/*

 * Copyright 1999-2008 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.jmx.mbeanserver;

import com.sun.jmx.remote.util.EnvHelp;

import java.beans.BeanInfo;

import java.beans.PropertyDescriptor;

import java.lang.annotation.Annotation;

import java.lang.reflect.AnnotatedElement;

import java.lang.reflect.Array;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.lang.reflect.Proxy;

import java.lang.reflect.UndeclaredThrowableException;

import java.util.Arrays;

import java.util.HashMap;

import java.util.Map;

import java.util.logging.Level;

import javax.management.AttributeNotFoundException;

import javax.management.Description;

import javax.management.Descriptor;

import javax.management.DescriptorFields;

import javax.management.DescriptorKey;

import javax.management.DynamicMBean;

import javax.management.ImmutableDescriptor;

import javax.management.MBean;

import javax.management.MBeanInfo;

import javax.management.MXBean;

import javax.management.NotCompliantMBeanException;

import javax.management.openmbean.CompositeData;

import javax.management.openmbean.MXBeanMappingFactory;

import static com.sun.jmx.defaults.JmxProperties.MBEANSERVER_LOGGER;

import com.sun.jmx.mbeanserver.Util;

import com.sun.jmx.remote.util.EnvHelp;

import java.beans.BeanInfo;

import java.beans.PropertyDescriptor;

import java.lang.reflect.Array;

import java.lang.reflect.InvocationTargetException;

import java.util.LinkedHashSet;

import java.util.Set;

import javax.management.AttributeNotFoundException;

import javax.management.JMX;

import javax.management.openmbean.CompositeData;

import javax.management.openmbean.MXBeanMappingFactory;

/**

 * This class contains the methods for performing all the tests needed to verify

 * that a class represents a JMX compliant MBean.

 *

 * @since 1.5

 */

public class Introspector {

     /*

     * ------------------------------------------

     *  PRIVATE CONSTRUCTORS

     * ------------------------------------------

     */

    // private constructor defined to "hide" the default public constructor

    private Introspector() {

        // ------------------------------

        // ------------------------------

    }

    /*

     * ------------------------------------------

     *  PUBLIC METHODS

     * ------------------------------------------

     */

    /**

     * Tell whether a MBean of the given class is a Dynamic MBean.

     * This method does nothing more than returning

     * <pre>

     * javax.management.DynamicMBean.class.isAssignableFrom(c)

     * </pre>

     * This method does not check for any JMX MBean compliance:

     * <ul><li>If <code>true</code> is returned, then instances of

     *     <code>c</code> are DynamicMBean.</li>

     *     <li>If <code>false</code> is returned, then no further

     *     assumption can be made on instances of <code>c</code>.

     *     In particular, instances of <code>c</code> may, or may not

     *     be JMX standard MBeans.</li>

     * </ul>

     * @param c The class of the MBean under examination.

     * @return <code>true</code> if instances of <code>c</code> are

     *         Dynamic MBeans, <code>false</code> otherwise.

     *

     **/

    public static final boolean isDynamic(final Class<?> c) {

        // Check if the MBean implements the DynamicMBean interface

        return javax.management.DynamicMBean.class.isAssignableFrom(c);

    }

    /**

     * Basic method for testing that a MBean of a given class can be

     * instantiated by the MBean server.<p>

     * This method checks that:

     * <ul><li>The given class is a concrete class.</li>

     *     <li>The given class exposes at least one public constructor.</li>

     * </ul>

     * If these conditions are not met, throws a NotCompliantMBeanException.

     * @param c The class of the MBean we want to create.

     * @exception NotCompliantMBeanException if the MBean class makes it

     *            impossible to instantiate the MBean from within the

     *            MBeanServer.

     *

     **/

    public static void testCreation(Class<?> c)

        throws NotCompliantMBeanException {

        // Check if the class is a concrete class

        final int mods = c.getModifiers();

        if (Modifier.isAbstract(mods) || Modifier.isInterface(mods)) {

            throw new NotCompliantMBeanException("MBean class must be concrete");

        }

        // Check if the MBean has a public constructor

        final Constructor<?>[] consList = c.getConstructors();

        if (consList.length == 0) {

            throw new NotCompliantMBeanException("MBean class must have public constructor");

        }

    }

    public static void checkCompliance(Class<?> mbeanClass)

    throws NotCompliantMBeanException {

        // Check that @Resource is used correctly (if it used).

