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         outstanding = total;
  36     }
  37
  38     static BatchedExistenceCheck start(final DOMDataTreeReadOperations tx, final LogicalDatastoreType datastore,
  39             final YangInstanceIdentifier parentPath, final Collection<? extends NormalizedNode> children) {
  40         final var ret = new BatchedExistenceCheck(children.size());
  41         for (var child : children) {
  42             final var path = parentPath.node(child.name());
  43             tx.exists(datastore, path).addCallback(new FutureCallback<Boolean>() {
  44                 @Override
  45                 public void onSuccess(final Boolean result) {
  46                     ret.complete(path, result);
  47                 }
  48
  49                 @Override
  50                 @SuppressFBWarnings("BC_UNCONFIRMED_CAST_OF_RETURN_VALUE")
  51                 public void onFailure(final Throwable throwable) {
  52                     final Exception e;
  53                     if (throwable instanceof Exception) {
  54                         e = (Exception) throwable;
  55                     } else {
  56                         e = new ExecutionException(throwable);
  57                     }
  58
  59                     ret.complete(path, ReadFailedException.MAPPER.apply(e));
  60                 }
  61             }, MoreExecutors.directExecutor());
  62         }
  63         return ret;
  64     }
  65
  66     Entry<YangInstanceIdentifier, ReadFailedException> getFailure() throws InterruptedException {
  67         try {
  68             return future.get();
  69         } catch (ExecutionException e) {
  70             // This should never happen
  71             throw new IllegalStateException(e);
  72         }
  73     }
  74
  75     private void complete(final YangInstanceIdentifier childPath, final boolean present) {
  76         final int count = UPDATER.decrementAndGet(this);
  77         if (present) {
  78             future.set(new SimpleImmutableEntry<>(childPath, null));
  79         } else if (count == 0) {
  80             future.set(null);
  81         }
  82     }
  83
  84     private void complete(final YangInstanceIdentifier childPath, final ReadFailedException cause) {
  85         UPDATER.decrementAndGet(this);
  86         future.set(new SimpleImmutableEntry<>(childPath, cause));
  87     }
  88 }