Java example source code file (DiagnosticCommandImpl.java)

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

Learn more about this Java project at its project page.

Java - Java tags/keywords

attributelist, diagnosticcommandinfo, hashmap, illegalargumentexception, immutabledescriptor, instantiationexception, management, mbeannotificationinfo, mbeanparameterinfo, object, override, reflection, reflectionexception, security, string, stringbuilder, util, wrapper

The DiagnosticCommandImpl.java Java example source code

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.management;

import com.sun.management.DiagnosticCommandMBean;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.security.Permission;
import java.util.*;
import javax.management.*;

/**
 * Implementation class for the diagnostic commands subsystem.
 *
 * @since 8
 */
class DiagnosticCommandImpl extends NotificationEmitterSupport
    implements DiagnosticCommandMBean {

    private final VMManagement jvm;
    private volatile Map<String, Wrapper> wrappers = null;
    private static final String strClassName = "".getClass().getName();
    private static final String strArrayClassName = String[].class.getName();
    private final boolean isSupported;

    @Override
    public Object getAttribute(String attribute) throws AttributeNotFoundException,
        MBeanException, ReflectionException {
        throw new AttributeNotFoundException(attribute);
    }

    @Override
    public void setAttribute(Attribute attribute) throws AttributeNotFoundException,
        InvalidAttributeValueException, MBeanException, ReflectionException {
        throw new AttributeNotFoundException(attribute.getName());
    }

    @Override
    public AttributeList getAttributes(String[] attributes) {
        return new AttributeList();
    }

    @Override
    public AttributeList setAttributes(AttributeList attributes) {
        return new AttributeList();
    }

    private class Wrapper {

        String name;
        String cmd;
        DiagnosticCommandInfo info;
        Permission permission;

        Wrapper(String name, String cmd, DiagnosticCommandInfo info)
                throws InstantiationException {
            this.name = name;
            this.cmd = cmd;
            this.info = info;
            this.permission = null;
            Exception cause = null;
            if (info.getPermissionClass() != null) {
                try {
                    Class c = Class.forName(info.getPermissionClass());
                    if (info.getPermissionAction() == null) {
                        try {
                            Constructor constructor = c.getConstructor(String.class);
                            permission = (Permission) constructor.newInstance(info.getPermissionName());

                        } catch (InstantiationException | IllegalAccessException
                                | IllegalArgumentException | InvocationTargetException
                                | NoSuchMethodException | SecurityException ex) {
                            cause = ex;
                        }
                    }
                    if (permission == null) {
                        try {
                            Constructor constructor = c.getConstructor(String.class, String.class);
                            permission = (Permission) constructor.newInstance(
                                    info.getPermissionName(),
                                    info.getPermissionAction());
                        } catch (InstantiationException | IllegalAccessException
                                | IllegalArgumentException | InvocationTargetException
                                | NoSuchMethodException | SecurityException ex) {
                            cause = ex;
                        }
                    }
                } catch (ClassNotFoundException ex) { }
                if (permission == null) {
                    InstantiationException iex =
                            new InstantiationException("Unable to instantiate required permission");
                    iex.initCause(cause);
                }
            }
        }

        public String execute(String[] args) {
            if (permission != null) {
                SecurityManager sm = System.getSecurityManager();
                if (sm != null) {
                    sm.checkPermission(permission);
                }
            }
            if(args == null) {
                return executeDiagnosticCommand(cmd);
            } else {
                StringBuilder sb = new StringBuilder();
                sb.append(cmd);
                for(int i=0; i<args.length; i++) {
                    if(args[i] == null) {
                        throw new IllegalArgumentException("Invalid null argument");
                    }
                    sb.append(" ");
                    sb.append(args[i]);
                }
                return executeDiagnosticCommand(sb.toString());
            }
        }
    }

    DiagnosticCommandImpl(VMManagement jvm) {
        this.jvm = jvm;
        isSupported = jvm.isRemoteDiagnosticCommandsSupported();
    }

    private static class OperationInfoComparator implements Comparator<MBeanOperationInfo> {
        @Override
        public int compare(MBeanOperationInfo o1, MBeanOperationInfo o2) {
            return o1.getName().compareTo(o2.getName());
        }
    }

