Java tutorial
// Copyright (C) 2015 The Android Open Source Project // // 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.google.gerrit.metrics.dropwizard; import com.codahale.metrics.Counter; import com.codahale.metrics.Gauge; import com.codahale.metrics.Histogram; import com.codahale.metrics.Meter; import com.codahale.metrics.Metric; import com.codahale.metrics.Snapshot; import com.codahale.metrics.Timer; import com.google.common.base.Function; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; import com.google.gerrit.metrics.Description; import com.google.gerrit.metrics.Field; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.TreeMap; class MetricJson { String description; String unit; Boolean constant; Boolean rate; Boolean gauge; Boolean cumulative; Long count; Object value; Double rate_1m; Double rate_5m; Double rate_15m; Double rate_mean; Double p50; Double p75; Double p95; Double p98; Double p99; Double p99_9; Double min; Double avg; Double max; Double sum; Double std_dev; List<FieldJson> fields; Map<String, Object> buckets; MetricJson(Metric metric, ImmutableMap<String, String> atts, boolean dataOnly) { if (!dataOnly) { description = atts.get(Description.DESCRIPTION); unit = atts.get(Description.UNIT); constant = toBool(atts, Description.CONSTANT); rate = toBool(atts, Description.RATE); gauge = toBool(atts, Description.GAUGE); cumulative = toBool(atts, Description.CUMULATIVE); } init(metric, atts); } private void init(Metric metric, ImmutableMap<String, String> atts) { if (metric instanceof BucketedMetric) { BucketedMetric m = (BucketedMetric) metric; if (m.getTotal() != null) { init(m.getTotal(), atts); } Field<?>[] fieldList = m.getFields(); fields = new ArrayList<>(fieldList.length); for (Field<?> f : fieldList) { fields.add(new FieldJson(f)); } buckets = makeBuckets(fieldList, m.getCells(), atts); } else if (metric instanceof Counter) { Counter c = (Counter) metric; count = c.getCount(); } else if (metric instanceof Gauge) { Gauge<?> g = (Gauge<?>) metric; value = g.getValue(); } else if (metric instanceof Meter) { Meter m = (Meter) metric; count = m.getCount(); rate_1m = m.getOneMinuteRate(); rate_5m = m.getFiveMinuteRate(); rate_15m = m.getFifteenMinuteRate(); } else if (metric instanceof Timer) { Timer m = (Timer) metric; Snapshot s = m.getSnapshot(); count = m.getCount(); rate_1m = m.getOneMinuteRate(); rate_5m = m.getFiveMinuteRate(); rate_15m = m.getFifteenMinuteRate(); double div = Description.getTimeUnit(atts.get(Description.UNIT)).toNanos(1); p50 = s.getMedian() / div; p75 = s.get75thPercentile() / div; p95 = s.get95thPercentile() / div; p98 = s.get98thPercentile() / div; p99 = s.get99thPercentile() / div; p99_9 = s.get999thPercentile() / div; min = s.getMin() / div; max = s.getMax() / div; std_dev = s.getStdDev() / div; } else if (metric instanceof Histogram) { Histogram m = (Histogram) metric; Snapshot s = m.getSnapshot(); count = m.getCount(); p50 = s.getMedian(); p75 = s.get75thPercentile(); p95 = s.get95thPercentile(); p98 = s.get98thPercentile(); p99 = s.get99thPercentile(); p99_9 = s.get999thPercentile(); min = (double) s.getMin(); avg = (double) s.getMean(); max = (double) s.getMax(); sum = s.getMean() * m.getCount(); std_dev = s.getStdDev(); } } private static Boolean toBool(ImmutableMap<String, String> atts, String key) { return Description.TRUE_VALUE.equals(atts.get(key)) ? true : null; } @SuppressWarnings("unchecked") private static Map<String, Object> makeBuckets(Field<?>[] fields, Map<?, Metric> metrics, ImmutableMap<String, String> atts) { if (fields.length == 1) { Function<Object, String> fmt = (Function<Object, String>) fields[0].formatter(); Map<String, Object> out = new TreeMap<>(); for (Map.Entry<?, Metric> e : metrics.entrySet()) { out.put(fmt.apply(e.getKey()), new MetricJson(e.getValue(), atts, true)); } return out; } Map<String, Object> out = new TreeMap<>(); for (Map.Entry<?, Metric> e : metrics.entrySet()) { ImmutableList<Object> keys = (ImmutableList<Object>) e.getKey(); Map<String, Object> dst = out; for (int i = 0; i < fields.length - 1; i++) { Function<Object, String> fmt = (Function<Object, String>) fields[i].formatter(); String key = fmt.apply(keys.get(i)); Map<String, Object> t = (Map<String, Object>) dst.get(key); if (t == null) { t = new TreeMap<>(); dst.put(key, t); } dst = t; } Function<Object, String> fmt = (Function<Object, String>) fields[fields.length - 1].formatter(); dst.put(fmt.apply(keys.get(fields.length - 1)), new MetricJson(e.getValue(), atts, true)); } return out; } static class FieldJson { String name; String type; String description; FieldJson(Field<?> field) { this.name = field.getName(); this.description = field.getDescription(); this.type = Enum.class.isAssignableFrom(field.getType()) ? field.getType().getSimpleName() : null; } } }