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
   9 package org.opendaylight.mdsal.dom.broker;
  10
  11 import com.google.common.base.Function;
  12 import com.google.common.base.Optional;
  13 import com.google.common.base.Preconditions;
  14 import com.google.common.collect.Lists;
  15 import com.google.common.util.concurrent.CheckedFuture;
  16 import com.google.common.util.concurrent.FutureCallback;
  17 import com.google.common.util.concurrent.Futures;
  18 import com.google.common.util.concurrent.ListenableFuture;
  19 import com.google.common.util.concurrent.SettableFuture;
  20 import java.util.Collection;
  21 import java.util.Collections;
  22 import java.util.List;
  23 import java.util.Map;
  24 import javax.annotation.Nullable;
  25 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  26 import org.opendaylight.mdsal.common.api.ReadFailedException;
  27 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  28 import org.opendaylight.mdsal.dom.api.DOMDataTreeListener;
  29 import org.opendaylight.mdsal.dom.api.DOMDataTreeListeningException;
  30 import org.opendaylight.mdsal.dom.api.DOMDataTreeLoopException;
  31 import org.opendaylight.mdsal.dom.api.DOMDataTreeReadTransaction;
  32 import org.opendaylight.mdsal.dom.api.DOMDataTreeService;
  33 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  34 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  35 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  36 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  37 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  38 import org.slf4j.Logger;
  39 import org.slf4j.LoggerFactory;
  40
  41 public class ShardedDOMReadTransactionAdapter implements DOMDataTreeReadTransaction {
  42
  43     private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMReadTransactionAdapter.class.getName());
  44
  45     private final List<ListenerRegistration<DOMDataTreeListener>> registrations = Lists.newArrayList();
  46     private final DOMDataTreeService service;
  47     private final Object txIdentifier;
  48
  49     private boolean finished = false;
  50
  51     ShardedDOMReadTransactionAdapter(final Object identifier, final DOMDataTreeService service) {
  52         this.service = Preconditions.checkNotNull(service);
  53         this.txIdentifier = Preconditions.checkNotNull(identifier);
  54     }
  55
  56     @Override
  57     public void close() {
  58         // TODO should we also cancel all read futures?
  59         LOG.debug("{}: Closing read transaction", txIdentifier);
  60         if (finished == true) {
  61             return;
  62         }
  63
  64         registrations.forEach(ListenerRegistration::close);
  65         finished = true;
  66     }
  67
  68     @Override
  69     public Object getIdentifier() {
  70         return txIdentifier;
  71     }
  72
  73     @Override
  74     public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(final LogicalDatastoreType store,
  75             final YangInstanceIdentifier path) {
  76         checkRunning();
  77         LOG.debug("{}: Invoking read at {}:{}", txIdentifier, store, path);
  78         final ListenerRegistration<DOMDataTreeListener> reg;
  79         final SettableFuture<Optional<NormalizedNode<?, ?>>> initialDataTreeChangeFuture = SettableFuture.create();
  80         try {
  81             reg = service.registerListener(new ReadShardedListener(initialDataTreeChangeFuture),
  82                     Collections.singleton(new DOMDataTreeIdentifier(store, path)), false, Collections.emptyList());
  83             registrations.add(reg);
  84         } catch (final DOMDataTreeLoopException e) {
  85             // This should not happen, we are not specifying any
  86             // producers when registering listener
  87             throw new IllegalStateException("Loop in listener and producers detected", e);
  88         }
  89
  90         // After data tree change future is finished, we can close the listener registration
  91         Futures.addCallback(initialDataTreeChangeFuture, new FutureCallback<Optional<NormalizedNode<?, ?>>>() {
  92             @Override
  93             public void onSuccess(@Nullable final Optional<NormalizedNode<?, ?>> result) {
  94                 reg.close();
  95             }
  96
  97             @Override
  98             public void onFailure(final Throwable throwable) {
  99                 reg.close();
 100             }
 101         });
 102
 103         return Futures.makeChecked(initialDataTreeChangeFuture, ReadFailedException.MAPPER);
 104     }
 105
 106     @Override
 107     public CheckedFuture<Boolean, ReadFailedException> exists(final LogicalDatastoreType store,
 108             final YangInstanceIdentifier path) {
 109         checkRunning();
 110         LOG.debug("{}: Invoking exists at {}:{}", txIdentifier, store, path);
 111         final Function<Optional<NormalizedNode<?, ?>>, Boolean> transform =
 112             optionalNode -> optionalNode.isPresent() ? Boolean.TRUE : Boolean.FALSE;
 113         final ListenableFuture<Boolean> existsResult = Futures.transform(read(store, path), transform);
 114         return Futures.makeChecked(existsResult, ReadFailedException.MAPPER);
 115     }
 116
 117     private void checkRunning() {
 118         Preconditions.checkState(finished == false, "Transaction is already closed");
 119     }
 120
 121     static class ReadShardedListener implements DOMDataTreeListener {
 122
 123         private final SettableFuture<Optional<NormalizedNode<?, ?>>> readResultFuture;
 124
 125         ReadShardedListener(final SettableFuture<Optional<NormalizedNode<?, ?>>> future) {
 126             this.readResultFuture = Preconditions.checkNotNull(future);
 127         }
 128
 129         @Override
 130         public void onDataTreeChanged(final Collection<DataTreeCandidate> changes,
 131                 final Map<DOMDataTreeIdentifier, NormalizedNode<?, ?>> subtrees) {
 132             Preconditions.checkState(changes.size() == 1 && subtrees.size() == 1,
 133                     "DOMDataTreeListener registered exactly on one subtree");
 134
 135             for (final DataTreeCandidate change : changes) {
 136                 if (change.getRootNode().getModificationType().equals(ModificationType.UNMODIFIED)) {
 137                     readResultFuture.set(Optional.absent());
 138                     return;
 139                 }
 140             }
 141
 142             for (final NormalizedNode<?, ?> initialState : subtrees.values()) {
 143                 readResultFuture.set(Optional.of(initialState));
 144             }
 145         }
 146
 147         @Override
 148         public void onDataTreeFailed(final Collection<DOMDataTreeListeningException> causes) {
 149             // TODO If we get just one exception, we don't need to do
 150             // chaining
 151
 152             // We chain all exceptions and return aggregated one
 153             readResultFuture.setException(new DOMDataTreeListeningException("Aggregated DOMDataTreeListening exception",
 154                     causes.stream().reduce((e1, e2) -> {
 155                         e1.addSuppressed(e2);
 156                         return e1;
 157                     }).get()));
 158         }
 159     }
 160 }