        MBeanInjector.validate(mbeanClass);

        // Is DynamicMBean?

        //

        if (DynamicMBean.class.isAssignableFrom(mbeanClass))

            return;

        // Is Standard MBean?

        //

        final Exception mbeanException;

        try {

            getStandardMBeanInterface(mbeanClass);

            return;

        } catch (NotCompliantMBeanException e) {

            mbeanException = e;

        }

        // Is MXBean?

        //

        final Exception mxbeanException;

        try {

            getMXBeanInterface(mbeanClass);

            return;

        } catch (NotCompliantMBeanException e) {

            mxbeanException = e;

        }

        // Is @MBean or @MXBean class?

        // In fact we find @MBean or @MXBean as a hacky variant of

        // getStandardMBeanInterface or getMXBeanInterface.  If we get here

        // then nothing worked.

        final String msg =

            "MBean class " + mbeanClass.getName() + " does not implement " +

            "DynamicMBean; does not follow the Standard MBean conventions (" +

            mbeanException.toString() + "); does not follow the MXBean conventions (" +

            mxbeanException.toString() + "); and does not have or inherit the @" +

            MBean.class.getSimpleName() + " or @" + MXBean.class.getSimpleName() +

            " annotation";

        throw new NotCompliantMBeanException(msg);

    }

    /**

     * <p>Make a DynamicMBean out of the existing MBean object.  The object

     * may already be a DynamicMBean, or it may be a Standard MBean or

     * MXBean, possibly defined using {@code @MBean} or {@code @MXBean}.</p>

     * @param mbean the object to convert to a DynamicMBean.

     * @param <T> a type parameter defined for implementation convenience

     * (which would have to be removed if this method were part of the public

     * API).

     * @return the converted DynamicMBean.

     * @throws NotCompliantMBeanException if {@code mbean} is not a compliant

     * MBean object, including the case where it is null.

     */

    public static <T> DynamicMBean makeDynamicMBean(T mbean)

    throws NotCompliantMBeanException {

        if (mbean == null)

            throw new NotCompliantMBeanException("Null MBean object");

        if (mbean instanceof DynamicMBean)

            return (DynamicMBean) mbean;

        final Class<?> mbeanClass = mbean.getClass();

        Class<? super T> c = null;

        try {

            c = Util.cast(getStandardMBeanInterface(mbeanClass));

        } catch (NotCompliantMBeanException e) {

            // Ignore exception - we need to check whether

            // mbean is an MXBean first.

        }

        if (c != null)

            return new StandardMBeanSupport(mbean, c);

        try {

            c = Util.cast(getMXBeanInterface(mbeanClass));

        } catch (NotCompliantMBeanException e) {

            // Ignore exception - we cannot decide whether mbean was supposed

            // to be an MBean or an MXBean. We will call checkCompliance()

            // to generate the appropriate exception.

        }

        if (c != null) {

            MXBeanMappingFactory factory;

            try {

                factory = MXBeanMappingFactory.forInterface(c);

            } catch (IllegalArgumentException e) {

                NotCompliantMBeanException ncmbe =

                        new NotCompliantMBeanException(e.getMessage());

                ncmbe.initCause(e);

                throw ncmbe;

            }

            return new MXBeanSupport(mbean, c, factory);

        }

        checkCompliance(mbeanClass);

        throw new NotCompliantMBeanException("Not compliant"); // not reached

    }

    /**

     * Basic method for testing if a given class is a JMX compliant MBean.

     *

     * @param baseClass The class to be tested

     *

     * @return <code>null</code> if the MBean is a DynamicMBean,

     *         the computed {@link javax.management.MBeanInfo} otherwise.

     * @exception NotCompliantMBeanException The specified class is not a

     *            JMX compliant MBean

     */

    public static MBeanInfo testCompliance(Class<?> baseClass)

        throws NotCompliantMBeanException {

        // ------------------------------

        // ------------------------------

        // Check if the MBean implements the MBean or the Dynamic

        // MBean interface

        if (isDynamic(baseClass))

            return null;

        return testCompliance(baseClass, null);

    }

    public static void testComplianceMXBeanInterface(Class<?> interfaceClass,

                                                     MXBeanMappingFactory factory)

            throws NotCompliantMBeanException {

        MXBeanIntrospector.getInstance(factory).getAnalyzer(interfaceClass);

    }

    /**

     * Basic method for testing if a given class is a JMX compliant

     * Standard MBean.  This method is only called by the legacy code

     * in com.sun.management.jmx.

