Google Git
Sign in
apache / logging-log4j-site / 9755b12b39efbc0142688f9b1a11ec68db89f97b / . / 2.13.3 / log4j-core / apidocs / src-html / org / apache / logging / log4j / core / async / JCToolsBlockingQueueFactory.WaitStrategy.html
blob: 4e3230079001a8335f4ca05d7993e1143a7ef80a [file] [log] [blame]
<!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 or more<a name="line.2"></a>
<span class="sourceLineNo">003</span> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a>
<span class="sourceLineNo">004</span> * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<span class="sourceLineNo">005</span> * The ASF licenses this file to You under the Apache license, Version 2.0<a name="line.5"></a>
<span class="sourceLineNo">006</span> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<span class="sourceLineNo">007</span> * the License. You may obtain a copy of the License at<a name="line.7"></a>
<span class="sourceLineNo">008</span> *<a name="line.8"></a>
<span class="sourceLineNo">009</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<span class="sourceLineNo">010</span> *<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<span class="sourceLineNo">012</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<span class="sourceLineNo">013</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<span class="sourceLineNo">014</span> * See the license for the specific language governing permissions and<a name="line.14"></a>
<span class="sourceLineNo">015</span> * limitations under the license.<a name="line.15"></a>
<span class="sourceLineNo">016</span> */<a name="line.16"></a>
<span class="sourceLineNo">017</span>package org.apache.logging.log4j.core.async;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import java.util.Collection;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.concurrent.BlockingQueue;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.util.concurrent.TimeUnit;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.util.concurrent.locks.LockSupport;<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>import org.apache.logging.log4j.core.config.Node;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import org.apache.logging.log4j.core.config.plugins.Plugin;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import org.apache.logging.log4j.core.config.plugins.PluginAttribute;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.logging.log4j.core.config.plugins.PluginFactory;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.jctools.queues.MpscArrayQueue;<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>/**<a name="line.30"></a>
<span class="sourceLineNo">031</span> * Factory for creating instances of BlockingQueues backed by JCTools {@link MpscArrayQueue}.<a name="line.31"></a>
<span class="sourceLineNo">032</span> *<a name="line.32"></a>
<span class="sourceLineNo">033</span> * @since 2.7<a name="line.33"></a>
<span class="sourceLineNo">034</span> */<a name="line.34"></a>
<span class="sourceLineNo">035</span>@Plugin(name = "JCToolsBlockingQueue", category = Node.CATEGORY, elementType = BlockingQueueFactory.ELEMENT_TYPE)<a name="line.35"></a>
<span class="sourceLineNo">036</span>public class JCToolsBlockingQueueFactory&lt;E&gt; implements BlockingQueueFactory&lt;E&gt; {<a name="line.36"></a>
<span class="sourceLineNo">037</span><a name="line.37"></a>
<span class="sourceLineNo">038</span> private final WaitStrategy waitStrategy;<a name="line.38"></a>
<span class="sourceLineNo">039</span><a name="line.39"></a>
<span class="sourceLineNo">040</span> private JCToolsBlockingQueueFactory(final WaitStrategy waitStrategy) {<a name="line.40"></a>
<span class="sourceLineNo">041</span> this.waitStrategy = waitStrategy;<a name="line.41"></a>
<span class="sourceLineNo">042</span> }<a name="line.42"></a>
<span class="sourceLineNo">043</span><a name="line.43"></a>
<span class="sourceLineNo">044</span> @Override<a name="line.44"></a>
<span class="sourceLineNo">045</span> public BlockingQueue&lt;E&gt; create(final int capacity) {<a name="line.45"></a>
