opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/InMemoryDOMDataStore.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 static com.google.common.base.Preconditions.checkState;
  11
  12 import java.util.Collections;
  13 import java.util.concurrent.Callable;
  14 import java.util.concurrent.atomic.AtomicLong;
  15
  16 import javax.annotation.concurrent.GuardedBy;
  17
  18 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope;
  19 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  20 import org.opendaylight.controller.md.sal.dom.store.impl.SnapshotBackedWriteTransaction.TransactionReadyPrototype;
  21 import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataPreconditionFailedException;
  22 import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataTree;
  23 import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataTreeCandidate;
  24 import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataTreeModification;
  25 import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataTreeSnapshot;
  26 import org.opendaylight.controller.md.sal.dom.store.impl.tree.ListenerTree;
  27 import org.opendaylight.controller.md.sal.dom.store.impl.tree.data.InMemoryDataTreeFactory;
  28 import org.opendaylight.controller.sal.core.spi.data.DOMStore;
  29 import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadTransaction;
  30 import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadWriteTransaction;
  31 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  32 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionChain;
  33 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  34 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
  35 import org.opendaylight.yangtools.concepts.Identifiable;
  36 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  37 import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
  38 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  39 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  40 import org.opendaylight.yangtools.yang.model.api.SchemaContextListener;
  41 import org.slf4j.Logger;
  42 import org.slf4j.LoggerFactory;
  43
  44 import com.google.common.base.Optional;
  45 import com.google.common.base.Preconditions;
  46 import com.google.common.util.concurrent.FutureCallback;
  47 import com.google.common.util.concurrent.Futures;
  48 import com.google.common.util.concurrent.ListenableFuture;
  49 import com.google.common.util.concurrent.ListeningExecutorService;
  50
  51 /**
  52  * In-memory DOM Data Store
  53  *
  54  * Implementation of {@link DOMStore} which uses {@link DataTree} and other
  55  * classes such as {@link SnapshotBackedWriteTransaction}.
  56  * {@link SnapshotBackedReadTransaction} and {@link ResolveDataChangeEventsTask}
  57  * to implement {@link DOMStore} contract.
  58  *
  59  */
  60 public class InMemoryDOMDataStore implements DOMStore, Identifiable<String>, SchemaContextListener,
  61         TransactionReadyPrototype {
  62     private static final Logger LOG = LoggerFactory.getLogger(InMemoryDOMDataStore.class);
  63     private final DataTree dataTree = InMemoryDataTreeFactory.getInstance().create();
  64     private final ListenerTree listenerTree = ListenerTree.create();
  65     private final AtomicLong txCounter = new AtomicLong(0);
  66     private final ListeningExecutorService executor;
  67     private final String name;
  68
  69     public InMemoryDOMDataStore(final String name, final ListeningExecutorService executor) {
  70         this.name = Preconditions.checkNotNull(name);
  71         this.executor = Preconditions.checkNotNull(executor);
  72     }
  73
  74     @Override
  75     public final String getIdentifier() {
  76         return name;
  77     }
  78
  79     @Override
  80     public DOMStoreReadTransaction newReadOnlyTransaction() {
  81         return new SnapshotBackedReadTransaction(nextIdentifier(), dataTree.takeSnapshot());
  82     }
  83
  84     @Override
  85     public DOMStoreReadWriteTransaction newReadWriteTransaction() {
  86         return new SnapshotBackedReadWriteTransaction(nextIdentifier(), dataTree.takeSnapshot(), this);
  87     }
  88
  89     @Override
  90     public DOMStoreWriteTransaction newWriteOnlyTransaction() {
  91         return new SnapshotBackedWriteTransaction(nextIdentifier(), dataTree.takeSnapshot(), this);
  92     }
  93
  94     @Override
  95     public DOMStoreTransactionChain createTransactionChain() {
  96         return new DOMStoreTransactionChainImpl();
  97     }
  98
  99     @Override
 100     public synchronized void onGlobalContextUpdated(final SchemaContext ctx) {
 101         dataTree.setSchemaContext(ctx);
 102     }
 103
 104     @Override
 105     public <L extends AsyncDataChangeListener<InstanceIdentifier, NormalizedNode<?, ?>>> ListenerRegistration<L> registerChangeListener(
 106             final InstanceIdentifier path, final L listener, final DataChangeScope scope) {
 107
 108         /*
 109          * Make sure commit is not occurring right now. Listener has to be
 110          * registered and its state capture enqueued at a consistent point.
