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 com.google.common.base.Preconditions;
  11 import com.google.common.collect.Lists;
  12 import com.google.common.util.concurrent.FluentFuture;
  13 import com.google.common.util.concurrent.FutureCallback;
  14 import com.google.common.util.concurrent.MoreExecutors;
  15 import com.google.common.util.concurrent.SettableFuture;
  16 import java.util.Collection;
  17 import java.util.Collections;
  18 import java.util.List;
  19 import java.util.Map;
  20 import java.util.Optional;
  21 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  22 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  23 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  24 import org.opendaylight.mdsal.dom.api.DOMDataTreeListeningException;
  25 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  26 import org.opendaylight.mdsal.dom.api.DOMDataTreeReadTransaction;
  27 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  28 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  29 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  30 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  31 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  32 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 public class ShardedDOMReadTransactionAdapter implements DOMDataTreeReadTransaction {
  37
  38     private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMReadTransactionAdapter.class.getName());
  39
  40     private final List<ListenerRegistration<DOMDataTreeListener>> registrations = Lists.newArrayList();
  41     private final DOMDataTreeService service;
  42     private final Object txIdentifier;
  43
  44     private boolean finished = false;
  45
  46     ShardedDOMReadTransactionAdapter(final Object identifier, final DOMDataTreeService service) {
  47         this.service = Preconditions.checkNotNull(service);
  48         this.txIdentifier = Preconditions.checkNotNull(identifier);
  49     }
  50
  51     @Override
  52     public void close() {
  53         // TODO should we also cancel all read futures?
  54         LOG.debug("{}: Closing read transaction", txIdentifier);
  55         if (finished) {
  56             return;
  57         }
  58
  59         registrations.forEach(ListenerRegistration::close);
  60         finished = true;
  61     }
  62
  63     @Override
  64     public Object getIdentifier() {
  65         return txIdentifier;
  66     }
  67
  68     @Override
  69     public FluentFuture<Optional<NormalizedNode<?, ?>>> read(final LogicalDatastoreType store,
  70             final YangInstanceIdentifier path) {
  71         checkRunning();
  72         LOG.debug("{}: Invoking read at {}:{}", txIdentifier, store, path);
  73         final ListenerRegistration<DOMDataTreeListener> reg;
  74         final SettableFuture<Optional<NormalizedNode<?, ?>>> initialDataTreeChangeFuture = SettableFuture.create();
  75         try {
  76             reg = service.registerListener(new ReadShardedListener(initialDataTreeChangeFuture),
  77                     Collections.singleton(new DOMDataTreeIdentifier(store, path)), false, Collections.emptyList());
  78             registrations.add(reg);
  79         } catch (final DOMDataTreeLoopException e) {
  80             // This should not happen, we are not specifying any
  81             // 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.addCallback(new FutureCallback<Optional<NormalizedNode<?, ?>>>() {
  87             @Override
  88             public void onSuccess(final Optional<NormalizedNode<?, ?>> result) {
  89                 reg.close();
  90             }
  91
  92             @Override
  93             public void onFailure(final Throwable throwable) {
  94                 reg.close();
  95             }
  96         }, MoreExecutors.directExecutor());
  97
  98         return initialDataTreeChangeFuture;
  99     }
 100
 101     @Override
 102     public FluentFuture<Boolean> exists(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
 103         checkRunning();
 104         LOG.debug("{}: Invoking exists at {}:{}", txIdentifier, store, path);
 105         return read(store, path).transform(Optional::isPresent, MoreExecutors.directExecutor());
 106     }
 107
 108     private void checkRunning() {
 109         Preconditions.checkState(!finished, "Transaction is already closed");
 110     }
 111
 112     static class ReadShardedListener implements DOMDataTreeListener {
 113
 114         private final SettableFuture<Optional<NormalizedNode<?, ?>>> readResultFuture;
 115
 116         ReadShardedListener(final SettableFuture<Optional<NormalizedNode<?, ?>>> future) {
 117             this.readResultFuture = Preconditions.checkNotNull(future);
 118         }
 119
 120         @Override
 121         public void onDataTreeChanged(final Collection<DataTreeCandidate> changes,
 122                 final Map<DOMDataTreeIdentifier, NormalizedNode<?, ?>> subtrees) {
 123             Preconditions.checkState(changes.size() == 1 && subtrees.size() == 1,
 124                     "DOMDataTreeListener registered exactly on one subtree");
 125
 126             for (final DataTreeCandidate change : changes) {
 127                 if (change.getRootNode().getModificationType().equals(ModificationType.UNMODIFIED)) {
 128                     readResultFuture.set(Optional.empty());
 129                     return;
 130                 }
 131             }
 132
 133             for (final NormalizedNode<?, ?> initialState : subtrees.values()) {
 134                 readResultFuture.set(Optional.of(initialState));
 135             }
 136         }
 137
 138         @Override
 139         public void onDataTreeFailed(final Collection<DOMDataTreeListeningException> causes) {
 140             // TODO If we get just one exception, we don't need to do
 141             // chaining
 142
 143             // We chain all exceptions and return aggregated one
 144             readResultFuture.setException(new DOMDataTreeListeningException("Aggregated DOMDataTreeListening exception",
 145                     causes.stream().reduce((e1, e2) -> {
 146                         e1.addSuppressed(e2);
 147                         return e1;
 148                     }).get()));
 149         }
 150     }
 151 }