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.util; import java.beans.IntrospectionException; import java.io.IOException; import java.io.PrintWriter; import java.io.StringWriter; import java.lang.management.GarbageCollectorMXBean; import java.lang.management.ManagementFactory; import java.lang.management.MemoryPoolMXBean; import java.lang.management.RuntimeMXBean; import java.util.Hashtable; import java.util.List; import java.util.Set; import javax.management.InstanceNotFoundException; import javax.management.MBeanAttributeInfo; import javax.management.MBeanInfo; import javax.management.MBeanServer; import javax.management.MalformedObjectNameException; import javax.management.ObjectName; import javax.management.ReflectionException; import javax.management.openmbean.CompositeData; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.codehaus.jackson.JsonNode; import org.codehaus.jackson.JsonProcessingException; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jettison.json.JSONException; public final class JSONMetricUtil { private static final Log LOG = LogFactory.getLog(JSONMetricUtil.class); private static MBeanServer mbServer = ManagementFactory.getPlatformMBeanServer(); //MBeans ObjectName domain names public static final String JAVA_LANG_DOMAIN = "java.lang"; public static final String JAVA_NIO_DOMAIN = "java.nio"; public static final String SUN_MGMT_DOMAIN = "com.sun.management"; public static final String HADOOP_DOMAIN = "Hadoop"; //MBeans ObjectName properties key names public static final String TYPE_KEY = "type"; public static final String NAME_KEY = "name"; public static final String SERVICE_KEY = "service"; public static final String SUBSYSTEM_KEY = "sub"; /** * Utility for getting metric values. Collection of static methods intended for * easier access to metric values. */ private JSONMetricUtil() { // Not to be called } public static MBeanAttributeInfo[] getMBeanAttributeInfo(ObjectName bean) throws IntrospectionException, InstanceNotFoundException, ReflectionException, IntrospectionException, javax.management.IntrospectionException { MBeanInfo mbinfo = mbServer.getMBeanInfo(bean); return mbinfo.getAttributes(); } public static Object getValueFromMBean(ObjectName bean, String attribute) { Object value = null; try { value = mbServer.getAttribute(bean, attribute); } catch (Exception e) { LOG.error("Unable to get value from MBean= " + bean.toString() + "for attribute=" + attribute + " " + e.getMessage()); } return value; } /** * Returns a subset of mbeans defined by qry. * Modeled after {@link JSONBean#dumpRegionServerMetrics()} * Example: String qry= "java.lang:type=Memory" * @throws MalformedObjectNameException if json have bad format * @throws IOException / * @return String representation of json array. */ public static String dumpBeanToString(String qry) throws MalformedObjectNameException, IOException { StringWriter sw = new StringWriter(1024 * 100); // Guess this size try (PrintWriter writer = new PrintWriter(sw)) { JSONBean dumper = new JSONBean(); try (JSONBean.Writer jsonBeanWriter = dumper.open(writer)) { MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer(); jsonBeanWriter.write(mbeanServer, new ObjectName(qry), null, false); } } sw.close(); return sw.toString(); } public static JsonNode mappStringToJsonNode(String jsonString) throws JsonProcessingException, IOException { ObjectMapper mapper = new ObjectMapper(); JsonNode node = mapper.readTree(jsonString); return node; } public static JsonNode searchJson(JsonNode tree, String searchKey) throws JsonProcessingException, IOException { if (tree == null) { return null; } if (tree.has(searchKey)) { return tree.get(searchKey); } if (tree.isContainerNode()) { for (JsonNode branch : tree) { JsonNode branchResult = searchJson(branch, searchKey); if (branchResult != null && !branchResult.isMissingNode()) { return branchResult; } } } return null; } /** * Method for building hashtable used for constructing ObjectName. * Mapping is done with arrays indices * @param keys Hashtable keys * @param values Hashtable values * @return Hashtable or null if arrays are empty * or have different number of elements */ public static Hashtable<String, String> buldKeyValueTable(String[] keys, String[] values) { if (keys.length != values.length) { LOG.error("keys and values arrays must be same size"); return null; } if (keys.length == 0 || values.length == 0) { LOG.error("keys and values arrays can not be empty;"); return null; } Hashtable<String, String> table = new Hashtable<String, String>(); for (int i = 0; i < keys.length; i++) { table.put(keys[i], values[i]); } return table; } public static ObjectName buildObjectName(String pattern) throws MalformedObjectNameException { return new ObjectName(pattern); } public static ObjectName buildObjectName(String domain, Hashtable<String, String> keyValueTable) throws MalformedObjectNameException { return new ObjectName(domain, keyValueTable); } public static Set<ObjectName> getRegistredMBeans(ObjectName name, MBeanServer mbs) { return mbs.queryNames(name, null); } public static String getProcessPID() { return ManagementFactory.getRuntimeMXBean().getName().split("@")[0]; } public static String getCommmand() throws MalformedObjectNameException, IOException, JSONException { RuntimeMXBean runtimeBean = ManagementFactory.getRuntimeMXBean(); return runtimeBean.getSystemProperties().get("sun.java.command"); } public static List<GarbageCollectorMXBean> getGcCollectorBeans() { List<GarbageCollectorMXBean> gcBeans = ManagementFactory.getGarbageCollectorMXBeans(); return gcBeans; } public static long getLastGcDuration(ObjectName gcCollector) { long lastGcDuration = 0; Object lastGcInfo = getValueFromMBean(gcCollector, "LastGcInfo"); if (lastGcInfo != null && lastGcInfo instanceof CompositeData) { CompositeData cds = (CompositeData) lastGcInfo; lastGcDuration = (long) cds.get("duration"); } return lastGcDuration; } public static List<MemoryPoolMXBean> getMemoryPools() { List<MemoryPoolMXBean> mPools = ManagementFactory.getMemoryPoolMXBeans(); return mPools; } public static float calcPercentage(long a, long b) { if (a == 0 || b == 0) { return 0; } return ((float) a / (float) b) * 100; } }