maoling commented on a change in pull request #822: ZOOKEEPER-3281:Add a new CLI:watch URL: https://github.com/apache/zookeeper/pull/822#discussion_r265391612
########## File path: zookeeper-server/src/main/java/org/apache/zookeeper/cli/WatchCommand.java ########## @@ -0,0 +1,129 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.cli; + +import java.util.List; +import java.util.concurrent.CountDownLatch; + +import org.apache.commons.cli.CommandLine; +import org.apache.commons.cli.Option; +import org.apache.commons.cli.Options; +import org.apache.commons.cli.ParseException; +import org.apache.commons.cli.Parser; +import org.apache.commons.cli.PosixParser; +import org.apache.zookeeper.KeeperException; +import org.apache.zookeeper.WatchedEvent; +import org.apache.zookeeper.Watcher; + +/** + * watch command for CLI + */ +public class WatchCommand extends CliCommand { + private static Options options = new Options(); + private String[] args; + private CommandLine cl; + + public WatchCommand() { + super("watch", "[-d|-c|-e] path"); + + options.addOption(new Option("d", false, "data changed watch")); + options.addOption(new Option("c", false, "child changed watch")); + options.addOption(new Option("e", false, "exist watch")); + } + + @Override + public CliCommand parse(String[] cmdArgs) throws CliParseException { + Parser parser = new PosixParser(); + try { + cl = parser.parse(options, cmdArgs); + } catch (ParseException ex) { + throw new CliParseException(ex); + } + args = cl.getArgs(); + if (args.length < 2) { + throw new CliParseException(getUsageStr()); + } + + return this; + } + + @Override + public boolean exec() throws CliException { + try { + String path = args[1]; + CountDownLatch latch = new CountDownLatch(1); + SimpleCLIWatcher cliWatcher = new SimpleCLIWatcher(latch); + if (cl.hasOption("d") || cl.getOptions().length == 0) { + zk.getData(path, cliWatcher, null); + latch.await(); + WatchedEvent watchedEvent = cliWatcher.getEvent(); + printWatchedEvent(watchedEvent); + if (watchedEvent.getType().equals(Watcher.Event.EventType.NodeDataChanged)) { + byte[] newData = zk.getData(path, false, null); + out.println("new data:" + new String(newData)); + } + } else if (cl.hasOption("c")) { + zk.getChildren(path, cliWatcher); + latch.await(); + WatchedEvent watchedEvent = cliWatcher.getEvent(); + printWatchedEvent(watchedEvent); + if ((watchedEvent.getType().equals(Watcher.Event.EventType.NodeChildrenChanged))) { + List<String> newChildList = zk.getChildren(path, false); + out.println("new child list:" + newChildList.toString()); + } + } else if (cl.hasOption("e")) { + zk.exists(path, cliWatcher); + latch.await(); + WatchedEvent watchedEvent = cliWatcher.getEvent(); + printWatchedEvent(watchedEvent); + } + } catch (KeeperException | InterruptedException ex) { + throw new CliWrapperException(ex); + } + + return false; + } + + private void printWatchedEvent(WatchedEvent watchedEvent) { + out.println("WatchedEvent state:" + watchedEvent.getState()); + out.println("type:" + watchedEvent.getType()); + out.println("path:" + watchedEvent.getPath()); + } + + private static class SimpleCLIWatcher implements Watcher { + private CountDownLatch latch; + private WatchedEvent event; + + public SimpleCLIWatcher(CountDownLatch latch) { + this.latch = latch; + } + + public WatchedEvent getEvent() { + return event; + } + + public void process(WatchedEvent e) { + if (e.getType() == Event.EventType.None) { + return; + } + if (e.getState() == Event.KeeperState.SyncConnected) { Review comment: @enixon Yes,agreed! ---------------------------------------------------------------- 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
