[GitHub] [zookeeper] maoling commented on a change in pull request #822: ZOOKEEPER-3281:Add a new CLI:watch

[GitBox <gi...@apache.org>]

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
 
 

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 File path: zookeeper-server/src/main/java/org/apache/zookeeper/cli/WatchCommand.java
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+/**
+ * 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!

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