Google Git
Sign in
apache / hbase-site / b6f9c9b1e30074a15d99b9846edeb24f586c9d35 / . / devapidocs / src-html / org / apache / hadoop / hbase / regionserver / ReversedKeyValueHeap.ReversedKVScannerComparator.html
blob: 865b960e12a36cfff4fd36d6a6a26ec023ac09be [file] [log] [blame]
<!DOCTYPE HTML>
<html lang="en">
<head>
<!-- Generated by javadoc (17) -->
<title>Source code</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="source: package: org.apache.hadoop.hbase.regionserver, class: ReversedKeyValueHeap, class: ReversedKVScannerComparator">
<meta name="generator" content="javadoc/SourceToHTMLConverter">
<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
</head>
<body class="source-page">
<main role="main">
<div class="source-container">
<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.regionserver;</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 java.io.IOException;</span>
<span class="source-line-no">021</span><span id="line-21">import java.util.List;</span>
<span class="source-line-no">022</span><span id="line-22">import org.apache.commons.lang3.NotImplementedException;</span>
<span class="source-line-no">023</span><span id="line-23">import org.apache.hadoop.hbase.Cell;</span>
<span class="source-line-no">024</span><span id="line-24">import org.apache.hadoop.hbase.CellComparator;</span>
<span class="source-line-no">025</span><span id="line-25">import org.apache.hadoop.hbase.CellUtil;</span>
<span class="source-line-no">026</span><span id="line-26">import org.apache.hadoop.hbase.ExtendedCell;</span>
<span class="source-line-no">027</span><span id="line-27">import org.apache.hadoop.hbase.HConstants;</span>
<span class="source-line-no">028</span><span id="line-28">import org.apache.yetus.audience.InterfaceAudience;</span>
<span class="source-line-no">029</span><span id="line-29"></span>
<span class="source-line-no">030</span><span id="line-30">/**</span>
<span class="source-line-no">031</span><span id="line-31"> * ReversedKeyValueHeap is used for supporting reversed scanning. Compared with KeyValueHeap, its</span>
<span class="source-line-no">032</span><span id="line-32"> * scanner comparator is a little different (see ReversedKVScannerComparator), all seek is backward</span>
<span class="source-line-no">033</span><span id="line-33"> * seek(see {@link KeyValueScanner#backwardSeek}), and it will jump to the previous row if it is</span>
<span class="source-line-no">034</span><span id="line-34"> * already at the end of one row when calling next().</span>
<span class="source-line-no">035</span><span id="line-35"> */</span>
<span class="source-line-no">036</span><span id="line-36">@InterfaceAudience.Private</span>
<span class="source-line-no">037</span><span id="line-37">public class ReversedKeyValueHeap extends KeyValueHeap {</span>
<span class="source-line-no">038</span><span id="line-38"></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 ReversedKeyValueHeap(List&lt;? extends KeyValueScanner&gt; scanners, CellComparator comparator)</span>
<span class="source-line-no">042</span><span id="line-42"> throws IOException {</span>
<span class="source-line-no">043</span><span id="line-43"> super(scanners, new ReversedKVScannerComparator(comparator));</span>
<span class="source-line-no">044</span><span id="line-44"> }</span>
<span class="source-line-no">045</span><span id="line-45"></span>
<span class="source-line-no">046</span><span id="line-46"> @Override</span>
<span class="source-line-no">047</span><span id="line-47"> public boolean seek(ExtendedCell seekKey) throws IOException {</span>
<span class="source-line-no">048</span><span id="line-48"> throw new IllegalStateException("seek cannot be called on ReversedKeyValueHeap");</span>
<span class="source-line-no">049</span><span id="line-49"> }</span>
<span class="source-line-no">050</span><span id="line-50"></span>
<span class="source-line-no">051</span><span id="line-51"> @Override</span>
<span class="source-line-no">052</span><span id="line-52"> public boolean reseek(ExtendedCell seekKey) throws IOException {</span>
<span class="source-line-no">053</span><span id="line-53"> throw new IllegalStateException("reseek cannot be called on ReversedKeyValueHeap");</span>
<span class="source-line-no">054</span><span id="line-54"> }</span>
<span class="source-line-no">055</span><span id="line-55"></span>
<span class="source-line-no">056</span><span id="line-56"> @Override</span>
<span class="source-line-no">057</span><span id="line-57"> public boolean requestSeek(ExtendedCell key, boolean forward, boolean useBloom)</span>
<span class="source-line-no">058</span><span id="line-58"> throws IOException {</span>
<span class="source-line-no">059</span><span id="line-59"> throw new IllegalStateException("requestSeek cannot be called on ReversedKeyValueHeap");</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"> @Override</span>
<span class="source-line-no">063</span><span id="line-63"> public boolean seekToPreviousRow(ExtendedCell seekKey) throws IOException {</span>
<span class="source-line-no">064</span><span id="line-64"> if (current == null) {</span>
<span class="source-line-no">065</span><span id="line-65"> return false;</span>
