org.apache.hadoop.metrics2.util.MBeans.java Source code

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Here is the source code for org.apache.hadoop.metrics2.util.MBeans.java

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/**
 * 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.metrics2.util;

import java.lang.management.ManagementFactory;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

import javax.management.InstanceAlreadyExistsException;
import javax.management.MBeanServer;
import javax.management.ObjectName;

import com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;

import com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This util class provides a method to register an MBean using
 * our standard naming convention as described in the doc
 *  for {link {@link #register(String, String, Object)}.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public final class MBeans {
    private static final Logger LOG = LoggerFactory.getLogger(MBeans.class);
    private static final String DOMAIN_PREFIX = "Hadoop:";
    private static final String SERVICE_PREFIX = "service=";
    private static final String NAME_PREFIX = "name=";

    private static final Pattern MBEAN_NAME_PATTERN = Pattern
            .compile("^" + DOMAIN_PREFIX + SERVICE_PREFIX + "([^,]+)," + NAME_PREFIX + "(.+)$");

    private MBeans() {
    }

    /**
     * Register the MBean using our standard MBeanName format
     * "hadoop:service=<serviceName>,name=<nameName>"
     * Where the <serviceName> and <nameName> are the supplied parameters.
     *
     * @param serviceName
     * @param nameName
     * @param theMbean - the MBean to register
     * @return the named used to register the MBean
     */
    static public ObjectName register(String serviceName, String nameName, Object theMbean) {
        return register(serviceName, nameName, new HashMap<String, String>(), theMbean);
    }

    /**
     * Register the MBean using our standard MBeanName format
     * "hadoop:service=<serviceName>,name=<nameName>"
     * Where the <serviceName> and <nameName> are the supplied parameters.
     *
     * @param serviceName
     * @param nameName
     * @param properties - Key value pairs to define additional JMX ObjectName
     *                     properties.
     * @param theMbean    - the MBean to register
     * @return the named used to register the MBean
     */
    static public ObjectName register(String serviceName, String nameName, Map<String, String> properties,
            Object theMbean) {
        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        Preconditions.checkNotNull(properties,
                "JMX bean properties should not be null for " + "bean registration.");
        ObjectName name = getMBeanName(serviceName, nameName, properties);
        if (name != null) {
            try {
                mbs.registerMBean(theMbean, name);
                LOG.debug("Registered " + name);
                return name;
            } catch (InstanceAlreadyExistsException iaee) {
                if (LOG.isTraceEnabled()) {
                    LOG.trace("Failed to register MBean \"" + name + "\"", iaee);
                } else {
                    LOG.warn("Failed to register MBean \"" + name + "\": Instance already exists.");
                }
            } catch (Exception e) {
                LOG.warn("Failed to register MBean \"" + name + "\"", e);
            }
        }
        return null;
    }

    public static String getMbeanNameService(final ObjectName objectName) {
        Matcher matcher = MBEAN_NAME_PATTERN.matcher(objectName.toString());
        if (matcher.matches()) {
            return matcher.group(1);
        } else {
            throw new IllegalArgumentException(objectName + " is not a valid Hadoop mbean");
        }
    }

    public static String getMbeanNameName(final ObjectName objectName) {
        Matcher matcher = MBEAN_NAME_PATTERN.matcher(objectName.toString());
        if (matcher.matches()) {
            return matcher.group(2);
        } else {
            throw new IllegalArgumentException(objectName + " is not a valid Hadoop mbean");
        }
    }

    static public void unregister(ObjectName mbeanName) {
        LOG.debug("Unregistering " + mbeanName);
        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        if (mbeanName == null) {
            LOG.debug("Stacktrace: ", new Throwable());
            return;
        }
        try {
            mbs.unregisterMBean(mbeanName);
        } catch (Exception e) {
            LOG.warn("Error unregistering " + mbeanName, e);
        }
        DefaultMetricsSystem.removeMBeanName(mbeanName);
    }

    @VisibleForTesting
    static ObjectName getMBeanName(String serviceName, String nameName, Map<String, String> additionalParameters) {

        String additionalKeys = additionalParameters.entrySet().stream()
                .map(entry -> entry.getKey() + "=" + entry.getValue()).collect(Collectors.joining(","));

        String nameStr = DOMAIN_PREFIX + SERVICE_PREFIX + serviceName + "," + NAME_PREFIX + nameName
                + (additionalKeys.isEmpty() ? "" : "," + additionalKeys);
        try {
            return DefaultMetricsSystem.newMBeanName(nameStr);
        } catch (Exception e) {
            LOG.warn("Error creating MBean object name: " + nameStr, e);
            return null;
        }
    }
}