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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.metrics2.util;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span>import java.util.Arrays;<a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import java.util.HashMap;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import java.util.LinkedList;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span>import java.util.ListIterator;<a name="line.24"></a> |
| <span class="sourceLineNo">025</span>import java.util.Map;<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.26"></a> |
| <span class="sourceLineNo">027</span><a name="line.27"></a> |
| <span class="sourceLineNo">028</span>/**<a name="line.28"></a> |
| <span class="sourceLineNo">029</span> * Implementation of the Cormode, Korn, Muthukrishnan, and Srivastava algorithm for streaming<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> * calculation of targeted high-percentile epsilon-approximate quantiles. This is a generalization<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * of the earlier work by Greenwald and Khanna (GK), which essentially allows different error bounds<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> * on the targeted quantiles, which allows for far more efficient calculation of high-percentiles.<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> * See: Cormode, Korn, Muthukrishnan, and Srivastava "Effective Computation of Biased Quantiles over<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> * Data Streams" in ICDE 2005 Greenwald and Khanna, "Space-efficient online computation of quantile<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> * summaries" in SIGMOD 2001<a name="line.35"></a> |
| <span class="sourceLineNo">036</span> */<a name="line.36"></a> |
| <span class="sourceLineNo">037</span>@InterfaceAudience.Private<a name="line.37"></a> |
| <span class="sourceLineNo">038</span>@SuppressWarnings("JdkObsolete") // This is a use case for LinkedList<a name="line.38"></a> |
| <span class="sourceLineNo">039</span>public class MetricSampleQuantiles {<a name="line.39"></a> |
| <span class="sourceLineNo">040</span><a name="line.40"></a> |
| <span class="sourceLineNo">041</span> /**<a name="line.41"></a> |
| <span class="sourceLineNo">042</span> * Total number of items in stream<a name="line.42"></a> |
| <span class="sourceLineNo">043</span> */<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> private long count = 0;<a name="line.44"></a> |
| <span class="sourceLineNo">045</span><a name="line.45"></a> |
| <span class="sourceLineNo">046</span> /**<a name="line.46"></a> |
| <span class="sourceLineNo">047</span> * Current list of sampled items, maintained in sorted order with error bounds<a name="line.47"></a> |
| <span class="sourceLineNo">048</span> */<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> private LinkedList<SampleItem> samples;<a name="line.49"></a> |
| <span class="sourceLineNo">050</span><a name="line.50"></a> |
| <span class="sourceLineNo">051</span> /**<a name="line.51"></a> |
| <span class="sourceLineNo">052</span> * Buffers incoming items to be inserted in batch. Items are inserted into the buffer linearly.<a name="line.52"></a> |
| <span class="sourceLineNo">053</span> * When the buffer fills, it is flushed into the samples array in its entirety.<a name="line.53"></a> |
| <span class="sourceLineNo">054</span> */<a name="line.54"></a> |
| <span class="sourceLineNo">055</span> private long[] buffer = new long[500];<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> private int bufferCount = 0;<a name="line.56"></a> |
| <span class="sourceLineNo">057</span><a name="line.57"></a> |
| <span class="sourceLineNo">058</span> /**<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> * Array of Quantiles that we care about, along with desired error.<a name="line.59"></a> |
| <span class="sourceLineNo">060</span> */<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> private final MetricQuantile[] quantiles;<a name="line.61"></a> |
| <span class="sourceLineNo">062</span><a name="line.62"></a> |
