| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.bookkeeper.stream.storage.impl.kv; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.collect.Maps; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ConcurrentMap; |
| import org.apache.bookkeeper.common.concurrent.FutureUtils; |
| import org.apache.bookkeeper.stream.protocol.RangeId; |
| import org.apache.bookkeeper.stream.storage.api.kv.TableStore; |
| import org.apache.bookkeeper.stream.storage.impl.store.MVCCStoreFactory; |
| |
| /** |
| * A cache for managing table stores. |
| */ |
| public class TableStoreCache { |
| |
| private final MVCCStoreFactory mvccStoreFactory; |
| private final TableStoreFactory tableStoreFactory; |
| private final ConcurrentMap<RangeId, TableStore> tableStores; |
| private final ConcurrentMap<RangeId, CompletableFuture<TableStore>> tableStoresOpening; |
| |
| public TableStoreCache(MVCCStoreFactory mvccStoreFactory) { |
| this(mvccStoreFactory, store -> new TableStoreImpl(store)); |
| } |
| |
| public TableStoreCache(MVCCStoreFactory mvccStoreFactory, |
| TableStoreFactory tableStoreFactory) { |
| this.mvccStoreFactory = mvccStoreFactory; |
| this.tableStoreFactory = tableStoreFactory; |
| this.tableStores = Maps.newConcurrentMap(); |
| this.tableStoresOpening = Maps.newConcurrentMap(); |
| } |
| |
| @VisibleForTesting |
| public ConcurrentMap<RangeId, TableStore> getTableStores() { |
| return tableStores; |
| } |
| |
| @VisibleForTesting |
| ConcurrentMap<RangeId, CompletableFuture<TableStore>> getTableStoresOpening() { |
| return tableStoresOpening; |
| } |
| |
| public TableStore getTableStore(RangeId rid) { |
| return tableStores.get(rid); |
| } |
| |
| public CompletableFuture<TableStore> openTableStore(long scId, RangeId rid, int ttlSeconds) { |
| TableStore store = tableStores.get(rid); |
| if (null != store) { |
| return FutureUtils.value(store); |
| } |
| |
| CompletableFuture<TableStore> openFuture = tableStoresOpening.get(rid); |
| if (null != openFuture) { |
| return openFuture; |
| } |
| |
| // no store is cached, and there is no outstanding open request |
| openFuture = FutureUtils.createFuture(); |
| CompletableFuture<TableStore> existingOpenFuture = tableStoresOpening.putIfAbsent(rid, openFuture); |
| if (null != existingOpenFuture) { |
| // there is already an ongoing open request |
| return existingOpenFuture; |
| } |
| |
| // I am the first one to open a table store |
| final CompletableFuture<TableStore> openingFuture = openFuture; |
| mvccStoreFactory.openStore(scId, rid.getStreamId(), rid.getRangeId(), ttlSeconds) |
| .thenAccept(mvccStore -> { |
| TableStore newStore = tableStoreFactory.createStore(mvccStore); |
| TableStore oldStore = tableStores.putIfAbsent(rid, newStore); |
| if (null != oldStore) { |
| openingFuture.complete(oldStore); |
| } else { |
| openingFuture.complete(newStore); |
| } |
| tableStoresOpening.remove(rid, openingFuture); |
| }) |
| .exceptionally(cause -> { |
| openingFuture.completeExceptionally(cause); |
| tableStoresOpening.remove(rid, openingFuture); |
| return null; |
| }); |
| return openingFuture; |
| } |
| |
| |
| } |