| /* |
| * 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.drill.exec.store.sys; |
| |
| import org.apache.drill.exec.exception.StoreException; |
| import org.apache.drill.exec.store.sys.store.UndefinedVersionDelegatingStore; |
| |
| /** |
| * A factory used to create {@link PersistentStore store} instances. |
| */ |
| public interface PersistentStoreProvider extends AutoCloseable { |
| |
| /** |
| * Gets or creates a {@link PersistentStore persistent store} for the given configuration. |
| * |
| * Note that implementors have liberty to cache previous {@link PersistentStore store} instances. |
| * |
| * @param config store configuration |
| * @param <V> store value type |
| * @return persistent store instance |
| * @throws StoreException in case when unable to create store |
| */ |
| <V> PersistentStore<V> getOrCreateStore(PersistentStoreConfig<V> config) throws StoreException; |
| |
| /** |
| * Override this method if store supports versioning and return versioning instance. |
| * By default, undefined version wrapper will be used. |
| * |
| * @param config store configuration |
| * @param <V> store value type |
| * @return versioned persistent store instance |
| * @throws StoreException in case when unable to create store |
| */ |
| default <V> VersionedPersistentStore<V> getOrCreateVersionedStore(PersistentStoreConfig<V> config) throws StoreException { |
| // for those stores that do not support versioning |
| return new UndefinedVersionDelegatingStore<>(getOrCreateStore(config)); |
| } |
| |
| /** |
| * Sets up the provider. |
| */ |
| void start() throws Exception; |
| } |