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
  27 /**
  28  * Read-only frontend transaction state as observed by the shard leader.
  29  *
  30  * @author Robert Varga
  31  */
  32 @NotThreadSafe
  33 final class FrontendReadOnlyTransaction extends FrontendTransaction {
  34     private final ReadOnlyShardDataTreeTransaction openTransaction;
  35
  36     private FrontendReadOnlyTransaction(final AbstractFrontendHistory history,
  37             final ReadOnlyShardDataTreeTransaction transaction) {
  38         super(history, transaction.getIdentifier());
  39         this.openTransaction = Preconditions.checkNotNull(transaction);
  40     }
  41
  42     static FrontendReadOnlyTransaction create(final AbstractFrontendHistory history,
  43             final ReadOnlyShardDataTreeTransaction transaction) {
  44         return new FrontendReadOnlyTransaction(history, transaction);
  45     }
  46
  47     // Sequence has already been checked
  48     @Override
  49     @Nullable TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
  50             final long now) throws RequestException {
  51         if (request instanceof ExistsTransactionRequest) {
  52             return handleExistsTransaction((ExistsTransactionRequest) request);
  53         } else if (request instanceof ReadTransactionRequest) {
  54             return handleReadTransaction((ReadTransactionRequest) request);
  55         } else if (request instanceof TransactionAbortRequest) {
  56             handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
  57             return null;
  58         } else {
  59             throw new UnsupportedRequestException(request);
  60         }
  61     }
  62
  63     private void handleTransactionAbort(final TransactionAbortRequest request, final RequestEnvelope envelope,
  64             final long now) throws RequestException {
  65         openTransaction.abort(() -> recordAndSendSuccess(envelope, now, new TransactionAbortSuccess(request.getTarget(),
  66             request.getSequence())));
  67     }
  68
  69     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
  70             throws RequestException {
  71         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
  72         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(openTransaction.getIdentifier(),
  73             request.getSequence(), data.isPresent()));
  74     }
  75
  76     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
  77             throws RequestException {
  78         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
  79         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(openTransaction.getIdentifier(),
  80             request.getSequence(), data));
  81     }
  82 }