com.azaptree.services.http.impl.ExecutorThreadPoolWithGracefulShutdown.java Source code

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Here is the source code for com.azaptree.services.http.impl.ExecutorThreadPoolWithGracefulShutdown.java

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package com.azaptree.services.http.impl;

/*
 * #%L
 * AZAPTREE-HTTP-SERVICE
 * %%
 * Copyright (C) 2012 - 2013 AZAPTREE.COM
 * %%
 * 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.
 * #L%
 */

import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;
import org.eclipse.jetty.util.thread.ExecutorThreadPool;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;

/**
 * 
 * Enhances Jetty's ExecutorThreadPool to shutdown gracefully.
 * 
 * If there are any executor tasks still processing or in the executor queue, then the server will wait up to the specified time limit.
 * 
 * @author alfio
 * 
 */
public class ExecutorThreadPoolWithGracefulShutdown extends ExecutorThreadPool {
    private final ExecutorService executor;
    private final int shutdownTimeoutSecs;

    public ExecutorThreadPoolWithGracefulShutdown(final ExecutorService executor, final int shutdownTimeoutSecs) {
        super(executor);
        Assert.notNull(executor);
        Assert.isTrue(shutdownTimeoutSecs > 0, "constraint failed: shutdownTimeoutSecs > 0");
        this.executor = executor;
        this.shutdownTimeoutSecs = shutdownTimeoutSecs;
    }

    @Override
    protected void doStop() throws Exception {
        final Logger log = LoggerFactory.getLogger(getClass());
        log.info("STOPPING ...");
        executor.shutdown();

        int totalWaitTime = 0;
        final int waitTimeInterval = shutdownTimeoutSecs * 1000 / 2;
        final int shutdownTimeout = (shutdownTimeoutSecs * 1000);
        log.debug("waitTimeInterval = {} msec", waitTimeInterval);
        log.debug("shutdownTimeout = {} msec", shutdownTimeout);
        while (true) {
            if (executor.awaitTermination(waitTimeInterval, TimeUnit.MILLISECONDS)) {
                break;
            }
            totalWaitTime += waitTimeInterval;
            log.debug("totalWaitTime = {} msec", totalWaitTime);
            if (totalWaitTime >= shutdownTimeout) {
                log.error("Executor tasks failed to shutdown within specified max wait time: {}",
                        shutdownTimeoutSecs);
                final List<Runnable> tasks = executor.shutdownNow();
                if (!CollectionUtils.isEmpty(tasks)) {
                    log.error("Number of tasks left in the executor queue that were not processed = {}",
                            tasks.size());
                    for (final Runnable task : tasks) {
                        log.error("Unprocessed task: {}", task);
                    }
                }
                break;
            }
            log.warn("Waiting for executor tasks to complete - Current Wait Time / Max Wait Time = {}/{}",
                    totalWaitTime, shutdownTimeoutSecs);
        }

        super.doStop();
        log.info("STOPPED");
    }

    public int getShutdownTimeoutSecs() {
        return shutdownTimeoutSecs;
    }

    @Override
    public String toString() {
        return new ToStringBuilder(this, ToStringStyle.MULTI_LINE_STYLE)
                .append("executor.class", executor.getClass().getName())
                .append("shutdownTimeoutSecs", shutdownTimeoutSecs).toString();
    }
}