/*

 * Copyright (c) 2003, 2018, 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 java.lang.management.*;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import javax.management.InstanceAlreadyExistsException;

import javax.management.InstanceNotFoundException;

import javax.management.MBeanServer;

import javax.management.MBeanRegistrationException;

import javax.management.NotCompliantMBeanException;

import javax.management.ObjectName;

import javax.management.RuntimeOperationsException;

import java.security.AccessController;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.util.ArrayList;

import java.util.List;

import java.lang.reflect.UndeclaredThrowableException;

import java.security.PrivilegedAction;

import java.util.Arrays;

import java.util.Collections;

import java.util.HashMap;

import java.util.Map;

import java.util.Optional;

/**

 * ManagementFactoryHelper provides static factory methods to create

 * instances of the management interface.

 */

public class ManagementFactoryHelper {

    static {

        // make sure that the management lib is loaded within

        // java.lang.management.ManagementFactory

        jdk.internal.misc.Unsafe.getUnsafe().ensureClassInitialized(ManagementFactory.class);

    }

    private static final VMManagement jvm = new VMManagementImpl();

    private ManagementFactoryHelper() {};

    public static VMManagement getVMManagement() {

        return jvm;

    }

    static final String LOGGING_MXBEAN_NAME = "java.util.logging:type=Logging";

    private static ClassLoadingImpl    classMBean = null;

    private static MemoryImpl          memoryMBean = null;

    private static ThreadImpl          threadMBean = null;

    private static RuntimeImpl         runtimeMBean = null;

    private static CompilationImpl     compileMBean = null;

    private static BaseOperatingSystemImpl osMBean = null;

    public static synchronized ClassLoadingMXBean getClassLoadingMXBean() {

        if (classMBean == null) {

            classMBean = new ClassLoadingImpl(jvm);

        }

        return classMBean;

    }

    public static synchronized MemoryMXBean getMemoryMXBean() {

        if (memoryMBean == null) {

            memoryMBean = new MemoryImpl(jvm);

        }

        return memoryMBean;

    }

    public static synchronized ThreadMXBean getThreadMXBean() {

        if (threadMBean == null) {

            threadMBean = new ThreadImpl(jvm);

        }

        return threadMBean;

    }

    public static synchronized RuntimeMXBean getRuntimeMXBean() {

        if (runtimeMBean == null) {

            runtimeMBean = new RuntimeImpl(jvm);

        }

        return runtimeMBean;

    }

    public static synchronized CompilationMXBean getCompilationMXBean() {

        if (compileMBean == null && jvm.getCompilerName() != null) {

            compileMBean = new CompilationImpl(jvm);

        }

        return compileMBean;

    }

    public static synchronized OperatingSystemMXBean getOperatingSystemMXBean() {

        if (osMBean == null) {

            osMBean = new BaseOperatingSystemImpl(jvm);

        }

        return osMBean;

    }

    public static List<MemoryPoolMXBean> getMemoryPoolMXBeans() {

        MemoryPoolMXBean[] pools = MemoryImpl.getMemoryPools();

        List<MemoryPoolMXBean> list = new ArrayList<>(pools.length);

        for (MemoryPoolMXBean p : pools) {

            list.add(p);

        }

        return list;

    }

    public static List<MemoryManagerMXBean> getMemoryManagerMXBeans() {

        MemoryManagerMXBean[]  mgrs = MemoryImpl.getMemoryManagers();

        List<MemoryManagerMXBean> result = new ArrayList<>(mgrs.length);

        for (MemoryManagerMXBean m : mgrs) {

            result.add(m);

        }

        return result;

    }

     public static List<GarbageCollectorMXBean> getGarbageCollectorMXBeans() {

        MemoryManagerMXBean[]  mgrs = MemoryImpl.getMemoryManagers();

        List<GarbageCollectorMXBean> result = new ArrayList<>(mgrs.length);

        for (MemoryManagerMXBean m : mgrs) {

            if (GarbageCollectorMXBean.class.isInstance(m)) {

                 result.add(GarbageCollectorMXBean.class.cast(m));

            }

        }

        return result;

    }

    public static PlatformLoggingMXBean getPlatformLoggingMXBean() {

        if (LoggingMXBeanAccess.isAvailable()) {

            return PlatformLoggingImpl.MBEAN;

        } else {

            return null;

        }

    }

    public static boolean isPlatformLoggingMXBeanAvailable() {

        return LoggingMXBeanAccess.isAvailable();

    }

    /**

     * Returns an array of the name of all memory pools.  The order of the memory pools is

     * significant and maintained in the VM.

     */

    public static String[] getAllMemoryPoolNames() {

        return Arrays.stream(MemoryImpl.getMemoryPools())

                .map(MemoryPoolMXBean::getName)

                .toArray(String[]::new);

    }

    // The LoggingMXBeanAccess class uses reflection to determine

    // whether java.util.logging is present, and load the actual LoggingMXBean

    // implementation.

