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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.hbase.client;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import java.util.Arrays;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span>import org.apache.hadoop.hbase.HConstants;<a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import org.apache.hadoop.hbase.util.Bytes;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span><a name="line.24"></a> |
| <span class="sourceLineNo">025</span>@InterfaceAudience.Private<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>public class ClientUtil {<a name="line.26"></a> |
| <span class="sourceLineNo">027</span><a name="line.27"></a> |
| <span class="sourceLineNo">028</span> public static boolean areScanStartRowAndStopRowEqual(byte[] startRow, byte[] stopRow) {<a name="line.28"></a> |
| <span class="sourceLineNo">029</span> return startRow != null && startRow.length > 0 && Bytes.equals(startRow, stopRow);<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> }<a name="line.30"></a> |
| <span class="sourceLineNo">031</span><a name="line.31"></a> |
| <span class="sourceLineNo">032</span> public static Cursor createCursor(byte[] row) {<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> return new Cursor(row);<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> }<a name="line.34"></a> |
| <span class="sourceLineNo">035</span><a name="line.35"></a> |
| <span class="sourceLineNo">036</span> /**<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> * <p><a name="line.37"></a> |
| <span class="sourceLineNo">038</span> * When scanning for a prefix the scan should stop immediately after the the last row that has the<a name="line.38"></a> |
| <span class="sourceLineNo">039</span> * specified prefix. This method calculates the closest next rowKey immediately following the<a name="line.39"></a> |
| <span class="sourceLineNo">040</span> * given rowKeyPrefix.<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> * </p><a name="line.41"></a> |
| <span class="sourceLineNo">042</span> * <p><a name="line.42"></a> |
| <span class="sourceLineNo">043</span> * <b>IMPORTANT: This converts a rowKey<u>Prefix</u> into a rowKey</b>.<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> * </p><a name="line.44"></a> |
| <span class="sourceLineNo">045</span> * <p><a name="line.45"></a> |
| <span class="sourceLineNo">046</span> * If the prefix is an 'ASCII' string put into a byte[] then this is easy because you can simply<a name="line.46"></a> |
| <span class="sourceLineNo">047</span> * increment the last byte of the array. But if your application uses real binary rowids you may<a name="line.47"></a> |
| <span class="sourceLineNo">048</span> * run into the scenario that your prefix is something like:<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> * </p><a name="line.49"></a> |
| <span class="sourceLineNo">050</span> * &nbsp;&nbsp;&nbsp;<b>{ 0x12, 0x23, 0xFF, 0xFF }</b><br/><a name="line.50"></a> |
| <span class="sourceLineNo">051</span> * Then this stopRow needs to be fed into the actual scan<br/><a name="line.51"></a> |
| <span class="sourceLineNo">052</span> * &nbsp;&nbsp;&nbsp;<b>{ 0x12, 0x24 }</b> (Notice that it is shorter now)<br/><a name="line.52"></a> |
| <span class="sourceLineNo">053</span> * This method calculates the correct stop row value for this usecase.<a name="line.53"></a> |
| <span class="sourceLineNo">054</span> * @param rowKeyPrefix the rowKey<u>Prefix</u>.<a name="line.54"></a> |
| <span class="sourceLineNo">055</span> * @return the closest next rowKey immediately following the given rowKeyPrefix.<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> */<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> public static byte[] calculateTheClosestNextRowKeyForPrefix(byte[] rowKeyPrefix) {<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> // Essentially we are treating it like an 'unsigned very very long' and doing +1 manually.<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> // Search for the place where the trailing 0xFFs start<a name="line.59"></a> |
| <span class="sourceLineNo">060</span> int offset = rowKeyPrefix.length;<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> while (offset > 0) {<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> if (rowKeyPrefix[offset - 1] != (byte) 0xFF) {<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> break;<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> }<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> offset--;<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> if (offset == 0) {<a name="line.68"></a> |
| <span class="sourceLineNo">069</span> // We got an 0xFFFF... (only FFs) stopRow value which is<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> // the last possible prefix before the end of the table.<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> // So set it to stop at the 'end of the table'<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> return HConstants.EMPTY_END_ROW;<a name="line.72"></a> |
| <span class="sourceLineNo">073</span> }<a name="line.73"></a> |
| <span class="sourceLineNo">074</span><a name="line.74"></a> |
| <span class="sourceLineNo">075</span> // Copy the right length of the original<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> byte[] newStopRow = Arrays.copyOfRange(rowKeyPrefix, 0, offset);<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> // And increment the last one<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> newStopRow[newStopRow.length - 1]++;<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> return newStopRow;<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> }<a name="line.80"></a> |
| <span class="sourceLineNo">081</span>}<a name="line.81"></a> |
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