package com.cloudhopper.mq.queue.impl;
/*
* #%L
* ch-mq
* %%
* Copyright (C) 2009 - 2013 Cloudhopper by Twitter
* %%
* 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 com.cloudhopper.mq.queue.Queue;
import com.codahale.metrics.ExponentiallyDecayingReservoir;
import com.codahale.metrics.Reservoir;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.WeakHashMap;
import java.util.Map;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A periodic probe that measures average queue size. Currently runs every 15 seconds.
* @author garth
*/
public class AverageQueueSize implements Runnable {
private static final Logger logger = LoggerFactory.getLogger(AverageQueueSize.class);
private static final long PROBE_EACH = 15000L; //15 seconds
private static AverageQueueSize instance;
static {
instance = new AverageQueueSize();
}
public static AverageQueueSize get() {
return instance;
}
private AverageQueueSize() {
this.executor = new ScheduledThreadPoolExecutor(1);
this.executor.scheduleAtFixedRate(this, 0L, PROBE_EACH, TimeUnit.MILLISECONDS);
this.queues = Collections.synchronizedMap(new WeakHashMap<Queue,Reservoir>());
}
private final ScheduledThreadPoolExecutor executor;
private final Map<Queue,Reservoir> queues;
public void add(Queue queue) {
queues.put(queue, new ExponentiallyDecayingReservoir());
}
public void addReservoir(Queue queue, Reservoir reservoir) {
queues.put(queue, reservoir);
}
public double getMean(Queue queue) {
return queues.get(queue).getSnapshot().getMean();
}
public double getMedian(Queue queue) {
return queues.get(queue).getSnapshot().getMedian();
}
public void run() {
try {
synchronized(queues) {
for (Map.Entry<Queue,Reservoir> entry:queues.entrySet()) {
entry.getValue().update(entry.getKey().getSize());
}
}
} catch (ConcurrentModificationException ce) {
logger.warn("Average queue size map altered during probe.", ce);
}
}
}