org.glowroot.jvm.LazyPlatformMBeanServer.java Source code

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Here is the source code for org.glowroot.jvm.LazyPlatformMBeanServer.java

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/*
 * Copyright 2014-2015 the original author or authors.
 *
 * Licensed 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.glowroot.jvm;

import java.lang.management.ManagementFactory;
import java.util.Set;

import javax.annotation.Nullable;
import javax.management.MBeanInfo;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import javax.management.QueryExp;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Stopwatch;
import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static java.util.concurrent.TimeUnit.SECONDS;

// this is needed for jboss-modules because calling ManagementFactory.getPlatformMBeanServer()
// before jboss-modules has set up its own logger will trigger the default JUL LogManager to be
// used, and then jboss/wildfly will fail to start
public class LazyPlatformMBeanServer {

    private static final Logger logger = LoggerFactory.getLogger(LazyPlatformMBeanServer.class);

    private final boolean jbossModules;

    private volatile @MonotonicNonNull MBeanServer mbeanServer;

    LazyPlatformMBeanServer(boolean jbossModules) {
        this.jbossModules = jbossModules;
    }

    void getObjectInstance(ObjectName name) throws Exception {
        ensureInit();
        mbeanServer.getObjectInstance(name);
    }

    void invoke(ObjectName name, String operationName, Object[] params, String[] signature) throws Exception {
        ensureInit();
        mbeanServer.invoke(name, operationName, params, signature);
    }

    public Set<ObjectName> queryNames(@Nullable ObjectName name, @Nullable QueryExp query)
            throws InterruptedException {
        ensureInit();
        return mbeanServer.queryNames(name, query);
    }

    public MBeanInfo getMBeanInfo(ObjectName name) throws Exception {
        ensureInit();
        return mbeanServer.getMBeanInfo(name);
    }

    public Object getAttribute(ObjectName name, String attribute) throws Exception {
        ensureInit();
        return mbeanServer.getAttribute(name, attribute);
    }

    @EnsuresNonNull("mbeanServer")
    private void ensureInit() throws InterruptedException {
        if (mbeanServer == null) {
            if (jbossModules) {
                // if running under jboss-modules, wait it to set up JUL before calling
                // getPlatformMBeanServer()
                waitForJBossModuleInitialization(Stopwatch.createUnstarted());
            }
            mbeanServer = ManagementFactory.getPlatformMBeanServer();
        }
    }

    @VisibleForTesting
    static void waitForJBossModuleInitialization(Stopwatch stopwatch) throws InterruptedException {
        stopwatch.start();
        while (stopwatch.elapsed(SECONDS) < 60) {
            if (System.getProperty("java.util.logging.manager") != null) {
                return;
            }
            Thread.sleep(100);
        }
        // something has gone wrong
        logger.error("this jvm appears to be running jboss-modules, but it did not set up"
                + " java.util.logging.manager");
    }
}