1 /*
2 * Copyright 2015 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.channel.pool;
17
18 import io.netty.channel.Channel;
19 import io.netty.channel.EventLoop;
20 import io.netty.util.concurrent.Future;
21 import io.netty.util.concurrent.Promise;
22
23 /**
24 * Called before a {@link Channel} will be returned via {@link ChannelPool#acquire()} or
25 * {@link ChannelPool#acquire(Promise)}.
26 */
27 public interface ChannelHealthChecker {
28
29 /**
30 * {@link ChannelHealthChecker} implementation that checks if {@link Channel#isActive()} returns {@code true}.
31 */
32 ChannelHealthChecker ACTIVE = new ChannelHealthChecker() {
33 @Override
34 public Future<Boolean> isHealthy(Channel channel) {
35 EventLoop loop = channel.eventLoop();
36 return channel.isActive()? loop.newSucceededFuture(Boolean.TRUE) : loop.newSucceededFuture(Boolean.FALSE);
37 }
38 };
39
40 /**
41 * Check if the given channel is healthy which means it can be used. The returned {@link Future} is notified once
42 * the check is complete. If notified with {@link Boolean#TRUE} it can be used {@link Boolean#FALSE} otherwise.
43 *
44 * This method will be called by the {@link EventLoop} of the {@link Channel}.
45 */
46 Future<Boolean> isHealthy(Channel channel);
47 }