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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.util;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">021</span><span id="line-21"></span> |
| <span class="source-line-no">022</span><span id="line-22">/**</span> |
| <span class="source-line-no">023</span><span id="line-23"> * Instead of calculate a whole time average, this class focus on the last N. The last N is stored</span> |
| <span class="source-line-no">024</span><span id="line-24"> * in a circle array.</span> |
| <span class="source-line-no">025</span><span id="line-25"> */</span> |
| <span class="source-line-no">026</span><span id="line-26">@InterfaceAudience.Private</span> |
| <span class="source-line-no">027</span><span id="line-27">public class WindowMovingAverage<T> extends MovingAverage<T> {</span> |
| <span class="source-line-no">028</span><span id="line-28"> protected final static int DEFAULT_SIZE = 5;</span> |
| <span class="source-line-no">029</span><span id="line-29"></span> |
| <span class="source-line-no">030</span><span id="line-30"> // The last n statistics.</span> |
| <span class="source-line-no">031</span><span id="line-31"> protected long[] lastN;</span> |
| <span class="source-line-no">032</span><span id="line-32"> // The index of the most recent statistics.</span> |
| <span class="source-line-no">033</span><span id="line-33"> protected int mostRecent;</span> |
| <span class="source-line-no">034</span><span id="line-34"> // If it travels a round.</span> |
| <span class="source-line-no">035</span><span id="line-35"> protected boolean oneRound;</span> |
| <span class="source-line-no">036</span><span id="line-36"></span> |
| <span class="source-line-no">037</span><span id="line-37"> public WindowMovingAverage(String label) {</span> |
| <span class="source-line-no">038</span><span id="line-38"> this(label, DEFAULT_SIZE);</span> |
| <span class="source-line-no">039</span><span id="line-39"> }</span> |
| <span class="source-line-no">040</span><span id="line-40"></span> |
| <span class="source-line-no">041</span><span id="line-41"> public WindowMovingAverage(String label, int size) {</span> |
| <span class="source-line-no">042</span><span id="line-42"> super(label);</span> |
| <span class="source-line-no">043</span><span id="line-43"> this.lastN = new long[size <= 0 ? DEFAULT_SIZE : size];</span> |
| <span class="source-line-no">044</span><span id="line-44"> this.mostRecent = -1;</span> |
| <span class="source-line-no">045</span><span id="line-45"> this.oneRound = false;</span> |
| <span class="source-line-no">046</span><span id="line-46"> }</span> |
| <span class="source-line-no">047</span><span id="line-47"></span> |
| <span class="source-line-no">048</span><span id="line-48"> @Override</span> |
| <span class="source-line-no">049</span><span id="line-49"> protected void updateMostRecentTime(long elapsed) {</span> |
| <span class="source-line-no">050</span><span id="line-50"> int index = moveForwardMostRecentPosition();</span> |
| <span class="source-line-no">051</span><span id="line-51"> lastN[index] = elapsed;</span> |
| <span class="source-line-no">052</span><span id="line-52"> }</span> |
| <span class="source-line-no">053</span><span id="line-53"></span> |
| <span class="source-line-no">054</span><span id="line-54"> @Override</span> |
| <span class="source-line-no">055</span><span id="line-55"> public double getAverageTime() {</span> |
| <span class="source-line-no">056</span><span id="line-56"> return enoughStatistics()</span> |
| <span class="source-line-no">057</span><span id="line-57"> ? (double) sum(getNumberOfStatistics()) / getNumberOfStatistics()</span> |
| <span class="source-line-no">058</span><span id="line-58"> : (double) sum(getMostRecentPosition() + 1) / (getMostRecentPosition() + 1);</span> |
| <span class="source-line-no">059</span><span id="line-59"> }</span> |
| <span class="source-line-no">060</span><span id="line-60"></span> |
| <span class="source-line-no">061</span><span id="line-61"> /**</span> |
| <span class="source-line-no">062</span><span id="line-62"> * Check if there are enough statistics.</span> |
| <span class="source-line-no">063</span><span id="line-63"> * @return true if lastN is full</span> |
| <span class="source-line-no">064</span><span id="line-64"> */</span> |
| <span class="source-line-no">065</span><span id="line-65"> protected boolean enoughStatistics() {</span> |
