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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a>
<span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a>
<span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<span class="sourceLineNo">011</span> *<a name="line.11"></a>
<span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.io;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.nio.file.ClosedWatchServiceException;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.nio.file.FileSystem;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.nio.file.Path;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.nio.file.StandardWatchEventKinds;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.nio.file.WatchEvent;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.nio.file.WatchKey;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.nio.file.WatchService;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import java.util.function.Consumer;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.slf4j.Logger;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.slf4j.LoggerFactory;<a name="line.31"></a>
<span class="sourceLineNo">032</span><a name="line.32"></a>
<span class="sourceLineNo">033</span>/**<a name="line.33"></a>
<span class="sourceLineNo">034</span> * Instances of this class can be used to watch a directory for file changes. When a file is added<a name="line.34"></a>
<span class="sourceLineNo">035</span> * to, deleted from, or is modified in the given directory, the callback provided by the user will<a name="line.35"></a>
<span class="sourceLineNo">036</span> * be called from a background thread. Some things to keep in mind:<a name="line.36"></a>
<span class="sourceLineNo">037</span> * &lt;ul&gt;<a name="line.37"></a>
<span class="sourceLineNo">038</span> * &lt;li&gt;The callback should be thread-safe.&lt;/li&gt;<a name="line.38"></a>
<span class="sourceLineNo">039</span> * &lt;li&gt;Changes that happen around the time the thread is started may be missed.&lt;/li&gt;<a name="line.39"></a>
<span class="sourceLineNo">040</span> * &lt;li&gt;There is a delay between a file changing and the callback firing.&lt;/li&gt;<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;li&gt;The watch is not recursive - changes to subdirectories will not trigger a callback.&lt;/li&gt;<a name="line.41"></a>
<span class="sourceLineNo">042</span> * &lt;/ul&gt;<a name="line.42"></a>
<span class="sourceLineNo">043</span> * &lt;p/&gt;<a name="line.43"></a>
<span class="sourceLineNo">044</span> * This file has been copied from the Apache ZooKeeper project.<a name="line.44"></a>
<span class="sourceLineNo">045</span> * @see &lt;a href=<a name="line.45"></a>
<span class="sourceLineNo">046</span> * "https://github.com/apache/zookeeper/blob/8148f966947d3ecf3db0b756d93c9ffa88174af9/zookeeper-server/src/main/java/org/apache/zookeeper/common/FileChangeWatcher.java"&gt;Base<a name="line.46"></a>
<span class="sourceLineNo">047</span> * revision&lt;/a&gt;<a name="line.47"></a>
<span class="sourceLineNo">048</span> */<a name="line.48"></a>
<span class="sourceLineNo">049</span>@InterfaceAudience.Private<a name="line.49"></a>
<span class="sourceLineNo">050</span>public final class FileChangeWatcher {<a name="line.50"></a>
<span class="sourceLineNo">051</span><a name="line.51"></a>
<span class="sourceLineNo">052</span> private static final Logger LOG = LoggerFactory.getLogger(FileChangeWatcher.class);<a name="line.52"></a>
<span class="sourceLineNo">053</span><a name="line.53"></a>
<span class="sourceLineNo">054</span> public enum State {<a name="line.54"></a>
<span class="sourceLineNo">055</span> NEW, // object created but start() not called yet<a name="line.55"></a>
