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.AbstractReadTransactionRequest;
  17 import org.opendaylight.controller.cluster.access.commands.CommitLocalTransactionRequest;
  18 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
  19 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  20 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  21 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
  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.TransactionIdentifier;
  25 import org.opendaylight.yangtools.concepts.Identifiable;
  26 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29
  30 /**
  31  * Abstract class for providing logical tracking of frontend local histories. This class is specialized for
  32  * standalone transactions and chained transactions.
  33  *
  34  * @author Robert Varga
  35  */
  36 abstract class AbstractFrontendHistory implements Identifiable<LocalHistoryIdentifier> {
  37     private static final Logger LOG = LoggerFactory.getLogger(AbstractFrontendHistory.class);
  38     private static final OutOfOrderRequestException UNSEQUENCED_START = new OutOfOrderRequestException(0);
  39
  40     private final Map<TransactionIdentifier, FrontendTransaction> transactions = new HashMap<>();
  41     private final String persistenceId;
  42     private final Ticker ticker;
  43
  44     AbstractFrontendHistory(final String persistenceId, final Ticker ticker) {
  45         this.persistenceId = Preconditions.checkNotNull(persistenceId);
  46         this.ticker = Preconditions.checkNotNull(ticker);
  47     }
  48
  49     final String persistenceId() {
  50         return persistenceId;
  51     }
  52
  53     final long readTime() {
  54         return ticker.read();
  55     }
  56
  57     final @Nullable TransactionSuccess<?> handleTransactionRequest(final TransactionRequest<?> request,
  58             final RequestEnvelope envelope, final long now) throws RequestException {
  59
  60         // FIXME: handle purging of transactions
  61
  62         final TransactionIdentifier id = request.getTarget();
  63         FrontendTransaction tx = transactions.get(id);
  64         if (tx == null) {
  65             // The transaction does not exist and we are about to create it, check sequence number
  66             if (request.getSequence() != 0) {
  67                 LOG.debug("{}: no transaction state present, unexpected request {}", persistenceId(), request);
  68                 throw UNSEQUENCED_START;
  69             }
  70
  71             tx = createTransaction(request, id);
  72             transactions.put(id, tx);
  73         } else {
  74             final Optional<TransactionSuccess<?>> maybeReplay = tx.replaySequence(request.getSequence());
  75             if (maybeReplay.isPresent()) {
  76                 final TransactionSuccess<?> replay = maybeReplay.get();
  77                 LOG.debug("{}: envelope {} replaying response {}", persistenceId(), envelope, replay);
  78                 return replay;
  79             }
  80         }
  81
  82         return tx.handleRequest(request, envelope, now);
  83     }
  84
  85     private FrontendTransaction createTransaction(final TransactionRequest<?> request, final TransactionIdentifier id)
  86             throws RequestException {
  87         if (request instanceof CommitLocalTransactionRequest) {
  88             LOG.debug("{}: allocating new ready transaction {}", persistenceId(), id);
  89             return createReadyTransaction(id, ((CommitLocalTransactionRequest) request).getModification());
  90         }
  91         if (request instanceof AbstractReadTransactionRequest) {
  92             if (((AbstractReadTransactionRequest<?>) request).isSnapshotOnly()) {
  93                 LOG.debug("{}: allocatint new open snapshot {}", persistenceId(), id);
  94                 return createOpenSnapshot(id);
  95             }
  96         }
  97
  98         LOG.debug("{}: allocating new open transaction {}", persistenceId(), id);
  99         return createOpenTransaction(id);
 100     }
 101
 102     abstract FrontendTransaction createOpenSnapshot(TransactionIdentifier id) throws RequestException;
 103
 104     abstract FrontendTransaction createOpenTransaction(TransactionIdentifier id) throws RequestException;
 105
 106     abstract FrontendTransaction createReadyTransaction(TransactionIdentifier id, DataTreeModification mod)
 107         throws RequestException;
 108
 109     abstract ShardDataTreeCohort createReadyCohort(final TransactionIdentifier id, final DataTreeModification mod);
 110 }