| /** |
| * 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 com.twitter.distributedlog.service.stream; |
| |
| import com.google.common.base.Optional; |
| import com.twitter.util.Future; |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Manage lifecycle of streams. |
| * |
| * StreamManager is responsible for creating, destroying, and keeping track of Stream objects. |
| * |
| * Stream objects, which are managed by StreamManager and created by StreamFactory, are essentially the |
| * per stream request handlers, responsible fo dispatching ex. write requests to an underlying AsyncLogWriter, |
| * managing stream lock, interpreting exceptions, error conditions, and etc. |
| */ |
| public interface StreamManager { |
| |
| /** |
| * Get a cached stream, returning null if it doesnt exist. |
| * @param stream name |
| * @return the cached stream |
| */ |
| Stream getStream(String stream); |
| |
| /** |
| * Get a cached stream and create a new one if it doesnt exist. |
| * @param stream name |
| * @return future satisfied once close complete |
| */ |
| Stream getOrCreateStream(String stream) throws IOException; |
| |
| /** |
| * Asynchronously create a new stream. |
| * @param stream |
| * @return Future satisfied once the stream is created |
| */ |
| Future<Void> createStreamAsync(String stream); |
| |
| /** |
| * Is acquiring stream allowed? |
| * |
| * @param stream |
| * stream instance |
| * @return true if it is allowed to acquire this stream, otherwise false. |
| */ |
| boolean allowAcquire(Stream stream); |
| |
| /** |
| * Notify the manager that a stream was acquired. |
| * @param stream being acquired |
| */ |
| void notifyAcquired(Stream stream); |
| |
| /** |
| * Notify the manager that a stream was released. |
| * @param stream being released |
| */ |
| void notifyReleased(Stream stream); |
| |
| /** |
| * Notify the manager that a stream was completely removed. |
| * @param stream being uncached |
| * @return whether the stream existed or not |
| */ |
| boolean notifyRemoved(Stream stream); |
| |
| /** |
| * Asynchronous delete method. |
| * @param streamName stream name |
| * @return future satisfied once delete complete |
| */ |
| Future<Void> deleteAndRemoveAsync(String streamName); |
| |
| /** |
| * Asynchronous close and uncache method. |
| * @param streamName stream name |
| * @return future satisfied once close and uncache complete |
| */ |
| Future<Void> closeAndRemoveAsync(String streamName); |
| |
| /** |
| * Close and uncache after delayMs. |
| * @param stream to remove |
| */ |
| void scheduleRemoval(Stream stream, long delayMs); |
| |
| /** |
| * Close all stream. |
| * @return future satisfied all streams closed |
| */ |
| Future<List<Void>> closeStreams(); |
| |
| /** |
| * Return map with stream ownership info. |
| * @param regex for filtering streams |
| * @return map containing ownership info |
| */ |
| Map<String, String> getStreamOwnershipMap(Optional<String> regex); |
| |
| /** |
| * Number of acquired streams. |
| * @return number of acquired streams |
| */ |
| int numAcquired(); |
| |
| /** |
| * Number of cached streams. |
| * @return number of cached streams |
| */ |
| int numCached(); |
| |
| /** |
| * Is the stream denoted by streamName in the acquired state. |
| * @return true if the stream is in the acquired state |
| */ |
| boolean isAcquired(String streamName); |
| |
| /** |
| * Close manager and disallow further activity. |
| */ |
| void close(); |
| } |