<span class="sourceLineNo">056</span> STARTING, // start() called but background thread has not entered main loop<a name="line.56"></a>
<span class="sourceLineNo">057</span> RUNNING, // background thread is running<a name="line.57"></a>
<span class="sourceLineNo">058</span> STOPPING, // stop() called but background thread has not exited main loop<a name="line.58"></a>
<span class="sourceLineNo">059</span> STOPPED // stop() called and background thread has exited, or background thread crashed<a name="line.59"></a>
<span class="sourceLineNo">060</span> }<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span> private final WatcherThread watcherThread;<a name="line.62"></a>
<span class="sourceLineNo">063</span> private State state; // protected by synchronized(this)<a name="line.63"></a>
<span class="sourceLineNo">064</span><a name="line.64"></a>
<span class="sourceLineNo">065</span> /**<a name="line.65"></a>
<span class="sourceLineNo">066</span> * Creates a watcher that watches &lt;code&gt;dirPath&lt;/code&gt; and invokes &lt;code&gt;callback&lt;/code&gt; on<a name="line.66"></a>
<span class="sourceLineNo">067</span> * changes.<a name="line.67"></a>
<span class="sourceLineNo">068</span> * @param dirPath the directory to watch.<a name="line.68"></a>
<span class="sourceLineNo">069</span> * @param callback the callback to invoke with events. &lt;code&gt;event.kind()&lt;/code&gt; will return the<a name="line.69"></a>
<span class="sourceLineNo">070</span> * type of event, and &lt;code&gt;event.context()&lt;/code&gt; will return the filename<a name="line.70"></a>
<span class="sourceLineNo">071</span> * relative to &lt;code&gt;dirPath&lt;/code&gt;.<a name="line.71"></a>
<span class="sourceLineNo">072</span> * @throws IOException if there is an error creating the WatchService.<a name="line.72"></a>
<span class="sourceLineNo">073</span> */<a name="line.73"></a>
<span class="sourceLineNo">074</span> public FileChangeWatcher(Path dirPath, String threadNameSuffix, Consumer&lt;WatchEvent&lt;?&gt;&gt; callback)<a name="line.74"></a>
<span class="sourceLineNo">075</span> throws IOException {<a name="line.75"></a>
<span class="sourceLineNo">076</span> FileSystem fs = dirPath.getFileSystem();<a name="line.76"></a>
<span class="sourceLineNo">077</span> WatchService watchService = fs.newWatchService();<a name="line.77"></a>
<span class="sourceLineNo">078</span><a name="line.78"></a>
<span class="sourceLineNo">079</span> LOG.debug("Registering with watch service: {}", dirPath);<a name="line.79"></a>
<span class="sourceLineNo">080</span><a name="line.80"></a>
<span class="sourceLineNo">081</span> dirPath.register(watchService,<a name="line.81"></a>
<span class="sourceLineNo">082</span> new WatchEvent.Kind&lt;?&gt;[] { StandardWatchEventKinds.ENTRY_CREATE,<a name="line.82"></a>
<span class="sourceLineNo">083</span> StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY,<a name="line.83"></a>
<span class="sourceLineNo">084</span> StandardWatchEventKinds.OVERFLOW });<a name="line.84"></a>
<span class="sourceLineNo">085</span> state = State.NEW;<a name="line.85"></a>
<span class="sourceLineNo">086</span> this.watcherThread = new WatcherThread(threadNameSuffix, watchService, callback);<a name="line.86"></a>
<span class="sourceLineNo">087</span> this.watcherThread.setDaemon(true);<a name="line.87"></a>
<span class="sourceLineNo">088</span> }<a name="line.88"></a>
<span class="sourceLineNo">089</span><a name="line.89"></a>
<span class="sourceLineNo">090</span> /**<a name="line.90"></a>
<span class="sourceLineNo">091</span> * Returns the current {@link FileChangeWatcher.State}.<a name="line.91"></a>
<span class="sourceLineNo">092</span> * @return the current state.<a name="line.92"></a>
<span class="sourceLineNo">093</span> */<a name="line.93"></a>
