Java example source code file (ChannelHealthChecker.java)

This example Java source code file (ChannelHealthChecker.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

active, channelhealthchecker, eventloop, future, override

The ChannelHealthChecker.java Java example source code

/*
 * 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.channel.pool;

import io.netty.channel.Channel;
import io.netty.channel.EventLoop;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.Promise;

/**
 * Called before a {@link Channel} will be returned via {@link ChannelPool#acquire()} or
 * {@link ChannelPool#acquire(Promise)}.
 */
public interface ChannelHealthChecker {

    /**
     * {@link ChannelHealthChecker} implementation that checks if {@link Channel#isActive()} returns {@code true}.
     */
    ChannelHealthChecker ACTIVE = new ChannelHealthChecker() {
        @Override
        public Future<Boolean> isHealthy(Channel channel) {
            EventLoop loop = channel.eventLoop();
            return channel.isActive()? loop.newSucceededFuture(Boolean.TRUE) : loop.newSucceededFuture(Boolean.FALSE);
        }
    };

    /**
     * Check if the given channel is healthy which means it can be used. The returned {@link Future} is notified once
     * the check is complete. If notified with {@link Boolean#TRUE} it can be used {@link Boolean#FALSE} otherwise.
     *
     * This method will be called by the {@link EventLoop} of the {@link Channel}.
     */
    Future<Boolean> isHealthy(Channel channel);
}