opendaylight/md-sal/sal-inmemory-datastore/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/ResolveDataChangeEventsTask.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.md.sal.dom.store.impl;
   9
  10 import com.google.common.annotations.Beta;
  11 import com.google.common.base.Optional;
  12 import com.google.common.base.Preconditions;
  13 import com.google.common.collect.ArrayListMultimap;
  14 import com.google.common.collect.Multimap;
  15 import java.util.Collection;
  16 import java.util.Map.Entry;
  17 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
  18 import org.opendaylight.controller.md.sal.dom.spi.RegistrationTreeSnapshot;
  19 import org.opendaylight.controller.md.sal.dom.store.impl.DOMImmutableDataChangeEvent.Builder;
  20 import org.opendaylight.controller.md.sal.dom.store.impl.DOMImmutableDataChangeEvent.SimpleEventFactory;
  21 import org.opendaylight.controller.md.sal.dom.store.impl.tree.ListenerTree;
  22 import org.opendaylight.yangtools.util.concurrent.NotificationManager;
  23 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  24 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  25 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
  26 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  27 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateNode;
  28 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 /**
  33  * Resolve Data Change Events based on modifications and listeners
  34  *
  35  * Computes data change events for all affected registered listeners in data
  36  * tree.
  37  */
  38 @Beta
  39 public final class ResolveDataChangeEventsTask {
  40     private static final Logger LOG = LoggerFactory.getLogger(ResolveDataChangeEventsTask.class);
  41
  42     private final DataTreeCandidate candidate;
  43     private final ListenerTree listenerRoot;
  44
  45     private Multimap<DataChangeListenerRegistration<?>, DOMImmutableDataChangeEvent> collectedEvents;
  46
  47     private ResolveDataChangeEventsTask(final DataTreeCandidate candidate, final ListenerTree listenerTree) {
  48         this.candidate = Preconditions.checkNotNull(candidate);
  49         this.listenerRoot = Preconditions.checkNotNull(listenerTree);
  50     }
  51
  52     /**
  53      * Resolves and submits notification tasks to the specified manager.
  54      */
  55     public synchronized void resolve(final NotificationManager<DataChangeListenerRegistration<?>, DOMImmutableDataChangeEvent> manager) {
  56         try (final RegistrationTreeSnapshot<DataChangeListenerRegistration<?>> w = listenerRoot.takeSnapshot()) {
  57             // Defensive: reset internal state
  58             collectedEvents = ArrayListMultimap.create();
  59
  60             // Run through the tree
  61             final ResolveDataChangeState s = ResolveDataChangeState.initial(candidate.getRootPath(), w.getRootNode());
  62             resolveAnyChangeEvent(s, candidate.getRootNode());
  63
  64             /*
  65              * Convert to tasks, but be mindful of multiple values -- those indicate multiple
  66              * wildcard matches, which need to be merged.
  67              */
  68             for (Entry<DataChangeListenerRegistration<?>, Collection<DOMImmutableDataChangeEvent>> e : collectedEvents.asMap().entrySet()) {
  69                 final Collection<DOMImmutableDataChangeEvent> col = e.getValue();
  70                 final DOMImmutableDataChangeEvent event;
  71
  72                 if (col.size() != 1) {
  73                     final Builder b = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE);
  74                     for (DOMImmutableDataChangeEvent i : col) {
  75                         b.merge(i);
  76                     }
  77
  78                     event = b.build();
  79                     LOG.trace("Merged events {} into event {}", col, event);
  80                 } else {
  81                     event = col.iterator().next();
  82                 }
  83
  84                 manager.submitNotification(e.getKey(), event);
  85             }
  86         }
  87     }
  88
  89     /**
  90      * Resolves data change event for supplied node
  91      *
  92      * @param path
  93      *            Path to current node in tree
  94      * @param listeners
  95      *            Collection of Listener registration nodes interested in
  96      *            subtree
  97      * @param modification
  98      *            Modification of current node
  99      * @param before
 100      *            - Original (before) state of current node
 101      * @param after
 102      *            - After state of current node
 103      * @return True if the subtree changed, false otherwise
 104      */
 105     private boolean resolveAnyChangeEvent(final ResolveDataChangeState state, final DataTreeCandidateNode node) {
 106         final Optional<NormalizedNode<?, ?>> maybeBefore = node.getDataBefore();
 107         final Optional<NormalizedNode<?, ?>> maybeAfter = node.getDataAfter();
 108         final ModificationType type = node.getModificationType();
 109
 110         if (type != ModificationType.UNMODIFIED && !maybeAfter.isPresent() && !maybeBefore.isPresent()) {
