Java tutorial
/** * 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. */ /* * Copyright 2016 Josh Elser * * 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 org.apache.hadoop.hbase.metrics.impl; import java.util.Map; import org.apache.commons.lang.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hbase.metrics.Counter; import org.apache.hadoop.hbase.metrics.Gauge; import org.apache.hadoop.hbase.metrics.Histogram; import org.apache.hadoop.hbase.metrics.Meter; import org.apache.hadoop.hbase.metrics.Metric; import org.apache.hadoop.hbase.metrics.MetricRegistry; import org.apache.hadoop.hbase.metrics.MetricRegistryInfo; import org.apache.hadoop.hbase.metrics.Timer; import org.apache.hadoop.metrics2.MetricsCollector; import org.apache.hadoop.metrics2.MetricsInfo; import org.apache.hadoop.metrics2.MetricsRecordBuilder; import org.apache.hadoop.metrics2.lib.Interns; import org.apache.hadoop.metrics2.lib.MutableHistogram; /** * This is the adapter from "HBase Metrics Framework", implemented in hbase-metrics-api and * hbase-metrics modules to the Hadoop Metrics2 framework. This adapter is not a metric source, * but a helper to be able to collect all of the Metric's in the MetricRegistry using the * MetricsCollector and MetricsRecordBuilder. * * Some of the code is forked from https://github.com/joshelser/dropwizard-hadoop-metrics2. */ public class HBaseMetrics2HadoopMetricsAdapter { private static final Log LOG = LogFactory.getLog(HBaseMetrics2HadoopMetricsAdapter.class); private static final String EMPTY_STRING = ""; public HBaseMetrics2HadoopMetricsAdapter() { } /** * Iterates over the MetricRegistry and adds them to the {@code collector}. * * @param collector A metrics collector */ public void snapshotAllMetrics(MetricRegistry metricRegistry, MetricsCollector collector) { MetricRegistryInfo info = metricRegistry.getMetricRegistryInfo(); MetricsRecordBuilder builder = collector .addRecord(Interns.info(info.getMetricsName(), info.getMetricsDescription())); builder.setContext(info.getMetricsContext()); snapshotAllMetrics(metricRegistry, builder); } /** * Iterates over the MetricRegistry and adds them to the {@code builder}. * * @param builder A record builder */ public void snapshotAllMetrics(MetricRegistry metricRegistry, MetricsRecordBuilder builder) { Map<String, Metric> metrics = metricRegistry.getMetrics(); for (Map.Entry<String, Metric> e : metrics.entrySet()) { // Always capitalize the name String name = StringUtils.capitalize(e.getKey()); Metric metric = e.getValue(); if (metric instanceof Gauge) { addGauge(name, (Gauge<?>) metric, builder); } else if (metric instanceof Counter) { addCounter(name, (Counter) metric, builder); } else if (metric instanceof Histogram) { addHistogram(name, (Histogram) metric, builder); } else if (metric instanceof Meter) { addMeter(name, (Meter) metric, builder); } else if (metric instanceof Timer) { addTimer(name, (Timer) metric, builder); } else { LOG.info("Ignoring unknown Metric class " + metric.getClass().getName()); } } } private void addGauge(String name, Gauge<?> gauge, MetricsRecordBuilder builder) { final MetricsInfo info = Interns.info(name, EMPTY_STRING); final Object o = gauge.getValue(); // Figure out which gauge types metrics2 supports and call the right method if (o instanceof Integer) { builder.addGauge(info, (int) o); } else if (o instanceof Long) { builder.addGauge(info, (long) o); } else if (o instanceof Float) { builder.addGauge(info, (float) o); } else if (o instanceof Double) { builder.addGauge(info, (double) o); } else { LOG.warn("Ignoring Gauge (" + name + ") with unhandled type: " + o.getClass()); } } private void addCounter(String name, Counter counter, MetricsRecordBuilder builder) { MetricsInfo info = Interns.info(name, EMPTY_STRING); builder.addCounter(info, counter.getCount()); } /** * Add Histogram value-distribution data to a Hadoop-Metrics2 record building. * * @param builder A Hadoop-Metrics2 record builder. * @param name A base name for this record. * @param desc A description for this record. * @param snapshot The distribution of measured values. */ private void addHistogram(String name, Histogram histogram, MetricsRecordBuilder builder) { MutableHistogram.snapshot(name, EMPTY_STRING, histogram, builder, true); } /** * Add Dropwizard-Metrics rate information to a Hadoop-Metrics2 record builder, converting the * rates to the appropriate unit. * * @param builder A Hadoop-Metrics2 record builder. * @param name A base name for this record. */ private void addMeter(String name, Meter meter, MetricsRecordBuilder builder) { builder.addGauge(Interns.info(name + "_count", EMPTY_STRING), meter.getCount()); builder.addGauge(Interns.info(name + "_mean_rate", EMPTY_STRING), meter.getMeanRate()); builder.addGauge(Interns.info(name + "_1min_rate", EMPTY_STRING), meter.getOneMinuteRate()); builder.addGauge(Interns.info(name + "_5min_rate", EMPTY_STRING), meter.getFiveMinuteRate()); builder.addGauge(Interns.info(name + "_15min_rate", EMPTY_STRING), meter.getFifteenMinuteRate()); } private void addTimer(String name, Timer timer, MetricsRecordBuilder builder) { addMeter(name, timer.getMeter(), builder); addHistogram(name, timer.getHistogram(), builder); } }