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Posted to commits@hbase.apache.org by gi...@apache.org on 2017/12/03 15:18:23 UTC
[13/51] [partial] hbase-site git commit: Published site at .
http://git-wip-us.apache.org/repos/asf/hbase-site/blob/c54c242b/devapidocs/src-html/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.Task.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<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.zookeeper;<a name="line.18"></a>
+<span class="sourceLineNo">019</span><a name="line.19"></a>
+<span class="sourceLineNo">020</span>import static org.apache.hadoop.hbase.HConstants.DEFAULT_ZK_SESSION_TIMEOUT;<a name="line.20"></a>
+<span class="sourceLineNo">021</span>import static org.apache.hadoop.hbase.HConstants.ZK_SESSION_TIMEOUT;<a name="line.21"></a>
+<span class="sourceLineNo">022</span><a name="line.22"></a>
+<span class="sourceLineNo">023</span>import java.io.Closeable;<a name="line.23"></a>
+<span class="sourceLineNo">024</span>import java.io.IOException;<a name="line.24"></a>
+<span class="sourceLineNo">025</span>import java.util.Arrays;<a name="line.25"></a>
+<span class="sourceLineNo">026</span>import java.util.EnumSet;<a name="line.26"></a>
+<span class="sourceLineNo">027</span>import java.util.concurrent.CompletableFuture;<a name="line.27"></a>
+<span class="sourceLineNo">028</span>import java.util.concurrent.DelayQueue;<a name="line.28"></a>
+<span class="sourceLineNo">029</span>import java.util.concurrent.Delayed;<a name="line.29"></a>
+<span class="sourceLineNo">030</span>import java.util.concurrent.TimeUnit;<a name="line.30"></a>
+<span class="sourceLineNo">031</span>import java.util.concurrent.atomic.AtomicBoolean;<a name="line.31"></a>
+<span class="sourceLineNo">032</span><a name="line.32"></a>
+<span class="sourceLineNo">033</span>import org.apache.commons.logging.Log;<a name="line.33"></a>
+<span class="sourceLineNo">034</span>import org.apache.commons.logging.LogFactory;<a name="line.34"></a>
+<span class="sourceLineNo">035</span>import org.apache.hadoop.conf.Configuration;<a name="line.35"></a>
+<span class="sourceLineNo">036</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.36"></a>
+<span class="sourceLineNo">037</span>import org.apache.zookeeper.KeeperException;<a name="line.37"></a>
+<span class="sourceLineNo">038</span>import org.apache.zookeeper.KeeperException.Code;<a name="line.38"></a>
+<span class="sourceLineNo">039</span>import org.apache.zookeeper.ZooKeeper;<a name="line.39"></a>
+<span class="sourceLineNo">040</span>import org.apache.zookeeper.data.Stat;<a name="line.40"></a>
+<span class="sourceLineNo">041</span><a name="line.41"></a>
+<span class="sourceLineNo">042</span>import org.apache.hadoop.hbase.shaded.com.google.common.annotations.VisibleForTesting;<a name="line.42"></a>
+<span class="sourceLineNo">043</span><a name="line.43"></a>
+<span class="sourceLineNo">044</span>/**<a name="line.44"></a>
+<span class="sourceLineNo">045</span> * A very simple read only zookeeper implementation without watcher support.<a name="line.45"></a>
+<span class="sourceLineNo">046</span> */<a name="line.46"></a>
+<span class="sourceLineNo">047</span>@InterfaceAudience.Private<a name="line.47"></a>
+<span class="sourceLineNo">048</span>public final class ReadOnlyZKClient implements Closeable {<a name="line.48"></a>
+<span class="sourceLineNo">049</span><a name="line.49"></a>
+<span class="sourceLineNo">050</span> private static final Log LOG = LogFactory.getLog(ReadOnlyZKClient.class);<a name="line.50"></a>
+<span class="sourceLineNo">051</span><a name="line.51"></a>
+<span class="sourceLineNo">052</span> public static final String RECOVERY_RETRY = "zookeeper.recovery.retry";<a name="line.52"></a>
+<span class="sourceLineNo">053</span><a name="line.53"></a>
+<span class="sourceLineNo">054</span> private static final int DEFAULT_RECOVERY_RETRY = 30;<a name="line.54"></a>
+<span class="sourceLineNo">055</span><a name="line.55"></a>
+<span class="sourceLineNo">056</span> public static final String RECOVERY_RETRY_INTERVAL_MILLIS =<a name="line.56"></a>
+<span class="sourceLineNo">057</span> "zookeeper.recovery.retry.intervalmill";<a name="line.57"></a>
+<span class="sourceLineNo">058</span><a name="line.58"></a>
+<span class="sourceLineNo">059</span> private static final int DEFAULT_RECOVERY_RETRY_INTERVAL_MILLIS = 1000;<a name="line.59"></a>
+<span class="sourceLineNo">060</span><a name="line.60"></a>
+<span class="sourceLineNo">061</span> public static final String KEEPALIVE_MILLIS = "zookeeper.keep-alive.time";<a name="line.61"></a>
+<span class="sourceLineNo">062</span><a name="line.62"></a>
+<span class="sourceLineNo">063</span> private static final int DEFAULT_KEEPALIVE_MILLIS = 60000;<a name="line.63"></a>
+<span class="sourceLineNo">064</span><a name="line.64"></a>
+<span class="sourceLineNo">065</span> private static final EnumSet<Code> FAIL_FAST_CODES = EnumSet.of(Code.NOAUTH, Code.AUTHFAILED);<a name="line.65"></a>
+<span class="sourceLineNo">066</span><a name="line.66"></a>
+<span class="sourceLineNo">067</span> private final String connectString;<a name="line.67"></a>
+<span class="sourceLineNo">068</span><a name="line.68"></a>
+<span class="sourceLineNo">069</span> private final int sessionTimeoutMs;<a name="line.69"></a>
+<span class="sourceLineNo">070</span><a name="line.70"></a>
+<span class="sourceLineNo">071</span> private final int maxRetries;<a name="line.71"></a>
+<span class="sourceLineNo">072</span><a name="line.72"></a>
+<span class="sourceLineNo">073</span> private final int retryIntervalMs;<a name="line.73"></a>
+<span class="sourceLineNo">074</span><a name="line.74"></a>
+<span class="sourceLineNo">075</span> private final int keepAliveTimeMs;<a name="line.75"></a>
+<span class="sourceLineNo">076</span><a name="line.76"></a>
+<span class="sourceLineNo">077</span> private static abstract class Task implements Delayed {<a name="line.77"></a>
+<span class="sourceLineNo">078</span><a name="line.78"></a>
+<span class="sourceLineNo">079</span> protected long time = System.nanoTime();<a name="line.79"></a>
+<span class="sourceLineNo">080</span><a name="line.80"></a>
+<span class="sourceLineNo">081</span> public boolean needZk() {<a name="line.81"></a>
+<span class="sourceLineNo">082</span> return false;<a name="line.82"></a>
