com.github.robozonky.app.runtime.DaemonShutdownHook Maven / Gradle / Ivy

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/*
 * Copyright 2019 The RoboZonky Project
 *
 * Licensed 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 com.github.robozonky.app.runtime;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

class DaemonShutdownHook extends Thread {

    private static final Logger LOGGER = LogManager.getLogger(DaemonShutdownHook.class);

    private final ShutdownEnabler shutdownEnabler;
    private final Lifecycle lifecycle;

    public DaemonShutdownHook(final Lifecycle handler, final ShutdownEnabler shutdownEnabler) {
        this.shutdownEnabler = shutdownEnabler;
        this.lifecycle = handler;
    }

    @Override
    public void run() {
        LOGGER.debug("Shutdown requested through {}.", lifecycle);
        // will release the main thread and thus terminate the daemon
        lifecycle.resumeToShutdown();
        // only allow to shut down after the daemon has been closed by the app
        try {
            shutdownEnabler.waitUntilTriggered();
        } finally {
            LOGGER.debug("Shutdown allowed.");
        }
    }
}