| <span class="sourceLineNo">063</span> public MetricSampleQuantiles(MetricQuantile[] quantiles) {<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> this.quantiles = Arrays.copyOf(quantiles, quantiles.length);<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> this.samples = new LinkedList<>();<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> }<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> * Specifies the allowable error for this rank, depending on which quantiles are being targeted.<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> * This is the f(r_i, n) function from the CKMS paper. It's basically how wide the range of this<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> * rank can be. n * the index in the list of samples<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> */<a name="line.72"></a> |
| <span class="sourceLineNo">073</span> private double allowableError(int rank) {<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> int size = samples.size();<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> double minError = size + 1;<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> for (MetricQuantile q : quantiles) {<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> double error;<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> if (rank <= q.quantile * size) {<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> error = (2.0 * q.error * (size - rank)) / (1.0 - q.quantile);<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> } else {<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> error = (2.0 * q.error * rank) / q.quantile;<a name="line.81"></a> |
| <span class="sourceLineNo">082</span> }<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> if (error < minError) {<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> minError = error;<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> }<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> return minError;<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> * Add a new value from the stream.<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> * @param v the value to insert<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> */<a name="line.94"></a> |
| <span class="sourceLineNo">095</span> synchronized public void insert(long v) {<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> buffer[bufferCount] = v;<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> bufferCount++;<a name="line.97"></a> |
| <span class="sourceLineNo">098</span><a name="line.98"></a> |
| <span class="sourceLineNo">099</span> count++;<a name="line.99"></a> |
| <span class="sourceLineNo">100</span><a name="line.100"></a> |
| <span class="sourceLineNo">101</span> if (bufferCount == buffer.length) {<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> insertBatch();<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> compress();<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><a name="line.106"></a> |
| <span class="sourceLineNo">107</span> /**<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> * Merges items from buffer into the samples array in one pass. This is more efficient than doing<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> * an insert on every item.<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> */<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> private void insertBatch() {<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> if (bufferCount == 0) {<a name="line.112"></a> |
| <span class="sourceLineNo">113</span> return;<a name="line.113"></a> |
| <span class="sourceLineNo">114</span> }<a name="line.114"></a> |
| <span class="sourceLineNo">115</span><a name="line.115"></a> |
| <span class="sourceLineNo">116</span> Arrays.sort(buffer, 0, bufferCount);<a name="line.116"></a> |
| <span class="sourceLineNo">117</span><a name="line.117"></a> |
| <span class="sourceLineNo">118</span> // Base case: no samples<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> int start = 0;<a name="line.119"></a> |
| <span class="sourceLineNo">120</span> if (samples.isEmpty()) {<a name="line.120"></a> |
| <span class="sourceLineNo">121</span> SampleItem newItem = new SampleItem(buffer[0], 1, 0);<a name="line.121"></a> |
| <span class="sourceLineNo">122</span> samples.add(newItem);<a name="line.122"></a> |
| <span class="sourceLineNo">123</span> start++;<a name="line.123"></a> |
| <span class="sourceLineNo">124</span> }<a name="line.124"></a> |
| <span class="sourceLineNo">125</span><a name="line.125"></a> |
| <span class="sourceLineNo">126</span> ListIterator<SampleItem> it = samples.listIterator();<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> SampleItem item = it.next();<a name="line.127"></a> |