+<span class="sourceLineNo">083</span> }<a name="line.83"></a>
+<span class="sourceLineNo">084</span><a name="line.84"></a>
+<span class="sourceLineNo">085</span> public void exec(ZooKeeper zk) {<a name="line.85"></a>
+<span class="sourceLineNo">086</span> }<a name="line.86"></a>
+<span class="sourceLineNo">087</span><a name="line.87"></a>
+<span class="sourceLineNo">088</span> public void connectFailed(IOException e) {<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> public void closed(IOException e) {<a name="line.91"></a>
+<span class="sourceLineNo">092</span> }<a name="line.92"></a>
+<span class="sourceLineNo">093</span><a name="line.93"></a>
+<span class="sourceLineNo">094</span> @Override<a name="line.94"></a>
+<span class="sourceLineNo">095</span> public int compareTo(Delayed o) {<a name="line.95"></a>
+<span class="sourceLineNo">096</span> Task that = (Task) o;<a name="line.96"></a>
+<span class="sourceLineNo">097</span> int c = Long.compare(time, that.time);<a name="line.97"></a>
+<span class="sourceLineNo">098</span> if (c != 0) {<a name="line.98"></a>
+<span class="sourceLineNo">099</span> return c;<a name="line.99"></a>
+<span class="sourceLineNo">100</span> }<a name="line.100"></a>
+<span class="sourceLineNo">101</span> return Integer.compare(System.identityHashCode(this), System.identityHashCode(that));<a name="line.101"></a>
+<span class="sourceLineNo">102</span> }<a name="line.102"></a>
+<span class="sourceLineNo">103</span><a name="line.103"></a>
+<span class="sourceLineNo">104</span> @Override<a name="line.104"></a>
+<span class="sourceLineNo">105</span> public long getDelay(TimeUnit unit) {<a name="line.105"></a>
+<span class="sourceLineNo">106</span> return unit.convert(time - System.nanoTime(), TimeUnit.NANOSECONDS);<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> private static final Task CLOSE = new Task() {<a name="line.110"></a>
+<span class="sourceLineNo">111</span> };<a name="line.111"></a>
+<span class="sourceLineNo">112</span><a name="line.112"></a>
+<span class="sourceLineNo">113</span> private final DelayQueue<Task> tasks = new DelayQueue<>();<a name="line.113"></a>
+<span class="sourceLineNo">114</span><a name="line.114"></a>
+<span class="sourceLineNo">115</span> private final AtomicBoolean closed = new AtomicBoolean(false);<a name="line.115"></a>
+<span class="sourceLineNo">116</span><a name="line.116"></a>
+<span class="sourceLineNo">117</span> private ZooKeeper zookeeper;<a name="line.117"></a>
+<span class="sourceLineNo">118</span><a name="line.118"></a>
+<span class="sourceLineNo">119</span> private String getId() {<a name="line.119"></a>
+<span class="sourceLineNo">120</span> return String.format("0x%08x", System.identityHashCode(this));<a name="line.120"></a>
+<span class="sourceLineNo">121</span> }<a name="line.121"></a>
+<span class="sourceLineNo">122</span><a name="line.122"></a>
+<span class="sourceLineNo">123</span> public ReadOnlyZKClient(Configuration conf) {<a name="line.123"></a>
+<span class="sourceLineNo">124</span> this.connectString = ZKConfig.getZKQuorumServersString(conf);<a name="line.124"></a>
+<span class="sourceLineNo">125</span> this.sessionTimeoutMs = conf.getInt(ZK_SESSION_TIMEOUT, DEFAULT_ZK_SESSION_TIMEOUT);<a name="line.125"></a>
+<span class="sourceLineNo">126</span> this.maxRetries = conf.getInt(RECOVERY_RETRY, DEFAULT_RECOVERY_RETRY);<a name="line.126"></a>
+<span class="sourceLineNo">127</span> this.retryIntervalMs =<a name="line.127"></a>
+<span class="sourceLineNo">128</span> conf.getInt(RECOVERY_RETRY_INTERVAL_MILLIS, DEFAULT_RECOVERY_RETRY_INTERVAL_MILLIS);<a name="line.128"></a>
+<span class="sourceLineNo">129</span> this.keepAliveTimeMs = conf.getInt(KEEPALIVE_MILLIS, DEFAULT_KEEPALIVE_MILLIS);<a name="line.129"></a>
+<span class="sourceLineNo">130</span> LOG.info("Start read only zookeeper connection " + getId() + " to " + connectString +<a name="line.130"></a>
+<span class="sourceLineNo">131</span> ", session timeout " + sessionTimeoutMs + " ms, retries " + maxRetries +<a name="line.131"></a>
+<span class="sourceLineNo">132</span> ", retry interval " + retryIntervalMs + " ms, keep alive " + keepAliveTimeMs + " ms");<a name="line.132"></a>
+<span class="sourceLineNo">133</span> Thread t = new Thread(this::run, "ReadOnlyZKClient");<a name="line.133"></a>
+<span class="sourceLineNo">134</span> t.setDaemon(true);<a name="line.134"></a>
+<span class="sourceLineNo">135</span> t.start();<a name="line.135"></a>
+<span class="sourceLineNo">136</span> }<a name="line.136"></a>
+<span class="sourceLineNo">137</span><a name="line.137"></a>
+<span class="sourceLineNo">138</span> private abstract class ZKTask<T> extends Task {<a name="line.138"></a>
+<span class="sourceLineNo">139</span><a name="line.139"></a>
+<span class="sourceLineNo">140</span> protected final String path;<a name="line.140"></a>
+<span class="sourceLineNo">141</span><a name="line.141"></a>
+<span class="sourceLineNo">142</span> private final CompletableFuture<T> future;<a name="line.142"></a>
+<span class="sourceLineNo">143</span><a name="line.143"></a>
+<span class="sourceLineNo">144</span> private final String operationType;<a name="line.144"></a>
+<span class="sourceLineNo">145</span><a name="line.145"></a>
+<span class="sourceLineNo">146</span> private int retries;<a name="line.146"></a>
+<span class="sourceLineNo">147</span><a name="line.147"></a>
+<span class="sourceLineNo">148</span> protected ZKTask(String path, CompletableFuture<T> future, String operationType) {<a name="line.148"></a>
+<span class="sourceLineNo">149</span> this.path = path;<a name="line.149"></a>
+<span class="sourceLineNo">150</span> this.future = future;<a name="line.150"></a>
+<span class="sourceLineNo">151</span> this.operationType = operationType;<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> protected final void onComplete(ZooKeeper zk, int rc, T ret, boolean errorIfNoNode) {<a name="line.154"></a>
+<span class="sourceLineNo">155</span> tasks.add(new Task() {<a name="line.155"></a>
+<span class="sourceLineNo">156</span><a name="line.156"></a>
+<span class="sourceLineNo">157</span> @Override<a name="line.157"></a>
+<span class="sourceLineNo">158</span> public void exec(ZooKeeper alwaysNull) {<a name="line.158"></a>
+<span class="sourceLineNo">159</span> Code code = Code.get(rc);<a name="line.159"></a>
