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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 java.util.Arrays;</span> |
| <span class="source-line-no">021</span><span id="line-21">import org.apache.hadoop.hbase.HConstants;</span> |
| <span class="source-line-no">022</span><span id="line-22">import org.apache.hadoop.hbase.util.Bytes;</span> |
| <span class="source-line-no">023</span><span id="line-23">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">024</span><span id="line-24"></span> |
| <span class="source-line-no">025</span><span id="line-25">@InterfaceAudience.Private</span> |
| <span class="source-line-no">026</span><span id="line-26">public class ClientUtil {</span> |
| <span class="source-line-no">027</span><span id="line-27"></span> |
| <span class="source-line-no">028</span><span id="line-28"> public static boolean areScanStartRowAndStopRowEqual(byte[] startRow, byte[] stopRow) {</span> |
| <span class="source-line-no">029</span><span id="line-29"> return startRow != null && startRow.length > 0 && Bytes.equals(startRow, stopRow);</span> |
| <span class="source-line-no">030</span><span id="line-30"> }</span> |
| <span class="source-line-no">031</span><span id="line-31"></span> |
| <span class="source-line-no">032</span><span id="line-32"> public static Cursor createCursor(byte[] row) {</span> |
| <span class="source-line-no">033</span><span id="line-33"> return new Cursor(row);</span> |
| <span class="source-line-no">034</span><span id="line-34"> }</span> |
| <span class="source-line-no">035</span><span id="line-35"></span> |
| <span class="source-line-no">036</span><span id="line-36"> /**</span> |
| <span class="source-line-no">037</span><span id="line-37"> * <p></span> |
| <span class="source-line-no">038</span><span id="line-38"> * When scanning for a prefix the scan should stop immediately after the the last row that has the</span> |
| <span class="source-line-no">039</span><span id="line-39"> * specified prefix. This method calculates the closest next rowKey immediately following the</span> |
| <span class="source-line-no">040</span><span id="line-40"> * given rowKeyPrefix.</span> |
| <span class="source-line-no">041</span><span id="line-41"> * </p></span> |
| <span class="source-line-no">042</span><span id="line-42"> * <p></span> |
| <span class="source-line-no">043</span><span id="line-43"> * <b>IMPORTANT: This converts a rowKey<u>Prefix</u> into a rowKey</b>.</span> |
| <span class="source-line-no">044</span><span id="line-44"> * </p></span> |
| <span class="source-line-no">045</span><span id="line-45"> * <p></span> |
| <span class="source-line-no">046</span><span id="line-46"> * If the prefix is an 'ASCII' string put into a byte[] then this is easy because you can simply</span> |
| <span class="source-line-no">047</span><span id="line-47"> * increment the last byte of the array. But if your application uses real binary rowids you may</span> |
| <span class="source-line-no">048</span><span id="line-48"> * run into the scenario that your prefix is something like:</span> |
| <span class="source-line-no">049</span><span id="line-49"> * </p></span> |
| <span class="source-line-no">050</span><span id="line-50"> * &nbsp;&nbsp;&nbsp;<b>{ 0x12, 0x23, 0xFF, 0xFF }</b><br/></span> |
| <span class="source-line-no">051</span><span id="line-51"> * Then this stopRow needs to be fed into the actual scan<br/></span> |
| <span class="source-line-no">052</span><span id="line-52"> * &nbsp;&nbsp;&nbsp;<b>{ 0x12, 0x24 }</b> (Notice that it is shorter now)<br/></span> |
| <span class="source-line-no">053</span><span id="line-53"> * This method calculates the correct stop row value for this usecase.</span> |
| <span class="source-line-no">054</span><span id="line-54"> * @param rowKeyPrefix the rowKey<u>Prefix</u>.</span> |
| <span class="source-line-no">055</span><span id="line-55"> * @return the closest next rowKey immediately following the given rowKeyPrefix.</span> |
| <span class="source-line-no">056</span><span id="line-56"> */</span> |
| <span class="source-line-no">057</span><span id="line-57"> public static byte[] calculateTheClosestNextRowKeyForPrefix(byte[] rowKeyPrefix) {</span> |
| <span class="source-line-no">058</span><span id="line-58"> // Essentially we are treating it like an 'unsigned very very long' and doing +1 manually.</span> |
| <span class="source-line-no">059</span><span id="line-59"> // Search for the place where the trailing 0xFFs start</span> |
| <span class="source-line-no">060</span><span id="line-60"> int offset = rowKeyPrefix.length;</span> |
| <span class="source-line-no">061</span><span id="line-61"> while (offset > 0) {</span> |
| <span class="source-line-no">062</span><span id="line-62"> if (rowKeyPrefix[offset - 1] != (byte) 0xFF) {</span> |
| <span class="source-line-no">063</span><span id="line-63"> break;</span> |
| <span class="source-line-no">064</span><span id="line-64"> }</span> |
| <span class="source-line-no">065</span><span id="line-65"> offset--;</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 (offset == 0) {</span> |
| <span class="source-line-no">069</span><span id="line-69"> // We got an 0xFFFF... (only FFs) stopRow value which is</span> |
| <span class="source-line-no">070</span><span id="line-70"> // the last possible prefix before the end of the table.</span> |
| <span class="source-line-no">071</span><span id="line-71"> // So set it to stop at the 'end of the table'</span> |
| <span class="source-line-no">072</span><span id="line-72"> return HConstants.EMPTY_END_ROW;</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"> // Copy the right length of the original</span> |
| <span class="source-line-no">076</span><span id="line-76"> byte[] newStopRow = Arrays.copyOfRange(rowKeyPrefix, 0, offset);</span> |
| <span class="source-line-no">077</span><span id="line-77"> // And increment the last one</span> |
| <span class="source-line-no">078</span><span id="line-78"> newStopRow[newStopRow.length - 1]++;</span> |
| <span class="source-line-no">079</span><span id="line-79"> return newStopRow;</span> |
| <span class="source-line-no">080</span><span id="line-80"> }</span> |
| <span class="source-line-no">081</span><span id="line-81">}</span> |
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