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 WRITE:
 122             Preconditions.checkArgument(maybeAfter.isPresent(),
 123                     "Modification at {} has type {} but no after-data", state.getPath(), type);
 124             if (!maybeBefore.isPresent()) {
 125                 @SuppressWarnings({ "unchecked", "rawtypes" })
 126                 final NormalizedNode<PathArgument, ?> afterNode = (NormalizedNode)maybeAfter.get();
 127                 resolveSameEventRecursivelly(state, afterNode, DOMImmutableDataChangeEvent.getCreateEventFactory());
 128                 return true;
 129             }
 130
 131             return resolveReplacedEvent(state, maybeBefore.get(), maybeAfter.get());
 132         case DELETE:
 133             Preconditions.checkArgument(maybeBefore.isPresent(),
 134                     "Modification at {} has type {} but no before-data", state.getPath(), type);
 135
 136             @SuppressWarnings({ "unchecked", "rawtypes" })
 137             final NormalizedNode<PathArgument, ?> beforeNode = (NormalizedNode)maybeBefore.get();
 138             resolveSameEventRecursivelly(state, beforeNode, DOMImmutableDataChangeEvent.getRemoveEventFactory());
 139             return true;
 140         case UNMODIFIED:
 141             return false;
 142         }
 143
 144         throw new IllegalStateException(String.format("Unhandled node state %s at %s", type, state.getPath()));
 145     }
 146
 147     private boolean resolveReplacedEvent(final ResolveDataChangeState state,
 148             final NormalizedNode<?, ?> beforeData, final NormalizedNode<?, ?> afterData) {
 149
 150         if (beforeData instanceof NormalizedNodeContainer<?, ?, ?>) {
 151             /*
 152              * Node is a container (contains a child) and we have interested
 153              * listeners registered for it, that means we need to do
 154              * resolution of changes on children level and can not
 155              * shortcut resolution.
 156              */
 157             LOG.trace("Resolving subtree replace event for {} before {}, after {}", state.getPath(), beforeData, afterData);
 158             @SuppressWarnings("unchecked")
 159             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> beforeCont = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) beforeData;
 160             @SuppressWarnings("unchecked")
 161             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> afterCont = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) afterData;
 162             return resolveNodeContainerReplaced(state, beforeCont, afterCont);
 163         }
 164
 165         // Node is a Leaf type (does not contain child nodes)
 166         // so normal equals method is sufficient for determining change.
 167         if (beforeData.equals(afterData)) {
 168             LOG.trace("Skipping equal leaf {}", state.getPath());
 169             return false;
 170         }
 171
 172         LOG.trace("Resolving leaf replace event for {} , before {}, after {}", state.getPath(), beforeData, afterData);
 173         DOMImmutableDataChangeEvent event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE).addUpdated(state.getPath(), beforeData, afterData).build();
 174         state.addEvent(event);
 175         state.collectEvents(beforeData, afterData, collectedEvents);
 176         return true;
 177     }
 178
 179     private boolean resolveNodeContainerReplaced(final ResolveDataChangeState state,
 180             final NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> beforeCont,
 181                     final NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> afterCont) {
 182         if (!state.needsProcessing()) {
 183             LOG.trace("Not processing replaced container {}", state.getPath());
 184             return true;
 185         }
 186
 187         // We look at all children from before and compare it with after state.
 188         boolean childChanged = false;
 189         for (NormalizedNode<PathArgument, ?> beforeChild : beforeCont.getValue()) {
 190             final PathArgument childId = beforeChild.getIdentifier();
 191
 192             if (resolveNodeContainerChildUpdated(state.child(childId), beforeChild, afterCont.getChild(childId))) {
 193                 childChanged = true;
 194             }
 195         }
 196
 197         for (NormalizedNode<PathArgument, ?> afterChild : afterCont.getValue()) {
 198             final PathArgument childId = afterChild.getIdentifier();
 199
 200             /*
 201              * We have already iterated of the before-children, so have already
 202              * emitted modify/delete events. This means the child has been
 203              * created.
