContextWrapper) contextWrapper |
| 603 | .clone(); |
| 604 | List<ContextWrapper> contextWrapperList = contextWrapper |
| 605 | .getContextWrapperFor(call); |
| 606 | |
| 607 | // FIXME: The Reliability solver does not support replication yet |
| 608 | if (contextWrapperList.size() > 1) { |
| 609 | logger |
| 610 | .error("The Reliability solver only supports one AllocationContext per AssemblyContext. Picking one of the called Allocation contexts for call " |
| 611 | + call.getEntityName() |
| 612 | + " " |
| 613 | + call.getId() |
| 614 | + " ignoring the others. Results will be inaccurate."); |
| 615 | } else if (contextWrapperList.size() == 0) { |
| 616 | throw new RuntimeException( |
| 617 | "Internal Error: Could not create a Context Wrapper for call " |
| 618 | + call.getEntityName() + " " + call.getId()); |
| 619 | } |
| 620 | ContextWrapper newContextWrapper = contextWrapperList.get(0); |
| 621 | contextWrapper = originalContextWrapper; |
| 622 | |
| 623 | // Build the Markov chain of the executing SEFF: |
| 624 | MarkovChain resultChain = null; |
| 625 | MarkovChain innerMarkovChain = new MarkovSeffVisitor( |
| 626 | this.transformationState, newContextWrapper, prefixes, |
| 627 | evaluationType, simplifiedStateHandling, optimize, recordTraces) |
| 628 | .doSwitch(seff); |
| 629 | |
| 630 | // Check if the external call crosses the border of one resource |
| 631 | // container and uses a communication link (if the specification |
| 632 | // of the communication link is omitted in the model, we treat |
| 633 | // the link as being perfect, i.e. never failing): |
| 634 | CommunicationLinkResourceSpecification commLink = contextWrapper |
| 635 | .getConcreteLinkingResource(call, newContextWrapper.getAllCtx()); |
| 636 | |
| 637 | // If a communication link is specified and used by the call, |
| 638 | // consider the possibility that the call fails: |
| 639 | if (commLink != null) { |
| 640 | |
| 641 | // The call can be modeled as a behavior with three steps: the |
| 642 | // sending of the message, the remote execution, and the message |
| 643 | // return. All of these steps contribute a potential for failure: |
| 644 | ArrayList<State> states = new ArrayList<State>(); |
| 645 | ArrayList<String> names = new ArrayList<String>(); |
| 646 | names.add("MessageTransfer(1)"); |
| 647 | names.add("ServiceExecution"); |
| 648 | names.add("MessageTransfer(2)"); |
| 649 | MarkovChain aggregateMarkovChain = markovBuilder |
| 650 | .initSequentialMarkovChain(prefixes, names, states); |
| 651 | |
| 652 | // The first and last steps can be modeled like an Internal |
| 653 | // Action which either fails or succeeds: |
| 654 | prefixes.add(names.get(0)); |
| 655 | MarkovChain messagingMarkovChain = caseMessageTransfer(commLink); |
| 656 | prefixes.remove(prefixes.size() - 1); |
| 657 | prefixes.add(names.get(2)); |
| 658 | MarkovChain returnMarkovChain = caseMessageTransfer(commLink); |
| 659 | prefixes.remove(prefixes.size() - 1); |
| 660 | |
| 661 | // The second step is the already computed inner Markov Chain. |
| 662 | // Incorporate all steps into the aggregate chain: |
| 663 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 664 | messagingMarkovChain, states.get(0), optimize, false); |
| 665 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 666 | innerMarkovChain, states.get(1), optimize, false); |
| 667 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 668 | returnMarkovChain, states.get(2), optimize, false); |
| 669 | |
| 670 | // Return the result: |
| 671 | resultChain = aggregateMarkovChain; |
| 672 | |
| 673 | } else { |
| 674 | |
| 675 | // If the call is local, or if the specification of the |
| 676 | // communication link has been omitted, then the Markov |
| 677 | // Chain just has to reflect the inner SEFF behavior: |
| 678 | resultChain = innerMarkovChain; |
| 679 | } |
| 680 | |
| 681 | // Return the result: |
| 682 | return resultChain; |
| 683 | } |
| 684 | |
| 685 | /** |
| 686 | * Evaluates an external call action that leaves the system boundaries. |
| 687 | * Returns a corresponding Markov chain. |
| 688 | * |
| 689 | * @param externalCallAction |
| 690 | * @return the resulting Markov chain |
| 691 | */ |
| 692 | private MarkovChain caseExternalCallActionOutsideSystem( |
| 693 | final ExternalCallAction externalCallAction) { |
| 694 | |
| 695 | // Create the result chain: |
| 696 | MarkovChain resultChain; |
| 697 | |
| 698 | // Get the raw failure occurrence descriptions of the system-external |
| 699 | // call: |
| 700 | List<ExternalFailureOccurrenceDescription> rawFailureDescriptions = contextWrapper |
| 701 | .getFailureOccurrenceDescriptionsForSystemExternalCall(externalCallAction); |
| 702 | |
| 703 | // Retrieve the failure descriptions list: |
| 704 | List<FailureDescription> resultFailureDescriptions = new ArrayList<FailureDescription>(); |
