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 com.google.common.base.Ticker;
  12 import java.util.HashMap;
  13 import java.util.Map;
  14 import java.util.Optional;
  15 import javax.annotation.Nullable;
  16 import org.opendaylight.controller.cluster.access.commands.CommitLocalTransactionRequest;
  17 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
  18 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  19 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  20 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  21 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  22 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  23 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  24 import org.opendaylight.yangtools.concepts.Identifiable;
  25 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28
  29 /**
  30  * Abstract class for providing logical tracking of frontend local histories. This class is specialized for
  31  * standalone transactions and chained transactions.
  32  *
  33  * @author Robert Varga
  34  */
  35 abstract class AbstractFrontendHistory implements Identifiable<LocalHistoryIdentifier> {
  36     private static final Logger LOG = LoggerFactory.getLogger(AbstractFrontendHistory.class);
  37     private static final OutOfOrderRequestException UNSEQUENCED_START = new OutOfOrderRequestException(0);
  38
  39     private final Map<TransactionIdentifier, FrontendTransaction> transactions = new HashMap<>();
  40     private final String persistenceId;
  41     private final Ticker ticker;
  42
  43     AbstractFrontendHistory(final String persistenceId, final Ticker ticker) {
  44         this.persistenceId = Preconditions.checkNotNull(persistenceId);
  45         this.ticker = Preconditions.checkNotNull(ticker);
  46     }
  47
  48     final String persistenceId() {
  49         return persistenceId;
  50     }
  51
  52     final long readTime() {
  53         return ticker.read();
  54     }
  55
  56     final @Nullable TransactionSuccess<?> handleTransactionRequest(final TransactionRequest<?> request,
  57             final RequestEnvelope envelope, final long now) throws RequestException {
  58
  59         // FIXME: handle purging of transactions
  60
  61         final TransactionIdentifier id = request.getTarget();
  62         FrontendTransaction tx = transactions.get(id);
  63         if (tx == null) {
  64             // The transaction does not exist and we are about to create it, check sequence number
  65             if (request.getSequence() != 0) {
  66                 LOG.debug("{}: no transaction state present, unexpected request {}", persistenceId(), request);
  67                 throw UNSEQUENCED_START;
  68             }
  69
  70             if (request instanceof CommitLocalTransactionRequest) {
  71                 tx = createReadyTransaction(id, ((CommitLocalTransactionRequest) request).getModification());
  72                 LOG.debug("{}: allocated new ready transaction {}", persistenceId(), id);
  73             } else {
  74                 tx = createOpenTransaction(id);
  75                 LOG.debug("{}: allocated new open transaction {}", persistenceId(), id);
  76             }
  77
  78             transactions.put(id, tx);
  79         } else {
  80             final Optional<TransactionSuccess<?>> maybeReplay = tx.replaySequence(request.getSequence());
  81             if (maybeReplay.isPresent()) {
  82                 final TransactionSuccess<?> replay = maybeReplay.get();
  83                 LOG.debug("{}: envelope {} replaying response {}", persistenceId(), envelope, replay);
  84                 return replay;
  85             }
  86         }
  87
  88         return tx.handleRequest(request, envelope, now);
  89     }
  90
  91     abstract FrontendTransaction createOpenTransaction(TransactionIdentifier id) throws RequestException;
  92
  93     abstract FrontendTransaction createReadyTransaction(TransactionIdentifier id, DataTreeModification mod)
  94         throws RequestException;
  95
  96     abstract ShardDataTreeCohort createReadyCohort(final TransactionIdentifier id, final DataTreeModification mod);
  97 }