    @Override
    public MBeanInfo getMBeanInfo() {
        SortedSet<MBeanOperationInfo> operations = new TreeSet<>(new OperationInfoComparator());
        Map<String, Wrapper> wrappersmap;
        if (!isSupported) {
            wrappersmap = (Map<String, Wrapper>) Collections.EMPTY_MAP;
        } else {
            try {
                String[] command = getDiagnosticCommands();
                DiagnosticCommandInfo[] info = getDiagnosticCommandInfo(command);
                MBeanParameterInfo stringArgInfo[] = new MBeanParameterInfo[]{
                    new MBeanParameterInfo("arguments", strArrayClassName,
                    "Array of Diagnostic Commands Arguments and Options")
                };
                wrappersmap = new HashMap<>();
                for (int i = 0; i < command.length; i++) {
                    String name = transform(command[i]);
                    try {
                        Wrapper w = new Wrapper(name, command[i], info[i]);
                        wrappersmap.put(name, w);
                        operations.add(new MBeanOperationInfo(
                                w.name,
                                w.info.getDescription(),
                                (w.info.getArgumentsInfo() == null
                                    || w.info.getArgumentsInfo().isEmpty())
                                    ? null : stringArgInfo,
                                strClassName,
                                MBeanOperationInfo.ACTION_INFO,
                                commandDescriptor(w)));
                    } catch (InstantiationException ex) {
                        // If for some reasons the creation of a diagnostic command
                        // wrappers fails, the diagnostic command is just ignored
                        // and won't appear in the DynamicMBean
                    }
                }
            } catch (IllegalArgumentException | UnsupportedOperationException e) {
                wrappersmap = (Map<String, Wrapper>) Collections.EMPTY_MAP;
            }
        }
        wrappers =  Collections.unmodifiableMap(wrappersmap);
        HashMap<String, Object> map = new HashMap<>();
        map.put("immutableInfo", "false");
        map.put("interfaceClassName","com.sun.management.DiagnosticCommandMBean");
        map.put("mxbean", "false");
        Descriptor desc = new ImmutableDescriptor(map);
        return new MBeanInfo(
                this.getClass().getName(),
                "Diagnostic Commands",
                null, // attributes
                null, // constructors
                operations.toArray(new MBeanOperationInfo[operations.size()]), // operations
                getNotificationInfo(), // notifications
                desc);
    }

    @Override
    public Object invoke(String actionName, Object[] params, String[] signature)
            throws MBeanException, ReflectionException {
        if (!isSupported) {
            throw new UnsupportedOperationException();
        }
        if (wrappers == null) {
            getMBeanInfo();
        }
        Wrapper w = wrappers.get(actionName);
        if (w != null) {
            if (w.info.getArgumentsInfo().isEmpty()
                    && (params == null || params.length == 0)
                    && (signature == null || signature.length == 0)) {
                return w.execute(null);
            } else if((params != null && params.length == 1)
                    && (signature != null && signature.length == 1
                    && signature[0] != null
                    && signature[0].compareTo(strArrayClassName) == 0)) {
                return w.execute((String[]) params[0]);
            }
        }
        throw new ReflectionException(new NoSuchMethodException(actionName));
    }

    private static String transform(String name) {
        StringBuilder sb = new StringBuilder();
        boolean toLower = true;
        boolean toUpper = false;
        for (int i = 0; i < name.length(); i++) {
            char c = name.charAt(i);
            if (c == '.' || c == '_') {
                toLower = false;
                toUpper = true;
            } else {
                if (toUpper) {
                    toUpper = false;
                    sb.append(Character.toUpperCase(c));
                } else if(toLower) {
                    sb.append(Character.toLowerCase(c));
                } else {
                    sb.append(c);
                }
            }
        }
        return sb.toString();
    }