| 705 | for (ExternalFailureOccurrenceDescription description : rawFailureDescriptions) { |
| 706 | Role role = description |
| 707 | .getSpecifiedReliabilityAnnotation__ExternalFailureOccurrenceDescription() |
| 708 | .getRole_SpecifiedQoSAnnotation(); |
| 709 | Signature signature = description |
| 710 | .getSpecifiedReliabilityAnnotation__ExternalFailureOccurrenceDescription() |
| 711 | .getSignature_SpecifiedQoSAnnation(); |
| 712 | FailureType failureType = description |
| 713 | .getFailureType__ExternalFailureOccurrenceDescription(); |
| 714 | FailureDescription newFailureDescription = null; |
| 715 | if (failureType instanceof SoftwareInducedFailureType) { |
| 716 | newFailureDescription = new FailureDescription( |
| 717 | MarkovSoftwareInducedFailureType |
| 718 | .createExternalFailureType(evaluationType, |
| 719 | failureType.getId(), signature.getId(), |
| 720 | role.getId()), description |
| 721 | .getFailureProbability()); |
| 722 | } else if (failureType instanceof HardwareInducedFailureType) { |
| 723 | newFailureDescription = new FailureDescription( |
| 724 | MarkovHardwareInducedFailureType |
| 725 | .createExternalFailureType( |
| 726 | evaluationType, |
| 727 | ((HardwareInducedFailureType) failureType) |
| 728 | .getProcessingResourceType__HardwareInducedFailureType() |
| 729 | .getId(), signature.getId(), |
| 730 | role.getId()), description |
| 731 | .getFailureProbability()); |
| 732 | } else if (failureType instanceof NetworkInducedFailureType) { |
| 733 | newFailureDescription = new FailureDescription( |
| 734 | MarkovNetworkInducedFailureType |
| 735 | .createExternalFailureType( |
| 736 | evaluationType, |
| 737 | ((NetworkInducedFailureType) failureType) |
| 738 | .getCommunicationLinkResourceType__NetworkInducedFailureType() |
| 739 | .getId(), signature.getId(), |
| 740 | role.getId()), description |
| 741 | .getFailureProbability()); |
| 742 | } |
| 743 | addFailureDescription(resultFailureDescriptions, |
| 744 | newFailureDescription); |
| 745 | } |
| 746 | |
| 747 | // Check if failure descriptions exist for the system-external call: |
| 748 | if (resultFailureDescriptions.size() > 0) { |
| 749 | // Create a chain that reflects the existing failure descriptions: |
| 750 | resultChain = markovBuilder.initBasicMarkovChainWithFailures( |
| 751 | prefixes, resultFailureDescriptions); |
| 752 | } else { |
| 753 | // Create a basic chain: |
| 754 | resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 755 | } |
| 756 | |
| 757 | // Return the result: |
| 758 | return resultChain; |
| 759 | } |
| 760 | |
| 761 | /** |
| 762 | * Handles fork actions. |
| 763 | * |
| 764 | * All forked behaviours are handled sequentially. |
| 765 | */ |
| 766 | @Override |
| 767 | public MarkovChain caseForkAction(ForkAction forkAction) { |
| 768 | |
| 769 | // Logging & naming: |
| 770 | String name = forkAction.getEntityName() + "[" + forkAction.getId() |
| 771 | + "]"; |
| 772 | prefixes.add(name); |
| 773 | logger.debug("Visit ForkAction: " + name); |
| 774 | |
| 775 | // Go through the list of forked behaviours that are contained in the |
| 776 | // fork action. Each behaviour creates its own specific Markov Chain: |
| 777 | ArrayList<MarkovChain> chains = new ArrayList<MarkovChain>(); |
| 778 | ArrayList<ForkedBehaviour> behaviours = new ArrayList<ForkedBehaviour>(); |
| 779 | for (int i = 0; i < forkAction |
| 780 | .getAsynchronousForkedBehaviours_ForkAction().size(); i++) { |
| 781 | chains.add((MarkovChain) doSwitch(forkAction |
| 782 | .getAsynchronousForkedBehaviours_ForkAction().get(i))); |
| 783 | behaviours.add(forkAction |
| 784 | .getAsynchronousForkedBehaviours_ForkAction().get(i)); |
| 785 | } |
| 786 | SynchronisationPoint synch = forkAction |
| 787 | .getSynchronisingBehaviours_ForkAction(); |
| 788 | if (synch != null) { |
| 789 | for (int i = 0; i < synch |
| 790 | .getSynchronousForkedBehaviours_SynchronisationPoint() |
| 791 | .size(); i++) { |
| 792 | chains.add((MarkovChain) doSwitch(synch |
| 793 | .getSynchronousForkedBehaviours_SynchronisationPoint() |
| 794 | .get(i))); |
| 795 | behaviours.add(synch |
| 796 | .getSynchronousForkedBehaviours_SynchronisationPoint() |
| 797 | .get(i)); |
| 798 | } |
| 799 | } |
| 800 | |
| 801 | // Initialize a new aggregate Markov Chain that has one state for each |
| 802 | // behaviour of the fork action: |
| 803 | ArrayList<State> states = new ArrayList<State>(); |
| 804 | MarkovChain aggregateMarkovChain = markovBuilder.initForkMarkovChain( |
| 805 | prefixes, behaviours, states); |
| 806 | |
| 807 | // Incorporate the specific Chains into the aggregate Chain: |
| 808 | for (int i = 0; i < behaviours.size(); i++) { |
| 809 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, chains |
| 810 | .get(i), states.get(i), optimize, false); |
| 811 | } |
| 812 | |
| 813 | // Naming: |
| 814 | prefixes.remove(prefixes.size() - 1); |
| 815 | |
| 816 | // Return the result: |
