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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.client;</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 static org.apache.hadoop.hbase.client.ConnectionUtils.filterCells;</span>
<span class="source-line-no">021</span><span id="line-21"></span>
<span class="source-line-no">022</span><span id="line-22">import java.io.IOException;</span>
<span class="source-line-no">023</span><span id="line-23">import java.util.Arrays;</span>
<span class="source-line-no">024</span><span id="line-24">import org.apache.hadoop.hbase.CellUtil;</span>
<span class="source-line-no">025</span><span id="line-25">import org.apache.hadoop.hbase.ExtendedCell;</span>
<span class="source-line-no">026</span><span id="line-26">import org.apache.yetus.audience.InterfaceAudience;</span>
<span class="source-line-no">027</span><span id="line-27"></span>
<span class="source-line-no">028</span><span id="line-28">/**</span>
<span class="source-line-no">029</span><span id="line-29"> * A ScanResultCache that may return partial result.</span>
<span class="source-line-no">030</span><span id="line-30"> * &lt;p&gt;</span>
<span class="source-line-no">031</span><span id="line-31"> * As we can only scan from the starting of a row when error, so here we also implement the logic</span>
<span class="source-line-no">032</span><span id="line-32"> * that skips the cells that have already been returned.</span>
<span class="source-line-no">033</span><span id="line-33"> */</span>
<span class="source-line-no">034</span><span id="line-34">@InterfaceAudience.Private</span>
<span class="source-line-no">035</span><span id="line-35">class AllowPartialScanResultCache implements ScanResultCache {</span>
<span class="source-line-no">036</span><span id="line-36"></span>
<span class="source-line-no">037</span><span id="line-37"> // used to filter out the cells that already returned to user as we always start from the</span>
<span class="source-line-no">038</span><span id="line-38"> // beginning of a row when retry.</span>
<span class="source-line-no">039</span><span id="line-39"> private ExtendedCell lastCell;</span>
<span class="source-line-no">040</span><span id="line-40"></span>
<span class="source-line-no">041</span><span id="line-41"> private boolean lastResultPartial;</span>
<span class="source-line-no">042</span><span id="line-42"></span>
<span class="source-line-no">043</span><span id="line-43"> private int numberOfCompleteRows;</span>
<span class="source-line-no">044</span><span id="line-44"></span>
<span class="source-line-no">045</span><span id="line-45"> private void recordLastResult(Result result) {</span>
<span class="source-line-no">046</span><span id="line-46"> lastCell = result.rawExtendedCells()[result.rawExtendedCells().length - 1];</span>
<span class="source-line-no">047</span><span id="line-47"> lastResultPartial = result.mayHaveMoreCellsInRow();</span>
<span class="source-line-no">048</span><span id="line-48"> }</span>
<span class="source-line-no">049</span><span id="line-49"></span>
<span class="source-line-no">050</span><span id="line-50"> @Override</span>
<span class="source-line-no">051</span><span id="line-51"> public Result[] addAndGet(Result[] results, boolean isHeartbeatMessage) throws IOException {</span>
<span class="source-line-no">052</span><span id="line-52"> if (results.length == 0) {</span>
<span class="source-line-no">053</span><span id="line-53"> if (!isHeartbeatMessage &amp;&amp; lastResultPartial) {</span>
<span class="source-line-no">054</span><span id="line-54"> // An empty non heartbeat result indicate that there must be a row change. So if the</span>
<span class="source-line-no">055</span><span id="line-55"> // lastResultPartial is true then we need to increase numberOfCompleteRows.</span>
<span class="source-line-no">056</span><span id="line-56"> numberOfCompleteRows++;</span>
<span class="source-line-no">057</span><span id="line-57"> }</span>
<span class="source-line-no">058</span><span id="line-58"> return EMPTY_RESULT_ARRAY;</span>
<span class="source-line-no">059</span><span id="line-59"> }</span>
<span class="source-line-no">060</span><span id="line-60"> int i;</span>
<span class="source-line-no">061</span><span id="line-61"> for (i = 0; i &lt; results.length; i++) {</span>
<span class="source-line-no">062</span><span id="line-62"> Result r = filterCells(results[i], lastCell);</span>
<span class="source-line-no">063</span><span id="line-63"> if (r != null) {</span>
<span class="source-line-no">064</span><span id="line-64"> results[i] = r;</span>
<span class="source-line-no">065</span><span id="line-65"> break;</span>
<span class="source-line-no">066</span><span id="line-66"> }</span>
<span class="source-line-no">067</span><span id="line-67"> }</span>
<span class="source-line-no">068</span><span id="line-68"> if (i == results.length) {</span>
<span class="source-line-no">069</span><span id="line-69"> return EMPTY_RESULT_ARRAY;</span>
<span class="source-line-no">070</span><span id="line-70"> }</span>
<span class="source-line-no">071</span><span id="line-71"> if (lastResultPartial &amp;&amp; !CellUtil.matchingRows(lastCell, results[0].getRow())) {</span>
<span class="source-line-no">072</span><span id="line-72"> // there is a row change, so increase numberOfCompleteRows</span>
<span class="source-line-no">073</span><span id="line-73"> numberOfCompleteRows++;</span>
<span class="source-line-no">074</span><span id="line-74"> }</span>
<span class="source-line-no">075</span><span id="line-75"> recordLastResult(results[results.length - 1]);</span>
<span class="source-line-no">076</span><span id="line-76"> if (i &gt; 0) {</span>
<span class="source-line-no">077</span><span id="line-77"> results = Arrays.copyOfRange(results, i, results.length);</span>
<span class="source-line-no">078</span><span id="line-78"> }</span>
<span class="source-line-no">079</span><span id="line-79"> for (Result result : results) {</span>
<span class="source-line-no">080</span><span id="line-80"> if (!result.mayHaveMoreCellsInRow()) {</span>
<span class="source-line-no">081</span><span id="line-81"> numberOfCompleteRows++;</span>
<span class="source-line-no">082</span><span id="line-82"> }</span>
<span class="source-line-no">083</span><span id="line-83"> }</span>
<span class="source-line-no">084</span><span id="line-84"> return results;</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"> @Override</span>
<span class="source-line-no">088</span><span id="line-88"> public void clear() {</span>
<span class="source-line-no">089</span><span id="line-89"> // we do not cache anything</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"> @Override</span>
<span class="source-line-no">093</span><span id="line-93"> public int numberOfCompleteRows() {</span>
<span class="source-line-no">094</span><span id="line-94"> return numberOfCompleteRows;</span>
<span class="source-line-no">095</span><span id="line-95"> }</span>
<span class="source-line-no">096</span><span id="line-96">}</span>
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