com.twitter.distributedlog.net.NetUtils Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.twitter.distributedlog.net;
import org.apache.bookkeeper.net.DNSToSwitchMapping;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
/**
* Utils about network
*/
public class NetUtils {
/**
* Get the dns resolver from class resolverClassName with optional
* hostRegionOverrides.
*
* It would try to load the class with the constructor with hostRegionOverrides.
* If it fails, it would fall back to load the class with default empty constructor.
* The interpretion of hostRegionOverrides is up to the implementation.
*
* @param resolverCls
* resolver class
* @param hostRegionOverrides
* host region overrides
* @return dns resolver
*/
public static DNSToSwitchMapping getDNSResolver(Class resolverCls,
String hostRegionOverrides) {
// first try to construct the dns resolver with overrides
Constructor constructor;
Object[] parameters;
try {
constructor = resolverCls.getDeclaredConstructor(String.class);
parameters = new Object[] { hostRegionOverrides };
} catch (NoSuchMethodException nsme) {
// no constructor with overrides
try {
constructor = resolverCls.getDeclaredConstructor();
parameters = new Object[0];
} catch (NoSuchMethodException nsme1) {
throw new RuntimeException("Unable to find constructor for dns resolver "
+ resolverCls, nsme1);
}
}
constructor.setAccessible(true);
try {
return constructor.newInstance(parameters);
} catch (InstantiationException ie) {
throw new RuntimeException("Unable to instantiate dns resolver " + resolverCls, ie);
} catch (IllegalAccessException iae) {
throw new RuntimeException("Illegal access to dns resolver " + resolverCls, iae);
} catch (InvocationTargetException ite) {
throw new RuntimeException("Unable to construct dns resolver " + resolverCls, ite);
}
}
}