 204              */
 205             if (!beforeCont.getChild(childId).isPresent()) {
 206                 resolveSameEventRecursivelly(state.child(childId), afterChild, DOMImmutableDataChangeEvent.getCreateEventFactory());
 207                 childChanged = true;
 208             }
 209         }
 210
 211         if (childChanged) {
 212             DOMImmutableDataChangeEvent event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE)
 213                     .addUpdated(state.getPath(), beforeCont, afterCont).build();
 214             state.addEvent(event);
 215         }
 216
 217         state.collectEvents(beforeCont, afterCont, collectedEvents);
 218         return childChanged;
 219     }
 220
 221     private boolean resolveNodeContainerChildUpdated(final ResolveDataChangeState state,
 222             final NormalizedNode<PathArgument, ?> before, final Optional<NormalizedNode<PathArgument, ?>> after) {
 223         if (after.isPresent()) {
 224             // REPLACE or SUBTREE Modified
 225             return resolveReplacedEvent(state, before, after.get());
 226         }
 227
 228         // AFTER state is not present - child was deleted.
 229         resolveSameEventRecursivelly(state, before, DOMImmutableDataChangeEvent.getRemoveEventFactory());
 230         return true;
 231     }
 232
 233     private void resolveSameEventRecursivelly(final ResolveDataChangeState state,
 234             final NormalizedNode<PathArgument, ?> node, final SimpleEventFactory eventFactory) {
 235         if (!state.needsProcessing()) {
 236             LOG.trace("Skipping child {}", state.getPath());
 237             return;
 238         }
 239
 240         // We have listeners for this node or it's children, so we will try
 241         // to do additional processing
 242         if (node instanceof NormalizedNodeContainer<?, ?, ?>) {
 243             LOG.trace("Resolving subtree recursive event for {}, type {}", state.getPath(), eventFactory);
 244
 245             // Node has children, so we will try to resolve it's children
 246             // changes.
 247             @SuppressWarnings("unchecked")
 248             NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>> container = (NormalizedNodeContainer<?, PathArgument, NormalizedNode<PathArgument, ?>>) node;
 249             for (NormalizedNode<PathArgument, ?> child : container.getValue()) {
 250                 final PathArgument childId = child.getIdentifier();
 251
 252                 LOG.trace("Resolving event for child {}", childId);
 253                 resolveSameEventRecursivelly(state.child(childId), child, eventFactory);
 254             }
 255         }
 256
 257         final DOMImmutableDataChangeEvent event = eventFactory.create(state.getPath(), node);
 258         LOG.trace("Adding event {} at path {}", event, state.getPath());
 259         state.addEvent(event);
 260         state.collectEvents(event.getOriginalSubtree(), event.getUpdatedSubtree(), collectedEvents);
 261     }
 262
 263     private boolean resolveSubtreeChangeEvent(final ResolveDataChangeState state, final DataTreeCandidateNode modification) {
 264         final Optional<NormalizedNode<?, ?>> maybeBefore = modification.getDataBefore();
 265         final Optional<NormalizedNode<?, ?>> maybeAfter = modification.getDataAfter();
 266
 267         Preconditions.checkArgument(maybeBefore.isPresent(), "Subtree change with before-data not present at path %s", state.getPath());
 268         Preconditions.checkArgument(maybeAfter.isPresent(), "Subtree change with after-data not present at path %s", state.getPath());
 269
 270         if (!state.needsProcessing()) {
 271             LOG.trace("Not processing modified subtree {}", state.getPath());
 272             return true;
 273         }
 274
 275         DataChangeScope scope = null;
 276         for (DataTreeCandidateNode childMod : modification.getChildNodes()) {
 277             final ResolveDataChangeState childState = state.child(childMod.getIdentifier());
 278
 279             switch (childMod.getModificationType()) {
 280             case WRITE:
 281             case DELETE:
 282                 if (resolveAnyChangeEvent(childState, childMod)) {
 283                     scope = DataChangeScope.ONE;
 284                 }
 285                 break;
 286             case SUBTREE_MODIFIED:
 287                 if (resolveSubtreeChangeEvent(childState, childMod) && scope == null) {
 288                     scope = DataChangeScope.SUBTREE;
 289                 }
 290                 break;
 291             case UNMODIFIED:
 292                 // no-op
 293                 break;
 294             }
 295         }
 296
 297         final NormalizedNode<?, ?> before = maybeBefore.get();
 298         final NormalizedNode<?, ?> after = maybeAfter.get();
 299
 300         if (scope != null) {
 301             DOMImmutableDataChangeEvent one = DOMImmutableDataChangeEvent.builder(scope).addUpdated(state.getPath(), before, after).build();
 302             state.addEvent(one);
 303         }
 304
 305         state.collectEvents(before, after, collectedEvents);
 306         return scope != null;
 307     }
 308
 309     public static ResolveDataChangeEventsTask create(final DataTreeCandidate candidate, final ListenerTree listenerTree) {
 310         return new ResolveDataChangeEventsTask(candidate, listenerTree);
 311     }
 312 }