<span class="sourceLineNo">046</span> return new MpscBlockingQueue&lt;&gt;(capacity, waitStrategy);<a name="line.46"></a>
<span class="sourceLineNo">047</span> }<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> @PluginFactory<a name="line.49"></a>
<span class="sourceLineNo">050</span> public static &lt;E&gt; JCToolsBlockingQueueFactory&lt;E&gt; createFactory(<a name="line.50"></a>
<span class="sourceLineNo">051</span> @PluginAttribute(value = "WaitStrategy", defaultString = "PARK") final WaitStrategy waitStrategy) {<a name="line.51"></a>
<span class="sourceLineNo">052</span> return new JCToolsBlockingQueueFactory&lt;&gt;(waitStrategy);<a name="line.52"></a>
<span class="sourceLineNo">053</span> }<a name="line.53"></a>
<span class="sourceLineNo">054</span><a name="line.54"></a>
<span class="sourceLineNo">055</span> /**<a name="line.55"></a>
<span class="sourceLineNo">056</span> * BlockingQueue wrapper for JCTools multiple producer single consumer array queue.<a name="line.56"></a>
<span class="sourceLineNo">057</span> */<a name="line.57"></a>
<span class="sourceLineNo">058</span> private static final class MpscBlockingQueue&lt;E&gt; extends MpscArrayQueue&lt;E&gt; implements BlockingQueue&lt;E&gt; {<a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span> private final JCToolsBlockingQueueFactory.WaitStrategy waitStrategy;<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span> MpscBlockingQueue(final int capacity, final JCToolsBlockingQueueFactory.WaitStrategy waitStrategy) {<a name="line.62"></a>
<span class="sourceLineNo">063</span> super(capacity);<a name="line.63"></a>
<span class="sourceLineNo">064</span> this.waitStrategy = waitStrategy;<a name="line.64"></a>
<span class="sourceLineNo">065</span> }<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span> @Override<a name="line.67"></a>
<span class="sourceLineNo">068</span> public int drainTo(final Collection&lt;? super E&gt; c) {<a name="line.68"></a>
<span class="sourceLineNo">069</span> return drainTo(c, capacity());<a name="line.69"></a>
<span class="sourceLineNo">070</span> }<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span> @Override<a name="line.72"></a>
<span class="sourceLineNo">073</span> public int drainTo(final Collection&lt;? super E&gt; c, final int maxElements) {<a name="line.73"></a>
<span class="sourceLineNo">074</span> return drain(new Consumer&lt;E&gt;() {<a name="line.74"></a>
<span class="sourceLineNo">075</span> @Override<a name="line.75"></a>
<span class="sourceLineNo">076</span> public void accept(final E e) {<a name="line.76"></a>
<span class="sourceLineNo">077</span> c.add(e);<a name="line.77"></a>
<span class="sourceLineNo">078</span> }<a name="line.78"></a>
<span class="sourceLineNo">079</span> }, maxElements);<a name="line.79"></a>
<span class="sourceLineNo">080</span> }<a name="line.80"></a>
<span class="sourceLineNo">081</span><a name="line.81"></a>
<span class="sourceLineNo">082</span> @Override<a name="line.82"></a>
<span class="sourceLineNo">083</span> public boolean offer(final E e, final long timeout, final TimeUnit unit) throws InterruptedException {<a name="line.83"></a>
<span class="sourceLineNo">084</span> int idleCounter = 0;<a name="line.84"></a>
<span class="sourceLineNo">085</span> final long timeoutNanos = System.nanoTime() + unit.toNanos(timeout);<a name="line.85"></a>
<span class="sourceLineNo">086</span> do {<a name="line.86"></a>
<span class="sourceLineNo">087</span> if (offer(e)) {<a name="line.87"></a>
<span class="sourceLineNo">088</span> return true;<a name="line.88"></a>
<span class="sourceLineNo">089</span> } else if (System.nanoTime() - timeoutNanos &gt; 0) {<a name="line.89"></a>
<span class="sourceLineNo">090</span> return false;<a name="line.90"></a>
<span class="sourceLineNo">091</span> }<a name="line.91"></a>
<span class="sourceLineNo">092</span> idleCounter = waitStrategy.idle(idleCounter);<a name="line.92"></a>