| 817 | return aggregateMarkovChain; |
| 818 | } |
| 819 | |
| 820 | /** |
| 821 | * An InternalAction is an actual possible point of failure, either because |
| 822 | * a software failure might happen, or because a required physical resource |
| 823 | * may be currently unavailable. |
| 824 | * |
| 825 | * A Markov chain is returned that reflects all possible outcomes and their |
| 826 | * probabilities. |
| 827 | * |
| 828 | * @param internalAction |
| 829 | * the InternalAction |
| 830 | * @return the resulting Markov Chain |
| 831 | */ |
| 832 | @Override |
| 833 | public MarkovChain caseInternalAction(final InternalAction internalAction) { |
| 834 | |
| 835 | // Logging & naming: |
| 836 | String name = internalAction.getEntityName() + "[" |
| 837 | + internalAction.getId() + "]"; |
| 838 | prefixes.add(name); |
| 839 | logger.debug("Visit InternalAction: " + name); |
| 840 | |
| 841 | // Check for the requested type of analysis: |
| 842 | MarkovChain resultChain = null; |
| 843 | if (simplifiedStateHandling) { |
| 844 | // Simplified state handling; iterate over all resource states like |
| 845 | // a branch: |
| 846 | resultChain = caseInternalActionForIteratedResourceStates(internalAction); |
| 847 | } else { |
| 848 | // Full state handling; internal action is evaluated |
| 849 | // only once (for the current resource state): |
| 850 | resultChain = caseInternalActionForResourceState(internalAction); |
| 851 | } |
| 852 | |
| 853 | // Naming: |
| 854 | prefixes.remove(prefixes.size() - 1); |
| 855 | |
| 856 | // Return the result: |
| 857 | return resultChain; |
| 858 | } |
| 859 | |
| 860 | /** |
| 861 | * Evaluates an internal action through iteration over the possible states |
| 862 | * of its required resources. Returns a corresponding Markov chain. |
| 863 | * |
| 864 | * @param internalAction |
| 865 | * the internal action |
| 866 | * @return the resulting Markov chain |
| 867 | */ |
| 868 | private MarkovChain caseInternalActionForIteratedResourceStates( |
| 869 | final InternalAction internalAction) { |
| 870 | |
| 871 | // Create the result chain: |
| 872 | MarkovChain resultChain; |
| 873 | |
| 874 | // Retrieve descriptors for the resources required by this internal |
| 875 | // action: |
| 876 | List<ProcessingResourceDescriptor> descriptors = getResourceDescriptors(internalAction); |
| 877 | |
| 878 | // Create the state probabilities and specific state chains: |
| 879 | ArrayList<Double> stateProbabilities = new ArrayList<Double>(); |
| 880 | ArrayList<MarkovChain> stateChains = new ArrayList<MarkovChain>(); |
| 881 | ArrayList<String> prefixesCopy = new ArrayList<String>(); |
| 882 | prefixesCopy.addAll(prefixes); |
| 883 | prefixes.clear(); |
| 884 | for (long i = 0; i < Math.pow(2, descriptors.size()); i++) { |
| 885 | setResourceState(descriptors, i); |
| 886 | stateProbabilities.add(getResourceStateProbability(descriptors)); |
| 887 | stateChains.add(caseInternalActionForResourceState(internalAction)); |
| 888 | } |
| 889 | prefixes.addAll(prefixesCopy); |
| 890 | |
| 891 | // Initialize the aggregate Markov chain representing the branch: |
| 892 | resultChain = markovBuilder.initBranchMarkovChain(prefixes, |
| 893 | stateProbabilities); |
| 894 | |
| 895 | // Incorporate the specific Markov chains into the aggregate one: |
| 896 | ArrayList<State> statesToReplace = new ArrayList<State>(); |
| 897 | for (int i = 0; i < resultChain.getStates().size(); i++) { |
| 898 | if (resultChain.getStates().get(i).getType().equals( |
| 899 | StateType.DEFAULT)) { |
| 900 | statesToReplace.add(resultChain.getStates().get(i)); |
| 901 | } |
| 902 | } |
| 903 | for (int i = 0; i < statesToReplace.size(); i++) { |
| 904 | markovBuilder.incorporateMarkovChain(resultChain, stateChains |
| 905 | .get(i), statesToReplace.get(i), optimize, true); |
| 906 | } |
| 907 | |
| 908 | // Return the result: |
| 909 | return resultChain; |
| 910 | } |
| 911 | |
| 912 | /** |
| 913 | * Evaluates an internal action for one specific resource state and returns |
| 914 | * the resulting Markov chain. |
| 915 | * |
| 916 | * @param internalAction |
| 917 | * the internal action |
| 918 | * @return the resulting Markov chain |
| 919 | */ |
| 920 | private MarkovChain caseInternalActionForResourceState( |
| 921 | final InternalAction internalAction) { |
| 922 | |
| 923 | // Retrieve descriptors for the resources required by this internal |
| 924 | // action: |
| 925 | List<ProcessingResourceDescriptor> descriptors = getResourceDescriptors(internalAction); |
| 926 | |
| 927 | // Retrieve the resource failure descriptions: |
| 928 | List<FailureDescription> failureDescriptions = getFailureDescriptionsForResourceState(descriptors); |
| 929 | |
| 930 | MarkovChain resultChain = null; |
| 931 | if (failureDescriptions.isEmpty()) { |
| 932 | |
| 933 | // If all required resources are available, build a Markov chain |
