opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/FrontendReadOnlyTransaction.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.controller.cluster.datastore;
   9
  10 import com.google.common.base.Optional;
  11 import com.google.common.base.Preconditions;
  12 import javax.annotation.Nullable;
  13 import javax.annotation.concurrent.NotThreadSafe;
  14 import org.opendaylight.controller.cluster.access.commands.ExistsTransactionRequest;
  15 import org.opendaylight.controller.cluster.access.commands.ExistsTransactionSuccess;
  16 import org.opendaylight.controller.cluster.access.commands.ReadTransactionRequest;
  17 import org.opendaylight.controller.cluster.access.commands.ReadTransactionSuccess;
  18 import org.opendaylight.controller.cluster.access.commands.TransactionAbortRequest;
  19 import org.opendaylight.controller.cluster.access.commands.TransactionAbortSuccess;
  20 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  21 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  22 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  23 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  24 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  25 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28
  29 /**
  30  * Read-only frontend transaction state as observed by the shard leader.
  31  *
  32  * @author Robert Varga
  33  */
  34 @NotThreadSafe
  35 final class FrontendReadOnlyTransaction extends FrontendTransaction {
  36     private static final Logger LOG = LoggerFactory.getLogger(FrontendReadOnlyTransaction.class);
  37
  38     private final ReadOnlyShardDataTreeTransaction openTransaction;
  39
  40     private FrontendReadOnlyTransaction(final AbstractFrontendHistory history,
  41             final ReadOnlyShardDataTreeTransaction transaction) {
  42         super(history, transaction.getIdentifier());
  43         this.openTransaction = Preconditions.checkNotNull(transaction);
  44     }
  45
  46     static FrontendReadOnlyTransaction create(final AbstractFrontendHistory history,
  47             final ReadOnlyShardDataTreeTransaction transaction) {
  48         return new FrontendReadOnlyTransaction(history, transaction);
  49     }
  50
  51     // Sequence has already been checked
  52     @Override
  53     @Nullable TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
  54             final long now) throws RequestException {
  55         if (request instanceof ExistsTransactionRequest) {
  56             return handleExistsTransaction((ExistsTransactionRequest) request);
  57         } else if (request instanceof ReadTransactionRequest) {
  58             return handleReadTransaction((ReadTransactionRequest) request);
  59         } else if (request instanceof TransactionAbortRequest) {
  60             handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
  61             return null;
  62         } else {
  63             LOG.warn("Rejecting unsupported request {}", request);
  64             throw new UnsupportedRequestException(request);
  65         }
  66     }
  67
  68     private void handleTransactionAbort(final TransactionAbortRequest request, final RequestEnvelope envelope,
  69             final long now) throws RequestException {
  70         openTransaction.abort(() -> recordAndSendSuccess(envelope, now, new TransactionAbortSuccess(request.getTarget(),
  71             request.getSequence())));
  72     }
  73
  74     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
  75             throws RequestException {
  76         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
  77         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(openTransaction.getIdentifier(),
  78             request.getSequence(), data.isPresent()));
  79     }
  80
  81     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
  82             throws RequestException {
  83         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
  84         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(openTransaction.getIdentifier(),
  85             request.getSequence(), data));
  86     }
  87 }