com.arpnetworking.clusteraggregator.AppShutdown Maven / Gradle / Ivy

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/*
 * Copyright 2017 Inscope Metrics, Inc
 *
 * 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.arpnetworking.clusteraggregator;

import com.arpnetworking.steno.Logger;
import com.arpnetworking.steno.LoggerFactory;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutionException;
import java.util.function.Supplier;

/**
 * Assists Guice-instantiated classes in shutting down.
 *
 * @author Brandon Arp (brandon dot arp at inscopemetrics dot io)
 */
public class AppShutdown implements LifecycleRegistration {
    /**
     * {@inheritDoc}
     */
    @Override
    public void registerShutdown(final Supplier> callback) {
        _shutdownCallbacks.offer(callback);
    }

    /**
     * Executes all of the registered shutdown hooks and waits for them to complete.
     */
    public void shutdown() {
        final CompletableFuture[] completionStages = _shutdownCallbacks.stream()
                .map(Supplier::get)
                .map(CompletionStage::toCompletableFuture)
                .toArray(CompletableFuture[]::new);

        try {
            CompletableFuture.allOf(completionStages).get();
        } catch (final InterruptedException | ExecutionException e) {
            LOGGER.error()
                    .setMessage("Exception in application shutdown")
                    .setThrowable(e)
                    .log();
        }
    }

    private final ConcurrentLinkedQueue>> _shutdownCallbacks = new ConcurrentLinkedQueue<>();

    private static final Logger LOGGER = LoggerFactory.getLogger(AppShutdown.class);
}