| <span class="source-line-no">066</span><span id="line-66"> return oneRound;</span> |
| <span class="source-line-no">067</span><span id="line-67"> }</span> |
| <span class="source-line-no">068</span><span id="line-68"></span> |
| <span class="source-line-no">069</span><span id="line-69"> /** Returns number of statistics */</span> |
| <span class="source-line-no">070</span><span id="line-70"> protected int getNumberOfStatistics() {</span> |
| <span class="source-line-no">071</span><span id="line-71"> return lastN.length;</span> |
| <span class="source-line-no">072</span><span id="line-72"> }</span> |
| <span class="source-line-no">073</span><span id="line-73"></span> |
| <span class="source-line-no">074</span><span id="line-74"> /**</span> |
| <span class="source-line-no">075</span><span id="line-75"> * Get statistics at index.</span> |
| <span class="source-line-no">076</span><span id="line-76"> * @param index index of bar</span> |
| <span class="source-line-no">077</span><span id="line-77"> */</span> |
| <span class="source-line-no">078</span><span id="line-78"> protected long getStatisticsAtIndex(int index) {</span> |
| <span class="source-line-no">079</span><span id="line-79"> if (index < 0 || index >= getNumberOfStatistics()) {</span> |
| <span class="source-line-no">080</span><span id="line-80"> // This case should not happen, but a prudent check.</span> |
| <span class="source-line-no">081</span><span id="line-81"> throw new IndexOutOfBoundsException();</span> |
| <span class="source-line-no">082</span><span id="line-82"> }</span> |
| <span class="source-line-no">083</span><span id="line-83"> return lastN[index];</span> |
| <span class="source-line-no">084</span><span id="line-84"> }</span> |
| <span class="source-line-no">085</span><span id="line-85"></span> |
| <span class="source-line-no">086</span><span id="line-86"> /** Returns index of most recent */</span> |
| <span class="source-line-no">087</span><span id="line-87"> protected int getMostRecentPosition() {</span> |
| <span class="source-line-no">088</span><span id="line-88"> return mostRecent;</span> |
| <span class="source-line-no">089</span><span id="line-89"> }</span> |
| <span class="source-line-no">090</span><span id="line-90"></span> |
| <span class="source-line-no">091</span><span id="line-91"> /**</span> |
| <span class="source-line-no">092</span><span id="line-92"> * Move forward the most recent index.</span> |
| <span class="source-line-no">093</span><span id="line-93"> * @return the most recent index</span> |
| <span class="source-line-no">094</span><span id="line-94"> */</span> |
| <span class="source-line-no">095</span><span id="line-95"> protected int moveForwardMostRecentPosition() {</span> |
| <span class="source-line-no">096</span><span id="line-96"> int index = ++mostRecent;</span> |
| <span class="source-line-no">097</span><span id="line-97"> if (!oneRound && index == getNumberOfStatistics()) {</span> |
| <span class="source-line-no">098</span><span id="line-98"> // Back to the head of the lastN, from now on will</span> |
| <span class="source-line-no">099</span><span id="line-99"> // start to evict oldest value.</span> |
| <span class="source-line-no">100</span><span id="line-100"> oneRound = true;</span> |
| <span class="source-line-no">101</span><span id="line-101"> }</span> |
| <span class="source-line-no">102</span><span id="line-102"> mostRecent = index % getNumberOfStatistics();</span> |
| <span class="source-line-no">103</span><span id="line-103"> return mostRecent;</span> |
| <span class="source-line-no">104</span><span id="line-104"> }</span> |
| <span class="source-line-no">105</span><span id="line-105"></span> |
| <span class="source-line-no">106</span><span id="line-106"> private long sum(int bound) {</span> |
| <span class="source-line-no">107</span><span id="line-107"> long sum = 0;</span> |
| <span class="source-line-no">108</span><span id="line-108"> for (int i = 0; i < bound; i++) {</span> |
| <span class="source-line-no">109</span><span id="line-109"> sum += getStatisticsAtIndex(i);</span> |
| <span class="source-line-no">110</span><span id="line-110"> }</span> |
| <span class="source-line-no">111</span><span id="line-111"> return sum;</span> |
| <span class="source-line-no">112</span><span id="line-112"> }</span> |
| <span class="source-line-no">113</span><span id="line-113">}</span> |
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| </pre> |
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