| <span class="sourceLineNo">128</span> for (int i = start; i < bufferCount; i++) {<a name="line.128"></a> |
| <span class="sourceLineNo">129</span> long v = buffer[i];<a name="line.129"></a> |
| <span class="sourceLineNo">130</span> while (it.nextIndex() < samples.size() && item.value < v) {<a name="line.130"></a> |
| <span class="sourceLineNo">131</span> item = it.next();<a name="line.131"></a> |
| <span class="sourceLineNo">132</span> }<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> // If we found that bigger item, back up so we insert ourselves before it<a name="line.133"></a> |
| <span class="sourceLineNo">134</span> if (item.value > v) {<a name="line.134"></a> |
| <span class="sourceLineNo">135</span> it.previous();<a name="line.135"></a> |
| <span class="sourceLineNo">136</span> }<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> // We use different indexes for the edge comparisons, because of the above<a name="line.137"></a> |
| <span class="sourceLineNo">138</span> // if statement that adjusts the iterator<a name="line.138"></a> |
| <span class="sourceLineNo">139</span> int delta;<a name="line.139"></a> |
| <span class="sourceLineNo">140</span> if (it.previousIndex() == 0 || it.nextIndex() == samples.size()) {<a name="line.140"></a> |
| <span class="sourceLineNo">141</span> delta = 0;<a name="line.141"></a> |
| <span class="sourceLineNo">142</span> } else {<a name="line.142"></a> |
| <span class="sourceLineNo">143</span> delta = ((int) Math.floor(allowableError(it.nextIndex()))) - 1;<a name="line.143"></a> |
| <span class="sourceLineNo">144</span> }<a name="line.144"></a> |
| <span class="sourceLineNo">145</span> SampleItem newItem = new SampleItem(v, 1, delta);<a name="line.145"></a> |
| <span class="sourceLineNo">146</span> it.add(newItem);<a name="line.146"></a> |
| <span class="sourceLineNo">147</span> item = newItem;<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> bufferCount = 0;<a name="line.150"></a> |
| <span class="sourceLineNo">151</span> }<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> * Try to remove extraneous items from the set of sampled items. This checks if an item is<a name="line.154"></a> |
| <span class="sourceLineNo">155</span> * unnecessary based on the desired error bounds, and merges it with the adjacent item if it is.<a name="line.155"></a> |
| <span class="sourceLineNo">156</span> */<a name="line.156"></a> |
| <span class="sourceLineNo">157</span> private void compress() {<a name="line.157"></a> |
| <span class="sourceLineNo">158</span> if (samples.size() < 2) {<a name="line.158"></a> |
| <span class="sourceLineNo">159</span> return;<a name="line.159"></a> |
| <span class="sourceLineNo">160</span> }<a name="line.160"></a> |
| <span class="sourceLineNo">161</span><a name="line.161"></a> |
| <span class="sourceLineNo">162</span> ListIterator<SampleItem> it = samples.listIterator();<a name="line.162"></a> |
| <span class="sourceLineNo">163</span> SampleItem prev = null;<a name="line.163"></a> |
| <span class="sourceLineNo">164</span> SampleItem next = it.next();<a name="line.164"></a> |
| <span class="sourceLineNo">165</span><a name="line.165"></a> |
| <span class="sourceLineNo">166</span> while (it.hasNext()) {<a name="line.166"></a> |
| <span class="sourceLineNo">167</span> prev = next;<a name="line.167"></a> |
| <span class="sourceLineNo">168</span> next = it.next();<a name="line.168"></a> |
| <span class="sourceLineNo">169</span> if (prev.g + next.g + next.delta <= allowableError(it.previousIndex())) {<a name="line.169"></a> |
| <span class="sourceLineNo">170</span> next.g += prev.g;<a name="line.170"></a> |
| <span class="sourceLineNo">171</span> // Remove prev. it.remove() kills the last thing returned.<a name="line.171"></a> |
| <span class="sourceLineNo">172</span> it.previous();<a name="line.172"></a> |
| <span class="sourceLineNo">173</span> it.previous();<a name="line.173"></a> |
| <span class="sourceLineNo">174</span> it.remove();<a name="line.174"></a> |
| <span class="sourceLineNo">175</span> // it.next() is now equal to next, skip it back forward again<a name="line.175"></a> |
| <span class="sourceLineNo">176</span> it.next();<a name="line.176"></a> |
| <span class="sourceLineNo">177</span> }<a name="line.177"></a> |
| <span class="sourceLineNo">178</span> }<a name="line.178"></a> |
| <span class="sourceLineNo">179</span> }<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> * Get the estimated value at the specified quantile.<a name="line.182"></a> |
