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