+<span class="sourceLineNo">160</span> if (code == Code.OK) {<a name="line.160"></a>
+<span class="sourceLineNo">161</span> future.complete(ret);<a name="line.161"></a>
+<span class="sourceLineNo">162</span> } else if (code == Code.NONODE) {<a name="line.162"></a>
+<span class="sourceLineNo">163</span> if (errorIfNoNode) {<a name="line.163"></a>
+<span class="sourceLineNo">164</span> future.completeExceptionally(KeeperException.create(code, path));<a name="line.164"></a>
+<span class="sourceLineNo">165</span> } else {<a name="line.165"></a>
+<span class="sourceLineNo">166</span> future.complete(ret);<a name="line.166"></a>
+<span class="sourceLineNo">167</span> }<a name="line.167"></a>
+<span class="sourceLineNo">168</span> } else if (FAIL_FAST_CODES.contains(code)) {<a name="line.168"></a>
+<span class="sourceLineNo">169</span> future.completeExceptionally(KeeperException.create(code, path));<a name="line.169"></a>
+<span class="sourceLineNo">170</span> } else {<a name="line.170"></a>
+<span class="sourceLineNo">171</span> if (code == Code.SESSIONEXPIRED) {<a name="line.171"></a>
+<span class="sourceLineNo">172</span> LOG.warn(getId() + " session expired, close and reconnect");<a name="line.172"></a>
+<span class="sourceLineNo">173</span> try {<a name="line.173"></a>
+<span class="sourceLineNo">174</span> zk.close();<a name="line.174"></a>
+<span class="sourceLineNo">175</span> } catch (InterruptedException e) {<a name="line.175"></a>
+<span class="sourceLineNo">176</span> }<a name="line.176"></a>
+<span class="sourceLineNo">177</span> }<a name="line.177"></a>
+<span class="sourceLineNo">178</span> if (ZKTask.this.delay(retryIntervalMs, maxRetries)) {<a name="line.178"></a>
+<span class="sourceLineNo">179</span> LOG.warn(getId() + " failed for " + operationType + " of " + path + ", code = " +<a name="line.179"></a>
+<span class="sourceLineNo">180</span> code + ", retries = " + ZKTask.this.retries);<a name="line.180"></a>
+<span class="sourceLineNo">181</span> tasks.add(ZKTask.this);<a name="line.181"></a>
+<span class="sourceLineNo">182</span> } else {<a name="line.182"></a>
+<span class="sourceLineNo">183</span> LOG.warn(getId() + " failed for " + operationType + " of " + path + ", code = " +<a name="line.183"></a>
+<span class="sourceLineNo">184</span> code + ", retries = " + ZKTask.this.retries + ", give up");<a name="line.184"></a>
+<span class="sourceLineNo">185</span> future.completeExceptionally(KeeperException.create(code, path));<a name="line.185"></a>
+<span class="sourceLineNo">186</span> }<a name="line.186"></a>
+<span class="sourceLineNo">187</span> }<a name="line.187"></a>
+<span class="sourceLineNo">188</span> }<a name="line.188"></a>
+<span class="sourceLineNo">189</span><a name="line.189"></a>
+<span class="sourceLineNo">190</span> @Override<a name="line.190"></a>
+<span class="sourceLineNo">191</span> public void closed(IOException e) {<a name="line.191"></a>
+<span class="sourceLineNo">192</span> // It may happen that a request is succeeded and the onComplete has been called and pushed<a name="line.192"></a>
+<span class="sourceLineNo">193</span> // us into the task queue, but before we get called a close is called and here we will<a name="line.193"></a>
+<span class="sourceLineNo">194</span> // fail the request, although it is succeeded actually.<a name="line.194"></a>
+<span class="sourceLineNo">195</span> // This is not a perfect solution but anyway, it is better than hang the requests for<a name="line.195"></a>
+<span class="sourceLineNo">196</span> // ever, and also acceptable as if you close the zk client before actually getting the<a name="line.196"></a>
+<span class="sourceLineNo">197</span> // response then a failure is always possible.<a name="line.197"></a>
+<span class="sourceLineNo">198</span> future.completeExceptionally(e);<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> }<a name="line.201"></a>
+<span class="sourceLineNo">202</span><a name="line.202"></a>
+<span class="sourceLineNo">203</span> @Override<a name="line.203"></a>
+<span class="sourceLineNo">204</span> public boolean needZk() {<a name="line.204"></a>
+<span class="sourceLineNo">205</span> return true;<a name="line.205"></a>
+<span class="sourceLineNo">206</span> }<a name="line.206"></a>
+<span class="sourceLineNo">207</span><a name="line.207"></a>
+<span class="sourceLineNo">208</span> public boolean delay(long intervalMs, int maxRetries) {<a name="line.208"></a>
+<span class="sourceLineNo">209</span> if (retries >= maxRetries) {<a name="line.209"></a>
+<span class="sourceLineNo">210</span> return false;<a name="line.210"></a>
+<span class="sourceLineNo">211</span> }<a name="line.211"></a>
+<span class="sourceLineNo">212</span> retries++;<a name="line.212"></a>
+<span class="sourceLineNo">213</span> time = System.nanoTime() + TimeUnit.MILLISECONDS.toNanos(intervalMs);<a name="line.213"></a>
+<span class="sourceLineNo">214</span> return true;<a name="line.214"></a>
+<span class="sourceLineNo">215</span> }<a name="line.215"></a>
+<span class="sourceLineNo">216</span><a name="line.216"></a>
+<span class="sourceLineNo">217</span> @Override<a name="line.217"></a>
+<span class="sourceLineNo">218</span> public void connectFailed(IOException e) {<a name="line.218"></a>
+<span class="sourceLineNo">219</span> if (delay(retryIntervalMs, maxRetries)) {<a name="line.219"></a>
+<span class="sourceLineNo">220</span> LOG.warn(getId() + " failed to connect to zk for " + operationType + " of " + path +<a name="line.220"></a>
+<span class="sourceLineNo">221</span> ", retries = " + retries,<a name="line.221"></a>
+<span class="sourceLineNo">222</span> e);<a name="line.222"></a>
+<span class="sourceLineNo">223</span> tasks.add(this);<a name="line.223"></a>
+<span class="sourceLineNo">224</span> } else {<a name="line.224"></a>
+<span class="sourceLineNo">225</span> LOG.warn(getId() + " failed to connect to zk for " + operationType + " of " + path +<a name="line.225"></a>
+<span class="sourceLineNo">226</span> ", retries = " + retries + ", give up",<a name="line.226"></a>
+<span class="sourceLineNo">227</span> e);<a name="line.227"></a>
+<span class="sourceLineNo">228</span> future.completeExceptionally(e);<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><a name="line.231"></a>
+<span class="sourceLineNo">232</span> @Override<a name="line.232"></a>