<span class="sourceLineNo">094</span> public synchronized State getState() {<a name="line.94"></a>
<span class="sourceLineNo">095</span> return state;<a name="line.95"></a>
<span class="sourceLineNo">096</span> }<a name="line.96"></a>
<span class="sourceLineNo">097</span><a name="line.97"></a>
<span class="sourceLineNo">098</span> /**<a name="line.98"></a>
<span class="sourceLineNo">099</span> * Blocks until the current state becomes &lt;code&gt;desiredState&lt;/code&gt;. Currently only used by tests,<a name="line.99"></a>
<span class="sourceLineNo">100</span> * thus package-private.<a name="line.100"></a>
<span class="sourceLineNo">101</span> * @param desiredState the desired state.<a name="line.101"></a>
<span class="sourceLineNo">102</span> * @throws InterruptedException if the current thread gets interrupted.<a name="line.102"></a>
<span class="sourceLineNo">103</span> */<a name="line.103"></a>
<span class="sourceLineNo">104</span> synchronized void waitForState(State desiredState) throws InterruptedException {<a name="line.104"></a>
<span class="sourceLineNo">105</span> while (this.state != desiredState) {<a name="line.105"></a>
<span class="sourceLineNo">106</span> this.wait();<a name="line.106"></a>
<span class="sourceLineNo">107</span> }<a name="line.107"></a>
<span class="sourceLineNo">108</span> }<a name="line.108"></a>
<span class="sourceLineNo">109</span><a name="line.109"></a>
<span class="sourceLineNo">110</span> /**<a name="line.110"></a>
<span class="sourceLineNo">111</span> * Sets the state to &lt;code&gt;newState&lt;/code&gt;.<a name="line.111"></a>
<span class="sourceLineNo">112</span> * @param newState the new state.<a name="line.112"></a>
<span class="sourceLineNo">113</span> */<a name="line.113"></a>
<span class="sourceLineNo">114</span> private synchronized void setState(State newState) {<a name="line.114"></a>
<span class="sourceLineNo">115</span> state = newState;<a name="line.115"></a>
<span class="sourceLineNo">116</span> this.notifyAll();<a name="line.116"></a>
<span class="sourceLineNo">117</span> }<a name="line.117"></a>
<span class="sourceLineNo">118</span><a name="line.118"></a>
<span class="sourceLineNo">119</span> /**<a name="line.119"></a>
<span class="sourceLineNo">120</span> * Atomically sets the state to &lt;code&gt;update&lt;/code&gt; if and only if the state is currently<a name="line.120"></a>
<span class="sourceLineNo">121</span> * &lt;code&gt;expected&lt;/code&gt;.<a name="line.121"></a>
<span class="sourceLineNo">122</span> * @param expected the expected state.<a name="line.122"></a>
<span class="sourceLineNo">123</span> * @param update the new state.<a name="line.123"></a>
<span class="sourceLineNo">124</span> * @return true if the update succeeds, or false if the current state does not equal<a name="line.124"></a>
<span class="sourceLineNo">125</span> * &lt;code&gt;expected&lt;/code&gt;.<a name="line.125"></a>
<span class="sourceLineNo">126</span> */<a name="line.126"></a>
<span class="sourceLineNo">127</span> private synchronized boolean compareAndSetState(State expected, State update) {<a name="line.127"></a>
<span class="sourceLineNo">128</span> if (state == expected) {<a name="line.128"></a>
<span class="sourceLineNo">129</span> setState(update);<a name="line.129"></a>
<span class="sourceLineNo">130</span> return true;<a name="line.130"></a>
<span class="sourceLineNo">131</span> } else {<a name="line.131"></a>
<span class="sourceLineNo">132</span> return false;<a name="line.132"></a>
<span class="sourceLineNo">133</span> }<a name="line.133"></a>
<span class="sourceLineNo">134</span> }<a name="line.134"></a>
<span class="sourceLineNo">135</span><a name="line.135"></a>
<span class="sourceLineNo">136</span> /**<a name="line.136"></a>