| 934 | // that reflects the potential application failures: |
| 935 | failureDescriptions = getInternalActionSoftwareFailureDescriptions(internalAction); |
| 936 | |
| 937 | // Build the Markov chain: |
| 938 | resultChain = markovBuilder.initBasicMarkovChainWithFailures( |
| 939 | prefixes, failureDescriptions); |
| 940 | } else { |
| 941 | |
| 942 | // If there are unavailable resources, build a Markov chain |
| 943 | // that reflects each unavailable resource: |
| 944 | resultChain = markovBuilder.initResourceFailureMarkovChain( |
| 945 | prefixes, failureDescriptions); |
| 946 | } |
| 947 | |
| 948 | // Return the result: |
| 949 | return resultChain; |
| 950 | } |
| 951 | |
| 952 | /** |
| 953 | * For a LoopAction, first the Markov Chain of the body behaviour is built. |
| 954 | * The result is then inserted into a new Markov Chain that has one State |
| 955 | * for each of the possible iteration counts of the loop. |
| 956 | * |
| 957 | * @param loopAction |
| 958 | * the LoopAction |
| 959 | * @return the resulting Markov Chain |
| 960 | */ |
| 961 | @Override |
| 962 | public MarkovChain caseLoopAction(final LoopAction loopAction) { |
| 963 | |
| 964 | // Logging & naming: |
| 965 | String name = loopAction.getEntityName() + "[" + loopAction.getId() |
| 966 | + "]"; |
| 967 | prefixes.add(name); |
| 968 | logger.debug("Visit LoopAction: " + name); |
| 969 | |
| 970 | // Determine the inner Markov Chain associated with the loop behaviour: |
| 971 | ArrayList<String> prefixesCopy = new ArrayList<String>(); |
| 972 | prefixesCopy.addAll(prefixes); |
| 973 | prefixes.clear(); |
| 974 | MarkovChain specificMarkovChain = (MarkovChain) doSwitch(loopAction |
| 975 | .getBodyBehaviour_Loop()); |
| 976 | prefixes.addAll(prefixesCopy); |
| 977 | |
| 978 | // Get the solved loop probability mass function: |
| 979 | ManagedPMF pmf = contextWrapper.getLoopIterations(loopAction); |
| 980 | |
| 981 | // Initialize the aggregate Markov Chain representing the loop: |
| 982 | MarkovChain aggregateMarkovChain = markovBuilder.initLoopMarkovChain( |
| 983 | prefixes, pmf); |
| 984 | |
| 985 | // Incorporate the specific MarkovChain into the aggregate one: |
| 986 | ArrayList<State> statesToReplace = new ArrayList<State>(); |
| 987 | for (int i = 0; i < aggregateMarkovChain.getStates().size(); i++) { |
| 988 | if (aggregateMarkovChain.getStates().get(i).getType().equals( |
| 989 | StateType.DEFAULT)) { |
| 990 | statesToReplace.add(aggregateMarkovChain.getStates().get(i)); |
| 991 | } |
| 992 | } |
| 993 | for (int i = 0; i < statesToReplace.size(); i++) { |
| 994 | markovBuilder |
| 995 | .incorporateMarkovChain(aggregateMarkovChain, |
| 996 | specificMarkovChain, statesToReplace.get(i), |
| 997 | optimize, true); |
| 998 | } |
| 999 | |
| 1000 | // Naming: |
| 1001 | prefixes.remove(prefixes.size() - 1); |
| 1002 | |
| 1003 | // Return the result: |
| 1004 | return aggregateMarkovChain; |
| 1005 | } |
| 1006 | |
| 1007 | /** |
| 1008 | * Evaluates a message transfer over a communication link. Returns a |
| 1009 | * corresponding Markov chain. |
| 1010 | * |
| 1011 | * @param commLink |
| 1012 | * the communication link |
| 1013 | * @return the resulting Markov chain |
| 1014 | */ |
| 1015 | private MarkovChain caseMessageTransfer( |
| 1016 | CommunicationLinkResourceSpecification commLink) { |
| 1017 | List<FailureDescription> commFailureDescriptions = getFailureDescriptionsForCommunicationLink(commLink); |
| 1018 | MarkovChain messagingMarkovChain = markovBuilder |
| 1019 | .initBasicMarkovChainWithFailures(prefixes, |
| 1020 | commFailureDescriptions); |
| 1021 | return messagingMarkovChain; |
| 1022 | } |
| 1023 | |
| 1024 | /** |
| 1025 | * A Release Action returns a trivial Markov Chain. |
| 1026 | * |
| 1027 | * @param releaseAction |
| 1028 | * the release action |
| 1029 | * @return the resulting Markov Chain. |
| 1030 | */ |
| 1031 | @Override |
| 1032 | public MarkovChain caseReleaseAction(final ReleaseAction releaseAction) { |
| 1033 | |
| 1034 | // Logging & naming: |
| 1035 | String name = releaseAction.getEntityName() + "[" |
| 1036 | + releaseAction.getId() + "]"; |
| 1037 | prefixes.add(name); |
| 1038 | logger.debug("Visit ReleaseAction: " + name); |
| 1039 | |
| 1040 | // Create a Markov chain for the Release action: |
| 1041 | MarkovChain resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 1042 | |
| 1043 | // Naming: |
| 1044 | prefixes.remove(prefixes.size() - 1); |
| 1045 | |
| 1046 | // Return the result: |
| 1047 | return resultChain; |
| 1048 | } |
| 1049 | |
| 1050 | /** |
| 1051 | * Evaluates a resource demanding behaviour by considering all actions in |
| 1052 | * the behaviour. Returns a corresponding Markov chain. |
| 1053 | * |
| 1054 | * @param behaviour |
| 1055 | * the ResourceDemandingBehaviour |
| 1056 | * @return the resulting Markov Chain |
| 1057 | */ |
| 1058 | @Override |
