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17 package org.apache.hadoop.hbase.util;
18
19 import java.lang.reflect.Method;
20 import java.net.UnknownHostException;
21
22 import org.apache.hadoop.hbase.classification.InterfaceAudience;
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27 @InterfaceAudience.Private
28 public class DNS {
29 private static boolean HAS_NEW_DNS_GET_DEFAULT_HOST_API;
30 private static Method GET_DEFAULT_HOST_METHOD;
31
32 static {
33 try {
34 GET_DEFAULT_HOST_METHOD = org.apache.hadoop.net.DNS.class
35 .getMethod("getDefaultHost", String.class, String.class, boolean.class);
36 HAS_NEW_DNS_GET_DEFAULT_HOST_API = true;
37 } catch (Exception e) {
38 HAS_NEW_DNS_GET_DEFAULT_HOST_API = false;
39 }
40 }
41
42 private DNS() {}
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47 public static String getDefaultHost(String strInterface, String nameserver)
48 throws UnknownHostException {
49 if (HAS_NEW_DNS_GET_DEFAULT_HOST_API) {
50 try {
51
52
53 return (String) GET_DEFAULT_HOST_METHOD.invoke(null, strInterface, nameserver, true);
54 } catch (Exception e) {
55
56 throw new RuntimeException("Failed to invoke DNS.getDefaultHost via reflection", e);
57 }
58 } else {
59 return org.apache.hadoop.net.DNS.getDefaultHost(strInterface, nameserver);
60 }
61 }
62 }