Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 1 | /* |
Brian O'Connor | 5ab426f | 2016-04-09 01:19:45 -0700 | [diff] [blame] | 2 | * Copyright 2015-present Open Networking Laboratory |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.onosproject.net.flowobjective.impl.composition; |
| 17 | |
Saurav Das | b5c236e | 2016-06-07 10:08:06 -0700 | [diff] [blame^] | 18 | import com.google.common.collect.ImmutableList; |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 19 | import com.google.common.collect.Maps; |
| 20 | import com.google.common.collect.Sets; |
| 21 | import org.apache.felix.scr.annotations.Activate; |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 22 | import org.apache.felix.scr.annotations.Deactivate; |
| 23 | import org.apache.felix.scr.annotations.Reference; |
| 24 | import org.apache.felix.scr.annotations.ReferenceCardinality; |
| 25 | import org.apache.felix.scr.annotations.Service; |
| 26 | import org.onlab.osgi.DefaultServiceDirectory; |
| 27 | import org.onlab.osgi.ServiceDirectory; |
| 28 | import org.onlab.util.ItemNotFoundException; |
| 29 | import org.onosproject.cluster.ClusterService; |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 30 | import org.onosproject.mastership.MastershipEvent; |
| 31 | import org.onosproject.mastership.MastershipListener; |
| 32 | import org.onosproject.mastership.MastershipService; |
| 33 | import org.onosproject.net.DeviceId; |
| 34 | import org.onosproject.net.behaviour.Pipeliner; |
| 35 | import org.onosproject.net.behaviour.PipelinerContext; |
| 36 | import org.onosproject.net.device.DeviceEvent; |
| 37 | import org.onosproject.net.device.DeviceListener; |
| 38 | import org.onosproject.net.device.DeviceService; |
| 39 | import org.onosproject.net.driver.DefaultDriverProviderService; |
| 40 | import org.onosproject.net.driver.DriverHandler; |
| 41 | import org.onosproject.net.driver.DriverService; |
| 42 | import org.onosproject.net.flow.FlowRuleService; |
| 43 | import org.onosproject.net.flow.criteria.Criterion; |
| 44 | import org.onosproject.net.flow.instructions.Instruction; |
| 45 | import org.onosproject.net.flowobjective.FilteringObjective; |
| 46 | import org.onosproject.net.flowobjective.FlowObjectiveService; |
| 47 | import org.onosproject.net.flowobjective.FlowObjectiveStore; |
| 48 | import org.onosproject.net.flowobjective.FlowObjectiveStoreDelegate; |
| 49 | import org.onosproject.net.flowobjective.ForwardingObjective; |
| 50 | import org.onosproject.net.flowobjective.NextObjective; |
| 51 | import org.onosproject.net.flowobjective.Objective; |
| 52 | import org.onosproject.net.flowobjective.ObjectiveError; |
| 53 | import org.onosproject.net.flowobjective.ObjectiveEvent; |
| 54 | import org.onosproject.net.group.GroupService; |
| 55 | import org.slf4j.Logger; |
| 56 | import org.slf4j.LoggerFactory; |
| 57 | |
| 58 | import java.util.List; |
| 59 | import java.util.Map; |
| 60 | import java.util.Set; |
| 61 | import java.util.concurrent.ExecutorService; |
| 62 | |
| 63 | import static com.google.common.base.Preconditions.checkNotNull; |
| 64 | import static java.util.concurrent.Executors.newFixedThreadPool; |
| 65 | import static org.onlab.util.Tools.groupedThreads; |
| 66 | import static org.onosproject.security.AppGuard.checkPermission; |
Jian Li | 1159916 | 2016-01-15 15:46:16 -0800 | [diff] [blame] | 67 | import static org.onosproject.security.AppPermission.Type.FLOWRULE_WRITE; |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 68 | |
| 69 | |
| 70 | /** |
| 71 | * Provides implementation of the flow objective programming service with composition feature. |
| 72 | * |
| 73 | * Note: This is an experimental, alternative implementation of the FlowObjectiveManager |
| 74 | * that supports composition. It can be enabled by setting the enable flag below to true, |
| 75 | * and you should also add "enabled = false" to the FlowObjectiveManager. |
| 76 | * |
| 77 | * The implementation relies a FlowObjectiveCompositionTree that is not yet distributed, |
| 78 | * so it will not have high availability and may break if device mastership changes. |
