Java tutorial
/** * Copyright 2013 Netflix, Inc. * * 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.netflix.servo.monitor; import com.google.common.base.Objects; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableList; import com.netflix.servo.tag.Tag; import com.netflix.servo.tag.Tags; import com.netflix.servo.util.Clock; import com.netflix.servo.util.ClockWithOffset; import java.util.Arrays; import java.util.List; import java.util.concurrent.TimeUnit; /** * A simple timer implementation providing the total time, count, min, and max for the times that * have been recorded. */ public class BucketTimer extends AbstractMonitor<Long> implements Timer, CompositeMonitor<Long> { private static final String STATISTIC = "statistic"; private static final String BUCKET = "servo.bucket"; private static final String UNIT = "unit"; private static final Tag STAT_TOTAL = Tags.newTag(STATISTIC, "totalTime"); private static final Tag STAT_COUNT = Tags.newTag(STATISTIC, "count"); private static final Tag STAT_MIN = Tags.newTag(STATISTIC, "min"); private static final Tag STAT_MAX = Tags.newTag(STATISTIC, "max"); private final TimeUnit timeUnit; private final Counter totalTime; private final Counter[] bucketCount; private final Counter overflowCount; private final MinGauge min; private final MaxGauge max; private final List<Monitor<?>> monitors; private final BucketConfig bucketConfig; /** * Creates a new instance of the timer with a unit of milliseconds. */ public BucketTimer(MonitorConfig config, BucketConfig bucketConfig) { this(config, bucketConfig, TimeUnit.MILLISECONDS); } /** * Creates a new instance of the timer. */ public BucketTimer(MonitorConfig config, BucketConfig bucketConfig, TimeUnit unit) { this(config, bucketConfig, unit, ClockWithOffset.INSTANCE); } BucketTimer(MonitorConfig config, BucketConfig bucketConfig, TimeUnit unit, Clock clock) { super(config); this.bucketConfig = Preconditions.checkNotNull(bucketConfig, "bucketConfig"); final Tag unitTag = Tags.newTag(UNIT, unit.name()); final MonitorConfig unitConfig = config.withAdditionalTag(unitTag); this.timeUnit = unit; this.totalTime = new BasicCounter(unitConfig.withAdditionalTag(STAT_TOTAL)); this.overflowCount = new BasicCounter( unitConfig.withAdditionalTag(STAT_COUNT).withAdditionalTag(Tags.newTag(BUCKET, "bucket=overflow"))); this.min = new MinGauge(unitConfig.withAdditionalTag(STAT_MIN), clock); this.max = new MaxGauge(unitConfig.withAdditionalTag(STAT_MAX), clock); final long[] buckets = bucketConfig.getBuckets(); final int numBuckets = buckets.length; final int numDigits = Long.toString(buckets[numBuckets - 1]).length(); final String label = bucketConfig.getTimeUnitAbbreviation(); this.bucketCount = new Counter[numBuckets]; for (int i = 0; i < numBuckets; i++) { bucketCount[i] = new BasicCounter(unitConfig.withAdditionalTag(STAT_COUNT).withAdditionalTag( Tags.newTag(BUCKET, String.format("bucket=%0" + numDigits + "d%s", buckets[i], label)))); } this.monitors = new ImmutableList.Builder<Monitor<?>>().add(totalTime).add(min).add(max) .addAll(Arrays.asList(bucketCount)).add(overflowCount).build(); } /** {@inheritDoc} */ @Override public List<Monitor<?>> getMonitors() { return monitors; } /** {@inheritDoc} */ @Override public Stopwatch start() { Stopwatch s = new TimedStopwatch(this); s.start(); return s; } /** {@inheritDoc} */ @Override public TimeUnit getTimeUnit() { return timeUnit; } /** {@inheritDoc} */ @Override public void record(long duration) { totalTime.increment(duration); min.update(duration); max.update(duration); final long[] buckets = bucketConfig.getBuckets(); for (int i = 0; i < buckets.length; i++) { if (duration <= buckets[i]) { bucketCount[i].increment(); return; } } overflowCount.increment(); } /** {@inheritDoc} */ @Override public void record(long duration, TimeUnit unit) { record(this.timeUnit.convert(duration, unit)); } /** {@inheritDoc} */ @Override public Long getValue(int pollerIndex) { final long cnt = getCount(pollerIndex); return (cnt == 0) ? 0L : totalTime.getValue().longValue() / cnt; } /** Get the total time for all updates. */ public Long getTotalTime() { return totalTime.getValue().longValue(); } /** Get the total number of updates. */ public Long getCount(int pollerIndex) { long updates = 0; for (Counter c : bucketCount) { updates += c.getValue(pollerIndex).longValue(); } updates += overflowCount.getValue(pollerIndex).longValue(); return updates; } /** Get the min value since the last reset. */ public Long getMin(int pollerIndex) { return min.getValue(pollerIndex); } /** Get the max value since the last reset. */ public Long getMax(int pollerIndex) { return max.getValue(pollerIndex); } /** {@inheritDoc} */ @Override public boolean equals(Object obj) { if (obj == null || !(obj instanceof BucketTimer)) { return false; } BucketTimer m = (BucketTimer) obj; return config.equals(m.getConfig()) && bucketConfig.equals(m.bucketConfig) && timeUnit.equals(m.timeUnit) && totalTime.equals(m.totalTime) && min.equals(m.min) && max.equals(m.max) && overflowCount.equals(m.overflowCount) && Arrays.equals(bucketCount, m.bucketCount); } /** {@inheritDoc} */ @Override public int hashCode() { return Objects.hashCode(config, bucketConfig, timeUnit, totalTime, min, max, overflowCount, Arrays.hashCode(bucketCount)); } /** {@inheritDoc} */ @Override public String toString() { return Objects.toStringHelper(this).add("config", config).add("bucketConfig", bucketConfig) .add("timeUnit", timeUnit).add("totalTime", totalTime).add("min", min).add("max", max) .add("bucketCount", bucketCount).add("overflowCount", overflowCount).toString(); } }