| /* |
| * Copyright 2016-present Open Networking Laboratory |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.onosproject.store.primitives.impl; |
| |
| import java.util.Set; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.stream.Collectors; |
| |
| import org.onlab.util.Tools; |
| import org.onosproject.store.primitives.TransactionId; |
| import org.onosproject.store.service.AsyncConsistentMap; |
| import org.onosproject.store.service.CommitStatus; |
| |
| /** |
| * Coordinator for a two-phase commit protocol. |
| */ |
| public class TransactionCoordinator { |
| |
| private final AsyncConsistentMap<TransactionId, Transaction.State> transactions; |
| |
| public TransactionCoordinator(AsyncConsistentMap<TransactionId, Transaction.State> transactions) { |
| this.transactions = transactions; |
| } |
| |
| /** |
| * Commits a transaction. |
| * |
| * @param transactionId transaction identifier |
| * @param transactionParticipants set of transaction participants |
| * @return future for commit result |
| */ |
| CompletableFuture<CommitStatus> commit(TransactionId transactionId, |
| Set<TransactionParticipant> transactionParticipants) { |
| int totalUpdates = transactionParticipants.stream() |
| .map(TransactionParticipant::totalUpdates) |
| .reduce(Math::addExact) |
| .orElse(0); |
| |
| if (totalUpdates == 0) { |
| return CompletableFuture.completedFuture(CommitStatus.SUCCESS); |
| } else if (totalUpdates == 1) { |
| return transactionParticipants.stream() |
| .filter(p -> p.totalUpdates() == 1) |
| .findFirst() |
| .get() |
| .prepareAndCommit() |
| .thenApply(v -> v ? CommitStatus.SUCCESS : CommitStatus.FAILURE); |
| } else { |
| CompletableFuture<CommitStatus> status = transactions.put(transactionId, Transaction.State.PREPARING) |
| .thenCompose(v -> this.doPrepare(transactionParticipants)) |
| .thenCompose(result -> result |
| ? transactions.put(transactionId, Transaction.State.COMMITTING) |
| .thenCompose(v -> doCommit(transactionParticipants)) |
| .thenApply(v -> CommitStatus.SUCCESS) |
| : transactions.put(transactionId, Transaction.State.ROLLINGBACK) |
| .thenCompose(v -> doRollback(transactionParticipants)) |
| .thenApply(v -> CommitStatus.FAILURE)); |
| return status.thenCompose(v -> transactions.remove(transactionId).thenApply(u -> v)); |
| } |
| } |
| |
| private CompletableFuture<Boolean> doPrepare(Set<TransactionParticipant> transactionParticipants) { |
| return Tools.allOf(transactionParticipants.stream() |
| .filter(TransactionParticipant::hasPendingUpdates) |
| .map(TransactionParticipant::prepare) |
| .collect(Collectors.toList())) |
| .thenApply(list -> list.stream().reduce(Boolean::logicalAnd).orElse(true)); |
| } |
| |
| private CompletableFuture<Void> doCommit(Set<TransactionParticipant> transactionParticipants) { |
| return CompletableFuture.allOf(transactionParticipants.stream() |
| .filter(TransactionParticipant::hasPendingUpdates) |
| .map(TransactionParticipant::commit) |
| .toArray(CompletableFuture[]::new)); |
| } |
| |
| private CompletableFuture<Void> doRollback(Set<TransactionParticipant> transactionParticipants) { |
| return CompletableFuture.allOf(transactionParticipants.stream() |
| .filter(TransactionParticipant::hasPendingUpdates) |
| .map(TransactionParticipant::rollback) |
| .toArray(CompletableFuture[]::new)); |
| } |
| } |