<span class="sourceLineNo">137</span> * Atomically sets the state to &lt;code&gt;update&lt;/code&gt; if and only if the state is currently one of<a name="line.137"></a>
<span class="sourceLineNo">138</span> * &lt;code&gt;expectedStates&lt;/code&gt;.<a name="line.138"></a>
<span class="sourceLineNo">139</span> * @param expectedStates the expected states.<a name="line.139"></a>
<span class="sourceLineNo">140</span> * @param update the new state.<a name="line.140"></a>
<span class="sourceLineNo">141</span> * @return true if the update succeeds, or false if the current state does not equal any of the<a name="line.141"></a>
<span class="sourceLineNo">142</span> * &lt;code&gt;expectedStates&lt;/code&gt;.<a name="line.142"></a>
<span class="sourceLineNo">143</span> */<a name="line.143"></a>
<span class="sourceLineNo">144</span> private synchronized boolean compareAndSetState(State[] expectedStates, State update) {<a name="line.144"></a>
<span class="sourceLineNo">145</span> for (State expected : expectedStates) {<a name="line.145"></a>
<span class="sourceLineNo">146</span> if (state == expected) {<a name="line.146"></a>
<span class="sourceLineNo">147</span> setState(update);<a name="line.147"></a>
<span class="sourceLineNo">148</span> return true;<a name="line.148"></a>
<span class="sourceLineNo">149</span> }<a name="line.149"></a>
<span class="sourceLineNo">150</span> }<a name="line.150"></a>
<span class="sourceLineNo">151</span> return false;<a name="line.151"></a>
<span class="sourceLineNo">152</span> }<a name="line.152"></a>
<span class="sourceLineNo">153</span><a name="line.153"></a>
<span class="sourceLineNo">154</span> /**<a name="line.154"></a>
<span class="sourceLineNo">155</span> * Tells the background thread to start. Does not wait for it to be running. Calling this method<a name="line.155"></a>
<span class="sourceLineNo">156</span> * more than once has no effect.<a name="line.156"></a>
<span class="sourceLineNo">157</span> */<a name="line.157"></a>
<span class="sourceLineNo">158</span> public void start() {<a name="line.158"></a>
<span class="sourceLineNo">159</span> if (!compareAndSetState(State.NEW, State.STARTING)) {<a name="line.159"></a>
<span class="sourceLineNo">160</span> // If previous state was not NEW, start() has already been called.<a name="line.160"></a>
<span class="sourceLineNo">161</span> return;<a name="line.161"></a>
<span class="sourceLineNo">162</span> }<a name="line.162"></a>
<span class="sourceLineNo">163</span> this.watcherThread.start();<a name="line.163"></a>
<span class="sourceLineNo">164</span> }<a name="line.164"></a>
<span class="sourceLineNo">165</span><a name="line.165"></a>
<span class="sourceLineNo">166</span> /**<a name="line.166"></a>
<span class="sourceLineNo">167</span> * Tells the background thread to stop. Does not wait for it to exit.<a name="line.167"></a>
<span class="sourceLineNo">168</span> */<a name="line.168"></a>
<span class="sourceLineNo">169</span> public void stop() {<a name="line.169"></a>
<span class="sourceLineNo">170</span> if (compareAndSetState(new State[] { State.RUNNING, State.STARTING }, State.STOPPING)) {<a name="line.170"></a>
<span class="sourceLineNo">171</span> watcherThread.interrupt();<a name="line.171"></a>
<span class="sourceLineNo">172</span> }<a name="line.172"></a>
<span class="sourceLineNo">173</span> }<a name="line.173"></a>
<span class="sourceLineNo">174</span><a name="line.174"></a>
<span class="sourceLineNo">175</span> String getWatcherThreadName() {<a name="line.175"></a>
<span class="sourceLineNo">176</span> return watcherThread.getName();<a name="line.176"></a>
<span class="sourceLineNo">177</span> }<a name="line.177"></a>
<span class="sourceLineNo">178</span><a name="line.178"></a>