<span class="sourceLineNo">093</span> } while (!Thread.interrupted()); //clear interrupted flag<a name="line.93"></a>
<span class="sourceLineNo">094</span> throw new InterruptedException();<a name="line.94"></a>
<span class="sourceLineNo">095</span> }<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span> @Override<a name="line.97"></a>
<span class="sourceLineNo">098</span> public E poll(final long timeout, final TimeUnit unit) throws InterruptedException {<a name="line.98"></a>
<span class="sourceLineNo">099</span> int idleCounter = 0;<a name="line.99"></a>
<span class="sourceLineNo">100</span> final long timeoutNanos = System.nanoTime() + unit.toNanos(timeout);<a name="line.100"></a>
<span class="sourceLineNo">101</span> do {<a name="line.101"></a>
<span class="sourceLineNo">102</span> final E result = poll();<a name="line.102"></a>
<span class="sourceLineNo">103</span> if (result != null) {<a name="line.103"></a>
<span class="sourceLineNo">104</span> return result;<a name="line.104"></a>
<span class="sourceLineNo">105</span> } else if (System.nanoTime() - timeoutNanos &gt; 0) {<a name="line.105"></a>
<span class="sourceLineNo">106</span> return null;<a name="line.106"></a>
<span class="sourceLineNo">107</span> }<a name="line.107"></a>
<span class="sourceLineNo">108</span> idleCounter = waitStrategy.idle(idleCounter);<a name="line.108"></a>
<span class="sourceLineNo">109</span> } while (!Thread.interrupted()); //clear interrupted flag<a name="line.109"></a>
<span class="sourceLineNo">110</span> throw new InterruptedException();<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> @Override<a name="line.113"></a>
<span class="sourceLineNo">114</span> public void put(final E e) throws InterruptedException {<a name="line.114"></a>
<span class="sourceLineNo">115</span> int idleCounter = 0;<a name="line.115"></a>
<span class="sourceLineNo">116</span> do {<a name="line.116"></a>
<span class="sourceLineNo">117</span> if (offer(e)) {<a name="line.117"></a>
<span class="sourceLineNo">118</span> return;<a name="line.118"></a>
<span class="sourceLineNo">119</span> }<a name="line.119"></a>
<span class="sourceLineNo">120</span> idleCounter = waitStrategy.idle(idleCounter);<a name="line.120"></a>
<span class="sourceLineNo">121</span> } while (!Thread.interrupted()); //clear interrupted flag<a name="line.121"></a>
<span class="sourceLineNo">122</span> throw new InterruptedException();<a name="line.122"></a>
<span class="sourceLineNo">123</span> }<a name="line.123"></a>
<span class="sourceLineNo">124</span><a name="line.124"></a>
<span class="sourceLineNo">125</span> @Override<a name="line.125"></a>
<span class="sourceLineNo">126</span> public boolean offer(final E e) {<a name="line.126"></a>
<span class="sourceLineNo">127</span> //keep 2 cache lines empty to avoid false sharing that will slow the consumer thread when queue is full.<a name="line.127"></a>
<span class="sourceLineNo">128</span> return offerIfBelowThreshold(e, capacity() - 32);<a name="line.128"></a>
<span class="sourceLineNo">129</span> }<a name="line.129"></a>
<span class="sourceLineNo">130</span><a name="line.130"></a>
<span class="sourceLineNo">131</span> @Override<a name="line.131"></a>
<span class="sourceLineNo">132</span> public int remainingCapacity() {<a name="line.132"></a>
<span class="sourceLineNo">133</span> return capacity() - size();<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> @Override<a name="line.136"></a>
<span class="sourceLineNo">137</span> public E take() throws InterruptedException {<a name="line.137"></a>
<span class="sourceLineNo">138</span> int idleCounter = 100;<a name="line.138"></a>
<span class="sourceLineNo">139</span> do {<a name="line.139"></a>
<span class="sourceLineNo">140</span> final E result = relaxedPoll();<a name="line.140"></a>
<span class="sourceLineNo">141</span> if (result != null) {<a name="line.141"></a>
<span class="sourceLineNo">142</span> return result;<a name="line.142"></a>
<span class="sourceLineNo">143</span> }<a name="line.143"></a>
