1 /*
2 * Copyright 2017 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.resolver.dns;
17
18 /**
19 * Provides an opportunity to override which {@link DnsServerAddressStream} is used to resolve a specific hostname.
20 * <p>
21 * For example this can be used to represent <a href="https://linux.die.net/man/5/resolver">/etc/resolv.conf</a> and
22 * <a href="https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man5/resolver.5.html">
23 * /etc/resolver</a>.
24 */
25 public interface DnsServerAddressStreamProvider {
26 /**
27 * Ask this provider for the name servers to query for {@code hostname}.
28 * @param hostname The hostname for which to lookup the DNS server addressed to use.
29 * If this is the final {@link DnsServerAddressStreamProvider} to be queried then generally empty
30 * string or {@code '.'} correspond to the default {@link DnsServerAddressStream}.
31 * @return The {@link DnsServerAddressStream} which should be used to resolve {@code hostname}.
32 */
33 DnsServerAddressStream nameServerAddressStream(String hostname);
34 }