| /** |
| * 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.v2.recipes.cache; |
| |
| import org.apache.curator.framework.CuratorFramework; |
| import org.apache.curator.framework.listen.Listenable; |
| import org.apache.curator.v2.CuratorFrameworkV2; |
| import java.io.Closeable; |
| |
| /** |
| * <p> |
| * A utility that attempts to keep the data from a node locally cached. Optionally the entire |
| * tree of children below the node can also be cached. Will respond to update/create/delete events, pull |
| * down the data, etc. You can register listeners that will get notified when changes occur. |
| * </p> |
| * |
| * <p> |
| * <b>IMPORTANT</b> - it's not possible to stay transactionally in sync. Users of this class must |
| * be prepared for false-positives and false-negatives. Additionally, always use the version number |
| * when updating data to avoid overwriting another process' change. |
| * </p> |
| */ |
| public interface CuratorCache extends Closeable |
| { |
| /** |
| * cache build options |
| */ |
| enum Options |
| { |
| /** |
| * Normally the entire tree of nodes starting at the given node are cached. This option |
| * causes only the given node to be cached (i.e. a single node cache) |
| */ |
| SINGLE_NODE_CACHE, |
| |
| /** |
| * Decompress data via {@link org.apache.curator.framework.api.GetDataBuilder#decompressed()} |
| */ |
| COMPRESSED_DATA, |
| |
| /** |
| * Normally, when the cache is closed via {@link CuratorCache#close()}, the storage is cleared |
| * via {@link CuratorCacheStorage#clear()}. This option prevents the storage from being cleared. |
| */ |
| DO_NOT_CLEAR_ON_CLOSE |
| } |
| |
| /** |
| * Return a Curator Cache for the given path with the given options using a standard storage instance |
| * |
| * @param client Curator client |
| * @param path path to cache |
| * @param options any options |
| * @return cache (note it must be started via {@link #start()} |
| */ |
| static CuratorCache build(CuratorFramework client, String path, Options... options) |
| { |
| return builder(client, path).withOptions(options).build(); |
| } |
| |
| /** |
| * Start a Curator Cache builder |
| * |
| * @param client Curator client |
| * @param path path to cache |
| * @return builder |
| */ |
| static CuratorCacheBuilder builder(CuratorFramework client, String path) |
| { |
| return new CuratorCacheBuilderImpl(client, path); |
| } |
| |
| /** |
| * Return a Curator Cache for the given path with the given options using a standard storage instance |
| * |
| * @param client Curator client |
| * @param path path to cache |
| * @param options any options |
| * @return cache (note it must be started via {@link #start()} |
| */ |
| static CuratorCache build(CuratorFrameworkV2 client, String path, Options... options) |
| { |
| return builder(client, path).withOptions(options).build(); |
| } |
| |
| /** |
| * Start a Curator Cache builder |
| * |
| * @param client Curator client |
| * @param path path to cache |
| * @return builder |
| */ |
| static CuratorCacheBuilder builder(CuratorFrameworkV2 client, String path) |
| { |
| return new CuratorCacheBuilderImpl(client, path); |
| } |
| |
| /** |
| * Start the cache. This will cause a complete refresh from the cache's root node and generate |
| * events for all nodes found, etc. |
| */ |
| void start(); |
| |
| /** |
| * Close the cache, stop responding to events, etc. |
| */ |
| @Override |
| void close(); |
| |
| /** |
| * Return the storage instance being used |
| * |
| * @return storage |
| */ |
| CuratorCacheStorage storage(); |
| |
| /** |
| * Return the listener container so that listeners can be registered to be notified of changes to the cache |
| * |
| * @return listener container |
| */ |
| Listenable<CuratorCacheListener> listenable(); |
| } |