dom/mdsal-dom-broker/src/main/java/org/opendaylight/mdsal/dom/broker/ShardedDOMDataTree.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.broker;
   9
  10 import com.google.common.base.Preconditions;
  11 import com.google.common.collect.Iterables;
  12 import java.util.Collection;
  13 import java.util.Collections;
  14 import java.util.HashMap;
  15 import java.util.Map;
  16 import java.util.Set;
  17 import javax.annotation.concurrent.GuardedBy;
  18 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  19 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  20 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  21 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer;
  22 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  23 import org.opendaylight.mdsal.dom.api.DOMDataTreeShard;
  24 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingConflictException;
  25 import org.opendaylight.mdsal.dom.api.DOMDataTreeShardingService;
  26 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTable;
  27 import org.opendaylight.mdsal.dom.spi.DOMDataTreePrefixTableEntry;
  28 import org.opendaylight.mdsal.dom.spi.store.DOMStoreTreeChangePublisher;
  29 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
  30 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33
  34 public final class ShardedDOMDataTree implements DOMDataTreeService, DOMDataTreeShardingService {
  35     private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMDataTree.class);
  36
  37     @GuardedBy("this")
  38     private final DOMDataTreePrefixTable<ShardRegistration<?>> shards = DOMDataTreePrefixTable.create();
  39     @GuardedBy("this")
  40     private final DOMDataTreePrefixTable<DOMDataTreeProducer> producers = DOMDataTreePrefixTable.create();
  41
  42     void removeShard(final ShardRegistration<?> reg) {
  43         final DOMDataTreeIdentifier prefix = reg.getPrefix();
  44         final ShardRegistration<?> parentReg;
  45
  46         synchronized (this) {
  47             shards.remove(prefix);
  48             parentReg = shards.lookup(prefix).getValue();
  49
  50             /*
  51              * FIXME: adjust all producers and listeners. This is tricky, as we need different
  52              * locking strategy, simply because we risk AB/BA deadlock with a producer being split
  53              * off from a producer.
  54              */
  55         }
  56
  57         if (parentReg != null) {
  58             parentReg.getInstance().onChildDetached(prefix, reg.getInstance());
  59         }
  60     }
  61
  62     @Override
  63     public <T extends DOMDataTreeShard> ListenerRegistration<T> registerDataTreeShard(final DOMDataTreeIdentifier prefix, final T shard, final DOMDataTreeProducer producer) throws DOMDataTreeShardingConflictException {
  64
  65         final DOMDataTreeIdentifier firstSubtree = Iterables.getOnlyElement(((ShardedDOMDataTreeProducer) producer).getSubtrees());
  66         Preconditions.checkArgument(firstSubtree != null, "Producer that is used to verify namespace claim can only claim a single namespace");
  67         Preconditions.checkArgument(prefix.equals(firstSubtree), "Trying to register shard to a different namespace than the producer has claimed");
  68
  69         final ShardRegistration<T> reg;
  70         final ShardRegistration<?> parentReg;
  71
  72         synchronized (this) {
  73             /*
  74              * Lookup the parent shard (e.g. the one which currently matches the prefix),
  75              * and if it exists, check if its registration prefix does not collide with
  76              * this registration.
  77              */
  78             final DOMDataTreePrefixTableEntry<ShardRegistration<?>> parent = shards.lookup(prefix);
  79             if (parent != null) {
  80                 parentReg = parent.getValue();
  81                 if (parentReg != null && prefix.equals(parentReg.getPrefix())) {
  82                     throw new DOMDataTreeShardingConflictException(String.format(
  83                             "Prefix %s is already occupied by shard %s", prefix, parentReg.getInstance()));
  84                 }
  85             } else {
  86                 parentReg = null;
  87             }
  88
  89             // FIXME: wrap the shard in a proper adaptor based on implemented interface
  90
  91             reg = new ShardRegistration<T>(this, prefix, shard);
  92
  93             shards.store(prefix, reg);
  94
  95             ((ShardedDOMDataTreeProducer) producer).subshardAdded(Collections.singletonMap(prefix, shard));
  96         }
  97
  98         // Notify the parent shard
  99         if (parentReg != null) {
 100             parentReg.getInstance().onChildAttached(prefix, shard);
 101         }
 102
 103         return reg;
 104     }
 105
 106     @GuardedBy("this")
 107     private DOMDataTreeProducer findProducer(final DOMDataTreeIdentifier subtree) {
 108
 109         final DOMDataTreePrefixTableEntry<DOMDataTreeProducer> producerEntry = producers.lookup(subtree);
 110         if (producerEntry != null) {
 111             return producerEntry.getValue();
 112         }
 113         return null;
 114     }
 115
 116     synchronized void destroyProducer(final ShardedDOMDataTreeProducer producer) {
 117         for (final DOMDataTreeIdentifier s : producer.getSubtrees()) {
 118             producers.remove(s);
 119         }
 120     }
 121
 122     @GuardedBy("this")