| 1059 | public MarkovChain caseResourceDemandingBehaviour( |
| 1060 | final ResourceDemandingBehaviour behaviour) { |
| 1061 | |
| 1062 | // Logging & naming: |
| 1063 | logger.debug("Visit ResourceDemandingBehaviour"); |
| 1064 | |
| 1065 | // Go through the chain of actions that constitute this Behaviour. Each |
| 1066 | // action is expected to create its own specific Markov Chain: |
| 1067 | ArrayList<AbstractAction> actions = new ArrayList<AbstractAction>(); |
| 1068 | ArrayList<MarkovChain> chains = new ArrayList<MarkovChain>(); |
| 1069 | AbstractAction action = (StartAction) EMFQueryHelper.getObjectByType( |
| 1070 | behaviour.getSteps_Behaviour(), StartAction.class); |
| 1071 | while (action != null) { |
| 1072 | MarkovChain specificMarkovChain = (MarkovChain) doSwitch(action); |
| 1073 | actions.add(action); |
| 1074 | chains.add(specificMarkovChain); |
| 1075 | action = action.getSuccessor_AbstractAction(); |
| 1076 | } |
| 1077 | |
| 1078 | // Initialize a new aggregate Markov Chain that has one state for each |
| 1079 | // action of the action chain: |
| 1080 | ArrayList<State> states = new ArrayList<State>(); |
| 1081 | MarkovChain aggregateMarkovChain = markovBuilder |
| 1082 | .initBehaviourMarkovChainByAction(prefixes, actions, states); |
| 1083 | |
| 1084 | // Incorporate the specific Chains into the aggregate Chain: |
| 1085 | for (int i = 0; i < actions.size(); i++) { |
| 1086 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, chains |
| 1087 | .get(i), states.get(i), optimize, false); |
| 1088 | } |
| 1089 | |
| 1090 | // Return the resulting Markov Chain: |
| 1091 | return aggregateMarkovChain; |
| 1092 | } |
| 1093 | |
| 1094 | /** |
| 1095 | * Evaluates a resource demanding SEFF. In addition to the behavioural |
| 1096 | * evaluation, also the availability of the executing resource container is |
| 1097 | * checked. Returns a corresponding Markov chain. |
| 1098 | * |
| 1099 | * @param seff |
| 1100 | * the ResourceDemandingSEFF |
| 1101 | * @return the resulting Markov Chain |
| 1102 | */ |
| 1103 | @Override |
| 1104 | public MarkovChain caseResourceDemandingSEFF( |
| 1105 | final ResourceDemandingSEFF seff) { |
| 1106 | |
| 1107 | // Logging & naming: |
| 1108 | logger.debug("Visit ResourceDemandingSEFF: [" + seff.getId() + "]"); |
| 1109 | |
| 1110 | // Consider both the execution of the SEFF itself and the possibility |
| 1111 | // that the executing resource container is unavailable: |
| 1112 | ArrayList<State> states = new ArrayList<State>(); |
| 1113 | ArrayList<String> names = new ArrayList<String>(); |
| 1114 | names.add("ContainerAvailability"); |
| 1115 | names.add("ServiceExecution"); |
| 1116 | MarkovChain aggregateMarkovChain = markovBuilder |
| 1117 | .initSequentialMarkovChain(prefixes, names, states); |
| 1118 | |
| 1119 | // Model both aspects with an own specific Markov chain: |
| 1120 | prefixes.add(names.get(0)); |
| 1121 | ResourceContainer container = contextWrapper.getAllCtx() |
| 1122 | .getResourceContainer_AllocationContext(); |
| 1123 | MarkovChain containerAvailabilityMarkovChain = caseContainerAvailability(container); |
| 1124 | prefixes.remove(prefixes.size() - 1); |
| 1125 | prefixes.add(names.get(1)); |
| 1126 | MarkovChain innerMarkovChain = caseResourceDemandingBehaviour(seff); |
| 1127 | prefixes.remove(prefixes.size() - 1); |
| 1128 | |
| 1129 | // Incorporate all steps into the aggregate chain: |
| 1130 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 1131 | containerAvailabilityMarkovChain, states.get(0), optimize, |
| 1132 | false); |
| 1133 | markovBuilder.incorporateMarkovChain(aggregateMarkovChain, |
| 1134 | innerMarkovChain, states.get(1), optimize, false); |
| 1135 | |
| 1136 | // Return the result: |
| 1137 | return aggregateMarkovChain; |
| 1138 | } |
| 1139 | |
| 1140 | /** |
| 1141 | * A SetVariableAction returns a trivial Markov Chain. |
| 1142 | * |
| 1143 | * @param setVariableAction |
| 1144 | * the SetVariableAction |
| 1145 | * @return the resulting Markov Chain |
| 1146 | */ |
| 1147 | @Override |
| 1148 | public MarkovChain caseSetVariableAction( |
| 1149 | final SetVariableAction setVariableAction) { |
| 1150 | |
| 1151 | // Logging & naming: |
| 1152 | String name = setVariableAction.getEntityName() + "[" |
| 1153 | + setVariableAction.getId() + "]"; |
| 1154 | prefixes.add(name); |
| 1155 | logger.debug("Visit SetVariableAction: " + name); |
| 1156 | |
| 1157 | // Build the Markov chain for the SetVariable action: |
| 1158 | MarkovChain resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 1159 | |
| 1160 | // Naming: |
| 1161 | prefixes.remove(prefixes.size() - 1); |
| 1162 | |
| 1163 | // Return the result: |
| 1164 | return resultChain; |
| 1165 | } |
| 1166 | |
| 1167 | /** |
| 1168 | * A StartAction returns a trivial Markov Chain. |
| 1169 | * |
| 1170 | * @param startAction |
| 1171 | * the StartAction |
| 1172 | * @return the resulting trivial Markov Chain |
