opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/AbstractFrontendHistory.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.Preconditions;
  11 import java.util.HashMap;
  12 import java.util.Map;
  13 import java.util.Optional;
  14 import javax.annotation.Nullable;
  15 import org.opendaylight.controller.cluster.access.commands.CommitLocalTransactionRequest;
  16 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
  17 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  18 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  19 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  20 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  21 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  22 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  23 import org.opendaylight.yangtools.concepts.Identifiable;
  24 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  25 import org.slf4j.Logger;
  26 import org.slf4j.LoggerFactory;
  27
  28 /**
  29  * Abstract class for providing logical tracking of frontend local histories. This class is specialized for
  30  * standalone transactions and chained transactions.
  31  *
  32  * @author Robert Varga
  33  */
  34 abstract class AbstractFrontendHistory implements Identifiable<LocalHistoryIdentifier> {
  35     private static final Logger LOG = LoggerFactory.getLogger(AbstractFrontendHistory.class);
  36     private static final OutOfOrderRequestException UNSEQUENCED_START = new OutOfOrderRequestException(0);
  37
  38     private final Map<TransactionIdentifier, FrontendTransaction> transactions = new HashMap<>();
  39     private final String persistenceId;
  40
  41     AbstractFrontendHistory(final String persistenceId) {
  42         this.persistenceId = Preconditions.checkNotNull(persistenceId);
  43     }
  44
  45     final String persistenceId() {
  46         return persistenceId;
  47     }
  48
  49     final @Nullable TransactionSuccess<?> handleTransactionRequest(final TransactionRequest<?> request,
  50             final RequestEnvelope envelope) throws RequestException {
  51
  52         // FIXME: handle purging of transactions
  53
  54         final TransactionIdentifier id = request.getTarget();
  55         FrontendTransaction tx = transactions.get(id);
  56         if (tx == null) {
  57             // The transaction does not exist and we are about to create it, check sequence number
  58             if (request.getSequence() != 0) {
  59                 LOG.debug("{}: no transaction state present, unexpected request {}", persistenceId(), request);
  60                 throw UNSEQUENCED_START;
  61             }
  62
  63             if (request instanceof CommitLocalTransactionRequest) {
  64                 tx = createReadyTransaction(id, ((CommitLocalTransactionRequest) request).getModification());
  65                 LOG.debug("{}: allocated new ready transaction {}", persistenceId(), id);
  66             } else {
  67                 tx = createOpenTransaction(id);
  68                 LOG.debug("{}: allocated new open transaction {}", persistenceId(), id);
  69             }
  70
  71             transactions.put(id, tx);
  72         } else {
  73             final Optional<TransactionSuccess<?>> replay = tx.replaySequence(request.getSequence());
  74             if (replay.isPresent()) {
  75                 return replay.get();
  76             }
  77         }
  78
  79         return tx.handleRequest(request, envelope);
  80     }
  81
  82     abstract FrontendTransaction createOpenTransaction(TransactionIdentifier id) throws RequestException;
  83
  84     abstract FrontendTransaction createReadyTransaction(TransactionIdentifier id, DataTreeModification mod)
  85         throws RequestException;
  86
  87     abstract ShardDataTreeCohort createReadyCohort(final TransactionIdentifier id, final DataTreeModification mod);
  88 }