001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 package org.apache.hadoop.metrics2.util; 019 020 import java.lang.management.ManagementFactory; 021 022 import javax.management.InstanceAlreadyExistsException; 023 import javax.management.MBeanServer; 024 import javax.management.ObjectName; 025 026 import org.apache.commons.logging.Log; 027 import org.apache.commons.logging.LogFactory; 028 import org.apache.hadoop.classification.InterfaceAudience; 029 import org.apache.hadoop.classification.InterfaceStability; 030 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem; 031 032 /** 033 * This util class provides a method to register an MBean using 034 * our standard naming convention as described in the doc 035 * for {link {@link #register(String, String, Object)} 036 */ 037 @InterfaceAudience.Public 038 @InterfaceStability.Stable 039 public class MBeans { 040 private static final Log LOG = LogFactory.getLog(MBeans.class); 041 042 /** 043 * Register the MBean using our standard MBeanName format 044 * "hadoop:service=<serviceName>,name=<nameName>" 045 * Where the <serviceName> and <nameName> are the supplied parameters 046 * 047 * @param serviceName 048 * @param nameName 049 * @param theMbean - the MBean to register 050 * @return the named used to register the MBean 051 */ 052 static public ObjectName register(String serviceName, String nameName, 053 Object theMbean) { 054 final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); 055 ObjectName name = getMBeanName(serviceName, nameName); 056 try { 057 mbs.registerMBean(theMbean, name); 058 LOG.debug("Registered "+ name); 059 return name; 060 } catch (InstanceAlreadyExistsException iaee) { 061 if (LOG.isTraceEnabled()) { 062 LOG.trace("Failed to register MBean \""+ name + "\"", iaee); 063 } else { 064 LOG.warn("Failed to register MBean \""+ name 065 + "\": Instance already exists."); 066 } 067 } catch (Exception e) { 068 LOG.warn("Failed to register MBean \""+ name + "\"", e); 069 } 070 return null; 071 } 072 073 static public void unregister(ObjectName mbeanName) { 074 LOG.debug("Unregistering "+ mbeanName); 075 final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); 076 if (mbeanName == null) { 077 LOG.debug("Stacktrace: ", new Throwable()); 078 return; 079 } 080 try { 081 mbs.unregisterMBean(mbeanName); 082 } catch (Exception e) { 083 LOG.warn("Error unregistering "+ mbeanName, e); 084 } 085 } 086 087 static private ObjectName getMBeanName(String serviceName, String nameName) { 088 ObjectName name = null; 089 String nameStr = "Hadoop:service="+ serviceName +",name="+ nameName; 090 try { 091 name = DefaultMetricsSystem.newMBeanName(nameStr); 092 } catch (Exception e) { 093 LOG.warn("Error creating MBean object name: "+ nameStr, e); 094 } 095 return name; 096 } 097 }