+<span class="sourceLineNo">233</span> public void closed(IOException e) {<a name="line.233"></a>
+<span class="sourceLineNo">234</span> future.completeExceptionally(e);<a name="line.234"></a>
+<span class="sourceLineNo">235</span> }<a name="line.235"></a>
+<span class="sourceLineNo">236</span> }<a name="line.236"></a>
+<span class="sourceLineNo">237</span><a name="line.237"></a>
+<span class="sourceLineNo">238</span> private static <T> CompletableFuture<T> failed(Throwable e) {<a name="line.238"></a>
+<span class="sourceLineNo">239</span> CompletableFuture<T> future = new CompletableFuture<>();<a name="line.239"></a>
+<span class="sourceLineNo">240</span> future.completeExceptionally(e);<a name="line.240"></a>
+<span class="sourceLineNo">241</span> return future;<a name="line.241"></a>
+<span class="sourceLineNo">242</span> }<a name="line.242"></a>
+<span class="sourceLineNo">243</span><a name="line.243"></a>
+<span class="sourceLineNo">244</span> public CompletableFuture<byte[]> get(String path) {<a name="line.244"></a>
+<span class="sourceLineNo">245</span> if (closed.get()) {<a name="line.245"></a>
+<span class="sourceLineNo">246</span> return failed(new IOException("Client already closed"));<a name="line.246"></a>
+<span class="sourceLineNo">247</span> }<a name="line.247"></a>
+<span class="sourceLineNo">248</span> CompletableFuture<byte[]> future = new CompletableFuture<>();<a name="line.248"></a>
+<span class="sourceLineNo">249</span> tasks.add(new ZKTask<byte[]>(path, future, "get") {<a name="line.249"></a>
+<span class="sourceLineNo">250</span><a name="line.250"></a>
+<span class="sourceLineNo">251</span> @Override<a name="line.251"></a>
+<span class="sourceLineNo">252</span> public void exec(ZooKeeper zk) {<a name="line.252"></a>
+<span class="sourceLineNo">253</span> zk.getData(path, false, (rc, path, ctx, data, stat) -> onComplete(zk, rc, data, true),<a name="line.253"></a>
+<span class="sourceLineNo">254</span> null);<a name="line.254"></a>
+<span class="sourceLineNo">255</span> }<a name="line.255"></a>
+<span class="sourceLineNo">256</span> });<a name="line.256"></a>
+<span class="sourceLineNo">257</span> return future;<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> public CompletableFuture<Stat> exists(String path) {<a name="line.260"></a>
+<span class="sourceLineNo">261</span> if (closed.get()) {<a name="line.261"></a>
+<span class="sourceLineNo">262</span> return failed(new IOException("Client already closed"));<a name="line.262"></a>
+<span class="sourceLineNo">263</span> }<a name="line.263"></a>
+<span class="sourceLineNo">264</span> CompletableFuture<Stat> future = new CompletableFuture<>();<a name="line.264"></a>
+<span class="sourceLineNo">265</span> tasks.add(new ZKTask<Stat>(path, future, "exists") {<a name="line.265"></a>
+<span class="sourceLineNo">266</span><a name="line.266"></a>
+<span class="sourceLineNo">267</span> @Override<a name="line.267"></a>
+<span class="sourceLineNo">268</span> public void exec(ZooKeeper zk) {<a name="line.268"></a>
+<span class="sourceLineNo">269</span> zk.exists(path, false, (rc, path, ctx, stat) -> onComplete(zk, rc, stat, false), null);<a name="line.269"></a>
+<span class="sourceLineNo">270</span> }<a name="line.270"></a>
+<span class="sourceLineNo">271</span> });<a name="line.271"></a>
+<span class="sourceLineNo">272</span> return future;<a name="line.272"></a>
+<span class="sourceLineNo">273</span> }<a name="line.273"></a>
+<span class="sourceLineNo">274</span><a name="line.274"></a>
+<span class="sourceLineNo">275</span> private void closeZk() {<a name="line.275"></a>
+<span class="sourceLineNo">276</span> if (zookeeper != null) {<a name="line.276"></a>
+<span class="sourceLineNo">277</span> try {<a name="line.277"></a>
+<span class="sourceLineNo">278</span> zookeeper.close();<a name="line.278"></a>
+<span class="sourceLineNo">279</span> } catch (InterruptedException e) {<a name="line.279"></a>
+<span class="sourceLineNo">280</span> }<a name="line.280"></a>
+<span class="sourceLineNo">281</span> zookeeper = null;<a name="line.281"></a>
+<span class="sourceLineNo">282</span> }<a name="line.282"></a>
+<span class="sourceLineNo">283</span> }<a name="line.283"></a>
+<span class="sourceLineNo">284</span><a name="line.284"></a>
+<span class="sourceLineNo">285</span> private ZooKeeper getZk() throws IOException {<a name="line.285"></a>
+<span class="sourceLineNo">286</span> // may be closed when session expired<a name="line.286"></a>
+<span class="sourceLineNo">287</span> if (zookeeper == null || !zookeeper.getState().isAlive()) {<a name="line.287"></a>
+<span class="sourceLineNo">288</span> zookeeper = new ZooKeeper(connectString, sessionTimeoutMs, e -> {<a name="line.288"></a>
+<span class="sourceLineNo">289</span> });<a name="line.289"></a>
+<span class="sourceLineNo">290</span> }<a name="line.290"></a>
+<span class="sourceLineNo">291</span> return zookeeper;<a name="line.291"></a>
+<span class="sourceLineNo">292</span> }<a name="line.292"></a>
+<span class="sourceLineNo">293</span><a name="line.293"></a>
+<span class="sourceLineNo">294</span> private void run() {<a name="line.294"></a>
+<span class="sourceLineNo">295</span> for (;;) {<a name="line.295"></a>
+<span class="sourceLineNo">296</span> Task task;<a name="line.296"></a>
+<span class="sourceLineNo">297</span> try {<a name="line.297"></a>
+<span class="sourceLineNo">298</span> task = tasks.poll(keepAliveTimeMs, TimeUnit.MILLISECONDS);<a name="line.298"></a>
+<span class="sourceLineNo">299</span> } catch (InterruptedException e) {<a name="line.299"></a>
+<span class="sourceLineNo">300</span> continue;<a name="line.300"></a>
+<span class="sourceLineNo">301</span> }<a name="line.301"></a>
+<span class="sourceLineNo">302</span> if (task == CLOSE) {<a name="line.302"></a>
+<span class="sourceLineNo">303</span> break;<a name="line.303"></a>
+<span class="sourceLineNo">304</span> }<a name="line.304"></a>
+<span class="sourceLineNo">305</span> if (task == null) {<a name="line.305"></a>
+<span class="sourceLineNo">306</span> LOG.info(getId() + " no activities for " + keepAliveTimeMs +<a name="line.306"></a>
+<span class="sourceLineNo">307</span> " ms, close active connection. Will reconnect next time when there are new requests.");<a name="line.307"></a>
+<span class="sourceLineNo">308</span> closeZk();<a name="line.308"></a>
