Glassfish example source code file (FlashlightProbeClientMediator.java)

This example Glassfish source code file (FlashlightProbeClientMediator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

arraylist, class, collection, file, file, flashlightprobe, flashlightprobeclientmediator, io, list, list, log, logging, object, object, reflection, runtimeexception, string, string, threading, threads

The Glassfish FlashlightProbeClientMediator.java source code

/*
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 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
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 * elects to include this software in this distribution under the [CDDL or GPL
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 * recipient has the option to distribute your version of this file under
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 * and therefore, elected the GPL Version 2 license, then the option applies
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 */

package org.glassfish.flashlight.impl.client;

//import org.glassfish.external.probe.provider.annotations.ProbeListener;

import java.lang.annotation.*;

/* BOOBY TRAP SITTING RIGHT HERE!!!  There is a ProbeListener in org.glassfish.flashlight.client
 * -- don't use that one or everything will fail!
 * Do not use this import --> import org.glassfish.flashlight.client.* --> import individually instead!!
 */

import org.glassfish.external.probe.provider.annotations.ProbeListener;
import org.glassfish.flashlight.client.ProbeClientInvoker;
import org.glassfish.flashlight.client.ProbeClientInvokerFactory;
import org.glassfish.flashlight.client.ProbeClientMediator;
import org.glassfish.flashlight.client.ProbeClientMethodHandle;
import org.glassfish.flashlight.provider.FlashlightProbe;
import org.glassfish.flashlight.provider.ProbeRegistry;
import org.jvnet.hk2.annotations.Service;
import org.jvnet.hk2.component.PostConstruct;
import com.sun.logging.LogDomains;
import com.sun.enterprise.util.LocalStringManagerImpl;

import java.lang.instrument.Instrumentation;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.lang.reflect.Method;
import java.util.logging.Logger;
import java.util.logging.Level;
import java.io.PrintWriter;
import java.io.File;
import org.glassfish.flashlight.impl.core.FlashlightProbeProvider;
import org.glassfish.flashlight.FlashlightUtils;
import static com.sun.enterprise.util.SystemPropertyConstants.INSTALL_ROOT_PROPERTY;
import com.sun.enterprise.universal.process.ProcessUtils;
import com.sun.tools.attach.VirtualMachine;

/**
 * @author Mahesh Kannan
 *         Date: Jan 27, 2008
 * @author Byron Nevins, significant rewrite/refactor August 2009
 */
@Service
public class FlashlightProbeClientMediator
        implements ProbeClientMediator, PostConstruct {

    private static final ProbeRegistry probeRegistry = ProbeRegistry.getInstance();
    private static boolean btraceAgentAttached = false;

    private static final Logger logger =
        LogDomains.getLogger(FlashlightProbeClientMediator.class, LogDomains.MONITORING_LOGGER);
    public final static LocalStringManagerImpl localStrings =
                            new LocalStringManagerImpl(FlashlightProbeClientMediator.class);

    private static final PrintWriter fpw =
        new FlashLightBTracePrintWriter(new NullStream(), logger);

    private static FlashlightProbeClientMediator _me = new FlashlightProbeClientMediator();

    private static AtomicBoolean agentInitialized =
            new AtomicBoolean(false);

    private AtomicInteger clientIdGenerator =
            new AtomicInteger(0);

    private static ConcurrentHashMap<Integer, Object> clients =
            new ConcurrentHashMap<Integer, Object>();

    Instrumentation inst = null;

    public void postConstruct() {
        FlashlightProbeClientMediator.initMe(this);
    }

    private static void initMe(FlashlightProbeClientMediator me) {
        _me = me;
    }

    public static FlashlightProbeClientMediator getInstance() {
        return _me;
    }

    public static Object getClient(int id) {
        return clients.get(id);
    }

    public static void setAgentInitialized(boolean b) {
            agentInitialized.set(b);
    }

    public static boolean isAgentAttached() {
        if (agentInitialized.get()) {
            return btraceAgentAttached;
        }
        synchronized (agentInitialized) {
            if (agentInitialized.get()) {
                return btraceAgentAttached;
            }
            try {
                ClassLoader scl = agentInitialized.getClass().getClassLoader().getSystemClassLoader();
                Class agentMainClass = scl.loadClass("com.sun.btrace.agent.Main");
                btraceAgentAttached = true;
            } catch(Exception e) {
                btraceAgentAttached = false;
            }
            agentInitialized.set(true);
        }
        return btraceAgentAttached;
    }

    public Collection<ProbeClientMethodHandle> registerListener(Object listener) {
        return (registerListener(listener, null));
    }

    public Collection<ProbeClientMethodHandle> 
        registerListener(Object listener, String invokerId) {

        List<ProbeClientMethodHandle>   pcms                                = new ArrayList();
        List<FlashlightProbe>           probesRequiringClassTransformation  = new ArrayList();
        if (invokerId != null) {
            invokerId = FlashlightUtils.getUniqueInvokerId(invokerId);
        }
        registerJavaListener(listener, pcms, probesRequiringClassTransformation, invokerId);
        transformProbes(listener, probesRequiringClassTransformation);

        return pcms;
    }

    public Collection<ProbeClientMethodHandle> registerDTraceListener(FlashlightProbeProvider propro) {

        List<ProbeClientMethodHandle>   pcms                                = new ArrayList();
        List<FlashlightProbe>           probesRequiringClassTransformation  = new ArrayList();

        Object listener = registerDTraceListener(propro, pcms, probesRequiringClassTransformation);
        transformProbes(listener, probesRequiringClassTransformation);

        return pcms;
    }

    private void registerJavaListener(
            Object listener,
            List<ProbeClientMethodHandle> pcms,
            List<FlashlightProbe> probesRequiringClassTransformation,
            String invokerId) {