<span class="source-line-no">066</span><span id="line-66"> }</span>
<span class="source-line-no">067</span><span id="line-67"> heap.add(current);</span>
<span class="source-line-no">068</span><span id="line-68"> current = null;</span>
<span class="source-line-no">069</span><span id="line-69"></span>
<span class="source-line-no">070</span><span id="line-70"> KeyValueScanner scanner;</span>
<span class="source-line-no">071</span><span id="line-71"> while ((scanner = heap.poll()) != null) {</span>
<span class="source-line-no">072</span><span id="line-72"> Cell topKey = scanner.peek();</span>
<span class="source-line-no">073</span><span id="line-73"> if (comparator.getComparator().compareRows(topKey, seekKey) &lt; 0) {</span>
<span class="source-line-no">074</span><span id="line-74"> // Row of Top KeyValue is before Seek row.</span>
<span class="source-line-no">075</span><span id="line-75"> heap.add(scanner);</span>
<span class="source-line-no">076</span><span id="line-76"> current = pollRealKV();</span>
<span class="source-line-no">077</span><span id="line-77"> return current != null;</span>
<span class="source-line-no">078</span><span id="line-78"> }</span>
<span class="source-line-no">079</span><span id="line-79"></span>
<span class="source-line-no">080</span><span id="line-80"> if (!scanner.seekToPreviousRow(seekKey)) {</span>
<span class="source-line-no">081</span><span id="line-81"> this.scannersForDelayedClose.add(scanner);</span>
<span class="source-line-no">082</span><span id="line-82"> } else {</span>
<span class="source-line-no">083</span><span id="line-83"> heap.add(scanner);</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"></span>
<span class="source-line-no">087</span><span id="line-87"> // Heap is returning empty, scanner is done</span>
<span class="source-line-no">088</span><span id="line-88"> return false;</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"> @Override</span>
<span class="source-line-no">092</span><span id="line-92"> public boolean backwardSeek(ExtendedCell seekKey) throws IOException {</span>
<span class="source-line-no">093</span><span id="line-93"> if (current == null) {</span>
<span class="source-line-no">094</span><span id="line-94"> return false;</span>
<span class="source-line-no">095</span><span id="line-95"> }</span>
<span class="source-line-no">096</span><span id="line-96"> heap.add(current);</span>
<span class="source-line-no">097</span><span id="line-97"> current = null;</span>
<span class="source-line-no">098</span><span id="line-98"></span>
<span class="source-line-no">099</span><span id="line-99"> KeyValueScanner scanner;</span>
<span class="source-line-no">100</span><span id="line-100"> while ((scanner = heap.poll()) != null) {</span>
<span class="source-line-no">101</span><span id="line-101"> Cell topKey = scanner.peek();</span>
<span class="source-line-no">102</span><span id="line-102"> if (</span>
<span class="source-line-no">103</span><span id="line-103"> (CellUtil.matchingRows(seekKey, topKey)</span>
<span class="source-line-no">104</span><span id="line-104"> &amp;&amp; comparator.getComparator().compare(seekKey, topKey) &lt;= 0)</span>
<span class="source-line-no">105</span><span id="line-105"> || comparator.getComparator().compareRows(seekKey, topKey) &gt; 0</span>
<span class="source-line-no">106</span><span id="line-106"> ) {</span>
<span class="source-line-no">107</span><span id="line-107"> heap.add(scanner);</span>
<span class="source-line-no">108</span><span id="line-108"> current = pollRealKV();</span>
<span class="source-line-no">109</span><span id="line-109"> return current != null;</span>
<span class="source-line-no">110</span><span id="line-110"> }</span>
<span class="source-line-no">111</span><span id="line-111"> if (!scanner.backwardSeek(seekKey)) {</span>
<span class="source-line-no">112</span><span id="line-112"> this.scannersForDelayedClose.add(scanner);</span>
<span class="source-line-no">113</span><span id="line-113"> } else {</span>
<span class="source-line-no">114</span><span id="line-114"> heap.add(scanner);</span>
<span class="source-line-no">115</span><span id="line-115"> }</span>
<span class="source-line-no">116</span><span id="line-116"> }</span>
<span class="source-line-no">117</span><span id="line-117"> return false;</span>
<span class="source-line-no">118</span><span id="line-118"> }</span>
<span class="source-line-no">119</span><span id="line-119"></span>
<span class="source-line-no">120</span><span id="line-120"> @Override</span>
<span class="source-line-no">121</span><span id="line-121"> public ExtendedCell next() throws IOException {</span>
<span class="source-line-no">122</span><span id="line-122"> if (this.current == null) {</span>
<span class="source-line-no">123</span><span id="line-123"> return null;</span>
<span class="source-line-no">124</span><span id="line-124"> }</span>
<span class="source-line-no">125</span><span id="line-125"> ExtendedCell kvReturn = this.current.next();</span>
<span class="source-line-no">126</span><span id="line-126"> ExtendedCell kvNext = this.current.peek();</span>
<span class="source-line-no">127</span><span id="line-127"> if (kvNext == null || this.comparator.kvComparator.compareRows(kvNext, kvReturn) &gt; 0) {</span>
