| /* |
| * Copyright 2015 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 static com.google.common.base.Preconditions.checkNotNull; |
| |
| import java.util.Collection; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.stream.Collectors; |
| |
| import org.onosproject.store.primitives.TransactionId; |
| import org.onosproject.store.primitives.resources.impl.CommitResult; |
| import org.onosproject.store.service.AsyncConsistentMap; |
| |
| import static org.onosproject.store.primitives.impl.Transaction.State.COMMITTED; |
| import static org.onosproject.store.primitives.impl.Transaction.State.COMMITTING; |
| import static org.onosproject.store.primitives.impl.Transaction.State.ROLLEDBACK; |
| import static org.onosproject.store.primitives.impl.Transaction.State.ROLLINGBACK; |
| |
| /** |
| * Agent that runs the two phase commit protocol. |
| */ |
| public class TransactionManager { |
| |
| private final Database database; |
| private final AsyncConsistentMap<TransactionId, Transaction> transactions; |
| |
| public TransactionManager(Database database, AsyncConsistentMap<TransactionId, Transaction> transactions) { |
| this.database = checkNotNull(database, "database cannot be null"); |
| this.transactions = transactions; |
| } |
| |
| /** |
| * Executes the specified transaction by employing a two phase commit protocol. |
| * |
| * @param transaction transaction to commit |
| * @return transaction commit result |
| */ |
| public CompletableFuture<CommitResult> execute(Transaction transaction) { |
| // short-circuit if there is only a single update |
| if (transaction.updates().size() <= 1) { |
| return database.prepareAndCommit(transaction) |
| .thenApply(response -> response.success() |
| ? CommitResult.OK : CommitResult.FAILURE_DURING_COMMIT); |
| } |
| // clean up if this transaction in already in a terminal state. |
| if (transaction.state() == COMMITTED || transaction.state() == ROLLEDBACK) { |
| return transactions.remove(transaction.id()).thenApply(v -> CommitResult.OK); |
| } else if (transaction.state() == COMMITTING) { |
| return commit(transaction); |
| } else if (transaction.state() == ROLLINGBACK) { |
| return rollback(transaction).thenApply(v -> CommitResult.FAILURE_TO_PREPARE); |
| } else { |
| return prepare(transaction).thenCompose(v -> v ? commit(transaction) : rollback(transaction)); |
| } |
| } |
| |
| /** |
| * Returns all pending transaction identifiers. |
| * |
| * @return future for a collection of transaction identifiers. |
| */ |
| public CompletableFuture<Collection<TransactionId>> getPendingTransactionIds() { |
| return transactions.values().thenApply(c -> c.stream() |
| .map(v -> v.value()) |
| .filter(v -> v.state() != COMMITTED && v.state() != ROLLEDBACK) |
| .map(Transaction::id) |
| .collect(Collectors.toList())); |
| } |
| |
| private CompletableFuture<Boolean> prepare(Transaction transaction) { |
| return transactions.put(transaction.id(), transaction) |
| .thenCompose(v -> database.prepare(transaction)) |
| .thenCompose(status -> transactions.put( |
| transaction.id(), |
| transaction.transition(status ? COMMITTING : ROLLINGBACK)) |
| .thenApply(v -> status)); |
| } |
| |
| private CompletableFuture<CommitResult> commit(Transaction transaction) { |
| return database.commit(transaction) |
| .thenCompose(r -> { |
| if (r.success()) { |
| return transactions.put(transaction.id(), transaction.transition(COMMITTED)) |
| .thenApply(v -> CommitResult.OK); |
| } else { |
| return CompletableFuture.completedFuture(CommitResult.FAILURE_DURING_COMMIT); |
| } |
| }); |
| } |
| |
| private CompletableFuture<CommitResult> rollback(Transaction transaction) { |
| return database.rollback(transaction) |
| .thenCompose(v -> transactions.put(transaction.id(), transaction.transition(ROLLEDBACK))) |
| .thenApply(v -> CommitResult.FAILURE_TO_PREPARE); |
| } |
| } |