        List<MethodProbe> methodProbePairs = 
            handleListenerAnnotations(listener.getClass(), invokerId);

        if(methodProbePairs.isEmpty()) {
            return;
        }

        for(MethodProbe mp : methodProbePairs) {
            FlashlightProbe probe = mp.probe;
            ProbeClientInvoker invoker = ProbeClientInvokerFactory.createInvoker(listener, mp.method, probe);
            ProbeClientMethodHandleImpl hi = new ProbeClientMethodHandleImpl(invoker.getId(), invoker, probe);
            pcms.add(hi);

            if (probe.addInvoker(invoker))
                probesRequiringClassTransformation.add(probe);
        }
    }

    private Object  registerDTraceListener(
            FlashlightProbeProvider propro,
            List<ProbeClientMethodHandle> pcms,
            List<FlashlightProbe> probesRequiringClassTransformation) {

        // The "listener" needs to be registered against every Probe in propro...

        Collection<FlashlightProbe> probes = propro.getProbes();
        Object listener = null;

        for(FlashlightProbe probe : probes) {
            ProbeClientInvoker invoker = ProbeClientInvokerFactory.createDTraceInvoker(probe);
            ProbeClientMethodHandleImpl hi = new ProbeClientMethodHandleImpl(invoker.getId(), invoker, probe);
            pcms.add(hi);

            if (probe.addInvoker(invoker))
                probesRequiringClassTransformation.add(probe);

            if(listener == null)
                listener = probe.getDTraceProviderImpl();    // all the probes in propro have the same "listener"
        }

        return listener;
    }

    public void transformProbes(Object listener, List<FlashlightProbe> probes) {
        int clientID = clientIdGenerator.incrementAndGet();
        clients.put(clientID, listener);

        if(probes.isEmpty())
            return;

        byte [] bArr = BtraceClientGenerator.generateBtraceClientClassData(clientID, probes);

        if (bArr == null) {
            String errStr = localStrings.getLocalString("btraceClientGeneratorError",
                                "Internal Error: BtraceClientGenerator.generateBtraceClientClassData() returned null");
            throw new RuntimeException(errStr);
        }

        if(isAgentAttached()) {
            submit2BTrace(bArr);
        }
    }

    /**
     * Pick out all methods in the listener with the correct annotation, look
     * up the referenced Probe and return a list of all such pairs.
     * @param listenerClass
     * @return 
     */
    private List<MethodProbe> 
        handleListenerAnnotations(Class listenerClass, String invokerId) {

        List<MethodProbe> mp = new LinkedList ();

        for (Method method : listenerClass.getMethods()) {
            Annotation[] anns = method.getAnnotations();
            ProbeListener probeAnn = method.getAnnotation(ProbeListener.class);

            if (probeAnn == null)
                continue;

            String probeString = probeAnn.value();
            if ((probeString != null) && (invokerId != null)) {
                String[] strArr = probeString.split(":");
                probeString = strArr[0] + ":" +
                              strArr[1] + ":" +
                              strArr[2] + invokerId + ":" +
                              strArr[3];
            }
            FlashlightProbe probe = probeRegistry.getProbe(probeString);
            if (probe == null) {
                String errStr = localStrings.getLocalString("probeNotRegistered",
                                    "Probe is not registered: {0}", probeString);
                throw new RuntimeException(errStr);
            }
            
            mp.add(new MethodProbe(method, probe));
        }
        
        return mp;
    }

    private void submit2BTrace(byte [] bArr) {
        try {
            ClassLoader scl = this.getClass().getClassLoader().getSystemClassLoader();
            Class agentMainClass = scl.loadClass("com.sun.btrace.agent.Main");
            Class[] params = new Class[] {(new byte[0]).getClass(), PrintWriter.class};
            Method mthd = agentMainClass.getMethod("handleFlashLightClient", params);
            mthd.invoke(null, new Object[] {bArr, fpw});
        } 
        catch(Exception e) {
            throw new RuntimeException("BTrace Error");
        }
    }


    // this is just used internally for cleanly organizing the code.
    private static class MethodProbe {
        MethodProbe(Method m, FlashlightProbe p) {
            method = m;
            probe = p;
        }
        Method          method;
        FlashlightProbe probe;
    }

    public static boolean attachAgent() {
        if (isAgentAttached()) {
            return true;
        }
        try {
            int pid = ProcessUtils.getPid();
            if (pid == -1) {
                logger.log(Level.WARNING, localStrings.getLocalString("invalid.pid", 
                    "invalid pid, start btrace-agent using asadmin enable-monitoring with --pid option, you may get pid using jps command"));
                return false;
            }
            VirtualMachine vm = VirtualMachine.attach(String.valueOf(pid));
            String ir = System.getProperty(INSTALL_ROOT_PROPERTY);
            File dir = new File(ir, "lib" + File.separator + "monitor");
            if (dir.isDirectory()) {
                File agentJar = new File(dir, "btrace-agent.jar");
                if (agentJar.isFile()) {
                    setAgentInitialized(false);
                    vm.loadAgent(agentJar.getPath(), "unsafe=true,noServer=true");
                } else {
                    logger.log(Level.WARNING, localStrings.getLocalString("missing.btrace-agent.jar",
                        "btrace-agent.jar does not exist under {0}", dir));
                    return false;
                }
            } else {
                logger.log(Level.WARNING, localStrings.getLocalString("missing.btrace-agent.jar.dir",
                    "btrace-agent.jar directory {0} does not exist", dir));
                return false;
            }
        } catch (Exception e) {
            logger.log(Level.WARNING, localStrings.getLocalString("attach.agent.exception",
                "Encountered exception during agent attach {0}", e.getMessage()));
        }
        return (isAgentAttached());
    }
}