dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/AbstractDOMStoreTreeChangePublisher.java

   1 /*
   2  * Copyright (c) 2015 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.mdsal.dom.spi.store;
   9
  10 import com.google.common.collect.ImmutableList;
  11 import com.google.common.collect.ListMultimap;
  12 import com.google.common.collect.Multimap;
  13 import com.google.common.collect.Multimaps;
  14 import java.util.ArrayList;
  15 import java.util.Collection;
  16 import java.util.IdentityHashMap;
  17 import java.util.List;
  18 import org.eclipse.jdt.annotation.NonNull;
  19 import org.opendaylight.mdsal.dom.api.DOMDataTreeChangeListener;
  20 import org.opendaylight.mdsal.dom.spi.AbstractDOMDataTreeChangeListenerRegistration;
  21 import org.opendaylight.mdsal.dom.spi.AbstractRegistrationTree;
  22 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  23 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  24 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidate;
  25 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidateNode;
  26 import org.opendaylight.yangtools.yang.data.tree.api.ModificationType;
  27 import org.opendaylight.yangtools.yang.data.tree.spi.DataTreeCandidates;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30
  31 /**
  32  * Abstract base class for {@link DOMStoreTreeChangePublisher} implementations.
  33  */
  34 public abstract class AbstractDOMStoreTreeChangePublisher
  35     extends AbstractRegistrationTree<AbstractDOMDataTreeChangeListenerRegistration<?>>
  36         implements DOMStoreTreeChangePublisher {
  37     private static final Logger LOG = LoggerFactory.getLogger(AbstractDOMStoreTreeChangePublisher.class);
  38
  39     /**
  40      * Callback for subclass to notify a specified registration of a list of candidates. This method is guaranteed
  41      * to be only called from within {@link #processCandidateTree(DataTreeCandidate)}.
  42      * @param registration the registration to notify
  43      * @param changes the list of DataTreeCandidate changes
  44      */
  45     protected abstract void notifyListener(@NonNull AbstractDOMDataTreeChangeListenerRegistration<?> registration,
  46             @NonNull List<DataTreeCandidate> changes);
  47
  48     /**
  49      * Callback notifying the subclass that the specified registration is being
  50      * closed and it's user no longer
  51      * wishes to receive notifications. This notification is invoked while
  52      * the {@link org.opendaylight.yangtools.concepts.ListenerRegistration#close()}
  53      * method is executing. Subclasses can use this callback to properly
  54      * remove any delayed notifications pending
  55      * towards the registration.
  56      *
  57      * @param registration Registration which is being closed
  58      */
  59     protected abstract void registrationRemoved(
  60             @NonNull AbstractDOMDataTreeChangeListenerRegistration<?> registration);
  61
  62     /**
  63      * Process a candidate tree with respect to registered listeners.
  64      *
  65      * @param candidate candidate three which needs to be processed
  66      * @return true if at least one listener was notified or false.
