restconf/restconf-nb-bierman02/src/main/java/org/opendaylight/netconf/sal/restconf/impl/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.netconf.sal.restconf.impl;
   9
  10 import com.google.common.util.concurrent.FutureCallback;
  11 import com.google.common.util.concurrent.Futures;
  12 import com.google.common.util.concurrent.ListenableFuture;
  13 import com.google.common.util.concurrent.MoreExecutors;
  14 import com.google.common.util.concurrent.SettableFuture;
  15 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  16 import java.util.AbstractMap.SimpleImmutableEntry;
  17 import java.util.Collection;
  18 import java.util.Map.Entry;
  19 import java.util.concurrent.ExecutionException;
  20 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
  21 import javax.annotation.Nonnull;
  22 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  23 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
  24 import org.opendaylight.controller.md.sal.dom.api.DOMDataReadTransaction;
  25 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  26 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  27
  28 final class BatchedExistenceCheck {
  29     private static final AtomicIntegerFieldUpdater<BatchedExistenceCheck> UPDATER =
  30             AtomicIntegerFieldUpdater.newUpdater(BatchedExistenceCheck.class, "outstanding");
  31
  32     private final SettableFuture<Entry<YangInstanceIdentifier, ReadFailedException>> future = SettableFuture.create();
  33
  34     @SuppressWarnings("unused")
  35     private volatile int outstanding;
  36
  37     private BatchedExistenceCheck(final int total) {
  38         this.outstanding = total;
  39     }
  40
  41     static BatchedExistenceCheck start(final DOMDataReadTransaction readTx,
  42             final LogicalDatastoreType datastore, final YangInstanceIdentifier parentPath,
  43             final Collection<? extends NormalizedNode<?, ?>> children) {
  44         final BatchedExistenceCheck ret = new BatchedExistenceCheck(children.size());
  45         for (NormalizedNode<?, ?> child : children) {
  46             final YangInstanceIdentifier path = parentPath.node(child.getIdentifier());
  47             final ListenableFuture<Boolean> f = readTx.exists(datastore, path);
  48             Futures.addCallback(f, new FutureCallback<Boolean>() {
  49                 @Override
  50                 public void onSuccess(@Nonnull final Boolean result) {
  51                     ret.complete(path, result.booleanValue());
  52                 }
  53
  54                 @Override
  55                 @SuppressFBWarnings("BC_UNCONFIRMED_CAST_OF_RETURN_VALUE")
  56                 public void onFailure(final Throwable throwable) {
  57                     final Exception e;
  58                     if (throwable instanceof Exception) {
  59                         e = (Exception) throwable;
  60                     } else {
  61                         e = new ExecutionException(throwable);
  62                     }
  63
  64                     ret.complete(path, ReadFailedException.MAPPER.apply(e));
  65                 }
  66             }, MoreExecutors.directExecutor());
  67         }
  68
  69         return ret;
  70     }
  71
  72     Entry<YangInstanceIdentifier, ReadFailedException> getFailure() throws InterruptedException {
  73         try {
  74             return future.get();
  75         } catch (ExecutionException e) {
  76             // This should never happen
  77             throw new IllegalStateException(e);
  78         }
  79     }
  80
  81     private void complete(final YangInstanceIdentifier childPath, final boolean present) {
  82         final int count = UPDATER.decrementAndGet(this);
  83         if (present) {
  84             future.set(new SimpleImmutableEntry<>(childPath, null));
  85         } else if (count == 0) {
  86             future.set(null);
  87         }
  88     }
  89
  90     private void complete(final YangInstanceIdentifier childPath, final ReadFailedException cause) {
  91         UPDATER.decrementAndGet(this);
  92         future.set(new SimpleImmutableEntry<>(childPath, cause));
  93     }
  94 }