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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.util;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.lang.reflect.InvocationTargetException;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.lang.reflect.Method;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import org.apache.hadoop.hdfs.protocol.DatanodeInfo;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import org.apache.hadoop.hdfs.protocol.LocatedBlock;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>/**<a name="line.26"></a>
<span class="sourceLineNo">027</span> * hadoop 3.3.1 changed the return value of this method from {@code DatanodeInfo[]} to<a name="line.27"></a>
<span class="sourceLineNo">028</span> * {@code DatanodeInfoWithStorage[]}, which causes the JVM can not locate the method if we are<a name="line.28"></a>
<span class="sourceLineNo">029</span> * compiled with hadoop 3.2 and then link with hadoop 3.3+, so here we need to use reflection to<a name="line.29"></a>
<span class="sourceLineNo">030</span> * make it work for both hadoop versions, otherwise we need to publish more artifacts for different<a name="line.30"></a>
<span class="sourceLineNo">031</span> * hadoop versions...<a name="line.31"></a>
<span class="sourceLineNo">032</span> */<a name="line.32"></a>
<span class="sourceLineNo">033</span>@InterfaceAudience.Private<a name="line.33"></a>
<span class="sourceLineNo">034</span>public final class LocatedBlockHelper {<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span> private static final Method GET_LOCATED_BLOCK_LOCATIONS_METHOD;<a name="line.36"></a>
<span class="sourceLineNo">037</span><a name="line.37"></a>
<span class="sourceLineNo">038</span> static {<a name="line.38"></a>
<span class="sourceLineNo">039</span> try {<a name="line.39"></a>
<span class="sourceLineNo">040</span> GET_LOCATED_BLOCK_LOCATIONS_METHOD = LocatedBlock.class.getMethod("getLocations");<a name="line.40"></a>
<span class="sourceLineNo">041</span> } catch (Exception e) {<a name="line.41"></a>
<span class="sourceLineNo">042</span> throw new Error("Can not initialize access to HDFS LocatedBlock.getLocations method", e);<a name="line.42"></a>
<span class="sourceLineNo">043</span> }<a name="line.43"></a>
<span class="sourceLineNo">044</span> }<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span> private LocatedBlockHelper() {<a name="line.46"></a>
<span class="sourceLineNo">047</span> }<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> public static DatanodeInfo[] getLocatedBlockLocations(LocatedBlock block) {<a name="line.49"></a>
<span class="sourceLineNo">050</span> try {<a name="line.50"></a>
<span class="sourceLineNo">051</span> // DatanodeInfoWithStorage[] can be casted to DatanodeInfo[] directly<a name="line.51"></a>
<span class="sourceLineNo">052</span> return (DatanodeInfo[]) GET_LOCATED_BLOCK_LOCATIONS_METHOD.invoke(block);<a name="line.52"></a>
<span class="sourceLineNo">053</span> } catch (IllegalAccessException | InvocationTargetException e) {<a name="line.53"></a>
<span class="sourceLineNo">054</span> throw new RuntimeException(e);<a name="line.54"></a>
<span class="sourceLineNo">055</span> }<a name="line.55"></a>
<span class="sourceLineNo">056</span> }<a name="line.56"></a>
<span class="sourceLineNo">057</span>}<a name="line.57"></a>
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