| 79 | * Therefore, it is safest to use this component in a single instance scenario. |
| 80 | * This comment will be removed when a distributed implementation is available. |
| 81 | */ |
Jian Li | 1159916 | 2016-01-15 15:46:16 -0800 | [diff] [blame] | 82 | //@Component(immediate = true, enabled = false) |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 83 | @Service |
| 84 | public class FlowObjectiveCompositionManager implements FlowObjectiveService { |
| 85 | |
| 86 | public enum PolicyOperator { |
| 87 | Parallel, |
| 88 | Sequential, |
| 89 | Override, |
| 90 | Application |
| 91 | } |
| 92 | |
| 93 | public static final int INSTALL_RETRY_ATTEMPTS = 5; |
| 94 | public static final long INSTALL_RETRY_INTERVAL = 1000; // ms |
| 95 | |
| 96 | private final Logger log = LoggerFactory.getLogger(getClass()); |
| 97 | |
| 98 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 99 | protected DriverService driverService; |
| 100 | |
| 101 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 102 | protected DeviceService deviceService; |
| 103 | |
| 104 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 105 | protected MastershipService mastershipService; |
| 106 | |
| 107 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 108 | protected ClusterService clusterService; |
| 109 | |
| 110 | // Note: The following dependencies are added on behalf of the pipeline |
| 111 | // driver behaviours to assure these services are available for their |
| 112 | // initialization. |
| 113 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 114 | protected FlowRuleService flowRuleService; |
| 115 | |
| 116 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 117 | protected GroupService groupService; |
| 118 | |
| 119 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 120 | protected FlowObjectiveStore flowObjectiveStore; |
| 121 | |
| 122 | // Note: This must remain an optional dependency to allow re-install of default drivers. |
| 123 | // Note: For now disabled until we can move to OPTIONAL_UNARY dependency |
| 124 | // @Reference(cardinality = ReferenceCardinality.OPTIONAL_UNARY, policy = ReferencePolicy.DYNAMIC) |
| 125 | @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| 126 | protected DefaultDriverProviderService defaultDriverService; |
| 127 | |
| 128 | private final FlowObjectiveStoreDelegate delegate = new InternalStoreDelegate(); |
| 129 | |
| 130 | private final Map<DeviceId, DriverHandler> driverHandlers = Maps.newConcurrentMap(); |
| 131 | private final Map<DeviceId, Pipeliner> pipeliners = Maps.newConcurrentMap(); |
| 132 | |
| 133 | private final PipelinerContext context = new InnerPipelineContext(); |
| 134 | private final MastershipListener mastershipListener = new InnerMastershipListener(); |
| 135 | private final DeviceListener deviceListener = new InnerDeviceListener(); |
| 136 | |
| 137 | protected ServiceDirectory serviceDirectory = new DefaultServiceDirectory(); |
| 138 | |
| 139 | private Map<Integer, Set<PendingNext>> pendingForwards = Maps.newConcurrentMap(); |
| 140 | |
| 141 | private ExecutorService executorService; |
| 142 | |
| 143 | private String policy; |
| 144 | private Map<DeviceId, FlowObjectiveCompositionTree> deviceCompositionTreeMap; |
| 145 | |
| 146 | @Activate |
| 147 | protected void activate() { |
| 148 | executorService = newFixedThreadPool(4, groupedThreads("onos/objective-installer", "%d")); |
| 149 | flowObjectiveStore.setDelegate(delegate); |
| 150 | mastershipService.addListener(mastershipListener); |
| 151 | deviceService.addListener(deviceListener); |
| 152 | deviceService.getDevices().forEach(device -> setupPipelineHandler(device.id())); |
| 153 | deviceCompositionTreeMap = Maps.newConcurrentMap(); |
| 154 | log.info("Started"); |
| 155 | } |
| 156 | |
| 157 | @Deactivate |
| 158 | protected void deactivate() { |
| 159 | flowObjectiveStore.unsetDelegate(delegate); |
| 160 | mastershipService.removeListener(mastershipListener); |
| 161 | deviceService.removeListener(deviceListener); |
| 162 | executorService.shutdown(); |