 111          *
 112          * FIXME: improve this to read-write lock, such that multiple listener
 113          * registrations can occur simultaneously
 114          */
 115         final DataChangeListenerRegistration<L> reg;
 116         synchronized (this) {
 117             LOG.debug("{}: Registering data change listener {} for {}", name, listener, path);
 118
 119             reg = listenerTree.registerDataChangeListener(path, listener, scope);
 120
 121             Optional<NormalizedNode<?, ?>> currentState = dataTree.takeSnapshot().readNode(path);
 122             if (currentState.isPresent()) {
 123                 final NormalizedNode<?, ?> data = currentState.get();
 124
 125                 final DOMImmutableDataChangeEvent event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE) //
 126                         .setAfter(data) //
 127                         .addCreated(path, data) //
 128                         .build();
 129                 executor.submit(new ChangeListenerNotifyTask(Collections.singletonList(reg), event));
 130             }
 131         }
 132
 133         return new AbstractListenerRegistration<L>(listener) {
 134             @Override
 135             protected void removeRegistration() {
 136                 synchronized (InMemoryDOMDataStore.this) {
 137                     reg.close();
 138                 }
 139             }
 140         };
 141     }
 142
 143     @Override
 144     public synchronized DOMStoreThreePhaseCommitCohort ready(final SnapshotBackedWriteTransaction writeTx) {
 145         LOG.debug("Tx: {} is submitted. Modifications: {}", writeTx.getIdentifier(), writeTx.getMutatedView());
 146         return new ThreePhaseCommitImpl(writeTx);
 147     }
 148
 149     private Object nextIdentifier() {
 150         return name + "-" + txCounter.getAndIncrement();
 151     }
 152
 153     private class DOMStoreTransactionChainImpl implements DOMStoreTransactionChain, TransactionReadyPrototype {
 154
 155         @GuardedBy("this")
 156         private SnapshotBackedWriteTransaction latestOutstandingTx;
 157
 158         private boolean chainFailed = false;
 159
 160         private void checkFailed() {
 161             Preconditions.checkState(!chainFailed, "Transaction chain is failed.");
 162         }
 163
 164         @Override
 165         public synchronized DOMStoreReadTransaction newReadOnlyTransaction() {
 166             final DataTreeSnapshot snapshot;
 167             checkFailed();
 168             if (latestOutstandingTx != null) {
 169                 checkState(latestOutstandingTx.isReady(), "Previous transaction in chain must be ready.");
 170                 snapshot = latestOutstandingTx.getMutatedView();
 171             } else {
 172                 snapshot = dataTree.takeSnapshot();
 173             }
 174             return new SnapshotBackedReadTransaction(nextIdentifier(), snapshot);
 175         }
 176
 177         @Override
 178         public synchronized DOMStoreReadWriteTransaction newReadWriteTransaction() {
 179             final DataTreeSnapshot snapshot;
 180             checkFailed();
 181             if (latestOutstandingTx != null) {
 182                 checkState(latestOutstandingTx.isReady(), "Previous transaction in chain must be ready.");
 183                 snapshot = latestOutstandingTx.getMutatedView();
 184             } else {
 185                 snapshot = dataTree.takeSnapshot();
 186             }
 187             final SnapshotBackedReadWriteTransaction ret = new SnapshotBackedReadWriteTransaction(nextIdentifier(),
 188                     snapshot, this);
 189             latestOutstandingTx = ret;
 190             return ret;
 191         }
 192
 193         @Override
 194         public synchronized DOMStoreWriteTransaction newWriteOnlyTransaction() {
 195             final DataTreeSnapshot snapshot;
 196             checkFailed();
 197             if (latestOutstandingTx != null) {
 198                 checkState(latestOutstandingTx.isReady(), "Previous transaction in chain must be ready.");
 199                 snapshot = latestOutstandingTx.getMutatedView();
 200             } else {
 201                 snapshot = dataTree.takeSnapshot();
 202             }
 203             final SnapshotBackedWriteTransaction ret = new SnapshotBackedWriteTransaction(nextIdentifier(), snapshot,
 204                     this);
 205             latestOutstandingTx = ret;
 206             return ret;
 207         }
 208
 209         @Override
 210         public DOMStoreThreePhaseCommitCohort ready(final SnapshotBackedWriteTransaction tx) {
 211             DOMStoreThreePhaseCommitCohort storeCohort = InMemoryDOMDataStore.this.ready(tx);
 212             return new ChainedTransactionCommitImpl(tx, storeCohort, this);
 213         }
 214
 215         @Override
 216         public void close() {
 217
 218         }
 219
 220         protected synchronized void onTransactionFailed(final SnapshotBackedWriteTransaction transaction,
 221                 final Throwable t) {
 222             chainFailed = true;
 223
 224         }
 225
 226         public synchronized void onTransactionCommited(final SnapshotBackedWriteTransaction transaction) {
 227             // If commited transaction is latestOutstandingTx we clear
 228             // latestOutstandingTx
 229             // field in order to base new transactions on Datastore Data Tree
 230             // directly.
