Java tutorial
/** * The MIT License (MIT) * * Copyright (c) 2016 Krzysztof Bacalski * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package org.kbac.throttle; import org.apache.commons.lang3.Validate; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Iterator; import java.util.Map; import java.util.TimerTask; import java.util.concurrent.ConcurrentMap; /** * Created by krzysztof on 16/01/2016. * <p/> * Runnable extension allowing to schedule bucket drain invocations * * @author Krzysztof Bacalski * * @since 2016-01-17 * * @see LeakyBucket */ public class FixedTimeTimerTask extends TimerTask { public static final String IDLE_BUCKET_REMOVE_MILLIS_PROP_NAME = FixedTimeTimerTask.class.getCanonicalName() + ".removeIdleBucketsMillis"; public static final long IDLE_BUCKET_REMOVE_MILLIS = 3000; public static final long IDLE_BUCKET_REMOVE_MILLIS_DEFAULT = Long .valueOf(System.getProperty(IDLE_BUCKET_REMOVE_MILLIS_PROP_NAME, "" + IDLE_BUCKET_REMOVE_MILLIS)); private static final Logger LOGGER = LoggerFactory.getLogger(FixedTimeTimerTask.class); private final ConcurrentMap<String, ? extends LeakyBucket> buckets; private final long idleBucketRemoveIntervalMillis; public FixedTimeTimerTask(final ConcurrentMap<String, ? extends LeakyBucket> buckets) { this(buckets, IDLE_BUCKET_REMOVE_MILLIS_DEFAULT); } public FixedTimeTimerTask(final ConcurrentMap<String, ? extends LeakyBucket> buckets, final long idleBucketRemoveIntervalMillis) { Validate.notNull(buckets, "bucket container must not be null"); Validate.isTrue(idleBucketRemoveIntervalMillis > 0, "idle interval must be greater than zero"); this.buckets = buckets; this.idleBucketRemoveIntervalMillis = idleBucketRemoveIntervalMillis; } @Override public void run() { final Iterator<? extends Map.Entry<String, ? extends LeakyBucket>> bucketsIterator = buckets.entrySet() .iterator(); while (bucketsIterator.hasNext()) { final Map.Entry<String, ? extends LeakyBucket> entry = bucketsIterator.next(); final LeakyBucket bucket = entry.getValue(); final long drainedDropCount = bucket.drain(); final long idleMillis = System.currentTimeMillis() - bucket.getLastUsedMillis(); if (drainedDropCount == 0 && idleMillis >= this.idleBucketRemoveIntervalMillis) { bucketsIterator.remove(); LOGGER.debug("removed unused bucket: {} idle for {}ms", bucket, idleMillis); } } } }