Categories:
Audio (13)
Biotech (29)
Bytecode (36)
Database (77)
Framework (7)
Game (7)
General (507)
Graphics (53)
I/O (35)
IDE (2)
JAR Tools (101)
JavaBeans (21)
JDBC (121)
JDK (426)
JSP (20)
Logging (108)
Mail (58)
Messaging (8)
Network (84)
PDF (97)
Report (7)
Scripting (84)
Security (32)
Server (121)
Servlet (26)
SOAP (24)
Testing (54)
Web (15)
XML (309)
Collections:
Other Resources:
Apache ZooKeeper 3.7.0 Server Source Code
Apache ZooKeeper is an open-source server which enables highly
reliable distributed coordination.
Apache ZooKeeper Server Source Code files are provided in the source packge (apache-zookeeper-3.7.0.tar.gz). You can download it at Apache ZooKeeper Website.
You can also browse Apache ZooKeeper Server Source Code below:
✍: FYIcenter.com
⏎ org/apache/zookeeper/common/FileChangeWatcher.java
/* * 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.zookeeper.common; import java.io.IOException; import java.nio.file.ClosedWatchServiceException; import java.nio.file.FileSystem; import java.nio.file.Path; import java.nio.file.StandardWatchEventKinds; import java.nio.file.WatchEvent; import java.nio.file.WatchKey; import java.nio.file.WatchService; import java.util.function.Consumer; import org.apache.zookeeper.server.ZooKeeperThread; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Instances of this class can be used to watch a directory for file changes. When a file is added to, deleted from, * or is modified in the given directory, the callback provided by the user will be called from a background thread. * Some things to keep in mind: * <ul> * <li>The callback should be thread-safe.</li> * <li>Changes that happen around the time the thread is started may be missed.</li> * <li>There is a delay between a file changing and the callback firing.</li> * <li>The watch is not recursive - changes to subdirectories will not trigger a callback.</li> * </ul> */ public final class FileChangeWatcher { private static final Logger LOG = LoggerFactory.getLogger(FileChangeWatcher.class); public enum State { NEW, // object created but start() not called yet STARTING, // start() called but background thread has not entered main loop RUNNING, // background thread is running STOPPING, // stop() called but background thread has not exited main loop STOPPED // stop() called and background thread has exited, or background thread crashed } private final WatcherThread watcherThread; private State state; // protected by synchronized(this) /** * Creates a watcher that watches <code>dirPath</code> and invokes <code>callback</code> on changes. * * @param dirPath the directory to watch. * @param callback the callback to invoke with events. <code>event.kind()</code> will return the type of event, * and <code>event.context()</code> will return the filename relative to <code>dirPath</code>. * @throws IOException if there is an error creating the WatchService. */ public FileChangeWatcher(Path dirPath, Consumer<WatchEvent<?>> callback) throws IOException { FileSystem fs = dirPath.getFileSystem(); WatchService watchService = fs.newWatchService(); LOG.debug("Registering with watch service: {}", dirPath); dirPath.register(watchService, new WatchEvent.Kind<?>[]{StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY, StandardWatchEventKinds.OVERFLOW}); state = State.NEW; this.watcherThread = new WatcherThread(watchService, callback); this.watcherThread.setDaemon(true); } /** * Returns the current {@link FileChangeWatcher.State}. * @return the current state. */ public synchronized State getState() { return state; } /** * Blocks until the current state becomes <code>desiredState</code>. * Currently only used by tests, thus package-private. * @param desiredState the desired state. * @throws InterruptedException if the current thread gets interrupted. */ synchronized void waitForState(State desiredState) throws InterruptedException { while (this.state != desiredState) { this.wait(); } } /** * Sets the state to <code>newState</code>. * @param newState the new state. */ private synchronized void setState(State newState) { state = newState; this.notifyAll(); } /** * Atomically sets the state to <code>update</code> if and only if the * state is currently <code>expected</code>. * @param expected the expected state. * @param update the new