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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.util;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span><a name="line.21"></a> |
| <span class="sourceLineNo">022</span>/**<a name="line.22"></a> |
| <span class="sourceLineNo">023</span> * Instead of calculate a whole time average, this class focus on the last N. The last N is stored<a name="line.23"></a> |
| <span class="sourceLineNo">024</span> * in a circle array.<a name="line.24"></a> |
| <span class="sourceLineNo">025</span> */<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>@InterfaceAudience.Private<a name="line.26"></a> |
| <span class="sourceLineNo">027</span>public class WindowMovingAverage<T> extends MovingAverage<T> {<a name="line.27"></a> |
| <span class="sourceLineNo">028</span> protected final static int DEFAULT_SIZE = 5;<a name="line.28"></a> |
| <span class="sourceLineNo">029</span><a name="line.29"></a> |
| <span class="sourceLineNo">030</span> // The last n statistics.<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> protected long[] lastN;<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> // The index of the most recent statistics.<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> protected int mostRecent;<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> // If it travels a round.<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> protected boolean oneRound;<a name="line.35"></a> |
| <span class="sourceLineNo">036</span><a name="line.36"></a> |
| <span class="sourceLineNo">037</span> public WindowMovingAverage(String label) {<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> this(label, DEFAULT_SIZE);<a name="line.38"></a> |
| <span class="sourceLineNo">039</span> }<a name="line.39"></a> |
| <span class="sourceLineNo">040</span><a name="line.40"></a> |
| <span class="sourceLineNo">041</span> public WindowMovingAverage(String label, int size) {<a name="line.41"></a> |
| <span class="sourceLineNo">042</span> super(label);<a name="line.42"></a> |
| <span class="sourceLineNo">043</span> this.lastN = new long[size <= 0 ? DEFAULT_SIZE : size];<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> this.mostRecent = -1;<a name="line.44"></a> |
| <span class="sourceLineNo">045</span> this.oneRound = false;<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> }<a name="line.46"></a> |
| <span class="sourceLineNo">047</span><a name="line.47"></a> |
| <span class="sourceLineNo">048</span> @Override<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> protected void updateMostRecentTime(long elapsed) {<a name="line.49"></a> |
| <span class="sourceLineNo">050</span> int index = moveForwardMostRecentPosition();<a name="line.50"></a> |
| <span class="sourceLineNo">051</span> lastN[index] = elapsed;<a name="line.51"></a> |
| <span class="sourceLineNo">052</span> }<a name="line.52"></a> |
| <span class="sourceLineNo">053</span><a name="line.53"></a> |
| <span class="sourceLineNo">054</span> @Override<a name="line.54"></a> |
| <span class="sourceLineNo">055</span> public double getAverageTime() {<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> return enoughStatistics()<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> ? (double) sum(getNumberOfStatistics()) / getNumberOfStatistics()<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> : (double) sum(getMostRecentPosition() + 1) / (getMostRecentPosition() + 1);<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> }<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> * Check if there are enough statistics.<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> * @return true if lastN is full<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> */<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> protected boolean enoughStatistics() {<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> return oneRound;<a name="line.66"></a> |
| <span class="sourceLineNo">067</span> }<a name="line.67"></a> |
| <span class="sourceLineNo">068</span><a name="line.68"></a> |
| <span class="sourceLineNo">069</span> /** Returns number of statistics */<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> protected int getNumberOfStatistics() {<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> return lastN.length;<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> }<a name="line.72"></a> |
| <span class="sourceLineNo">073</span><a name="line.73"></a> |
| <span class="sourceLineNo">074</span> /**<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> * Get statistics at index.<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> * @param index index of bar<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> */<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> protected long getStatisticsAtIndex(int index) {<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> if (index < 0 || index >= getNumberOfStatistics()) {<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> // This case should not happen, but a prudent check.<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> throw new IndexOutOfBoundsException();<a name="line.81"></a> |
| <span class="sourceLineNo">082</span> }<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> return lastN[index];<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> }<a name="line.84"></a> |
| <span class="sourceLineNo">085</span><a name="line.85"></a> |
| <span class="sourceLineNo">086</span> /** Returns index of most recent */<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> protected int getMostRecentPosition() {<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> return mostRecent;<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> /**<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> * Move forward the most recent index.<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> * @return the most recent index<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> */<a name="line.94"></a> |
| <span class="sourceLineNo">095</span> protected int moveForwardMostRecentPosition() {<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> int index = ++mostRecent;<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> if (!oneRound && index == getNumberOfStatistics()) {<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> // Back to the head of the lastN, from now on will<a name="line.98"></a> |
| <span class="sourceLineNo">099</span> // start to evict oldest value.<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> oneRound = true;<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> }<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> mostRecent = index % getNumberOfStatistics();<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> return mostRecent;<a name="line.103"></a> |
| <span class="sourceLineNo">104</span> }<a name="line.104"></a> |
| <span class="sourceLineNo">105</span><a name="line.105"></a> |
| <span class="sourceLineNo">106</span> private long sum(int bound) {<a name="line.106"></a> |
| <span class="sourceLineNo">107</span> long sum = 0;<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> for (int i = 0; i < bound; i++) {<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> sum += getStatisticsAtIndex(i);<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> }<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> return sum;<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> }<a name="line.112"></a> |
| <span class="sourceLineNo">113</span>}<a name="line.113"></a> |
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