    private Descriptor commandDescriptor(Wrapper w) throws IllegalArgumentException {
        HashMap<String, Object> map = new HashMap<>();
        map.put("dcmd.name", w.info.getName());
        map.put("dcmd.description", w.info.getDescription());
        map.put("dcmd.vmImpact", w.info.getImpact());
        map.put("dcmd.permissionClass", w.info.getPermissionClass());
        map.put("dcmd.permissionName", w.info.getPermissionName());
        map.put("dcmd.permissionAction", w.info.getPermissionAction());
        map.put("dcmd.enabled", w.info.isEnabled());
        StringBuilder sb = new StringBuilder();
        sb.append("help ");
        sb.append(w.info.getName());
        map.put("dcmd.help", executeDiagnosticCommand(sb.toString()));
        if (w.info.getArgumentsInfo() != null && !w.info.getArgumentsInfo().isEmpty()) {
            HashMap<String, Object> allargmap = new HashMap<>();
            for (DiagnosticCommandArgumentInfo arginfo : w.info.getArgumentsInfo()) {
                HashMap<String, Object> argmap = new HashMap<>();
                argmap.put("dcmd.arg.name", arginfo.getName());
                argmap.put("dcmd.arg.type", arginfo.getType());
                argmap.put("dcmd.arg.description", arginfo.getDescription());
                argmap.put("dcmd.arg.isMandatory", arginfo.isMandatory());
                argmap.put("dcmd.arg.isMultiple", arginfo.isMultiple());
                boolean isOption = arginfo.isOption();
                argmap.put("dcmd.arg.isOption", isOption);
                if(!isOption) {
                    argmap.put("dcmd.arg.position", arginfo.getPosition());
                } else {
                    argmap.put("dcmd.arg.position", -1);
                }
                allargmap.put(arginfo.getName(), new ImmutableDescriptor(argmap));
            }
            map.put("dcmd.arguments", new ImmutableDescriptor(allargmap));
        }
        return new ImmutableDescriptor(map);
    }

    private final static String notifName =
        "javax.management.Notification";

    private final static String[] diagFramNotifTypes = {
        "jmx.mbean.info.changed"
    };

    private MBeanNotificationInfo[] notifInfo = null;

    @Override
    public MBeanNotificationInfo[] getNotificationInfo() {
        synchronized (this) {
            if (notifInfo == null) {
                 notifInfo = new MBeanNotificationInfo[1];
                 notifInfo[0] =
                         new MBeanNotificationInfo(diagFramNotifTypes,
                                                   notifName,
                                                   "Diagnostic Framework Notification");
            }
        }
        return notifInfo;
    }

    private static long seqNumber = 0;
    private static long getNextSeqNumber() {
        return ++seqNumber;
    }

    private void createDiagnosticFrameworkNotification() {

        if (!hasListeners()) {
            return;
        }
        ObjectName on = null;
        try {
            on = ObjectName.getInstance(ManagementFactoryHelper.HOTSPOT_DIAGNOSTIC_COMMAND_MBEAN_NAME);
        } catch (MalformedObjectNameException e) { }
        Notification notif = new Notification("jmx.mbean.info.changed",
                                              on,
                                              getNextSeqNumber());
        notif.setUserData(getMBeanInfo());
        sendNotification(notif);
    }

    @Override
    public synchronized void addNotificationListener(NotificationListener listener,
            NotificationFilter filter,
            Object handback) {
        boolean before = hasListeners();
        super.addNotificationListener(listener, filter, handback);
        boolean after = hasListeners();
        if (!before && after) {
            setNotificationEnabled(true);
        }
    }

    @Override
    public synchronized void removeNotificationListener(NotificationListener listener)
            throws ListenerNotFoundException {
        boolean before = hasListeners();
        super.removeNotificationListener(listener);
        boolean after = hasListeners();
        if (before && !after) {
            setNotificationEnabled(false);
        }
    }

    @Override
    public synchronized void removeNotificationListener(NotificationListener listener,
            NotificationFilter filter,
            Object handback)
            throws ListenerNotFoundException {
        boolean before = hasListeners();
        super.removeNotificationListener(listener, filter, handback);
        boolean after = hasListeners();
        if (before && !after) {
            setNotificationEnabled(false);
        }
    }

    private native void setNotificationEnabled(boolean enabled);
    private native String[] getDiagnosticCommands();
    private native DiagnosticCommandInfo[] getDiagnosticCommandInfo(String[] commands);
    private native String executeDiagnosticCommand(String command);

}