rmannibucau commented on code in PR #607: URL: https://github.com/apache/tomcat/pull/607#discussion_r1162439073
########## java/org/apache/catalina/util/TimeBucketCounter.java: ########## @@ -0,0 +1,217 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.catalina.util; + +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.atomic.AtomicInteger; + +/** + * this class maintains a thread safe hash map that has timestamp-based buckets + * followed by a string for a key, and a counter for a value. each time the + * increment() method is called it adds the key if it does not exist, increments + * its value and returns it. + * + * a maintenance thread cleans up keys that are prefixed by previous timestamp + * buckets. + */ +public class TimeBucketCounter { + + /** + * Map to hold the buckets + */ + private final ConcurrentHashMap<String, AtomicInteger> map = new ConcurrentHashMap<>(); + + /** + * Milliseconds bucket size as a Power of 2 for bit shift math, e.g. + * 16 for 65_536ms which is about 1:05 minute + */ + private final int numBits; + + /** + * ratio of actual duration to config duration + */ + private final double ratio; + + /** + * flag for the maintenance thread + */ + volatile boolean isRunning = false; + + /** + * + * @param bucketDuration duration in seconds, e.g. for 1 minute pass 60 + */ + public TimeBucketCounter(int bucketDuration) { + + int durationMillis = bucketDuration * 1000; + + int bits = 0; + int pof2 = nextPowerOf2(durationMillis); + int bitCheck = pof2; + while (bitCheck > 1) { + bitCheck = pof2 >> ++bits; + } + + this.numBits = bits; + + this.ratio = ratioToPowerOf2(durationMillis); + + int cleanupsPerBucketDuration = (durationMillis >= 60_000) ? 6 : 3; + Thread mt = new MaintenanceThread(durationMillis / cleanupsPerBucketDuration); Review Comment: @rmaucher hmm, there is hat I mention in my previous comment ie use a scheduled executor service and not an active awaiting impl plus share the executor between the filters in the app at least (if the tomcat's one is too hard to reach, this part is ok) to avoid to consume 3 threads (and related resources) for nothing which can be an issue in some loaded env, in particular when pools are not fixed (ThreadPoolExecutor with max >> core size) or other needs. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
