restconf/restconf-nb/src/main/java/org/opendaylight/restconf/nb/rfc8040/rests/transactions/BatchedExistenceCheck.java

   1 /*
   2  * Copyright (c) 2017 Pantheon Technologies, s.r.o. 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.restconf.nb.rfc8040.rests.transactions;
   9
  10 import com.google.common.util.concurrent.FutureCallback;
  11 import com.google.common.util.concurrent.MoreExecutors;
  12 import com.google.common.util.concurrent.SettableFuture;
  13 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  14 import java.util.AbstractMap.SimpleImmutableEntry;
  15 import java.util.Collection;
  16 import java.util.Map.Entry;
  17 import java.util.concurrent.ExecutionException;
  18 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
  19 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  20 import org.opendaylight.mdsal.common.api.ReadFailedException;
  21 import org.opendaylight.mdsal.dom.api.DOMDataTreeReadOperations;
  22 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  23 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  24
  25 final class BatchedExistenceCheck {
  26     private static final AtomicIntegerFieldUpdater<BatchedExistenceCheck> UPDATER =
  27         AtomicIntegerFieldUpdater.newUpdater(BatchedExistenceCheck.class, "outstanding");
  28
  29     private final SettableFuture<Entry<YangInstanceIdentifier, ReadFailedException>> future = SettableFuture.create();
  30
  31     @SuppressWarnings("unused")
  32     private volatile int outstanding;
  33
  34     private BatchedExistenceCheck(final int total) {
  35         this.outstanding = total;
  36     }
  37
  38     static BatchedExistenceCheck start(final DOMDataTreeReadOperations tx,
  39                                        final LogicalDatastoreType datastore, final YangInstanceIdentifier parentPath,
  40                                        final Collection<? extends NormalizedNode> children) {
  41         final BatchedExistenceCheck ret = new BatchedExistenceCheck(children.size());
  42         for (NormalizedNode child : children) {
  43             final YangInstanceIdentifier path = parentPath.node(child.getIdentifier());
  44             tx.exists(datastore, path).addCallback(new FutureCallback<Boolean>() {
  45                 @Override
  46                 public void onSuccess(final Boolean result) {
  47                     ret.complete(path, result);
  48                 }
  49
  50                 @Override
  51                 @SuppressFBWarnings("BC_UNCONFIRMED_CAST_OF_RETURN_VALUE")
  52                 public void onFailure(final Throwable throwable) {
  53                     final Exception e;
  54                     if (throwable instanceof Exception) {
  55                         e = (Exception) throwable;
  56                     } else {
  57                         e = new ExecutionException(throwable);
  58                     }
  59
  60                     ret.complete(path, ReadFailedException.MAPPER.apply(e));
  61                 }
  62             }, MoreExecutors.directExecutor());
  63         }
  64         return ret;
  65     }
  66
  67     Entry<YangInstanceIdentifier, ReadFailedException> getFailure() throws InterruptedException {
  68         try {
  69             return future.get();
  70         } catch (ExecutionException e) {
  71             // This should never happen
  72             throw new IllegalStateException(e);
  73         }
  74     }
  75
  76     private void complete(final YangInstanceIdentifier childPath, final boolean present) {
  77         final int count = UPDATER.decrementAndGet(this);
  78         if (present) {
  79             future.set(new SimpleImmutableEntry<>(childPath, null));
  80         } else if (count == 0) {
  81             future.set(null);
  82         }
  83     }
  84
  85     private void complete(final YangInstanceIdentifier childPath, final ReadFailedException cause) {
  86         UPDATER.decrementAndGet(this);
  87         future.set(new SimpleImmutableEntry<>(childPath, cause));
  88     }
  89 }