  67      */
  68     protected final boolean processCandidateTree(final @NonNull DataTreeCandidate candidate) {
  69         final DataTreeCandidateNode node = candidate.getRootNode();
  70         if (node.modificationType() == ModificationType.UNMODIFIED) {
  71             LOG.debug("Skipping unmodified candidate {}", candidate);
  72             return false;
  73         }
  74
  75         try (var snapshot = takeSnapshot()) {
  76             final List<PathArgument> toLookup = ImmutableList.copyOf(candidate.getRootPath().getPathArguments());
  77             final ListMultimap<AbstractDOMDataTreeChangeListenerRegistration<?>, DataTreeCandidate> listenerChanges =
  78                     Multimaps.newListMultimap(new IdentityHashMap<>(), ArrayList::new);
  79             lookupAndNotify(toLookup, 0, snapshot.getRootNode(), candidate, listenerChanges);
  80
  81             for (var entry : Multimaps.asMap(listenerChanges).entrySet()) {
  82                 notifyListener(entry.getKey(), entry.getValue());
  83             }
  84
  85             return !listenerChanges.isEmpty();
  86         }
  87     }
  88
  89     @Override
  90     public <L extends DOMDataTreeChangeListener> AbstractDOMDataTreeChangeListenerRegistration<L>
  91         registerTreeChangeListener(final YangInstanceIdentifier treeId, final L listener) {
  92         // Take the write lock
  93         takeLock();
  94         try {
  95             final Node<AbstractDOMDataTreeChangeListenerRegistration<?>> node =
  96                     findNodeFor(treeId.getPathArguments());
  97             final var reg = new AbstractDOMDataTreeChangeListenerRegistration<>(listener) {
  98                 @Override
  99                 protected void removeRegistration() {
 100                     AbstractDOMStoreTreeChangePublisher.this.removeRegistration(node, this);
 101                     registrationRemoved(this);
 102                 }
 103             };
 104
 105             addRegistration(node, reg);
 106             return reg;
 107         } finally {
 108             // Always release the lock
 109             releaseLock();
 110         }
 111     }
 112
 113     private void lookupAndNotify(final List<PathArgument> args,
 114             final int offset, final Node<AbstractDOMDataTreeChangeListenerRegistration<?>> node,
 115             final DataTreeCandidate candidate,
 116             final Multimap<AbstractDOMDataTreeChangeListenerRegistration<?>, DataTreeCandidate> listenerChanges) {
 117         if (args.size() != offset) {
 118             final PathArgument arg = args.get(offset);
 119
 120             final Node<AbstractDOMDataTreeChangeListenerRegistration<?>> exactChild
 121                 = node.getExactChild(arg);
 122             if (exactChild != null) {
 123                 lookupAndNotify(args, offset + 1, exactChild, candidate, listenerChanges);
 124             }
 125
 126             for (Node<AbstractDOMDataTreeChangeListenerRegistration<?>> c :
 127                     node.getInexactChildren(arg)) {
 128                 lookupAndNotify(args, offset + 1, c, candidate, listenerChanges);
 129             }
 130         } else {
 131             notifyNode(candidate.getRootPath(), node, candidate.getRootNode(), listenerChanges);
 132         }
 133     }
 134
 135     private void notifyNode(final YangInstanceIdentifier path,
 136             final Node<AbstractDOMDataTreeChangeListenerRegistration<?>> regNode,
 137             final DataTreeCandidateNode candNode,
 138             final Multimap<AbstractDOMDataTreeChangeListenerRegistration<?>, DataTreeCandidate> listenerChanges) {
 139         if (candNode.modificationType() == ModificationType.UNMODIFIED) {
 140             LOG.debug("Skipping unmodified candidate {}", path);
 141             return;
 142         }
 143
 144         final var regs = regNode.getRegistrations();
 145         if (!regs.isEmpty()) {
 146             addToListenerChanges(regs, path, candNode, listenerChanges);
 147         }
 148
 149         for (var candChild : candNode.childNodes()) {
 150             if (candChild.modificationType() != ModificationType.UNMODIFIED) {
 151                 final var regChild = regNode.getExactChild(candChild.name());
 152                 if (regChild != null) {
 153                     notifyNode(path.node(candChild.name()), regChild, candChild, listenerChanges);
 154                 }
 155
 156                 for (var rc : regNode.getInexactChildren(candChild.name())) {
 157                     notifyNode(path.node(candChild.name()), rc, candChild, listenerChanges);
 158                 }
 159             }
 160         }
 161     }
 162
 163     private static void addToListenerChanges(
 164             final Collection<AbstractDOMDataTreeChangeListenerRegistration<?>> registrations,
 165             final YangInstanceIdentifier path, final DataTreeCandidateNode node,
 166             final Multimap<AbstractDOMDataTreeChangeListenerRegistration<?>, DataTreeCandidate> listenerChanges) {
 167         final DataTreeCandidate dataTreeCandidate = DataTreeCandidates.newDataTreeCandidate(path, node);
 168
 169         for (AbstractDOMDataTreeChangeListenerRegistration<?> reg : registrations) {
 170             listenerChanges.put(reg, dataTreeCandidate);
 171         }
 172     }
 173 }