Randgalt commented on a change in pull request #335: [CURATOR-549] Recipes based on Persistent Recursive Watchers URL: https://github.com/apache/curator/pull/335#discussion_r399665263
########## File path: curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/CuratorCacheImpl.java ########## @@ -0,0 +1,301 @@ +/** + * 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.curator.framework.recipes.cache; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Preconditions; +import com.google.common.collect.Sets; +import org.apache.curator.framework.CuratorFramework; +import org.apache.curator.framework.api.BackgroundCallback; +import org.apache.curator.framework.api.CuratorEvent; +import org.apache.curator.framework.listen.Listenable; +import org.apache.curator.framework.listen.StandardListenerManager; +import org.apache.curator.framework.recipes.watch.PersistentWatcher; +import org.apache.curator.utils.ThreadUtils; +import org.apache.curator.utils.ZKPaths; +import org.apache.zookeeper.KeeperException; +import org.apache.zookeeper.WatchedEvent; +import org.apache.zookeeper.data.Stat; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import java.util.Collections; +import java.util.Optional; +import java.util.Set; +import java.util.concurrent.atomic.AtomicReference; +import java.util.function.Consumer; +import java.util.stream.Stream; + +import static org.apache.curator.framework.recipes.cache.CuratorCacheListener.Type.*; +import static org.apache.zookeeper.KeeperException.Code.NONODE; +import static org.apache.zookeeper.KeeperException.Code.OK; + +class CuratorCacheImpl implements CuratorCache +{ + private final Logger log = LoggerFactory.getLogger(getClass()); + private final AtomicReference<State> state = new AtomicReference<>(State.LATENT); + private final PersistentWatcher persistentWatcher; + private final CuratorFramework client; + private final CuratorCacheStorage storage; + private final String path; + private final boolean recursive; + private final boolean compressedData; + private final boolean clearOnClose; + private final StandardListenerManager<CuratorCacheListener> listenerManager = StandardListenerManager.standard(); + private final Consumer<Exception> exceptionHandler; + private final OutstandingOps outstandingOps = new OutstandingOps(() -> callListeners(CuratorCacheListener::initialized)); + + private enum State + { + LATENT, + STARTED, + CLOSED + } + + CuratorCacheImpl(CuratorFramework client, CuratorCacheStorage storage, String path, Options[] optionsArg, Consumer<Exception> exceptionHandler) + { + Set<Options> options = (optionsArg != null) ? Sets.newHashSet(optionsArg) : Collections.emptySet(); + this.client = client; + this.storage = (storage != null) ? storage : CuratorCacheStorage.standard(); + this.path = path; + recursive = !options.contains(Options.SINGLE_NODE_CACHE); + compressedData = options.contains(Options.COMPRESSED_DATA); + clearOnClose = !options.contains(Options.DO_NOT_CLEAR_ON_CLOSE); + persistentWatcher = new PersistentWatcher(client, path, recursive); + persistentWatcher.getListenable().addListener(this::processEvent); + persistentWatcher.getResetListenable().addListener(this::rebuild); + this.exceptionHandler = (exceptionHandler != null) ? exceptionHandler : e -> log.error("CuratorCache error", e); + } + + @Override + public void start() + { + Preconditions.checkState(state.compareAndSet(State.LATENT, State.STARTED), "Already started"); + persistentWatcher.start(); + } + + @Override + public void close() + { + if ( state.compareAndSet(State.STARTED, State.CLOSED) ) Review comment: This pattern is used throughout Curator. It's actually an error to call `close()` without first calling `start()`. Maybe it should be an exception. We can deal with all instances of this pattern in a separate issue. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services