org.eclipse.gyrex.monitoring.internal.MetricSetTracker.java Source code

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Here is the source code for org.eclipse.gyrex.monitoring.internal.MetricSetTracker.java

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/*******************************************************************************
 * Copyright (c) 2010, 2012 AGETO Service GmbH and others.
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html.
 *
 * Contributors:
 *     Gunnar Wagenknecht - initial API and implementation
 *******************************************************************************/
package org.eclipse.gyrex.monitoring.internal;

import java.lang.management.ManagementFactory;
import java.util.Hashtable;
import java.util.Map.Entry;

import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;

import org.eclipse.gyrex.monitoring.internal.MetricSetTracker.MetricSetJmxRegistration;
import org.eclipse.gyrex.monitoring.internal.mbeans.MetricSetMBean;
import org.eclipse.gyrex.monitoring.metrics.MetricSet;

import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.exception.ExceptionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Tracker for {@link MetricSet}.
 */
public class MetricSetTracker extends ServiceTracker<MetricSet, MetricSetJmxRegistration> {

    static class MetricSetJmxRegistration {
        final ObjectName objectName;
        final MetricSet metricSet;

        MetricSetJmxRegistration(final ObjectName objectName, final MetricSet metricSet) {
            this.objectName = objectName;
            this.metricSet = metricSet;
        }
    }

    private static final Logger LOG = LoggerFactory.getLogger(MetricSetTracker.class);

    public MetricSetTracker(final BundleContext context) {
        super(context, MetricSet.class, null);
    }

    @Override
    public MetricSetJmxRegistration addingService(final ServiceReference<MetricSet> reference) {
        // get service
        final MetricSet metricSet = context.getService(reference);
        if (metricSet == null) {
            return null;
        }

        try {
            final MBeanServer beanServer = ManagementFactory.getPlatformMBeanServer();
            final ObjectName objectName = getObjectName(reference, metricSet);
            beanServer.registerMBean(new MetricSetMBean(metricSet, reference), objectName);
            return new MetricSetJmxRegistration(objectName, metricSet);
        } catch (final Exception e) {
            LOG.warn("Failed to expose metric {} using JMX. {}", metricSet, ExceptionUtils.getRootCauseMessage(e));
        }
        return null;
    }

    private ObjectName getObjectName(final ServiceReference<MetricSet> reference, final MetricSet metricSet)
            throws MalformedObjectNameException {
        // get symbolic name
        final String symbolicName = reference.getBundle().getSymbolicName();

        // set properties
        final String[] propertyKeys = reference.getPropertyKeys();
        final Hashtable<String, String> properties = new Hashtable<String, String>(propertyKeys.length + 2);

        // common properties first
        properties.put("type", "MetricSet");
        properties.put("name", StringUtils.removeStart(metricSet.getId(), symbolicName + "."));

        // we also remember the service id in order to allow multiple metrics instances with same id
        properties.put("service.id", String.valueOf(reference.getProperty(Constants.SERVICE_ID)));

        // check additional metric set properties
        for (final Entry<String, String> property : metricSet.getProperties().entrySet()) {
            // prefix each with "metric." to avoid name clash with common properties
            properties.put("metric.".concat(property.getKey()), property.getValue());
        }

        // create object name
        return new ObjectName(symbolicName, properties);
    }

    @Override
    public void removedService(final ServiceReference<MetricSet> reference,
            final MetricSetJmxRegistration metricSetJmxRegistration) {
        try {
            // unregister MBean
            final MBeanServer beanServer = ManagementFactory.getPlatformMBeanServer();
            beanServer.unregisterMBean(metricSetJmxRegistration.objectName);
        } catch (final Exception e) {
            LOG.warn("Failed to unregister metric JMX registration {}. {}", metricSetJmxRegistration.objectName,
                    ExceptionUtils.getRootCauseMessage(e));
        } finally {
            // unget service
            context.ungetService(reference);
        }
    }
}