io.netty.resolver.InetNameResolver Maven / Gradle / Ivy
/*
* Copyright 2015 The Netty Project
*
* The Netty Project 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 io.netty.resolver;
import io.netty.util.concurrent.EventExecutor;
import io.netty.util.concurrent.Future;
import java.net.InetAddress;
import java.net.InetSocketAddress;
/**
* A skeletal {@link NameResolver} implementation that resolves {@link InetAddress}.
*/
public abstract class InetNameResolver extends SimpleNameResolver {
private volatile AddressResolver addressResolver;
/**
* @param executor the {@link EventExecutor} which is used to notify the listeners of the {@link Future} returned
* by {@link #resolve(String)}
*/
protected InetNameResolver(EventExecutor executor) {
super(executor);
}
/**
* Return a {@link AddressResolver} that will use this name resolver underneath.
* It's cached internally, so the same instance is always returned.
*/
public AddressResolver asAddressResolver() {
AddressResolver result = addressResolver;
if (result == null) {
synchronized (this) {
result = addressResolver;
if (result == null) {
addressResolver = result = new InetSocketAddressResolver(executor(), this);
}
}
}
return result;
}
}