 111             LOG.debug("Modification at {} has type {}, but no before- and after-data. Assuming unchanged.",
 112                     state.getPath(), type);
 113             return false;
 114         }
 115
 116         // no before and after state is present
 117
 118         switch (type) {
 119         case SUBTREE_MODIFIED:
 120             return resolveSubtreeChangeEvent(state, node);
 121         case MERGE:
 122         case WRITE:
 123             Preconditions.checkArgument(maybeAfter.isPresent(),
 124                     "Modification at {} has type {} but no after-data", state.getPath(), type);
 125             if (!maybeBefore.isPresent()) {
 126                 @SuppressWarnings({ "unchecked", "rawtypes" })
 127                 final NormalizedNode<PathArgument, ?> afterNode = (NormalizedNode)maybeAfter.get();
 128                 resolveSameEventRecursivelly(state, afterNode, DOMImmutableDataChangeEvent.getCreateEventFactory());
 129                 return true;
 130             }
 131
 132             return resolveReplacedEvent(state, maybeBefore.get(), maybeAfter.get());
 133         case DELETE:
 134             Preconditions.checkArgument(maybeBefore.isPresent(),
 135                     "Modification at {} has type {} but no before-data", state.getPath(), type);
 136
 137             @SuppressWarnings({ "unchecked", "rawtypes" })
 138             final NormalizedNode<PathArgument, ?> beforeNode = (NormalizedNode)maybeBefore.get();
 139             resolveSameEventRecursivelly(state, beforeNode, DOMImmutableDataChangeEvent.getRemoveEventFactory());
 140             return true;
 141         case UNMODIFIED:
 142             return false;
 143         }
 144
 145         throw new IllegalStateException(String.format("Unhandled node state %s at %s", type, state.getPath()));
 146     }
 147
 148     private boolean resolveReplacedEvent(final ResolveDataChangeState state,
 149             final NormalizedNode<?, ?> beforeData, final NormalizedNode<?, ?> afterData) {
 150
 151         if (beforeData instanceof NormalizedNodeContainer<?, ?, ?>) {
 152             /*
 153              * Node is a container (contains a child) and we have interested
 154              * listeners registered for it, that means we need to do
 155              * resolution of changes on children level and can not
 156              * shortcut resolution.
 157              */
 158             LOG.trace("Resolving subtree replace event for {} before {}, after {}", state.getPath(), beforeData, afterData);
 159             @SuppressWarnings("unchecked")
 160             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> beforeCont = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) beforeData;
 161             @SuppressWarnings("unchecked")
 162             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> afterCont = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) afterData;
 163             return resolveNodeContainerReplaced(state, beforeCont, afterCont);
 164         }
 165
 166         // Node is a Leaf type (does not contain child nodes)
 167         // so normal equals method is sufficient for determining change.
 168         if (beforeData.equals(afterData)) {
 169             LOG.trace("Skipping equal leaf {}", state.getPath());
 170             return false;
 171         }
 172
 173         LOG.trace("Resolving leaf replace event for {} , before {}, after {}", state.getPath(), beforeData, afterData);
 174         DOMImmutableDataChangeEvent event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE).addUpdated(state.getPath(), beforeData, afterData).build();
 175         state.addEvent(event);
 176         state.collectEvents(beforeData, afterData, collectedEvents);
 177         return true;
 178     }
 179
 180     private boolean resolveNodeContainerReplaced(final ResolveDataChangeState state,
 181             final NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> beforeCont,
 182                     final NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> afterCont) {
 183         if (!state.needsProcessing()) {
 184             LOG.trace("Not processing replaced container {}", state.getPath());
 185             return true;
 186         }
 187
 188         // We look at all children from before and compare it with after state.
 189         boolean childChanged = false;
 190         for (NormalizedNode<PathArgument, ?> beforeChild : beforeCont.getValue()) {
 191             final PathArgument childId = beforeChild.getIdentifier();
 192
 193             if (resolveNodeContainerChildUpdated(state.child(childId), beforeChild, afterCont.getChild(childId))) {
 194                 childChanged = true;
 195             }
 196         }
 197
 198         for (NormalizedNode<PathArgument, ?> afterChild : afterCont.getValue()) {
 199             final PathArgument childId = afterChild.getIdentifier();
 200
 201             /*
 202              * We have already iterated of the before-children, so have already
 203              * emitted modify/delete events. This means the child has been
 204              * created.