state. * @return true if the update succeeds, or false if the current state * does not equal <code>expected</code>. */ private synchronized boolean compareAndSetState(State expected, State update) { if (state == expected) { setState(update); return true; } else { return false; } } /** * Atomically sets the state to <code>update</code> if and only if the * state is currently one of <code>expectedStates</code>. * @param expectedStates the expected states. * @param update the new state. * @return true if the update succeeds, or false if the current state * does not equal any of the <code>expectedStates</code>. */ private synchronized boolean compareAndSetState(State[] expectedStates, State update) { for (State expected : expectedStates) { if (state == expected) { setState(update); return true; } } return false; } /** * Tells the background thread to start. Does not wait for it to be running. * Calling this method more than once has no effect. */ public void start() { if (!compareAndSetState(State.NEW, State.STARTING)) { // If previous state was not NEW, start() has already been called. return; } this.watcherThread.start(); } /** * Tells the background thread to stop. Does not wait for it to exit. */ public void stop() { if (compareAndSetState(new State[]{State.RUNNING, State.STARTING}, State.STOPPING)) { watcherThread.interrupt(); } } /** * Inner class that implements the watcher thread logic. */ private class WatcherThread extends ZooKeeperThread { private static final String THREAD_NAME = "FileChangeWatcher"; final WatchService watchService; final Consumer<WatchEvent<?>> callback; WatcherThread(WatchService watchService, Consumer<WatchEvent<?>> callback) { super(THREAD_NAME); this.watchService = watchService; this.callback = callback; } @Override public void run() { try { LOG.info("{} thread started", getName()); if (!compareAndSetState(FileChangeWatcher.State.STARTING, FileChangeWatcher.State.RUNNING)) { // stop() called shortly after start(), before // this thread started running. FileChangeWatcher.State state = FileChangeWatcher.this.getState(); if (state != FileChangeWatcher.State.STOPPING) { throw new IllegalStateException("Unexpected state: " + state); } return; } runLoop(); } catch (Exception e) { LOG.warn("Error in runLoop()", e); throw e; } finally { try { watchService.close(); } catch (IOException e) { LOG.warn("Error closing watch service", e); } LOG.info("{} thread finished", getName()); FileChangeWatcher.this.setState(FileChangeWatcher.State.STOPPED); } } private void runLoop() { while (FileChangeWatcher.this.getState() == FileChangeWatcher.State.RUNNING) { WatchKey key; try { key = watchService.take(); } catch (InterruptedException | ClosedWatchServiceException e) { LOG.debug("{} was interrupted and is shutting down...", getName()); break; } for (WatchEvent<?> event : key.pollEvents()) { LOG.debug("Got file changed event: {} with context: {}", event.kind(), event.context()); try { callback.accept(event); } catch (Throwable e) { LOG.error("Error from callback", e); } } boolean isKeyValid = key.reset(); if (!isKeyValid) { // This is likely a problem, it means that file reloading is broken, probably because the // directory we are watching was deleted or otherwise became inaccessible (unmounted, permissions // changed, ???). // For now, we log an error and exit the watcher thread. LOG.error("Watch key no longer valid, maybe the directory is inaccessible?"); break; } } } } }
⏎ org/apache/zookeeper/common/FileChangeWatcher.java
Or download all of them as a single archive file:
File name: zookeeper-server-3.7.0-fyi.zip File size: 871011 bytes Release date: 2021-05-17 Download
⇒ Apache ZooKeeper 3.7.0 Jute Source Code
⇐ Download Apache ZooKeeper 3.7.0 Source Package
2022-11-16, 25592👍, 0💬
Popular Posts:
What Is jms.jar? I heard it's related to JMS (Java Message Service) 1.1? The if you have an jms.jar ...
What JAR files are required to run sax\Writer.java provided in the Apache Xerces package? 1 JAR file...
JDK 17 java.desktop.jmod is the JMOD file for JDK 17 Desktop module. JDK 17 Desktop module compiled ...
JDK 17 jdk.compiler.jmod is the JMOD file for JDK 17 Compiler tool, which can be invoked by the "jav...
How to download and install javamail-1_2.zip? The JavaMail API is a set of abstract APIs that model ...