<span class="source-line-no">128</span><span id="line-128"> if (this.current.seekToPreviousRow(kvReturn)) {</span>
<span class="source-line-no">129</span><span id="line-129"> this.heap.add(this.current);</span>
<span class="source-line-no">130</span><span id="line-130"> } else {</span>
<span class="source-line-no">131</span><span id="line-131"> this.scannersForDelayedClose.add(this.current);</span>
<span class="source-line-no">132</span><span id="line-132"> }</span>
<span class="source-line-no">133</span><span id="line-133"> this.current = null;</span>
<span class="source-line-no">134</span><span id="line-134"> this.current = pollRealKV();</span>
<span class="source-line-no">135</span><span id="line-135"> } else {</span>
<span class="source-line-no">136</span><span id="line-136"> KeyValueScanner topScanner = this.heap.peek();</span>
<span class="source-line-no">137</span><span id="line-137"> if (topScanner != null &amp;&amp; this.comparator.compare(this.current, topScanner) &gt; 0) {</span>
<span class="source-line-no">138</span><span id="line-138"> this.heap.add(this.current);</span>
<span class="source-line-no">139</span><span id="line-139"> this.current = null;</span>
<span class="source-line-no">140</span><span id="line-140"> this.current = pollRealKV();</span>
<span class="source-line-no">141</span><span id="line-141"> }</span>
<span class="source-line-no">142</span><span id="line-142"> }</span>
<span class="source-line-no">143</span><span id="line-143"> return kvReturn;</span>
<span class="source-line-no">144</span><span id="line-144"> }</span>
<span class="source-line-no">145</span><span id="line-145"></span>
<span class="source-line-no">146</span><span id="line-146"> /**</span>
<span class="source-line-no">147</span><span id="line-147"> * In ReversedKVScannerComparator, we compare the row of scanners' peek values first, sort bigger</span>
<span class="source-line-no">148</span><span id="line-148"> * one before the smaller one. Then compare the KeyValue if they have the equal row, sort smaller</span>
<span class="source-line-no">149</span><span id="line-149"> * one before the bigger one</span>
<span class="source-line-no">150</span><span id="line-150"> */</span>
<span class="source-line-no">151</span><span id="line-151"> private static class ReversedKVScannerComparator extends KVScannerComparator {</span>
<span class="source-line-no">152</span><span id="line-152"></span>
<span class="source-line-no">153</span><span id="line-153"> /**</span>
<span class="source-line-no">154</span><span id="line-154"> * Constructor</span>
<span class="source-line-no">155</span><span id="line-155"> */</span>
<span class="source-line-no">156</span><span id="line-156"> public ReversedKVScannerComparator(CellComparator kvComparator) {</span>
<span class="source-line-no">157</span><span id="line-157"> super(kvComparator);</span>
<span class="source-line-no">158</span><span id="line-158"> }</span>
<span class="source-line-no">159</span><span id="line-159"></span>
<span class="source-line-no">160</span><span id="line-160"> @Override</span>
<span class="source-line-no">161</span><span id="line-161"> public int compare(KeyValueScanner left, KeyValueScanner right) {</span>
<span class="source-line-no">162</span><span id="line-162"> int rowComparison = compareRows(left.peek(), right.peek());</span>
<span class="source-line-no">163</span><span id="line-163"> if (rowComparison != 0) {</span>
<span class="source-line-no">164</span><span id="line-164"> return -rowComparison;</span>
<span class="source-line-no">165</span><span id="line-165"> }</span>
<span class="source-line-no">166</span><span id="line-166"> return super.compare(left, right);</span>
<span class="source-line-no">167</span><span id="line-167"> }</span>
<span class="source-line-no">168</span><span id="line-168"></span>
<span class="source-line-no">169</span><span id="line-169"> /**</span>
<span class="source-line-no">170</span><span id="line-170"> * Compares rows of two KeyValue</span>
<span class="source-line-no">171</span><span id="line-171"> * @return less than 0 if left is smaller, 0 if equal etc..</span>
<span class="source-line-no">172</span><span id="line-172"> */</span>
<span class="source-line-no">173</span><span id="line-173"> public int compareRows(Cell left, Cell right) {</span>
<span class="source-line-no">174</span><span id="line-174"> return super.kvComparator.compareRows(left, right);</span>
<span class="source-line-no">175</span><span id="line-175"> }</span>
<span class="source-line-no">176</span><span id="line-176"> }</span>
<span class="source-line-no">177</span><span id="line-177"></span>
<span class="source-line-no">178</span><span id="line-178"> @Override</span>
<span class="source-line-no">179</span><span id="line-179"> public boolean seekToLastRow() throws IOException {</span>
<span class="source-line-no">180</span><span id="line-180"> throw new NotImplementedException(HConstants.NOT_IMPLEMENTED);</span>
<span class="source-line-no">181</span><span id="line-181"> }</span>
<span class="source-line-no">182</span><span id="line-182">}</span>
</pre>
</div>
</main>
</body>
</html>