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 import java.net.InetAddress;
19
20 /**
21 * Represents the results from a previous DNS query which can be cached.
22 */
23 public interface DnsCacheEntry {
24 /**
25 * Get the resolved address.
26 * <p>
27 * This may be null if the resolution failed, and in that case {@link #cause()} will describe the failure.
28 * @return the resolved address.
29 */
30 InetAddress address();
31
32 /**
33 * If the DNS query failed this will provide the rational.
34 * @return the rational for why the DNS query failed, or {@code null} if the query hasn't failed.
35 */
36 Throwable cause();
37 }