| 1173 | */ |
| 1174 | @Override |
| 1175 | public MarkovChain caseStartAction(final StartAction startAction) { |
| 1176 | |
| 1177 | // Logging & naming: |
| 1178 | String name = startAction.getEntityName() + "[" + startAction.getId() |
| 1179 | + "]"; |
| 1180 | prefixes.add(name); |
| 1181 | logger.debug("Visit StartAction: " + name); |
| 1182 | |
| 1183 | // Build the Markov chain for the Start action: |
| 1184 | MarkovChain resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 1185 | |
| 1186 | // Naming: |
| 1187 | prefixes.remove(prefixes.size() - 1); |
| 1188 | |
| 1189 | // Return the result: |
| 1190 | return resultChain; |
| 1191 | } |
| 1192 | |
| 1193 | /** |
| 1194 | * A StopAction returns a trivial Markov Chain. |
| 1195 | * |
| 1196 | * @param stopAction |
| 1197 | * the StopAction |
| 1198 | * @return the resulting trivial Markov Chain |
| 1199 | */ |
| 1200 | @Override |
| 1201 | public MarkovChain caseStopAction(final StopAction stopAction) { |
| 1202 | |
| 1203 | // Logging & naming: |
| 1204 | String name = stopAction.getEntityName() + "[" + stopAction.getId() |
| 1205 | + "]"; |
| 1206 | prefixes.add(name); |
| 1207 | logger.debug("Visit StopAction: " + name); |
| 1208 | |
| 1209 | // Build the Markov chain for the Stop action: |
| 1210 | MarkovChain resultChain = markovBuilder.initBasicMarkovChain(prefixes); |
| 1211 | |
| 1212 | // Naming: |
| 1213 | prefixes.remove(prefixes.size() - 1); |
| 1214 | |
| 1215 | // Return the result: |
| 1216 | return resultChain; |
| 1217 | } |
| 1218 | |
| 1219 | /** |
| 1220 | * Retrieves a list of failureDescriptions for a communication link. |
| 1221 | * |
| 1222 | * @param commLink |
| 1223 | * the communication link |
| 1224 | * @return the list of failure descriptions |
| 1225 | */ |
| 1226 | private List<FailureDescription> getFailureDescriptionsForCommunicationLink( |
| 1227 | CommunicationLinkResourceSpecification commLink) { |
| 1228 | List<FailureDescription> commFailureDescriptions = new ArrayList<FailureDescription>(); |
| 1229 | commFailureDescriptions |
| 1230 | .add(new FailureDescription( |
| 1231 | MarkovNetworkInducedFailureType |
| 1232 | .createInternalFailureType( |
| 1233 | evaluationType, |
| 1234 | commLink |
| 1235 | .getLinkingResource_CommunicationLinkResourceSpecification(), |
| 1236 | commLink |
| 1237 | .getCommunicationLinkResourceType_CommunicationLinkResourceSpecification()), |
| 1238 | commLink.getFailureProbability())); |
| 1239 | return commFailureDescriptions; |
| 1240 | } |
| 1241 | |
| 1242 | /** |
| 1243 | * Retrieves a list of failure descriptions for resource unavailability |
| 1244 | * failures under a given resource state. |
| 1245 | * |
| 1246 | * @param descriptors |
| 1247 | * the list of resources and their states |
| 1248 | * @return the list of failure descriptions |
| 1249 | */ |
| 1250 | private List<FailureDescription> getFailureDescriptionsForResourceState( |
| 1251 | final List<ProcessingResourceDescriptor> descriptors) { |
| 1252 | |
| 1253 | // List all possible unavailability failures: |
| 1254 | List<FailureDescription> failureDescriptions = new ArrayList<FailureDescription>(); |
| 1255 | FailureDescription newFailureDescription = null; |
| 1256 | |
| 1257 | // Check if any of the resources is unavailable: |
| 1258 | for (ProcessingResourceDescriptor descriptor : descriptors) { |
| 1259 | |
| 1260 | // Get the current state of the resource: |
| 1261 | MarkovResourceState state = descriptor.getCurrentState(); |
| 1262 | if (state == null) { |
| 1263 | logger.error("Resource state no set for " |
| 1264 | + descriptor.getType().getName() |
| 1265 | + " resource demand. Assume resource state = OK."); |
| 1266 | continue; |
| 1267 | } |
| 1268 | |
| 1269 | // If the resource is unavailable, create a corresponding |
| 1270 | // failure description: |
| 1271 | if (state.equals(MarkovResourceState.NA)) { |
| 1272 | newFailureDescription = new FailureDescription( |
| 1273 | MarkovHardwareInducedFailureType |
| 1274 | .createInternalFailureType(evaluationType, |
| 1275 | descriptor.getResourceContainerId(), |
| 1276 | descriptor.getType().getId()), 1.0); |
| 1277 | addFailureDescription(failureDescriptions, |
| 1278 | newFailureDescription); |
| 1279 | } |
| 1280 | } |
| 1281 | |
| 1282 | // Return the result: |
| 1283 | return failureDescriptions; |
| 1284 | } |
| 1285 | |
| 1286 | /** |
| 1287 | * Returns the ids of the failure types that a given failure handling entity |
| 1288 | * can handle. |
| 1289 | * |
| 1290 | * @param entity |
| 1291 | * the failure handling entity |
| 1292 | * @return the list of failure type names |
| 1293 | */ |
| 1294 | private List<String> getFailureTypeIds(final FailureHandlingEntity entity) { |
| 1295 | List<String> failureTypes = new ArrayList<String>(); |
| 1296 | for (FailureType failureType : entity |
| 1297 | .getFailureTypes_FailureHandlingEntity()) { |