| <span class="sourceLineNo">183</span> * @param quantile Queried quantile, e.g. 0.50 or 0.99.<a name="line.183"></a> |
| <span class="sourceLineNo">184</span> * @return Estimated value at that quantile.<a name="line.184"></a> |
| <span class="sourceLineNo">185</span> */<a name="line.185"></a> |
| <span class="sourceLineNo">186</span> private long query(double quantile) throws IOException {<a name="line.186"></a> |
| <span class="sourceLineNo">187</span> if (samples.isEmpty()) {<a name="line.187"></a> |
| <span class="sourceLineNo">188</span> throw new IOException("No samples present");<a name="line.188"></a> |
| <span class="sourceLineNo">189</span> }<a name="line.189"></a> |
| <span class="sourceLineNo">190</span><a name="line.190"></a> |
| <span class="sourceLineNo">191</span> int rankMin = 0;<a name="line.191"></a> |
| <span class="sourceLineNo">192</span> int desired = (int) (quantile * count);<a name="line.192"></a> |
| <span class="sourceLineNo">193</span><a name="line.193"></a> |
| <span class="sourceLineNo">194</span> for (int i = 1; i < samples.size(); i++) {<a name="line.194"></a> |
| <span class="sourceLineNo">195</span> SampleItem prev = samples.get(i - 1);<a name="line.195"></a> |
| <span class="sourceLineNo">196</span> SampleItem cur = samples.get(i);<a name="line.196"></a> |
| <span class="sourceLineNo">197</span><a name="line.197"></a> |
| <span class="sourceLineNo">198</span> rankMin += prev.g;<a name="line.198"></a> |
| <span class="sourceLineNo">199</span><a name="line.199"></a> |
| <span class="sourceLineNo">200</span> if (rankMin + cur.g + cur.delta > desired + (allowableError(i) / 2)) {<a name="line.200"></a> |
| <span class="sourceLineNo">201</span> return prev.value;<a name="line.201"></a> |
| <span class="sourceLineNo">202</span> }<a name="line.202"></a> |
| <span class="sourceLineNo">203</span> }<a name="line.203"></a> |
| <span class="sourceLineNo">204</span><a name="line.204"></a> |
| <span class="sourceLineNo">205</span> // edge case of wanting max value<a name="line.205"></a> |
| <span class="sourceLineNo">206</span> return samples.get(samples.size() - 1).value;<a name="line.206"></a> |
| <span class="sourceLineNo">207</span> }<a name="line.207"></a> |
| <span class="sourceLineNo">208</span><a name="line.208"></a> |
| <span class="sourceLineNo">209</span> /**<a name="line.209"></a> |
| <span class="sourceLineNo">210</span> * Get a snapshot of the current values of all the tracked quantiles.<a name="line.210"></a> |
| <span class="sourceLineNo">211</span> * @return snapshot of the tracked quantiles n * if no items have been added to the estimator<a name="line.211"></a> |
| <span class="sourceLineNo">212</span> */<a name="line.212"></a> |
| <span class="sourceLineNo">213</span> synchronized public Map<MetricQuantile, Long> snapshot() throws IOException {<a name="line.213"></a> |
| <span class="sourceLineNo">214</span> // flush the buffer first for best results<a name="line.214"></a> |
| <span class="sourceLineNo">215</span> insertBatch();<a name="line.215"></a> |
| <span class="sourceLineNo">216</span> Map<MetricQuantile, Long> values = new HashMap<>(quantiles.length);<a name="line.216"></a> |
| <span class="sourceLineNo">217</span> for (int i = 0; i < quantiles.length; i++) {<a name="line.217"></a> |
| <span class="sourceLineNo">218</span> values.put(quantiles[i], query(quantiles[i].quantile));<a name="line.218"></a> |
| <span class="sourceLineNo">219</span> }<a name="line.219"></a> |
| <span class="sourceLineNo">220</span><a name="line.220"></a> |
| <span class="sourceLineNo">221</span> return values;<a name="line.221"></a> |
| <span class="sourceLineNo">222</span> }<a name="line.222"></a> |
| <span class="sourceLineNo">223</span><a name="line.223"></a> |
| <span class="sourceLineNo">224</span> /**<a name="line.224"></a> |
| <span class="sourceLineNo">225</span> * Returns the number of items that the estimator has processed<a name="line.225"></a> |
| <span class="sourceLineNo">226</span> * @return count total number of items processed<a name="line.226"></a> |
| <span class="sourceLineNo">227</span> */<a name="line.227"></a> |
| <span class="sourceLineNo">228</span> synchronized public long getCount() {<a name="line.228"></a> |
| <span class="sourceLineNo">229</span> return count;<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> /**<a name="line.232"></a> |