<span class="sourceLineNo">179</span> private static void handleException(Thread thread, Throwable e) {<a name="line.179"></a>
<span class="sourceLineNo">180</span> LOG.warn("Exception occurred from thread {}", thread.getName(), e);<a name="line.180"></a>
<span class="sourceLineNo">181</span> }<a name="line.181"></a>
<span class="sourceLineNo">182</span><a name="line.182"></a>
<span class="sourceLineNo">183</span> /**<a name="line.183"></a>
<span class="sourceLineNo">184</span> * Inner class that implements the watcher thread logic.<a name="line.184"></a>
<span class="sourceLineNo">185</span> */<a name="line.185"></a>
<span class="sourceLineNo">186</span> private class WatcherThread extends Thread {<a name="line.186"></a>
<span class="sourceLineNo">187</span><a name="line.187"></a>
<span class="sourceLineNo">188</span> private static final String THREAD_NAME_PREFIX = "FileChangeWatcher-";<a name="line.188"></a>
<span class="sourceLineNo">189</span><a name="line.189"></a>
<span class="sourceLineNo">190</span> final WatchService watchService;<a name="line.190"></a>
<span class="sourceLineNo">191</span> final Consumer&lt;WatchEvent&lt;?&gt;&gt; callback;<a name="line.191"></a>
<span class="sourceLineNo">192</span><a name="line.192"></a>
<span class="sourceLineNo">193</span> WatcherThread(String threadNameSuffix, WatchService watchService,<a name="line.193"></a>
<span class="sourceLineNo">194</span> Consumer&lt;WatchEvent&lt;?&gt;&gt; callback) {<a name="line.194"></a>
<span class="sourceLineNo">195</span> super(THREAD_NAME_PREFIX + threadNameSuffix);<a name="line.195"></a>
<span class="sourceLineNo">196</span> this.watchService = watchService;<a name="line.196"></a>
<span class="sourceLineNo">197</span> this.callback = callback;<a name="line.197"></a>
<span class="sourceLineNo">198</span> setUncaughtExceptionHandler(FileChangeWatcher::handleException);<a name="line.198"></a>
<span class="sourceLineNo">199</span> }<a name="line.199"></a>
<span class="sourceLineNo">200</span><a name="line.200"></a>
<span class="sourceLineNo">201</span> @Override<a name="line.201"></a>
<span class="sourceLineNo">202</span> public void run() {<a name="line.202"></a>
<span class="sourceLineNo">203</span> try {<a name="line.203"></a>
<span class="sourceLineNo">204</span> LOG.info("{} thread started", getName());<a name="line.204"></a>
<span class="sourceLineNo">205</span> if (<a name="line.205"></a>
<span class="sourceLineNo">206</span> !compareAndSetState(FileChangeWatcher.State.STARTING, FileChangeWatcher.State.RUNNING)<a name="line.206"></a>
<span class="sourceLineNo">207</span> ) {<a name="line.207"></a>
<span class="sourceLineNo">208</span> // stop() called shortly after start(), before<a name="line.208"></a>
<span class="sourceLineNo">209</span> // this thread started running.<a name="line.209"></a>
<span class="sourceLineNo">210</span> FileChangeWatcher.State state = FileChangeWatcher.this.getState();<a name="line.210"></a>
<span class="sourceLineNo">211</span> if (state != FileChangeWatcher.State.STOPPING) {<a name="line.211"></a>
<span class="sourceLineNo">212</span> throw new IllegalStateException("Unexpected state: " + state);<a name="line.212"></a>
<span class="sourceLineNo">213</span> }<a name="line.213"></a>
<span class="sourceLineNo">214</span> return;<a name="line.214"></a>
<span class="sourceLineNo">215</span> }<a name="line.215"></a>
<span class="sourceLineNo">216</span> runLoop();<a name="line.216"></a>
<span class="sourceLineNo">217</span> } catch (Exception e) {<a name="line.217"></a>
<span class="sourceLineNo">218</span> LOG.warn("Error in runLoop()", e);<a name="line.218"></a>
<span class="sourceLineNo">219</span> throw e;<a name="line.219"></a>
<span class="sourceLineNo">220</span> } finally {<a name="line.220"></a>