+<span class="sourceLineNo">309</span> continue;<a name="line.309"></a>
+<span class="sourceLineNo">310</span> }<a name="line.310"></a>
+<span class="sourceLineNo">311</span> if (!task.needZk()) {<a name="line.311"></a>
+<span class="sourceLineNo">312</span> task.exec(null);<a name="line.312"></a>
+<span class="sourceLineNo">313</span> } else {<a name="line.313"></a>
+<span class="sourceLineNo">314</span> ZooKeeper zk;<a name="line.314"></a>
+<span class="sourceLineNo">315</span> try {<a name="line.315"></a>
+<span class="sourceLineNo">316</span> zk = getZk();<a name="line.316"></a>
+<span class="sourceLineNo">317</span> } catch (IOException e) {<a name="line.317"></a>
+<span class="sourceLineNo">318</span> task.connectFailed(e);<a name="line.318"></a>
+<span class="sourceLineNo">319</span> continue;<a name="line.319"></a>
+<span class="sourceLineNo">320</span> }<a name="line.320"></a>
+<span class="sourceLineNo">321</span> task.exec(zk);<a name="line.321"></a>
+<span class="sourceLineNo">322</span> }<a name="line.322"></a>
+<span class="sourceLineNo">323</span> }<a name="line.323"></a>
+<span class="sourceLineNo">324</span> closeZk();<a name="line.324"></a>
+<span class="sourceLineNo">325</span> IOException error = new IOException("Client already closed");<a name="line.325"></a>
+<span class="sourceLineNo">326</span> Arrays.stream(tasks.toArray(new Task[0])).forEach(t -> t.closed(error));<a name="line.326"></a>
+<span class="sourceLineNo">327</span> tasks.clear();<a name="line.327"></a>
+<span class="sourceLineNo">328</span> }<a name="line.328"></a>
+<span class="sourceLineNo">329</span><a name="line.329"></a>
+<span class="sourceLineNo">330</span> @Override<a name="line.330"></a>
+<span class="sourceLineNo">331</span> public void close() {<a name="line.331"></a>
+<span class="sourceLineNo">332</span> if (closed.compareAndSet(false, true)) {<a name="line.332"></a>
+<span class="sourceLineNo">333</span> LOG.info("Close zookeeper connection " + getId() + " to " + connectString);<a name="line.333"></a>
+<span class="sourceLineNo">334</span> tasks.add(CLOSE);<a name="line.334"></a>
+<span class="sourceLineNo">335</span> }<a name="line.335"></a>
+<span class="sourceLineNo">336</span> }<a name="line.336"></a>
+<span class="sourceLineNo">337</span><a name="line.337"></a>
+<span class="sourceLineNo">338</span> @VisibleForTesting<a name="line.338"></a>
+<span class="sourceLineNo">339</span> ZooKeeper getZooKeeper() {<a name="line.339"></a>
+<span class="sourceLineNo">340</span> return zookeeper;<a name="line.340"></a>
+<span class="sourceLineNo">341</span> }<a name="line.341"></a>
+<span class="sourceLineNo">342</span><a name="line.342"></a>
+<span class="sourceLineNo">343</span> @VisibleForTesting<a name="line.343"></a>
+<span class="sourceLineNo">344</span> public String getConnectString() {<a name="line.344"></a>
+<span class="sourceLineNo">345</span> return connectString;<a name="line.345"></a>
+<span class="sourceLineNo">346</span> }<a name="line.346"></a>
+<span class="sourceLineNo">347</span>}<a name="line.347"></a>
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+</pre>
+</div>
+</body>
+</html>
http://git-wip-us.apache.org/repos/asf/hbase-site/blob/c54c242b/devapidocs/src-html/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.ZKTask.html
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diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.ZKTask.html b/devapidocs/src-html/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.ZKTask.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<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.zookeeper;<a name="line.18"></a>
+<span class="sourceLineNo">019</span><a name="line.19"></a>
+<span class="sourceLineNo">020</span>import static org.apache.hadoop.hbase.HConstants.DEFAULT_ZK_SESSION_TIMEOUT;<a name="line.20"></a>
+<span class="sourceLineNo">021</span>import static org.apache.hadoop.hbase.HConstants.ZK_SESSION_TIMEOUT;<a name="line.21"></a>
+<span class="sourceLineNo">022</span><a name="line.22"></a>
+<span class="sourceLineNo">023</span>import java.io.Closeable;<a name="line.23"></a>
+<span class="sourceLineNo">024</span>import java.io.IOException;<a name="line.24"></a>
+<span class="sourceLineNo">025</span>import java.util.Arrays;<a name="line.25"></a>
+<span class="sourceLineNo">026</span>import java.util.EnumSet;<a name="line.26"></a>
+<span class="sourceLineNo">027</span>import java.util.concurrent.CompletableFuture;<a name="line.27"></a>
+<span class="sourceLineNo">028</span>import java.util.concurrent.DelayQueue;<a name="line.28"></a>
+<span class="sourceLineNo">029</span>import java.util.concurrent.Delayed;<a name="line.29"></a>
+<span class="sourceLineNo">030</span>import java.util.concurrent.TimeUnit;<a name="line.30"></a>
+<span class="sourceLineNo">031</span>import java.util.concurrent.atomic.AtomicBoolean;<a name="line.31"></a>
+<span class="sourceLineNo">032</span><a name="line.32"></a>
+<span class="sourceLineNo">033</span>import org.apache.commons.logging.Log;<a name="line.33"></a>
+<span class="sourceLineNo">034</span>import org.apache.commons.logging.LogFactory;<a name="line.34"></a>
+<span class="sourceLineNo">035</span>import org.apache.hadoop.conf.Configuration;<a name="line.35"></a>
+<span class="sourceLineNo">036</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.36"></a>
+<span class="sourceLineNo">037</span>import org.apache.zookeeper.KeeperException;<a name="line.37"></a>
+<span class="sourceLineNo">038</span>import org.apache.zookeeper.KeeperException.Code;<a name="line.38"></a>
+<span class="sourceLineNo">039</span>import org.apache.zookeeper.ZooKeeper;<a name="line.39"></a>
+<span class="sourceLineNo">040</span>import org.apache.zookeeper.data.Stat;<a name="line.40"></a>
+<span class="sourceLineNo">041</span><a name="line.41"></a>
+<span class="sourceLineNo">042</span>import org.apache.hadoop.hbase.shaded.com.google.common.annotations.VisibleForTesting;<a name="line.42"></a>
+<span class="sourceLineNo">043</span><a name="line.43"></a>
+<span class="sourceLineNo">044</span>/**<a name="line.44"></a>
+<span class="sourceLineNo">045</span> * A very simple read only zookeeper implementation without watcher support.<a name="line.45"></a>
+<span class="sourceLineNo">046</span> */<a name="line.46"></a>
+<span class="sourceLineNo">047</span>@InterfaceAudience.Private<a name="line.47"></a>