| <span class="sourceLineNo">233</span> * Returns the number of samples kept by the estimator<a name="line.233"></a> |
| <span class="sourceLineNo">234</span> * @return count current number of samples<a name="line.234"></a> |
| <span class="sourceLineNo">235</span> */<a name="line.235"></a> |
| <span class="sourceLineNo">236</span> synchronized public int getSampleCount() {<a name="line.236"></a> |
| <span class="sourceLineNo">237</span> return samples.size();<a name="line.237"></a> |
| <span class="sourceLineNo">238</span> }<a name="line.238"></a> |
| <span class="sourceLineNo">239</span><a name="line.239"></a> |
| <span class="sourceLineNo">240</span> /**<a name="line.240"></a> |
| <span class="sourceLineNo">241</span> * Resets the estimator, clearing out all previously inserted items<a name="line.241"></a> |
| <span class="sourceLineNo">242</span> */<a name="line.242"></a> |
| <span class="sourceLineNo">243</span> synchronized public void clear() {<a name="line.243"></a> |
| <span class="sourceLineNo">244</span> count = 0;<a name="line.244"></a> |
| <span class="sourceLineNo">245</span> bufferCount = 0;<a name="line.245"></a> |
| <span class="sourceLineNo">246</span> samples.clear();<a name="line.246"></a> |
| <span class="sourceLineNo">247</span> }<a name="line.247"></a> |
| <span class="sourceLineNo">248</span><a name="line.248"></a> |
| <span class="sourceLineNo">249</span> /**<a name="line.249"></a> |
| <span class="sourceLineNo">250</span> * Describes a measured value passed to the estimator, tracking additional metadata required by<a name="line.250"></a> |
| <span class="sourceLineNo">251</span> * the CKMS algorithm.<a name="line.251"></a> |
| <span class="sourceLineNo">252</span> */<a name="line.252"></a> |
| <span class="sourceLineNo">253</span> private static class SampleItem {<a name="line.253"></a> |
| <span class="sourceLineNo">254</span><a name="line.254"></a> |
| <span class="sourceLineNo">255</span> /**<a name="line.255"></a> |
| <span class="sourceLineNo">256</span> * Value of the sampled item (e.g. a measured latency value)<a name="line.256"></a> |
| <span class="sourceLineNo">257</span> */<a name="line.257"></a> |
| <span class="sourceLineNo">258</span> private final long value;<a name="line.258"></a> |
| <span class="sourceLineNo">259</span><a name="line.259"></a> |
| <span class="sourceLineNo">260</span> /**<a name="line.260"></a> |
| <span class="sourceLineNo">261</span> * Difference between the lowest possible rank of the previous item, and the lowest possible<a name="line.261"></a> |
| <span class="sourceLineNo">262</span> * rank of this item. The sum of the g of all previous items yields this item's lower bound.<a name="line.262"></a> |
| <span class="sourceLineNo">263</span> */<a name="line.263"></a> |
| <span class="sourceLineNo">264</span> private int g;<a name="line.264"></a> |
| <span class="sourceLineNo">265</span><a name="line.265"></a> |
| <span class="sourceLineNo">266</span> /**<a name="line.266"></a> |
| <span class="sourceLineNo">267</span> * Difference between the item's greatest possible rank and lowest possible rank.<a name="line.267"></a> |
| <span class="sourceLineNo">268</span> */<a name="line.268"></a> |
| <span class="sourceLineNo">269</span> private final int delta;<a name="line.269"></a> |
| <span class="sourceLineNo">270</span><a name="line.270"></a> |
| <span class="sourceLineNo">271</span> public SampleItem(long value, int lowerDelta, int delta) {<a name="line.271"></a> |
| <span class="sourceLineNo">272</span> this.value = value;<a name="line.272"></a> |
| <span class="sourceLineNo">273</span> this.g = lowerDelta;<a name="line.273"></a> |
| <span class="sourceLineNo">274</span> this.delta = delta;<a name="line.274"></a> |
| <span class="sourceLineNo">275</span> }<a name="line.275"></a> |
| <span class="sourceLineNo">276</span><a name="line.276"></a> |
| <span class="sourceLineNo">277</span> @Override<a name="line.277"></a> |
| <span class="sourceLineNo">278</span> public String toString() {<a name="line.278"></a> |
| <span class="sourceLineNo">279</span> return String.format("%d, %d, %d", value, g, delta);<a name="line.279"></a> |
| <span class="sourceLineNo">280</span> }<a name="line.280"></a> |
| <span class="sourceLineNo">281</span> }<a name="line.281"></a> |
| <span class="sourceLineNo">282</span>}<a name="line.282"></a> |
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| </pre> |
| </div> |
| </body> |
| </html> |