 205              */
 206             if (!beforeCont.getChild(childId).isPresent()) {
 207                 resolveSameEventRecursivelly(state.child(childId), afterChild, DOMImmutableDataChangeEvent.getCreateEventFactory());
 208                 childChanged = true;
 209             }
 210         }
 211
 212         if (childChanged) {
 213             DOMImmutableDataChangeEvent event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE)
 214                     .addUpdated(state.getPath(), beforeCont, afterCont).build();
 215             state.addEvent(event);
 216         }
 217
 218         state.collectEvents(beforeCont, afterCont, collectedEvents);
 219         return childChanged;
 220     }
 221
 222     private boolean resolveNodeContainerChildUpdated(final ResolveDataChangeState state,
 223             final NormalizedNode<PathArgument, ?> before, final Optional<NormalizedNode<PathArgument, ?>> after) {
 224         if (after.isPresent()) {
 225             // REPLACE or SUBTREE Modified
 226             return resolveReplacedEvent(state, before, after.get());
 227         }
 228
 229         // AFTER state is not present - child was deleted.
 230         resolveSameEventRecursivelly(state, before, DOMImmutableDataChangeEvent.getRemoveEventFactory());
 231         return true;
 232     }
 233
 234     private void resolveSameEventRecursivelly(final ResolveDataChangeState state,
 235             final NormalizedNode<PathArgument, ?> node, final SimpleEventFactory eventFactory) {
 236         if (!state.needsProcessing()) {
 237             LOG.trace("Skipping child {}", state.getPath());
 238             return;
 239         }
 240
 241         // We have listeners for this node or it's children, so we will try
 242         // to do additional processing
 243         if (node instanceof NormalizedNodeContainer<?, ?, ?>) {
 244             LOG.trace("Resolving subtree recursive event for {}, type {}", state.getPath(), eventFactory);
 245
 246             // Node has children, so we will try to resolve it's children
 247             // changes.
 248             @SuppressWarnings("unchecked")
 249             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> container = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) node;
 250             for (NormalizedNode<PathArgument, ?> child : container.getValue()) {
 251                 final PathArgument childId = child.getIdentifier();
 252
 253                 LOG.trace("Resolving event for child {}", childId);
 254                 resolveSameEventRecursivelly(state.child(childId), child, eventFactory);
 255             }
 256         }
 257
 258         final DOMImmutableDataChangeEvent event = eventFactory.create(state.getPath(), node);
 259         LOG.trace("Adding event {} at path {}", event, state.getPath());
 260         state.addEvent(event);
 261         state.collectEvents(event.getOriginalSubtree(), event.getUpdatedSubtree(), collectedEvents);
 262     }
 263
 264     private boolean resolveSubtreeChangeEvent(final ResolveDataChangeState state, final DataTreeCandidateNode modification) {
 265         final Optional<NormalizedNode<?, ?>> maybeBefore = modification.getDataBefore();
 266         final Optional<NormalizedNode<?, ?>> maybeAfter = modification.getDataAfter();
 267
 268         Preconditions.checkArgument(maybeBefore.isPresent(), "Subtree change with before-data not present at path %s", state.getPath());
 269         Preconditions.checkArgument(maybeAfter.isPresent(), "Subtree change with after-data not present at path %s", state.getPath());
 270
 271         if (!state.needsProcessing()) {
 272             LOG.trace("Not processing modified subtree {}", state.getPath());
 273             return true;
 274         }
 275
 276         DataChangeScope scope = null;
 277         for (DataTreeCandidateNode childMod : modification.getChildNodes()) {
 278             final ResolveDataChangeState childState = state.child(childMod.getIdentifier());
 279
 280             switch (childMod.getModificationType()) {
 281             case WRITE:
 282             case MERGE:
 283             case DELETE:
 284                 if (resolveAnyChangeEvent(childState, childMod)) {
 285                     scope = DataChangeScope.ONE;
 286                 }
 287                 break;
 288             case SUBTREE_MODIFIED:
 289                 if (resolveSubtreeChangeEvent(childState, childMod) && scope == null) {
 290                     scope = DataChangeScope.SUBTREE;
 291                 }
 292                 break;
 293             case UNMODIFIED:
 294                 // no-op
 295                 break;
 296             }
 297         }
 298
 299         final NormalizedNode<?, ?> before = maybeBefore.get();
 300         final NormalizedNode<?, ?> after = maybeAfter.get();
 301
 302         if (scope != null) {
 303             DOMImmutableDataChangeEvent one = DOMImmutableDataChangeEvent.builder(scope).addUpdated(state.getPath(), before, after).build();
 304             state.addEvent(one);
 305         }
 306
 307         state.collectEvents(before, after, collectedEvents);
 308         return scope != null;
 309     }
 310
 311     public static ResolveDataChangeEventsTask create(final DataTreeCandidate candidate, final ListenerTree listenerTree) {
 312         return new ResolveDataChangeEventsTask(candidate, listenerTree);
 313     }
 314 }