<span class="sourceLineNo">144</span> idleCounter = waitStrategy.idle(idleCounter);<a name="line.144"></a>
<span class="sourceLineNo">145</span> } while (!Thread.interrupted()); //clear interrupted flag<a name="line.145"></a>
<span class="sourceLineNo">146</span> throw new InterruptedException();<a name="line.146"></a>
<span class="sourceLineNo">147</span> }<a name="line.147"></a>
<span class="sourceLineNo">148</span> }<a name="line.148"></a>
<span class="sourceLineNo">149</span><a name="line.149"></a>
<span class="sourceLineNo">150</span> public enum WaitStrategy {<a name="line.150"></a>
<span class="sourceLineNo">151</span> SPIN(new Idle() {<a name="line.151"></a>
<span class="sourceLineNo">152</span> @Override<a name="line.152"></a>
<span class="sourceLineNo">153</span> public int idle(final int idleCounter) {<a name="line.153"></a>
<span class="sourceLineNo">154</span> return idleCounter + 1;<a name="line.154"></a>
<span class="sourceLineNo">155</span> }<a name="line.155"></a>
<span class="sourceLineNo">156</span> }),<a name="line.156"></a>
<span class="sourceLineNo">157</span> YIELD(new Idle() {<a name="line.157"></a>
<span class="sourceLineNo">158</span> @Override<a name="line.158"></a>
<span class="sourceLineNo">159</span> public int idle(final int idleCounter) {<a name="line.159"></a>
<span class="sourceLineNo">160</span> Thread.yield();<a name="line.160"></a>
<span class="sourceLineNo">161</span> return idleCounter + 1;<a name="line.161"></a>
<span class="sourceLineNo">162</span> }<a name="line.162"></a>
<span class="sourceLineNo">163</span> }),<a name="line.163"></a>
<span class="sourceLineNo">164</span> PARK(new Idle() {<a name="line.164"></a>
<span class="sourceLineNo">165</span> @Override<a name="line.165"></a>
<span class="sourceLineNo">166</span> public int idle(final int idleCounter) {<a name="line.166"></a>
<span class="sourceLineNo">167</span> LockSupport.parkNanos(1L);<a name="line.167"></a>
<span class="sourceLineNo">168</span> return idleCounter + 1;<a name="line.168"></a>
<span class="sourceLineNo">169</span> }<a name="line.169"></a>
<span class="sourceLineNo">170</span> }),<a name="line.170"></a>
<span class="sourceLineNo">171</span> PROGRESSIVE(new Idle() {<a name="line.171"></a>
<span class="sourceLineNo">172</span> @Override<a name="line.172"></a>
<span class="sourceLineNo">173</span> public int idle(final int idleCounter) {<a name="line.173"></a>
<span class="sourceLineNo">174</span> if (idleCounter &gt; 200) {<a name="line.174"></a>
<span class="sourceLineNo">175</span> LockSupport.parkNanos(1L);<a name="line.175"></a>
<span class="sourceLineNo">176</span> } else if (idleCounter &gt; 100) {<a name="line.176"></a>
<span class="sourceLineNo">177</span> Thread.yield();<a name="line.177"></a>
<span class="sourceLineNo">178</span> }<a name="line.178"></a>
<span class="sourceLineNo">179</span> return idleCounter + 1;<a name="line.179"></a>
<span class="sourceLineNo">180</span> }<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> private final Idle idle;<a name="line.183"></a>
<span class="sourceLineNo">184</span><a name="line.184"></a>
<span class="sourceLineNo">185</span> private int idle(final int idleCounter) {<a name="line.185"></a>
<span class="sourceLineNo">186</span> return idle.idle(idleCounter);<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> WaitStrategy(final Idle idle) {<a name="line.189"></a>
<span class="sourceLineNo">190</span> this.idle = idle;<a name="line.190"></a>
<span class="sourceLineNo">191</span> }<a name="line.191"></a>
<span class="sourceLineNo">192</span> }<a name="line.192"></a>
<span class="sourceLineNo">193</span><a name="line.193"></a>
<span class="sourceLineNo">194</span> private interface Idle {<a name="line.194"></a>
<span class="sourceLineNo">195</span> int idle(int idleCounter);<a name="line.195"></a>
<span class="sourceLineNo">196</span> }<a name="line.196"></a>
<span class="sourceLineNo">197</span><a name="line.197"></a>
<span class="sourceLineNo">198</span>}<a name="line.198"></a>
</pre>
</div>
</body>
</html>