+<span class="sourceLineNo">048</span>public final class ReadOnlyZKClient implements Closeable {<a name="line.48"></a>
+<span class="sourceLineNo">049</span><a name="line.49"></a>
+<span class="sourceLineNo">050</span> private static final Log LOG = LogFactory.getLog(ReadOnlyZKClient.class);<a name="line.50"></a>
+<span class="sourceLineNo">051</span><a name="line.51"></a>
+<span class="sourceLineNo">052</span> public static final String RECOVERY_RETRY = "zookeeper.recovery.retry";<a name="line.52"></a>
+<span class="sourceLineNo">053</span><a name="line.53"></a>
+<span class="sourceLineNo">054</span> private static final int DEFAULT_RECOVERY_RETRY = 30;<a name="line.54"></a>
+<span class="sourceLineNo">055</span><a name="line.55"></a>
+<span class="sourceLineNo">056</span> public static final String RECOVERY_RETRY_INTERVAL_MILLIS =<a name="line.56"></a>
+<span class="sourceLineNo">057</span> "zookeeper.recovery.retry.intervalmill";<a name="line.57"></a>
+<span class="sourceLineNo">058</span><a name="line.58"></a>
+<span class="sourceLineNo">059</span> private static final int DEFAULT_RECOVERY_RETRY_INTERVAL_MILLIS = 1000;<a name="line.59"></a>
+<span class="sourceLineNo">060</span><a name="line.60"></a>
+<span class="sourceLineNo">061</span> public static final String KEEPALIVE_MILLIS = "zookeeper.keep-alive.time";<a name="line.61"></a>
+<span class="sourceLineNo">062</span><a name="line.62"></a>
+<span class="sourceLineNo">063</span> private static final int DEFAULT_KEEPALIVE_MILLIS = 60000;<a name="line.63"></a>
+<span class="sourceLineNo">064</span><a name="line.64"></a>
+<span class="sourceLineNo">065</span> private static final EnumSet<Code> FAIL_FAST_CODES = EnumSet.of(Code.NOAUTH, Code.AUTHFAILED);<a name="line.65"></a>
+<span class="sourceLineNo">066</span><a name="line.66"></a>
+<span class="sourceLineNo">067</span> private final String connectString;<a name="line.67"></a>
+<span class="sourceLineNo">068</span><a name="line.68"></a>
+<span class="sourceLineNo">069</span> private final int sessionTimeoutMs;<a name="line.69"></a>
+<span class="sourceLineNo">070</span><a name="line.70"></a>
+<span class="sourceLineNo">071</span> private final int maxRetries;<a name="line.71"></a>
+<span class="sourceLineNo">072</span><a name="line.72"></a>
+<span class="sourceLineNo">073</span> private final int retryIntervalMs;<a name="line.73"></a>
+<span class="sourceLineNo">074</span><a name="line.74"></a>
+<span class="sourceLineNo">075</span> private final int keepAliveTimeMs;<a name="line.75"></a>
+<span class="sourceLineNo">076</span><a name="line.76"></a>
+<span class="sourceLineNo">077</span> private static abstract class Task implements Delayed {<a name="line.77"></a>
+<span class="sourceLineNo">078</span><a name="line.78"></a>
+<span class="sourceLineNo">079</span> protected long time = System.nanoTime();<a name="line.79"></a>
+<span class="sourceLineNo">080</span><a name="line.80"></a>
+<span class="sourceLineNo">081</span> public boolean needZk() {<a name="line.81"></a>
+<span class="sourceLineNo">082</span> return false;<a name="line.82"></a>
+<span class="sourceLineNo">083</span> }<a name="line.83"></a>
+<span class="sourceLineNo">084</span><a name="line.84"></a>
+<span class="sourceLineNo">085</span> public void exec(ZooKeeper zk) {<a name="line.85"></a>
+<span class="sourceLineNo">086</span> }<a name="line.86"></a>
+<span class="sourceLineNo">087</span><a name="line.87"></a>
+<span class="sourceLineNo">088</span> public void connectFailed(IOException e) {<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> public void closed(IOException e) {<a name="line.91"></a>
+<span class="sourceLineNo">092</span> }<a name="line.92"></a>
+<span class="sourceLineNo">093</span><a name="line.93"></a>
+<span class="sourceLineNo">094</span> @Override<a name="line.94"></a>
+<span class="sourceLineNo">095</span> public int compareTo(Delayed o) {<a name="line.95"></a>
+<span class="sourceLineNo">096</span> Task that = (Task) o;<a name="line.96"></a>
+<span class="sourceLineNo">097</span> int c = Long.compare(time, that.time);<a name="line.97"></a>
+<span class="sourceLineNo">098</span> if (c != 0) {<a name="line.98"></a>
+<span class="sourceLineNo">099</span> return c;<a name="line.99"></a>
+<span class="sourceLineNo">100</span> }<a name="line.100"></a>
+<span class="sourceLineNo">101</span> return Integer.compare(System.identityHashCode(this), System.identityHashCode(that));<a name="line.101"></a>
+<span class="sourceLineNo">102</span> }<a name="line.102"></a>
+<span class="sourceLineNo">103</span><a name="line.103"></a>
+<span class="sourceLineNo">104</span> @Override<a name="line.104"></a>
+<span class="sourceLineNo">105</span> public long getDelay(TimeUnit unit) {<a name="line.105"></a>
+<span class="sourceLineNo">106</span> return unit.convert(time - System.nanoTime(), TimeUnit.NANOSECONDS);<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> private static final Task CLOSE = new Task() {<a name="line.110"></a>
+<span class="sourceLineNo">111</span> };<a name="line.111"></a>
+<span class="sourceLineNo">112</span><a name="line.112"></a>
+<span class="sourceLineNo">113</span> private final DelayQueue<Task> tasks = new DelayQueue<>();<a name="line.113"></a>
+<span class="sourceLineNo">114</span><a name="line.114"></a>
+<span class="sourceLineNo">115</span> private final AtomicBoolean closed = new AtomicBoolean(false);<a name="line.115"></a>
+<span class="sourceLineNo">116</span><a name="line.116"></a>
+<span class="sourceLineNo">117</span> private ZooKeeper zookeeper;<a name="line.117"></a>
+<span class="sourceLineNo">118</span><a name="line.118"></a>
+<span class="sourceLineNo">119</span> private String getId() {<a name="line.119"></a>
+<span class="sourceLineNo">120</span> return String.format("0x%08x", System.identityHashCode(this));<a name="line.120"></a>
+<span class="sourceLineNo">121</span> }<a name="line.121"></a>
+<span class="sourceLineNo">122</span><a name="line.122"></a>
+<span class="sourceLineNo">123</span> public ReadOnlyZKClient(Configuration conf) {<a name="line.123"></a>
+<span class="sourceLineNo">124</span> this.connectString = ZKConfig.getZKQuorumServersString(conf);<a name="line.124"></a>
+<span class="sourceLineNo">125</span> this.sessionTimeoutMs = conf.getInt(ZK_SESSION_TIMEOUT, DEFAULT_ZK_SESSION_TIMEOUT);<a name="line.125"></a>