| 1298 | if (failureType instanceof SoftwareInducedFailureType) { |
| 1299 | failureTypes.add(failureType.getId()); |
| 1300 | } else if (failureType instanceof HardwareInducedFailureType) { |
| 1301 | failureTypes |
| 1302 | .add(((HardwareInducedFailureType) failureType) |
| 1303 | .getProcessingResourceType__HardwareInducedFailureType() |
| 1304 | .getId()); |
| 1305 | } else if (failureType instanceof NetworkInducedFailureType) { |
| 1306 | failureTypes |
| 1307 | .add(((NetworkInducedFailureType) failureType) |
| 1308 | .getCommunicationLinkResourceType__NetworkInducedFailureType() |
| 1309 | .getId()); |
| 1310 | } else { |
| 1311 | throw new MarkovException("Unsupported failure type " |
| 1312 | + failureType.getClass().getName()); |
| 1313 | } |
| 1314 | } |
| 1315 | |
| 1316 | return failureTypes; |
| 1317 | } |
| 1318 | |
| 1319 | /** |
| 1320 | * Retrieves a list of software failure descriptions for a given internal |
| 1321 | * action. |
| 1322 | * |
| 1323 | * @param internalAction |
| 1324 | * the internal action |
| 1325 | * @return the list of software failure descriptions |
| 1326 | */ |
| 1327 | private List<FailureDescription> getInternalActionSoftwareFailureDescriptions( |
| 1328 | final InternalAction internalAction) { |
| 1329 | |
| 1330 | // List all possible software failures: |
| 1331 | List<FailureDescription> failureDescriptions = new ArrayList<FailureDescription>(); |
| 1332 | FailureDescription newFailureDescription = null; |
| 1333 | |
| 1334 | // Go through all failure occurrence descriptions of the internal |
| 1335 | // action: |
| 1336 | for (InternalFailureOccurrenceDescription description : internalAction |
| 1337 | .getInternalFailureOccurrenceDescriptions__InternalAction()) { |
| 1338 | newFailureDescription = new FailureDescription( |
| 1339 | MarkovSoftwareInducedFailureType |
| 1340 | .createInternalFailureType( |
| 1341 | evaluationType, |
| 1342 | description |
| 1343 | .getSoftwareInducedFailureType__InternalFailureOccurrenceDescription() |
| 1344 | .getId(), internalAction.getId()), |
| 1345 | description.getFailureProbability()); |
| 1346 | addFailureDescription(failureDescriptions, newFailureDescription); |
| 1347 | } |
| 1348 | |
| 1349 | // Return the result: |
| 1350 | return failureDescriptions; |
| 1351 | } |
| 1352 | |
| 1353 | /** |
| 1354 | * Retrieves the list of required physical resources of a given internal |
| 1355 | * action. |
| 1356 | * |
| 1357 | * @param internalAction |
| 1358 | * the internal action |
| 1359 | * @return the resulting list of resources |
| 1360 | */ |
| 1361 | private List<ProcessingResourceDescriptor> getResourceDescriptors( |
| 1362 | final InternalAction internalAction) { |
| 1363 | |
| 1364 | // Create the resource list: |
| 1365 | ArrayList<ProcessingResourceDescriptor> resultList = new ArrayList<ProcessingResourceDescriptor>(); |
| 1366 | |
| 1367 | // Go through the list of resource demands: |
| 1368 | for (ParametricResourceDemand demand : internalAction |
| 1369 | .getResourceDemand_Action()) { |
| 1370 | |
| 1371 | // Special case: ignore resource demands of type |
| 1372 | // "SystemExternalResource", as they have been internally introduced |
| 1373 | // by the dependency solver: |
| 1374 | if (demand.getRequiredResource_ParametricResourceDemand() |
| 1375 | .getEntityName().equals("SystemExternalResource")) { |
| 1376 | continue; |
| 1377 | } |
| 1378 | |
| 1379 | // Get the descriptor that corresponds to the demand: |
| 1380 | ProcessingResourceDescriptor descriptor = transformationState |
| 1381 | .getDescriptor(demand, contextWrapper); |
| 1382 | if (descriptor == null) { |
| 1383 | logger.error("Missing resource description for " |
| 1384 | + demand.getRequiredResource_ParametricResourceDemand() |
| 1385 | .getEntityName() |
| 1386 | + " resource demand. Assume resource state = OK."); |
| 1387 | continue; |
| 1388 | } |
| 1389 | |
| 1390 | // Add the descriptor to the list: |
| 1391 | resultList.add(descriptor); |
| 1392 | } |
| 1393 | |
| 1394 | // Return the result: |
| 1395 | return resultList; |
| 1396 | } |
| 1397 | |
| 1398 | /** |
| 1399 | * Retrieves the list of physical resources contained within the given |
| 1400 | * resource container. |
| 1401 | * |
| 1402 | * @param resourceContainer |
| 1403 | * the resource container |
| 1404 | * @param searchForRequiredResources |
| 1405 | * if set to TRUE, only the resources required by this container |
| 1406 | * will be returned |
| 1407 | * @return the resulting list of resources |
| 1408 | */ |
| 1409 | private List<ProcessingResourceDescriptor> getResourceDescriptors( |
| 1410 | final ResourceContainer resourceContainer, |
| 1411 | final boolean searchForRequiredResources) { |
| 1412 | |
| 1413 | // Create the resource list: |
| 1414 | ArrayList<ProcessingResourceDescriptor> resultList = new ArrayList<ProcessingResourceDescriptor>(); |
| 1415 | |