    //

    static final class LoggingMXBeanAccess {

        final static String LOG_MANAGER_CLASS_NAME = "java.util.logging.LogManager";

        final static String LOGGING_MXBEAN_CLASS_NAME = "java.util.logging.LoggingMXBean";

        final static Class<?> LOG_MANAGER_CLASS = loadLoggingClass(LOG_MANAGER_CLASS_NAME);

        static boolean isAvailable() {

            return LOG_MANAGER_CLASS != null;

        }

        private static Class<?> loadLoggingClass(String className) {

            return AccessController.doPrivileged(new PrivilegedAction<>() {

                @Override

                public Class<?> run() {

                    Optional<Module> logging = ModuleLayer.boot().findModule("java.logging");

                    if (logging.isPresent()) {

                        return Class.forName(logging.get(), className);

                    }

                    return null;

                }

            });

        }

        private Map<String, Method> initMethodMap(Object impl) {

            if (impl == null) {

                return Collections.emptyMap();

            }

            Class<?> intfClass = loadLoggingClass(LOGGING_MXBEAN_CLASS_NAME);

            final Map<String, Method> methodsMap = new HashMap<>();

            for (Method m : intfClass.getMethods()) {

                try {

                    // Sanity checking: all public methods present in

                    // java.util.logging.LoggingMXBean should

                    // also be in PlatformLoggingMXBean

                    Method specMethod = PlatformLoggingMXBean.class

                             .getMethod(m.getName(), m.getParameterTypes());

                    if (specMethod.getReturnType().isAssignableFrom(m.getReturnType())) {

                        if (methodsMap.putIfAbsent(m.getName(), m) != null) {

                            throw new RuntimeException("unexpected polymorphic method: "

                                     + m.getName());

                        }

                    }

                } catch (NoSuchMethodException x) {

                    // All methods in java.util.logging.LoggingMXBean should

                    // also be in PlatformLoggingMXBean

                    throw new InternalError(x);

                }

            }

            return Collections.unmodifiableMap(methodsMap);

        }

        private static Object getMXBeanImplementation() {

            if (!isAvailable()) {

                // should not happen

                throw new NoClassDefFoundError(LOG_MANAGER_CLASS_NAME);

            }

            try {

                final Method m = LOG_MANAGER_CLASS.getMethod("getLoggingMXBean");

                return m.invoke(null);

            } catch (NoSuchMethodException

                    | IllegalAccessException

                    | InvocationTargetException x) {

                throw new ExceptionInInitializerError(x);

            }

         }

        // The implementation object, which will be invoked through

        // reflection. The implementation does not need to implement

        // PlatformLoggingMXBean, but must declare the same methods

        // with same signatures, and they must be public, with one

        // exception:

        // getObjectName will not be called on the implementation object,

        // so the implementation object does not need to declare such

        // a method.

        final Object impl = getMXBeanImplementation();

        final Map<String, Method> methods = initMethodMap(impl);

        LoggingMXBeanAccess() {

        }

        <T> T invoke(String methodName, Object... args) {

            Method m = methods.get(methodName);

            if (m == null) {

                throw new UnsupportedOperationException(methodName);

            }

            try {

                @SuppressWarnings("unchecked")

                T result = (T) m.invoke(impl, args);

                return result;

            } catch (IllegalAccessException ex) {

                throw new UnsupportedOperationException(ex);

            } catch (InvocationTargetException ex) {

                throw unwrap(ex);

            }

        }

        private static RuntimeException unwrap(InvocationTargetException x) {

            Throwable t = x.getCause();

            if (t instanceof RuntimeException) {

                return (RuntimeException)t;

            }

            if (t instanceof Error) {

                throw (Error)t;

            }

            return new UndeclaredThrowableException(t == null ? x : t);

        }

    }

    static final class PlatformLoggingImpl implements PlatformLoggingMXBean {

        private final LoggingMXBeanAccess loggingAccess;

        private PlatformLoggingImpl(LoggingMXBeanAccess loggingAccess) {

            this.loggingAccess = loggingAccess;

        }

        private volatile ObjectName objname;  // created lazily

        @Override

        public ObjectName getObjectName() {

            ObjectName result = objname;

            if (result == null) {

                synchronized (this) {

                    result = objname;

                    if (result == null) {

                        result = Util.newObjectName(LOGGING_MXBEAN_NAME);

                        objname = result;

                    }

                }

            }

            return result;

        }

        @Override

        public java.util.List<String> getLoggerNames() {

            return loggingAccess.invoke("getLoggerNames");

        }

        @Override

        public String getLoggerLevel(String loggerName) {

            return loggingAccess.invoke("getLoggerLevel", loggerName);

        }

        @Override

        public void setLoggerLevel(String loggerName, String levelName) {

            loggingAccess.invoke("setLoggerLevel", loggerName, levelName);

        }

        @Override

        public String getParentLoggerName(String loggerName) {

            return loggingAccess.invoke("getParentLoggerName", loggerName);

        }

        private static PlatformLoggingImpl getInstance() {

            return new PlatformLoggingImpl(new LoggingMXBeanAccess());

         }

        static final PlatformLoggingMXBean MBEAN = getInstance();

    }

    private static List<BufferPoolMXBean> bufferPools = null;

    public static synchronized List<BufferPoolMXBean> getBufferPoolMXBeans() {

        if (bufferPools == null) {

            bufferPools = new ArrayList<>(2);

            bufferPools.add(createBufferPoolMXBean(SharedSecrets.getJavaNioAccess()

                .getDirectBufferPool()));

            bufferPools.add(createBufferPoolMXBean(sun.nio.ch.FileChannelImpl

                .getMappedBufferPool()));

        }

        return bufferPools;

    }

    private final static String BUFFER_POOL_MXBEAN_NAME = "java.nio:type=BufferPool";

    /**

     * Creates management interface for the given buffer pool.

