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