com.aol.advertising.qiao.management.metrics.StatsCollector.java Source code

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Here is the source code for com.aol.advertising.qiao.management.metrics.StatsCollector.java

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/****************************************************************************
 * Copyright (c) 2015 AOL Inc.
 * @author:     ytung05
 *
 * 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.aol.advertising.qiao.management.metrics;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.jmx.export.annotation.ManagedAttribute;
import org.springframework.jmx.export.annotation.ManagedOperation;
import org.springframework.jmx.export.annotation.ManagedResource;

import com.aol.advertising.qiao.management.jmx.StatsControl;

/**
 * The StatsCollector object collects statistics metrics periodically.
 */
@ManagedResource(description = "Metrics Collector")
public class StatsCollector implements Runnable, ApplicationListener<StatsControl> {
    private Logger logger = LoggerFactory.getLogger(this.getClass());
    private List<Callable<?>> statsCallable = Collections.synchronizedList(new ArrayList<Callable<?>>());
    private long intervalSecs = 60;
    private long initDelaySecs = 15;
    private ScheduledExecutorService scheduler;
    private ScheduledFuture<?> schedulerHandler;
    private boolean running = false;

    /**
     * Initialize.
     */
    public void init() {
    }

    /**
     * Start the collection process.
     */
    public void start() {
        schedulerHandler = scheduler.scheduleAtFixedRate(this, initDelaySecs, intervalSecs, TimeUnit.SECONDS);
        logger.info("stats collector starts");
        running = true;
    }

    /**
     * Terminate the collection process.
     */
    @ManagedOperation(description = "Stop the collection process")
    public void stop() {
        if (running) {
            schedulerHandler.cancel(false);
            logger.info("stats collector stops");
            running = false;
        }
    }

    @ManagedOperation(description = "Restart the collection process")
    public void restart() {
        if (!running) {
            schedulerHandler = scheduler.scheduleAtFixedRate(this, initDelaySecs, intervalSecs, TimeUnit.SECONDS);

            logger.info("stats collector restarts");
            running = true;
        } else {
            logger.info("stats collector already running");
        }
    }

    public void shutdown() {
        stop();
        scheduler.shutdown();
    }

    @Override
    public void run() {
        for (Callable<?> c : statsCallable) {
            try {
                c.call();
            } catch (Throwable e) {
                logger.error(e.getMessage(), e);
            }
        }

    }

    /**
     * Register the callable object to be invoked at each interval.
     *
     * @param c
     */
    public void register(Callable<?> c) {
        statsCallable.add(c);
    }

    /**
     * Unregister the previously registered callable object.
     *
     * @param c
     */
    public void unregister(Callable<?> c) {
        statsCallable.remove(c);
    }

    /**
     * Set time in seconds between successive collector runs.
     *
     * @param intervalSecs
     */
    public void setIntervalSecs(long intervalSecs) {
        this.intervalSecs = intervalSecs;
    }

    @ManagedAttribute
    public boolean isRunning() {
        return running;
    }

    @Override
    public void onApplicationEvent(StatsControl event) {
        switch (event.getCommand()) {
        case START_STATS:
            restart();
            break;
        case STOP_STATS:
            stop();
            break;
        default:
            ;
        }

    }

    public void setInitDelaySecs(long initDelaySecs) {
        this.initDelaySecs = initDelaySecs;
    }

    public void setScheduler(ScheduledExecutorService scheduler) {
        this.scheduler = scheduler;
    }

}