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 static com.google.common.base.Preconditions.checkArgument;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import java.util.Optional;
  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.ModifyTransactionRequest;
  17 import org.opendaylight.controller.cluster.access.commands.ModifyTransactionSuccess;
  18 import org.opendaylight.controller.cluster.access.commands.PersistenceProtocol;
  19 import org.opendaylight.controller.cluster.access.commands.ReadTransactionRequest;
  20 import org.opendaylight.controller.cluster.access.commands.ReadTransactionSuccess;
  21 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  22 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  23 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  24 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  25 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  26 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29
  30 /**
  31  * Read-only frontend transaction state as observed by the shard leader. This class is NOT thread-safe.
  32  *
  33  * @author Robert Varga
  34  */
  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 = requireNonNull(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     TransactionSuccess<?> doHandleRequest(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 ModifyTransactionRequest) {
  60             handleModifyTransaction((ModifyTransactionRequest) request, envelope, now);
  61             return null;
  62         } else {
  63             LOG.warn("Rejecting unsupported request {}", request);
  64             throw new UnsupportedRequestException(request);
  65         }
  66     }
  67
  68     @Override
  69     void retire() {
  70         // No-op
  71     }
  72
  73     private void handleModifyTransaction(final ModifyTransactionRequest request, final RequestEnvelope envelope,
  74             final long now) {
  75         // The only valid request here is with abort protocol
  76         final Optional<PersistenceProtocol> optProto = request.getPersistenceProtocol();
  77         checkArgument(optProto.isPresent(), "Commit protocol is missing in %s", request);
  78         checkArgument(optProto.get() == PersistenceProtocol.ABORT, "Unsupported commit protocol in %s", request);
  79         openTransaction.abort(() -> recordAndSendSuccess(envelope, now,
  80             new ModifyTransactionSuccess(request.getTarget(), request.getSequence())));
  81     }
  82
  83     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request) {
  84         final Optional<NormalizedNode> data = openTransaction.getSnapshot().readNode(request.getPath());
  85         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(openTransaction.getIdentifier(),
  86             request.getSequence(), data.isPresent()));
  87     }
  88
  89     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request) {
  90         final Optional<NormalizedNode> data = openTransaction.getSnapshot().readNode(request.getPath());
  91         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(openTransaction.getIdentifier(),
  92             request.getSequence(), data));
  93     }
  94 }