| 163 | pipeliners.clear(); |
| 164 | driverHandlers.clear(); |
| 165 | deviceCompositionTreeMap.clear(); |
| 166 | log.info("Stopped"); |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Task that passes the flow objective down to the driver. The task will |
| 171 | * make a few attempts to find the appropriate driver, then eventually give |
| 172 | * up and report an error if no suitable driver could be found. |
| 173 | */ |
| 174 | private class ObjectiveInstaller implements Runnable { |
| 175 | private final DeviceId deviceId; |
| 176 | private final Objective objective; |
| 177 | |
| 178 | private final int numAttempts; |
| 179 | |
| 180 | public ObjectiveInstaller(DeviceId deviceId, Objective objective) { |
| 181 | this(deviceId, objective, 1); |
| 182 | } |
| 183 | |
| 184 | public ObjectiveInstaller(DeviceId deviceId, Objective objective, int attemps) { |
| 185 | this.deviceId = checkNotNull(deviceId); |
| 186 | this.objective = checkNotNull(objective); |
| 187 | this.numAttempts = checkNotNull(attemps); |
| 188 | } |
| 189 | |
| 190 | @Override |
| 191 | public void run() { |
| 192 | try { |
| 193 | Pipeliner pipeliner = getDevicePipeliner(deviceId); |
| 194 | |
| 195 | if (pipeliner != null) { |
| 196 | if (objective instanceof NextObjective) { |
| 197 | pipeliner.next((NextObjective) objective); |
| 198 | } else if (objective instanceof ForwardingObjective) { |
| 199 | pipeliner.forward((ForwardingObjective) objective); |
| 200 | } else { |
| 201 | pipeliner.filter((FilteringObjective) objective); |
| 202 | } |
| 203 | } else if (numAttempts < INSTALL_RETRY_ATTEMPTS) { |
| 204 | Thread.sleep(INSTALL_RETRY_INTERVAL); |
HIGUCHI Yuta | d9e0105 | 2016-04-14 09:31:42 -0700 | [diff] [blame] | 205 | executorService.execute(new ObjectiveInstaller(deviceId, objective, numAttempts + 1)); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 206 | } else { |
| 207 | // Otherwise we've tried a few times and failed, report an |
| 208 | // error back to the user. |
| 209 | objective.context().ifPresent( |
Andrea Campanella | 1f8188d | 2016-02-29 13:24:54 -0800 | [diff] [blame] | 210 | c -> c.onError(objective, ObjectiveError.NOPIPELINER)); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 211 | } |
| 212 | } catch (Exception e) { |
| 213 | log.warn("Exception while installing flow objective", e); |
| 214 | } |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | @Override |
| 219 | public void filter(DeviceId deviceId, FilteringObjective filteringObjective) { |
Changhoon Yoon | b856b81 | 2015-08-10 03:47:19 +0900 | [diff] [blame] | 220 | checkPermission(FLOWRULE_WRITE); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 221 | |
| 222 | List<FilteringObjective> filteringObjectives |
| 223 | = this.deviceCompositionTreeMap.get(deviceId).updateFilter(filteringObjective); |
| 224 | for (FilteringObjective tmp : filteringObjectives) { |
HIGUCHI Yuta | d9e0105 | 2016-04-14 09:31:42 -0700 | [diff] [blame] | 225 | executorService.execute(new ObjectiveInstaller(deviceId, tmp)); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 226 | } |
| 227 | } |
| 228 | |
| 229 | @Override |
| 230 | public void forward(DeviceId deviceId, ForwardingObjective forwardingObjective) { |
Changhoon Yoon | b856b81 | 2015-08-10 03:47:19 +0900 | [diff] [blame] | 231 | checkPermission(FLOWRULE_WRITE); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 232 | |
| 233 | if (queueObjective(deviceId, forwardingObjective)) { |
| 234 | return; |
| 235 | } |
| 236 | List<ForwardingObjective> forwardingObjectives |
| 237 | = this.deviceCompositionTreeMap.get(deviceId).updateForward(forwardingObjective); |
| 238 | for (ForwardingObjective tmp : forwardingObjectives) { |
HIGUCHI Yuta | d9e0105 | 2016-04-14 09:31:42 -0700 | [diff] [blame] | 239 | executorService.execute(new ObjectiveInstaller(deviceId, tmp)); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 240 | } |
| 241 | } |
| 242 | |
| 243 | @Override |
| 244 | public void next(DeviceId deviceId, NextObjective nextObjective) { |
