dom/mdsal-dom-broker/src/main/java/org/opendaylight/mdsal/dom/broker/ShardedDOMReadTransactionAdapter.java

   1 /*
   2  * Copyright (c) 2016 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 static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import com.google.common.util.concurrent.FluentFuture;
  14 import com.google.common.util.concurrent.MoreExecutors;
  15 import com.google.common.util.concurrent.SettableFuture;
  16 import java.util.ArrayList;
  17 import java.util.Collection;
  18 import java.util.Collections;
  19 import java.util.List;
  20 import java.util.Map;
  21 import java.util.Optional;
  22 import org.eclipse.jdt.annotation.NonNull;
  23 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  24 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  25 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  26 import org.opendaylight.mdsal.dom.api.DOMDataTreeListeningException;
  27 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  28 import org.opendaylight.mdsal.dom.api.DOMDataTreeReadTransaction;
  29 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  30 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  31 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  32 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  33 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  34 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37
  38 public class ShardedDOMReadTransactionAdapter implements DOMDataTreeReadTransaction {
  39     private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMReadTransactionAdapter.class.getName());
  40
  41     private final List<ListenerRegistration<DOMDataTreeListener>> registrations = new ArrayList<>();
  42     private final @NonNull DOMDataTreeService service;
  43     private final @NonNull Object txIdentifier;
  44
  45     private boolean finished = false;
  46
  47     ShardedDOMReadTransactionAdapter(final Object identifier, final DOMDataTreeService service) {
  48         this.service = requireNonNull(service);
  49         this.txIdentifier = requireNonNull(identifier);
  50     }
  51
  52     @Override
  53     public void close() {
  54         LOG.debug("{}: Closing read transaction", txIdentifier);
  55         if (finished) {
  56             return;
  57         }
  58
  59         registrations.forEach(ListenerRegistration::close);
  60         // TODO should we also cancel all read futures?
  61         finished = true;
  62     }
  63
  64     @Override
  65     public Object getIdentifier() {
  66         return txIdentifier;
  67     }
  68
  69     @Override
  70     public FluentFuture<Optional<NormalizedNode<?, ?>>> read(final LogicalDatastoreType store,
  71             final YangInstanceIdentifier path) {
  72         checkRunning();
  73         LOG.debug("{}: Invoking read at {}:{}", txIdentifier, store, path);
  74         final ListenerRegistration<DOMDataTreeListener> reg;
  75         final SettableFuture<Optional<NormalizedNode<?, ?>>> initialDataTreeChangeFuture = SettableFuture.create();
  76         try {
  77             reg = service.registerListener(new ReadShardedListener(initialDataTreeChangeFuture),
  78                     Collections.singleton(new DOMDataTreeIdentifier(store, path)), false, Collections.emptyList());
  79             registrations.add(reg);
  80         } catch (final DOMDataTreeLoopException e) {
  81             // This should not happen, we are not specifying any producers when registering listener
  82             throw new IllegalStateException("Loop in listener and producers detected", e);
  83         }
  84
  85         // After data tree change future is finished, we can close the listener registration
  86         initialDataTreeChangeFuture.addListener(reg::close, MoreExecutors.directExecutor());
  87         return FluentFuture.from(initialDataTreeChangeFuture);
  88     }
  89
  90     @Override
  91     public FluentFuture<Boolean> exists(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  92         checkRunning();
  93         LOG.debug("{}: Invoking exists at {}:{}", txIdentifier, store, path);
  94         return read(store, path).transform(Optional::isPresent, MoreExecutors.directExecutor());
  95     }
  96
  97     private void checkRunning() {
  98         checkState(!finished, "Transaction is already closed");
  99     }
 100
 101     static final class ReadShardedListener implements DOMDataTreeListener {
 102         private final SettableFuture<Optional<NormalizedNode<?, ?>>> readResultFuture;
 103
 104         ReadShardedListener(final SettableFuture<Optional<NormalizedNode<?, ?>>> future) {
 105             this.readResultFuture = requireNonNull(future);
 106         }
 107
 108         @Override
 109         public void onDataTreeChanged(final Collection<DataTreeCandidate> changes,
 110                 final Map<DOMDataTreeIdentifier, NormalizedNode<?, ?>> subtrees) {
 111             checkState(changes.size() == 1 && subtrees.size() == 1,
 112                     "DOMDataTreeListener registered exactly on one subtree");
 113             if (changes.iterator().next().getRootNode().getModificationType().equals(ModificationType.UNMODIFIED)) {
 114                 readResultFuture.set(Optional.empty());
 115             } else {
 116                 readResultFuture.set(Optional.of(subtrees.values().iterator().next()));
 117             }
 118         }
 119
 120         @Override
 121         public void onDataTreeFailed(final Collection<DOMDataTreeListeningException> causes) {
 122             // TODO If we get just one exception, we don't need to do chaining
 123
 124             // We chain all exceptions and return aggregated one
 125             readResultFuture.setException(new DOMDataTreeListeningException("Aggregated DOMDataTreeListening exception",
 126                     causes.stream().reduce((e1, e2) -> {
 127                         e1.addSuppressed(e2);
 128                         return e1;
 129                     }).get()));
 130         }
 131     }
 132 }