+<span class="sourceLineNo">126</span> this.maxRetries = conf.getInt(RECOVERY_RETRY, DEFAULT_RECOVERY_RETRY);<a name="line.126"></a>
+<span class="sourceLineNo">127</span> this.retryIntervalMs =<a name="line.127"></a>
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+<span class="sourceLineNo">173</span> try {<a name="line.173"></a>
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+<span class="sourceLineNo">180</span> code + ", retries = " + ZKTask.this.retries);<a name="line.180"></a>
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+<span class="sourceLineNo">182</span> } else {<a name="line.182"></a>
+<span class="sourceLineNo">183</span> LOG.warn(getId() + " failed for " + operationType + " of " + path + ", code = " +<a name="line.183"></a>
+<span class="sourceLineNo">184</span> code + ", retries = " + ZKTask.this.retries + ", give up");<a name="line.184"></a>
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+<span class="sourceLineNo">187</span> }<a name="line.187"></a>
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+<span class="sourceLineNo">189</span><a name="line.189"></a>
+<span class="sourceLineNo">190</span> @Override<a name="line.190"></a>
+<span class="sourceLineNo">191</span> public void closed(IOException e) {<a name="line.191"></a>
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+<span class="sourceLineNo">194</span> // fail the request, although it is succeeded actually.<a name="line.194"></a>
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+<span class="sourceLineNo">197</span> // response then a failure is always possible.<a name="line.197"></a>
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+<span class="sourceLineNo">204</span> public boolean needZk() {<a name="line.204"></a>
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+<span class="sourceLineNo">207</span><a name="line.207"></a>
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+<span class="sourceLineNo">216</span><a name="line.216"></a>
+<span class="sourceLineNo">217</span> @Override<a name="line.217"></a>
+<span class="sourceLineNo">218</span> public void connectFailed(IOException e) {<a name="line.218"></a>
+<span class="sourceLineNo">219</span> if (delay(retryIntervalMs, maxRetries)) {<a name="line.219"></a>
+<span class="sourceLineNo">220</span> LOG.warn(getId() + " failed to connect to zk for " + operationType + " of " + path +<a name="line.220"></a>
+<span class="sourceLineNo">221</span> ", retries = " + retries,<a name="line.221"></a>
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+<span class="sourceLineNo">223</span> tasks.add(this);<a name="line.223"></a>
+<span class="sourceLineNo">224</span> } else {<a name="line.224"></a>
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+<span class="sourceLineNo">226</span> ", retries = " + retries + ", give up",<a name="line.226"></a>
+<span class="sourceLineNo">227</span> e);<a name="line.227"></a>
+<span class="sourceLineNo">228</span> future.completeExceptionally(e);<a name="line.228"></a>
+<span class="sourceLineNo">229</span> }<a name="line.229"></a>
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+<span class="sourceLineNo">231</span><a name="line.231"></a>
+<span class="sourceLineNo">232</span> @Override<a name="line.232"></a>
+<span class="sourceLineNo">233</span> public void closed(IOException e) {<a name="line.233"></a>
+<span class="sourceLineNo">234</span> future.completeExceptionally(e);<a name="line.234"></a>
+<span class="sourceLineNo">235</span> }<a name="line.235"></a>
+<span class="sourceLineNo">236</span> }<a name="line.236"></a>
+<span class="sourceLineNo">237</span><a name="line.237"></a>
+<span class="sourceLineNo">238</span> private static <T> CompletableFuture<T> failed(Throwable e) {<a name="line.238"></a>
+<span class="sourceLineNo">239</span> CompletableFuture<T> future = new CompletableFuture<>();<a name="line.239"></a>
+<span class="sourceLineNo">240</span> future.completeExceptionally(e);<a name="line.240"></a>
+<span class="sourceLineNo">241</span> return future;<a name="line.241"></a>
+<span class="sourceLineNo">242</span> }<a name="line.242"></a>
+<span class="sourceLineNo">243</span><a name="line.243"></a>
+<span class="sourceLineNo">244</span> public CompletableFuture<byte[]> get(String path) {<a name="line.244"></a>
+<span class="sourceLineNo">245</span> if (closed.get()) {<a name="line.245"></a>
+<span class="sourceLineNo">246</span> return failed(new IOException("Client already closed"));<a name="line.246"></a>
+<span class="sourceLineNo">247</span> }<a name="line.247"></a>
+<span class="sourceLineNo">248</span> CompletableFuture<byte[]> future = new CompletableFuture<>();<a name="line.248"></a>
+<span class="sourceLineNo">249</span> tasks.add(new ZKTask<byte[]>(path, future, "get") {<a name="line.249"></a>
+<span class="sourceLineNo">250</span><a name="line.250"></a>
+<span class="sourceLineNo">251</span> @Override<a name="line.251"></a>
+<span class="sourceLineNo">252</span> public void exec(ZooKeeper zk) {<a name="line.252"></a>
+<span class="sourceLineNo">253</span> zk.getData(path, false, (rc, path, ctx, data, stat) -> onComplete(zk, rc, data, true),<a name="line.253"></a>
+<span class="sourceLineNo">254</span> null);<a name="line.254"></a>
+<span class="sourceLineNo">255</span> }<a name="line.255"></a>
+<span class="sourceLineNo">256</span> });<a name="line.256"></a>
+<span class="sourceLineNo">257</span> return future;<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> public CompletableFuture<Stat> exists(String path) {<a name="line.260"></a>
+<span class="sourceLineNo">261</span> if (closed.get()) {<a name="line.261"></a>
+<span class="sourceLineNo">262</span> return failed(new IOException("Client already closed"));<a name="line.262"></a>
+<span class="sourceLineNo">263</span> }<a name="line.263"></a>
+<span class="sourceLineNo">264</span> CompletableFuture<Stat> future = new CompletableFuture<>();<a name="line.264"></a>
+<span class="sourceLineNo">265</span> tasks.add(new ZKTask<Stat>(path, future, "exists") {<a name="line.265"></a>
+<span class="sourceLineNo">266</span><a name="line.266"></a>
+<span class="sourceLineNo">267</span> @Override<a name="line.267"></a>
+<span class="sourceLineNo">268</span> public void exec(ZooKeeper zk) {<a name="line.268"></a>