<span class="sourceLineNo">221</span> try {<a name="line.221"></a>
<span class="sourceLineNo">222</span> watchService.close();<a name="line.222"></a>
<span class="sourceLineNo">223</span> } catch (IOException e) {<a name="line.223"></a>
<span class="sourceLineNo">224</span> LOG.warn("Error closing watch service", e);<a name="line.224"></a>
<span class="sourceLineNo">225</span> }<a name="line.225"></a>
<span class="sourceLineNo">226</span> LOG.info("{} thread finished", getName());<a name="line.226"></a>
<span class="sourceLineNo">227</span> FileChangeWatcher.this.setState(FileChangeWatcher.State.STOPPED);<a name="line.227"></a>
<span class="sourceLineNo">228</span> }<a name="line.228"></a>
<span class="sourceLineNo">229</span> }<a name="line.229"></a>
<span class="sourceLineNo">230</span><a name="line.230"></a>
<span class="sourceLineNo">231</span> private void runLoop() {<a name="line.231"></a>
<span class="sourceLineNo">232</span> while (FileChangeWatcher.this.getState() == FileChangeWatcher.State.RUNNING) {<a name="line.232"></a>
<span class="sourceLineNo">233</span> WatchKey key;<a name="line.233"></a>
<span class="sourceLineNo">234</span> try {<a name="line.234"></a>
<span class="sourceLineNo">235</span> key = watchService.take();<a name="line.235"></a>
<span class="sourceLineNo">236</span> } catch (InterruptedException | ClosedWatchServiceException e) {<a name="line.236"></a>
<span class="sourceLineNo">237</span> LOG.debug("{} was interrupted and is shutting down...", getName());<a name="line.237"></a>
<span class="sourceLineNo">238</span> break;<a name="line.238"></a>
<span class="sourceLineNo">239</span> }<a name="line.239"></a>
<span class="sourceLineNo">240</span> for (WatchEvent&lt;?&gt; event : key.pollEvents()) {<a name="line.240"></a>
<span class="sourceLineNo">241</span> LOG.debug("Got file changed event: {} with context: {}", event.kind(), event.context());<a name="line.241"></a>
<span class="sourceLineNo">242</span> try {<a name="line.242"></a>
<span class="sourceLineNo">243</span> callback.accept(event);<a name="line.243"></a>
<span class="sourceLineNo">244</span> } catch (Throwable e) {<a name="line.244"></a>
<span class="sourceLineNo">245</span> LOG.error("Error from callback", e);<a name="line.245"></a>
<span class="sourceLineNo">246</span> }<a name="line.246"></a>
<span class="sourceLineNo">247</span> }<a name="line.247"></a>
<span class="sourceLineNo">248</span> boolean isKeyValid = key.reset();<a name="line.248"></a>
<span class="sourceLineNo">249</span> if (!isKeyValid) {<a name="line.249"></a>
<span class="sourceLineNo">250</span> // This is likely a problem, it means that file reloading is broken, probably because the<a name="line.250"></a>
<span class="sourceLineNo">251</span> // directory we are watching was deleted or otherwise became inaccessible (unmounted,<a name="line.251"></a>
<span class="sourceLineNo">252</span> // permissions<a name="line.252"></a>
<span class="sourceLineNo">253</span> // changed, ???).<a name="line.253"></a>
<span class="sourceLineNo">254</span> // For now, we log an error and exit the watcher thread.<a name="line.254"></a>
<span class="sourceLineNo">255</span> LOG.error("Watch key no longer valid, maybe the directory is inaccessible?");<a name="line.255"></a>
<span class="sourceLineNo">256</span> break;<a name="line.256"></a>
<span class="sourceLineNo">257</span> }<a name="line.257"></a>
<span class="sourceLineNo">258</span> }<a name="line.258"></a>
<span class="sourceLineNo">259</span> }<a name="line.259"></a>
<span class="sourceLineNo">260</span> }<a name="line.260"></a>
<span class="sourceLineNo">261</span>}<a name="line.261"></a>
</pre>
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