| 1416 | // Go through the list of specified resources: |
| 1417 | for (ProcessingResourceSpecification resource : resourceContainer |
| 1418 | .getActiveResourceSpecifications_ResourceContainer()) { |
| 1419 | |
| 1420 | // Check if this is a required resource: |
| 1421 | if (searchForRequiredResources && !resource.isRequiredByContainer()) { |
| 1422 | continue; |
| 1423 | } |
| 1424 | |
| 1425 | // Get the descriptor that corresponds to the specified resource: |
| 1426 | ProcessingResourceDescriptor descriptor = transformationState |
| 1427 | .getDescriptor(resource); |
| 1428 | if (descriptor == null) { |
| 1429 | logger |
| 1430 | .error("Missing resource description for resource " |
| 1431 | + resource |
| 1432 | .getActiveResourceType_ActiveResourceSpecification() |
| 1433 | .getEntityName() + " in container " |
| 1434 | + resourceContainer.getEntityName() |
| 1435 | + ". Assume resource state = OK."); |
| 1436 | continue; |
| 1437 | } |
| 1438 | |
| 1439 | // Add the descriptor to the list: |
| 1440 | resultList.add(descriptor); |
| 1441 | } |
| 1442 | |
| 1443 | // Return the result: |
| 1444 | return resultList; |
| 1445 | } |
| 1446 | |
| 1447 | /** |
| 1448 | * Retrieves the probability of a certain resource state. |
| 1449 | * |
| 1450 | * @param descriptors |
| 1451 | * the list of resources |
| 1452 | * @return the state probability |
| 1453 | */ |
| 1454 | private double getResourceStateProbability( |
| 1455 | List<ProcessingResourceDescriptor> descriptors) { |
| 1456 | // All single resource states are independent; hence, the |
| 1457 | // overall state probability is the product over all single |
| 1458 | // state probabilities: |
| 1459 | double stateProbability = 1.0; |
| 1460 | for (ProcessingResourceDescriptor descriptor : descriptors) { |
| 1461 | stateProbability *= descriptor.getStateProbability(descriptor |
| 1462 | .getCurrentState()); |
| 1463 | } |
| 1464 | return stateProbability; |
| 1465 | } |
| 1466 | |
| 1467 | /** |
| 1468 | * Returns a Markov chain that reflects a recovery action behaviour |
| 1469 | * including its failure handling alternatives. |
| 1470 | * |
| 1471 | * @param action |
| 1472 | * the surrounding recovery block action |
| 1473 | * @param behaviour |
| 1474 | * the behaviour to evaluate |
| 1475 | * @return the resulting Markov chain |
| 1476 | */ |
| 1477 | private MarkovChain processRecoveryActionBehaviour(RecoveryAction action, |
| 1478 | RecoveryActionBehaviour behaviour) { |
| 1479 | |
| 1480 | // Step 1: evaluate the behaviour itself: |
| 1481 | prefixes.add("Alternative(" |
| 1482 | + action.getRecoveryActionBehaviours__RecoveryAction().indexOf( |
| 1483 | behaviour) + ")"); |
| 1484 | MarkovChain resultChain = caseResourceDemandingBehaviour(behaviour); |
| 1485 | prefixes.remove(prefixes.size() - 1); |
| 1486 | |
| 1487 | // Step 2: consider any existing failure handling alternatives if |
| 1488 | // the differentiation of failure types is fine-grained enough: |
| 1489 | if ((evaluationType != MarkovEvaluationType.SINGLE) |
| 1490 | && (evaluationType != MarkovEvaluationType.CLASSES) |
| 1491 | && (behaviour |
| 1492 | .getFailureHandlingAlternatives__RecoveryActionBehaviour() |
| 1493 | .size() > 0)) { |
| 1494 | |
| 1495 | // Determine the chains and handled failure types of the |
| 1496 | // alternatives: |
| 1497 | List<MarkovChain> failureHandlingChains = new ArrayList<MarkovChain>(); |
| 1498 | List<List<String>> failureTypeLists = new ArrayList<List<String>>(); |
| 1499 | for (RecoveryActionBehaviour handlingAlternative : behaviour |
| 1500 | .getFailureHandlingAlternatives__RecoveryActionBehaviour()) { |
| 1501 | failureTypeLists.add(getFailureTypeIds(handlingAlternative)); |
| 1502 | failureHandlingChains.add(processRecoveryActionBehaviour( |
| 1503 | action, handlingAlternative)); |
| 1504 | } |
| 1505 | |
| 1506 | // Append the handling alternatives to the current chain: |
| 1507 | markovBuilder.appendFailureHandlingMarkovChains(resultChain, |
| 1508 | failureHandlingChains, failureTypeLists, optimize); |
| 1509 | } |
| 1510 | |
| 1511 | // Step 3: return the result: |
| 1512 | return resultChain; |
| 1513 | } |
| 1514 | |
| 1515 | /** |
| 1516 | * Sets a resource state according to the bit pattern of an numeric value. |
| 1517 | * |
| 1518 | * @param descriptors |
| 1519 | * the list of resources |
| 1520 | * @param number |
| 1521 | * the numeric value |
| 1522 | */ |
| 1523 | private void setResourceState( |
| 1524 | final List<ProcessingResourceDescriptor> descriptors, |
| 1525 | final long number) { |
| 1526 | |
| 1527 | // Iterate over all resources: |
| 1528 | for (int i = 0; i < descriptors.size(); i++) { |
| 1529 | MarkovResourceState state = (((number >> i) % 2) == 0) ? MarkovResourceState.OK |
| 1530 | : MarkovResourceState.NA; |
| 1531 | descriptors.get(i).setCurrentState(state); |
| 1532 | } |
| 1533 | } |
| 1534 | |
| 1535 | } |