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+<span class="sourceLineNo">270</span> }<a name="line.270"></a>
+<span class="sourceLineNo">271</span> });<a name="line.271"></a>
+<span class="sourceLineNo">272</span> return future;<a name="line.272"></a>
+<span class="sourceLineNo">273</span> }<a name="line.273"></a>
+<span class="sourceLineNo">274</span><a name="line.274"></a>
+<span class="sourceLineNo">275</span> private void closeZk() {<a name="line.275"></a>
+<span class="sourceLineNo">276</span> if (zookeeper != null) {<a name="line.276"></a>
+<span class="sourceLineNo">277</span> try {<a name="line.277"></a>
+<span class="sourceLineNo">278</span> zookeeper.close();<a name="line.278"></a>
+<span class="sourceLineNo">279</span> } catch (InterruptedException e) {<a name="line.279"></a>
+<span class="sourceLineNo">280</span> }<a name="line.280"></a>
+<span class="sourceLineNo">281</span> zookeeper = null;<a name="line.281"></a>
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+<span class="sourceLineNo">283</span> }<a name="line.283"></a>
+<span class="sourceLineNo">284</span><a name="line.284"></a>
+<span class="sourceLineNo">285</span> private ZooKeeper getZk() throws IOException {<a name="line.285"></a>
+<span class="sourceLineNo">286</span> // may be closed when session expired<a name="line.286"></a>
+<span class="sourceLineNo">287</span> if (zookeeper == null || !zookeeper.getState().isAlive()) {<a name="line.287"></a>
+<span class="sourceLineNo">288</span> zookeeper = new ZooKeeper(connectString, sessionTimeoutMs, e -> {<a name="line.288"></a>
+<span class="sourceLineNo">289</span> });<a name="line.289"></a>
+<span class="sourceLineNo">290</span> }<a name="line.290"></a>
+<span class="sourceLineNo">291</span> return zookeeper;<a name="line.291"></a>
+<span class="sourceLineNo">292</span> }<a name="line.292"></a>
+<span class="sourceLineNo">293</span><a name="line.293"></a>
+<span class="sourceLineNo">294</span> private void run() {<a name="line.294"></a>
+<span class="sourceLineNo">295</span> for (;;) {<a name="line.295"></a>
+<span class="sourceLineNo">296</span> Task task;<a name="line.296"></a>
+<span class="sourceLineNo">297</span> try {<a name="line.297"></a>
+<span class="sourceLineNo">298</span> task = tasks.poll(keepAliveTimeMs, TimeUnit.MILLISECONDS);<a name="line.298"></a>
+<span class="sourceLineNo">299</span> } catch (InterruptedException e) {<a name="line.299"></a>
+<span class="sourceLineNo">300</span> continue;<a name="line.300"></a>
+<span class="sourceLineNo">301</span> }<a name="line.301"></a>
+<span class="sourceLineNo">302</span> if (task == CLOSE) {<a name="line.302"></a>
+<span class="sourceLineNo">303</span> break;<a name="line.303"></a>
+<span class="sourceLineNo">304</span> }<a name="line.304"></a>
+<span class="sourceLineNo">305</span> if (task == null) {<a name="line.305"></a>
+<span class="sourceLineNo">306</span> LOG.info(getId() + " no activities for " + keepAliveTimeMs +<a name="line.306"></a>
+<span class="sourceLineNo">307</span> " ms, close active connection. Will reconnect next time when there are new requests.");<a name="line.307"></a>
+<span class="sourceLineNo">308</span> closeZk();<a name="line.308"></a>
+<span class="sourceLineNo">309</span> continue;<a name="line.309"></a>
+<span class="sourceLineNo">310</span> }<a name="line.310"></a>
+<span class="sourceLineNo">311</span> if (!task.needZk()) {<a name="line.311"></a>
+<span class="sourceLineNo">312</span> task.exec(null);<a name="line.312"></a>
+<span class="sourceLineNo">313</span> } else {<a name="line.313"></a>
+<span class="sourceLineNo">314</span> ZooKeeper zk;<a name="line.314"></a>
+<span class="sourceLineNo">315</span> try {<a name="line.315"></a>
+<span class="sourceLineNo">316</span> zk = getZk();<a name="line.316"></a>
+<span class="sourceLineNo">317</span> } catch (IOException e) {<a name="line.317"></a>
+<span class="sourceLineNo">318</span> task.connectFailed(e);<a name="line.318"></a>
+<span class="sourceLineNo">319</span> continue;<a name="line.319"></a>
+<span class="sourceLineNo">320</span> }<a name="line.320"></a>
+<span class="sourceLineNo">321</span> task.exec(zk);<a name="line.321"></a>
+<span class="sourceLineNo">322</span> }<a name="line.322"></a>
+<span class="sourceLineNo">323</span> }<a name="line.323"></a>
+<span class="sourceLineNo">324</span> closeZk();<a name="line.324"></a>
+<span class="sourceLineNo">325</span> IOException error = new IOException("Client already closed");<a name="line.325"></a>
+<span class="sourceLineNo">326</span> Arrays.stream(tasks.toArray(new Task[0])).forEach(t -> t.closed(error));<a name="line.326"></a>
+<span class="sourceLineNo">327</span> tasks.clear();<a name="line.327"></a>
+<span class="sourceLineNo">328</span> }<a name="line.328"></a>
+<span class="sourceLineNo">329</span><a name="line.329"></a>
+<span class="sourceLineNo">330</span> @Override<a name="line.330"></a>
+<span class="sourceLineNo">331</span> public void close() {<a name="line.331"></a>
+<span class="sourceLineNo">332</span> if (closed.compareAndSet(false, true)) {<a name="line.332"></a>
+<span class="sourceLineNo">333</span> LOG.info("Close zookeeper connection " + getId() + " to " + connectString);<a name="line.333"></a>
+<span class="sourceLineNo">334</span> tasks.add(CLOSE);<a name="line.334"></a>
+<span class="sourceLineNo">335</span> }<a name="line.335"></a>
+<span class="sourceLineNo">336</span> }<a name="line.336"></a>
+<span class="sourceLineNo">337</span><a name="line.337"></a>
+<span class="sourceLineNo">338</span> @VisibleForTesting<a name="line.338"></a>
+<span class="sourceLineNo">339</span> ZooKeeper getZooKeeper() {<a name="line.339"></a>
+<span class="sourceLineNo">340</span> return zookeeper;<a name="line.340"></a>
+<span class="sourceLineNo">341</span> }<a name="line.341"></a>
+<span class="sourceLineNo">342</span><a name="line.342"></a>
+<span class="sourceLineNo">343</span> @VisibleForTesting<a name="line.343"></a>
+<span class="sourceLineNo">344</span> public String getConnectString() {<a name="line.344"></a>
+<span class="sourceLineNo">345</span> return connectString;<a name="line.345"></a>
+<span class="sourceLineNo">346</span> }<a name="line.346"></a>
+<span class="sourceLineNo">347</span>}<a name="line.347"></a>
+
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+</pre>
+</div>
+</body>
+</html>