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. */ package org.apache.hadoop.hbase.metrics; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import javax.management.AttributeNotFoundException; import javax.management.MBeanAttributeInfo; import javax.management.MBeanException; import javax.management.MBeanInfo; import javax.management.ReflectionException; import com.yammer.metrics.stats.Snapshot; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.hbase.metrics.histogram.MetricsHistogram; import org.apache.hadoop.metrics.util.MetricsBase; import org.apache.hadoop.metrics.util.MetricsDynamicMBeanBase; import org.apache.hadoop.metrics.util.MetricsRegistry; /** * Extends the Hadoop MetricsDynamicMBeanBase class to provide JMX support for * custom HBase MetricsBase implementations. MetricsDynamicMBeanBase ignores * registered MetricsBase instance that are not instances of one of the * org.apache.hadoop.metrics.util implementations. * */ @Deprecated @InterfaceAudience.Private public class MetricsMBeanBase extends MetricsDynamicMBeanBase { private static final Log LOG = LogFactory.getLog("org.apache.hadoop.hbase.metrics"); protected final MetricsRegistry registry; protected final String description; protected int registryLength; /** HBase MetricsBase implementations that MetricsDynamicMBeanBase does * not understand */ protected Map<String, MetricsBase> extendedAttributes = new ConcurrentHashMap<String, MetricsBase>(); protected MBeanInfo extendedInfo; protected MetricsMBeanBase(MetricsRegistry mr, String description) { super(copyMinusHBaseMetrics(mr), description); this.registry = mr; this.description = description; this.init(); } /* * @param mr MetricsRegistry. * @return A copy of the passed MetricsRegistry minus the hbase metrics */ private static MetricsRegistry copyMinusHBaseMetrics(final MetricsRegistry mr) { MetricsRegistry copy = new MetricsRegistry(); for (MetricsBase metric : mr.getMetricsList()) { if (metric instanceof MetricsRate || metric instanceof MetricsString || metric instanceof MetricsHistogram || metric instanceof ExactCounterMetric) { continue; } copy.add(metric.getName(), metric); } return copy; } protected void init() { List<MBeanAttributeInfo> attributes = new ArrayList<MBeanAttributeInfo>(); MBeanInfo parentInfo = super.getMBeanInfo(); List<String> parentAttributes = new ArrayList<String>(); for (MBeanAttributeInfo attr : parentInfo.getAttributes()) { attributes.add(attr); parentAttributes.add(attr.getName()); } this.registryLength = this.registry.getMetricsList().size(); for (MetricsBase metric : this.registry.getMetricsList()) { if (metric.getName() == null || parentAttributes.contains(metric.getName())) continue; // add on custom HBase metric types if (metric instanceof MetricsRate) { attributes.add(new MBeanAttributeInfo(metric.getName(), "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metric.getName(), metric); } else if (metric instanceof MetricsString) { attributes.add(new MBeanAttributeInfo(metric.getName(), "java.lang.String", metric.getDescription(), true, false, false)); extendedAttributes.put(metric.getName(), metric); LOG.info("MetricsString added: " + metric.getName()); } else if (metric instanceof MetricsHistogram) { String metricName = metric.getName() + MetricsHistogram.NUM_OPS_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Long", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.MIN_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Long", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.MAX_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Long", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.MEAN_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.STD_DEV_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.MEDIAN_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.SEVENTY_FIFTH_PERCENTILE_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.NINETY_FIFTH_PERCENTILE_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); metricName = metric.getName() + MetricsHistogram.NINETY_NINETH_PERCENTILE_METRIC_NAME; attributes.add(new MBeanAttributeInfo(metricName, "java.lang.Float", metric.getDescription(), true, false, false)); extendedAttributes.put(metricName, metric); } // else, its probably a hadoop metric already registered. Skip it. } LOG.info("new MBeanInfo"); this.extendedInfo = new MBeanInfo(this.getClass().getName(), this.description, attributes.toArray(new MBeanAttributeInfo[0]), parentInfo.getConstructors(), parentInfo.getOperations(), parentInfo.getNotifications()); } private void checkAndUpdateAttributes() { if (this.registryLength != this.registry.getMetricsList().size()) this.init(); } @Override public Object getAttribute(String name) throws AttributeNotFoundException, MBeanException, ReflectionException { if (name == null) { throw new IllegalArgumentException("Attribute name is NULL"); } /* * Ugly. Since MetricsDynamicMBeanBase implementation is private, * we need to first check the parent class for the attribute. * In case that the MetricsRegistry contents have changed, this will * allow the parent to update it's internal structures (which we rely on * to update our own. */ try { return super.getAttribute(name); } catch (AttributeNotFoundException ex) { checkAndUpdateAttributes(); MetricsBase metric = this.extendedAttributes.get(name); if (metric != null) { if (metric instanceof MetricsRate) { return ((MetricsRate) metric).getPreviousIntervalValue(); } else if (metric instanceof MetricsString) { return ((MetricsString) metric).getValue(); } else if (metric instanceof MetricsHistogram) { MetricsHistogram hist = (MetricsHistogram) metric; if (name.endsWith(MetricsHistogram.NUM_OPS_METRIC_NAME)) { return hist.getCount(); } else if (name.endsWith(MetricsHistogram.MIN_METRIC_NAME)) { return hist.getMin(); } else if (name.endsWith(MetricsHistogram.MAX_METRIC_NAME)) { return hist.getMax(); } else if (name.endsWith(MetricsHistogram.MEAN_METRIC_NAME)) { return (float) hist.getMean(); } else if (name.endsWith(MetricsHistogram.STD_DEV_METRIC_NAME)) { return (float) hist.getStdDev(); } else if (name.endsWith(MetricsHistogram.MEDIAN_METRIC_NAME)) { Snapshot s = hist.getSnapshot(); return (float) s.getMedian(); } else if (name.endsWith(MetricsHistogram.SEVENTY_FIFTH_PERCENTILE_METRIC_NAME)) { Snapshot s = hist.getSnapshot(); return (float) s.get75thPercentile(); } else if (name.endsWith(MetricsHistogram.NINETY_FIFTH_PERCENTILE_METRIC_NAME)) { Snapshot s = hist.getSnapshot(); return (float) s.get95thPercentile(); } else if (name.endsWith(MetricsHistogram.NINETY_NINETH_PERCENTILE_METRIC_NAME)) { Snapshot s = hist.getSnapshot(); return (float) s.get99thPercentile(); } } else { LOG.warn(String.format("unknown metrics type %s for attribute %s", metric.getClass().getName(), name)); } } } throw new AttributeNotFoundException(); } @Override public MBeanInfo getMBeanInfo() { return this.extendedInfo; } }