 231             if (transaction.equals(latestOutstandingTx)) {
 232                 latestOutstandingTx = null;
 233             }
 234         }
 235
 236     }
 237
 238     private static class ChainedTransactionCommitImpl implements DOMStoreThreePhaseCommitCohort {
 239
 240         private final SnapshotBackedWriteTransaction transaction;
 241         private final DOMStoreThreePhaseCommitCohort delegate;
 242
 243         private final DOMStoreTransactionChainImpl txChain;
 244
 245         protected ChainedTransactionCommitImpl(final SnapshotBackedWriteTransaction transaction,
 246                 final DOMStoreThreePhaseCommitCohort delegate, final DOMStoreTransactionChainImpl txChain) {
 247             super();
 248             this.transaction = transaction;
 249             this.delegate = delegate;
 250             this.txChain = txChain;
 251         }
 252
 253         @Override
 254         public ListenableFuture<Boolean> canCommit() {
 255             return delegate.canCommit();
 256         }
 257
 258         @Override
 259         public ListenableFuture<Void> preCommit() {
 260             return delegate.preCommit();
 261         }
 262
 263         @Override
 264         public ListenableFuture<Void> abort() {
 265             return delegate.abort();
 266         }
 267
 268         @Override
 269         public ListenableFuture<Void> commit() {
 270             ListenableFuture<Void> commitFuture = delegate.commit();
 271             Futures.addCallback(commitFuture, new FutureCallback<Void>() {
 272                 @Override
 273                 public void onFailure(final Throwable t) {
 274                     txChain.onTransactionFailed(transaction, t);
 275                 }
 276
 277                 @Override
 278                 public void onSuccess(final Void result) {
 279                     txChain.onTransactionCommited(transaction);
 280                 }
 281
 282             });
 283             return commitFuture;
 284         }
 285
 286     }
 287
 288     private class ThreePhaseCommitImpl implements DOMStoreThreePhaseCommitCohort {
 289
 290         private final SnapshotBackedWriteTransaction transaction;
 291         private final DataTreeModification modification;
 292
 293         private ResolveDataChangeEventsTask listenerResolver;
 294         private DataTreeCandidate candidate;
 295
 296         public ThreePhaseCommitImpl(final SnapshotBackedWriteTransaction writeTransaction) {
 297             this.transaction = writeTransaction;
 298             this.modification = transaction.getMutatedView();
 299         }
 300
 301         @Override
 302         public ListenableFuture<Boolean> canCommit() {
 303             return executor.submit(new Callable<Boolean>() {
 304                 @Override
 305                 public Boolean call() {
 306                     try {
 307                         dataTree.validate(modification);
 308                         LOG.debug("Store Transaction: {} can be committed", transaction.getIdentifier());
 309                         return true;
 310                     } catch (DataPreconditionFailedException e) {
 311                         LOG.warn("Store Tx: {} Data Precondition failed for {}.", transaction.getIdentifier(),
 312                                 e.getPath(), e);
 313                         return false;
 314                     }
 315                 }
 316             });
 317         }
 318
 319         @Override
 320         public ListenableFuture<Void> preCommit() {
 321             return executor.submit(new Callable<Void>() {
 322                 @Override
 323                 public Void call() {
 324                     candidate = dataTree.prepare(modification);
 325                     listenerResolver = ResolveDataChangeEventsTask.create(candidate, listenerTree);
 326                     return null;
 327                 }
 328             });
 329         }
 330
 331         @Override
 332         public ListenableFuture<Void> abort() {
 333             candidate = null;
 334             return Futures.immediateFuture(null);
 335         }
 336
 337         @Override
 338         public ListenableFuture<Void> commit() {
 339             checkState(candidate != null, "Proposed subtree must be computed");
 340
 341             /*
 342              * The commit has to occur atomically with regard to listener
 343              * registrations.
 344              */
 345             synchronized (this) {
 346                 dataTree.commit(candidate);
 347
 348                 for (ChangeListenerNotifyTask task : listenerResolver.call()) {
 349                     LOG.trace("Scheduling invocation of listeners: {}", task);
 350                     executor.submit(task);
 351                 }
 352             }
 353
 354             return Futures.immediateFuture(null);
 355         }
 356     }
 357 }