 123     private DOMDataTreeProducer createProducer(final Collection<DOMDataTreeIdentifier> subtrees, final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
 124         // Record the producer's attachment points
 125         final DOMDataTreeProducer ret = ShardedDOMDataTreeProducer.create(this, subtrees, shardMap);
 126         for (final DOMDataTreeIdentifier subtree : subtrees) {
 127             producers.store(subtree, ret);
 128         }
 129
 130         return ret;
 131     }
 132
 133     @Override
 134     public synchronized DOMDataTreeProducer createProducer(final Collection<DOMDataTreeIdentifier> subtrees) {
 135         Preconditions.checkArgument(!subtrees.isEmpty(), "Subtrees may not be empty");
 136
 137         final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap = new HashMap<>();
 138         for (final DOMDataTreeIdentifier subtree : subtrees) {
 139             // Attempting to create a disconnected producer -- all subtrees have to be unclaimed
 140             final DOMDataTreeProducer producer = findProducer(subtree);
 141             Preconditions.checkArgument(producer == null, "Subtree %s is attached to producer %s", subtree, producer);
 142
 143             final DOMDataTreePrefixTableEntry<ShardRegistration<?>> possibleShardReg = shards.lookup(subtree);
 144             if (possibleShardReg != null && possibleShardReg.getValue() != null) {
 145                 shardMap.put(subtree, possibleShardReg.getValue().getInstance());
 146             }
 147         }
 148
 149         return createProducer(subtrees, shardMap);
 150     }
 151
 152     synchronized DOMDataTreeProducer createProducer(final ShardedDOMDataTreeProducer parent, final Collection<DOMDataTreeIdentifier> subtrees) {
 153         Preconditions.checkNotNull(parent);
 154
 155         final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap = new HashMap<>();
 156         for (final DOMDataTreeIdentifier s : subtrees) {
 157             shardMap.put(s, shards.lookup(s).getValue().getInstance());
 158         }
 159
 160         return createProducer(subtrees, shardMap);
 161     }
 162
 163     @Override
 164     public synchronized <T extends DOMDataTreeListener> ListenerRegistration<T> registerListener(final T listener,
 165             final Collection<DOMDataTreeIdentifier> subtrees, final boolean allowRxMerges,
 166             final Collection<DOMDataTreeProducer> producers) throws DOMDataTreeLoopException {
 167         Preconditions.checkNotNull(listener, "listener");
 168         Preconditions.checkArgument(!subtrees.isEmpty(), "Subtrees must not be empty.");
 169         final ShardedDOMDataTreeListenerContext<T> listenerContext =
 170                 ShardedDOMDataTreeListenerContext.create(listener, subtrees, allowRxMerges);
 171         try {
 172             // FIXME: Add attachment of producers
 173             for (final DOMDataTreeProducer producer : producers) {
 174                 Preconditions.checkArgument(producer instanceof ShardedDOMDataTreeProducer);
 175                 final ShardedDOMDataTreeProducer castedProducer = ((ShardedDOMDataTreeProducer) producer);
 176                 simpleLoopCheck(subtrees, castedProducer.getSubtrees());
 177                 // FIXME: We should also unbound listeners
 178                 castedProducer.boundToListener(listenerContext);
 179             }
 180
 181             for (final DOMDataTreeIdentifier subtree : subtrees) {
 182                 final DOMDataTreeShard shard = shards.lookup(subtree).getValue().getInstance();
 183                 // FIXME: What should we do if listener is wildcard? And shards are on per
 184                 // node basis?
 185                 Preconditions.checkArgument(shard instanceof DOMStoreTreeChangePublisher,
 186                         "Subtree %s does not point to listenable subtree.", subtree);
 187
 188                 listenerContext.register(subtree, (DOMStoreTreeChangePublisher) shard);
 189             }
 190         } catch (final Exception e) {
 191             listenerContext.close();
 192             throw e;
 193         }
 194         return new AbstractListenerRegistration<T>(listener) {
 195             @Override
 196             protected void removeRegistration() {
 197                 ShardedDOMDataTree.this.removeListener(listenerContext);
 198             }
 199         };
 200     }
 201
 202     private static void simpleLoopCheck(final Collection<DOMDataTreeIdentifier> listen, final Set<DOMDataTreeIdentifier> writes)
 203             throws DOMDataTreeLoopException {
 204         for(final DOMDataTreeIdentifier listenPath : listen) {
 205             for (final DOMDataTreeIdentifier writePath : writes) {
 206                 if (listenPath.contains(writePath)) {
 207                     throw new DOMDataTreeLoopException(String.format(
 208                             "Listener must not listen on parent (%s), and also writes child (%s)", listenPath,
 209                             writePath));
 210                 } else if (writePath.contains(listenPath)) {
 211                     throw new DOMDataTreeLoopException(
 212                             String.format("Listener must not write parent (%s), and also listen on child (%s)",
 213                                     writePath, listenPath));
 214                 }
 215             }
 216         }
 217     }
 218
 219     void removeListener(final ShardedDOMDataTreeListenerContext<?> listener) {
 220         // FIXME: detach producers
 221         listener.close();
 222     }
 223 }