Changhoon Yoon | b856b81 | 2015-08-10 03:47:19 +0900 | [diff] [blame] | 245 | checkPermission(FLOWRULE_WRITE); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 246 | |
| 247 | List<NextObjective> nextObjectives = this.deviceCompositionTreeMap.get(deviceId).updateNext(nextObjective); |
| 248 | for (NextObjective tmp : nextObjectives) { |
HIGUCHI Yuta | d9e0105 | 2016-04-14 09:31:42 -0700 | [diff] [blame] | 249 | executorService.execute(new ObjectiveInstaller(deviceId, tmp)); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 250 | } |
| 251 | } |
| 252 | |
| 253 | @Override |
| 254 | public int allocateNextId() { |
Changhoon Yoon | b856b81 | 2015-08-10 03:47:19 +0900 | [diff] [blame] | 255 | checkPermission(FLOWRULE_WRITE); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 256 | |
| 257 | return flowObjectiveStore.allocateNextId(); |
| 258 | } |
| 259 | |
| 260 | private boolean queueObjective(DeviceId deviceId, ForwardingObjective fwd) { |
| 261 | if (fwd.nextId() != null && |
| 262 | flowObjectiveStore.getNextGroup(fwd.nextId()) == null) { |
| 263 | log.trace("Queuing forwarding objective for nextId {}", fwd.nextId()); |
| 264 | if (pendingForwards.putIfAbsent(fwd.nextId(), |
| 265 | Sets.newHashSet(new PendingNext(deviceId, fwd))) != null) { |
| 266 | Set<PendingNext> pending = pendingForwards.get(fwd.nextId()); |
| 267 | pending.add(new PendingNext(deviceId, fwd)); |
| 268 | } |
| 269 | return true; |
| 270 | } |
| 271 | return false; |
| 272 | } |
| 273 | |
| 274 | @Override |
| 275 | public void initPolicy(String policy) { |
Heedo Kang | 4a47a30 | 2016-02-29 17:40:23 +0900 | [diff] [blame] | 276 | checkPermission(FLOWRULE_WRITE); |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 277 | this.policy = policy; |
| 278 | deviceService.getDevices().forEach(device -> |
| 279 | this.deviceCompositionTreeMap.put(device.id(), FlowObjectiveCompositionUtil.parsePolicyString(policy))); |
| 280 | log.info("Initialize policy {}", policy); |
| 281 | } |
| 282 | |
| 283 | // Retrieves the device pipeline behaviour from the cache. |
| 284 | private Pipeliner getDevicePipeliner(DeviceId deviceId) { |
| 285 | Pipeliner pipeliner = pipeliners.get(deviceId); |
| 286 | return pipeliner; |
| 287 | } |
| 288 | |
| 289 | private void setupPipelineHandler(DeviceId deviceId) { |
| 290 | if (defaultDriverService == null) { |
| 291 | // We're not ready to go to work yet. |
| 292 | return; |
| 293 | } |
| 294 | |
| 295 | // Attempt to lookup the handler in the cache |
| 296 | DriverHandler handler = driverHandlers.get(deviceId); |
| 297 | if (handler == null) { |
| 298 | try { |
| 299 | // Otherwise create it and if it has pipeline behaviour, cache it |
| 300 | handler = driverService.createHandler(deviceId); |
| 301 | if (!handler.driver().hasBehaviour(Pipeliner.class)) { |
| 302 | log.warn("Pipeline behaviour not supported for device {}", |
| 303 | deviceId); |
| 304 | return; |
| 305 | } |
| 306 | } catch (ItemNotFoundException e) { |
| 307 | log.warn("No applicable driver for device {}", deviceId); |
| 308 | return; |
| 309 | } |
| 310 | |
| 311 | driverHandlers.put(deviceId, handler); |
| 312 | } |
| 313 | |
| 314 | // Always (re)initialize the pipeline behaviour |
| 315 | log.info("Driver {} bound to device {} ... initializing driver", |
| 316 | handler.driver().name(), deviceId); |
| 317 | Pipeliner pipeliner = handler.behaviour(Pipeliner.class); |
| 318 | pipeliner.init(deviceId, context); |
| 319 | pipeliners.putIfAbsent(deviceId, pipeliner); |
| 320 | } |
| 321 | |
| 322 | // Triggers driver setup when the local node becomes a device master. |
| 323 | private class InnerMastershipListener implements MastershipListener { |
| 324 | @Override |
| 325 | public void event(MastershipEvent event) { |
| 326 | switch (event.type()) { |
| 327 | case MASTER_CHANGED: |
| 328 | log.debug("mastership changed on device {}", event.subject()); |
| 329 | if (deviceService.isAvailable(event.subject())) { |
| 330 | setupPipelineHandler(event.subject()); |
| 331 | } |
| 332 | break; |
| 333 | case BACKUPS_CHANGED: |
| 334 | break; |
| 335 | default: |
| 336 | break; |