     */

    private static BufferPoolMXBean

        createBufferPoolMXBean(final JavaNioAccess.BufferPool pool)

    {

        return new BufferPoolMXBean() {

            private volatile ObjectName objname;  // created lazily

            @Override

            public ObjectName getObjectName() {

                ObjectName result = objname;

                if (result == null) {

                    synchronized (this) {

                        result = objname;

                        if (result == null) {

                            result = Util.newObjectName(BUFFER_POOL_MXBEAN_NAME +

                                ",name=" + pool.getName());

                            objname = result;

                        }

                    }

                }

                return result;

            }

            @Override

            public String getName() {

                return pool.getName();

            }

            @Override

            public long getCount() {

                return pool.getCount();

            }

            @Override

            public long getTotalCapacity() {

                return pool.getTotalCapacity();

            }

            @Override

            public long getMemoryUsed() {

                return pool.getMemoryUsed();

            }

        };

    }

    private static HotspotRuntime hsRuntimeMBean = null;

    private static HotspotClassLoading hsClassMBean = null;

    private static HotspotThread hsThreadMBean = null;

    private static HotspotCompilation hsCompileMBean = null;

    private static HotspotMemory hsMemoryMBean = null;

    /**

     * This method is for testing only.

     */

    public static synchronized HotspotRuntimeMBean getHotspotRuntimeMBean() {

        if (hsRuntimeMBean == null) {

            hsRuntimeMBean = new HotspotRuntime(jvm);

        }

        return hsRuntimeMBean;

    }

    /**

     * This method is for testing only.

     */

    public static synchronized HotspotClassLoadingMBean getHotspotClassLoadingMBean() {

        if (hsClassMBean == null) {

            hsClassMBean = new HotspotClassLoading(jvm);

        }

        return hsClassMBean;

    }

    /**

     * This method is for testing only.

     */

    public static synchronized HotspotThreadMBean getHotspotThreadMBean() {

        if (hsThreadMBean == null) {

            hsThreadMBean = new HotspotThread(jvm);

        }

        return hsThreadMBean;

    }

    /**

     * This method is for testing only.

     */

    public static synchronized HotspotMemoryMBean getHotspotMemoryMBean() {

        if (hsMemoryMBean == null) {

            hsMemoryMBean = new HotspotMemory(jvm);

        }

        return hsMemoryMBean;

    }

    /**

     * This method is for testing only.

     */

    public static synchronized HotspotCompilationMBean getHotspotCompilationMBean() {

        if (hsCompileMBean == null) {

            hsCompileMBean = new HotspotCompilation(jvm);

        }

        return hsCompileMBean;

    }

    /**

     * Registers a given MBean if not registered in the MBeanServer;

     * otherwise, just return.

     */

    private static void addMBean(MBeanServer mbs, Object mbean, String mbeanName) {

        try {

            final ObjectName objName = Util.newObjectName(mbeanName);

            // inner class requires these fields to be final

            final MBeanServer mbs0 = mbs;

            final Object mbean0 = mbean;

            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {

                public Void run() throws MBeanRegistrationException,

                                         NotCompliantMBeanException {

                    try {

                        mbs0.registerMBean(mbean0, objName);

                        return null;

                    } catch (InstanceAlreadyExistsException e) {

                        // if an instance with the object name exists in

                        // the MBeanServer ignore the exception

                    }

                    return null;

                }

            });

        } catch (PrivilegedActionException e) {

            throw Util.newException(e.getException());

        }

    }

    private final static String HOTSPOT_CLASS_LOADING_MBEAN_NAME =

        "sun.management:type=HotspotClassLoading";

    private final static String HOTSPOT_COMPILATION_MBEAN_NAME =

        "sun.management:type=HotspotCompilation";

    private final static String HOTSPOT_MEMORY_MBEAN_NAME =

        "sun.management:type=HotspotMemory";

    private static final String HOTSPOT_RUNTIME_MBEAN_NAME =

        "sun.management:type=HotspotRuntime";

    private final static String HOTSPOT_THREAD_MBEAN_NAME =

        "sun.management:type=HotspotThreading";

    static void registerInternalMBeans(MBeanServer mbs) {

        // register all internal MBeans if not registered

        // No exception is thrown if a MBean with that object name

        // already registered

        addMBean(mbs, getHotspotClassLoadingMBean(),

            HOTSPOT_CLASS_LOADING_MBEAN_NAME);