| 337 | } |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | // Triggers driver setup when a device is (re)detected. |
| 342 | private class InnerDeviceListener implements DeviceListener { |
| 343 | @Override |
| 344 | public void event(DeviceEvent event) { |
| 345 | switch (event.type()) { |
| 346 | case DEVICE_ADDED: |
| 347 | case DEVICE_AVAILABILITY_CHANGED: |
| 348 | log.debug("Device either added or availability changed {}", |
| 349 | event.subject().id()); |
| 350 | if (deviceService.isAvailable(event.subject().id())) { |
| 351 | log.debug("Device is now available {}", event.subject().id()); |
| 352 | setupPipelineHandler(event.subject().id()); |
| 353 | } |
| 354 | break; |
| 355 | case DEVICE_UPDATED: |
| 356 | break; |
| 357 | case DEVICE_REMOVED: |
| 358 | break; |
| 359 | case DEVICE_SUSPENDED: |
| 360 | break; |
| 361 | case PORT_ADDED: |
| 362 | break; |
| 363 | case PORT_UPDATED: |
| 364 | break; |
| 365 | case PORT_REMOVED: |
| 366 | break; |
| 367 | default: |
| 368 | break; |
| 369 | } |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | // Processing context for initializing pipeline driver behaviours. |
| 374 | private class InnerPipelineContext implements PipelinerContext { |
| 375 | @Override |
| 376 | public ServiceDirectory directory() { |
| 377 | return serviceDirectory; |
| 378 | } |
| 379 | |
| 380 | @Override |
| 381 | public FlowObjectiveStore store() { |
| 382 | return flowObjectiveStore; |
| 383 | } |
| 384 | } |
| 385 | |
| 386 | private class InternalStoreDelegate implements FlowObjectiveStoreDelegate { |
| 387 | @Override |
| 388 | public void notify(ObjectiveEvent event) { |
| 389 | log.debug("Received notification of obj event {}", event); |
| 390 | Set<PendingNext> pending = pendingForwards.remove(event.subject()); |
| 391 | |
| 392 | if (pending == null) { |
| 393 | log.debug("Nothing pending for this obj event"); |
| 394 | return; |
| 395 | } |
| 396 | |
| 397 | log.debug("Processing pending forwarding objectives {}", pending.size()); |
| 398 | |
| 399 | pending.forEach(p -> getDevicePipeliner(p.deviceId()) |
| 400 | .forward(p.forwardingObjective())); |
| 401 | |
| 402 | } |
| 403 | } |
| 404 | |
| 405 | /** |
| 406 | * Data class used to hold a pending forwarding objective that could not |
| 407 | * be processed because the associated next object was not present. |
| 408 | */ |
| 409 | private class PendingNext { |
| 410 | private final DeviceId deviceId; |
| 411 | private final ForwardingObjective fwd; |
| 412 | |
| 413 | public PendingNext(DeviceId deviceId, ForwardingObjective fwd) { |
| 414 | this.deviceId = deviceId; |
| 415 | this.fwd = fwd; |
| 416 | } |
| 417 | |
| 418 | public DeviceId deviceId() { |
| 419 | return deviceId; |
| 420 | } |
| 421 | |
| 422 | public ForwardingObjective forwardingObjective() { |
| 423 | return fwd; |
| 424 | } |
| 425 | } |
| 426 | |
| 427 | public static String forwardingObjectiveToString(ForwardingObjective forwardingObjective) { |
| 428 | String str = forwardingObjective.priority() + " "; |
| 429 | str += "selector( "; |
| 430 | for (Criterion criterion : forwardingObjective.selector().criteria()) { |
| 431 | str += criterion + " "; |
| 432 | } |
| 433 | str += ") treatment( "; |
| 434 | for (Instruction instruction : forwardingObjective.treatment().allInstructions()) { |
| 435 | str += instruction + " "; |
| 436 | } |
| 437 | str += ")"; |
| 438 | return str; |
| 439 | } |
Saurav Das | 2443119 | 2016-03-07 19:13:00 -0800 | [diff] [blame] | 440 | |
| 441 | @Override |
| 442 | public List<String> getNextMappings() { |
| 443 | // TODO Implementation deferred as this is an experimental component. |
Saurav Das | b5c236e | 2016-06-07 10:08:06 -0700 | [diff] [blame^] | 444 | return ImmutableList.of(); |
| 445 | } |
| 446 | |
| 447 | @Override |
| 448 | public List<String> getPendingNexts() { |
| 449 | // TODO Implementation deferred as this is an experimental component. |
| 450 | return ImmutableList.of(); |
Saurav Das | 2443119 | 2016-03-07 19:13:00 -0800 | [diff] [blame] | 451 | } |
Xin Jin | 313708b | 2015-07-09 13:43:04 -0700 | [diff] [blame] | 452 | } |