     *

     * @param baseClass The class to be tested.

     *

     * @param mbeanInterface the MBean interface that the class implements,

     * or null if the interface must be determined by introspection.

     *

     * @return the computed {@link javax.management.MBeanInfo}.

     * @exception NotCompliantMBeanException The specified class is not a

     *            JMX compliant Standard MBean

     */

    public static synchronized MBeanInfo

            testCompliance(final Class<?> baseClass,

                           Class<?> mbeanInterface)

            throws NotCompliantMBeanException {

        if (mbeanInterface == null)

            mbeanInterface = getStandardMBeanInterface(baseClass);

        MBeanIntrospector<?> introspector = StandardMBeanIntrospector.getInstance();

        return getClassMBeanInfo(introspector, baseClass, mbeanInterface);

    }

    private static <M> MBeanInfo

            getClassMBeanInfo(MBeanIntrospector<M> introspector,

                              Class<?> baseClass, Class<?> mbeanInterface)

    throws NotCompliantMBeanException {

        PerInterface<M> perInterface = introspector.getPerInterface(mbeanInterface);

        return introspector.getClassMBeanInfo(baseClass, perInterface);

    }

    /**

     * Get the MBean interface implemented by a JMX Standard

     * MBean class. This method is only called by the legacy

     * code in "com.sun.management.jmx".

     *

     * @param baseClass The class to be tested.

     *

     * @return The MBean interface implemented by the MBean.

     *         Return <code>null</code> if the MBean is a DynamicMBean,

     *         or if no MBean interface is found.

     */

    public static Class<?> getMBeanInterface(Class<?> baseClass) {

        // Check if the given class implements the MBean interface

        // or the Dynamic MBean interface

        if (isDynamic(baseClass)) return null;

        try {

            return getStandardMBeanInterface(baseClass);

        } catch (NotCompliantMBeanException e) {

            return null;

        }

    }

    /**

     * Get the MBean interface implemented by a JMX Standard MBean class.

     *

     * @param baseClass The class to be tested.

     *

     * @return The MBean interface implemented by the Standard MBean.

     *

     * @throws NotCompliantMBeanException The specified class is

     * not a JMX compliant Standard MBean.

     */

    public static <T> Class<? super T> getStandardMBeanInterface(Class<T> baseClass)

    throws NotCompliantMBeanException {

        if (baseClass.isAnnotationPresent(MBean.class))

            return baseClass;

        Class<? super T> current = baseClass;

        Class<? super T> mbeanInterface = null;

        while (current != null) {

            mbeanInterface =

                findMBeanInterface(current, current.getName());

            if (mbeanInterface != null) break;

            current = current.getSuperclass();

        }

        if (mbeanInterface != null) {

            return mbeanInterface;

        } else {

            final String msg =

                "Class " + baseClass.getName() +

                " is not a JMX compliant Standard MBean";

            throw new NotCompliantMBeanException(msg);

        }

    }

    /**

     * Get the MXBean interface implemented by a JMX MXBean class.

     *

     * @param baseClass The class to be tested.

     *

     * @return The MXBean interface implemented by the MXBean.

     *

     * @throws NotCompliantMBeanException The specified class is

     * not a JMX compliant MXBean.

     */

    public static <T> Class<? super T> getMXBeanInterface(Class<T> baseClass)

        throws NotCompliantMBeanException {

        if (hasMXBeanAnnotation(baseClass))

            return baseClass;

        try {

            return MXBeanSupport.findMXBeanInterface(baseClass);

        } catch (Exception e) {

            throw throwException(baseClass,e);

        }

    }

    public static <T> Class<? super T> getStandardOrMXBeanInterface(

            Class<T> baseClass, boolean mxbean)

    throws NotCompliantMBeanException {

        if (mxbean)

            return getMXBeanInterface(baseClass);

        else

            return getStandardMBeanInterface(baseClass);

    }

    /*

     * ------------------------------------------

     *  PRIVATE METHODS

     * ------------------------------------------

     */

    static boolean hasMXBeanAnnotation(Class<?> c) {

        MXBean m = c.getAnnotation(MXBean.class);

        return (m != null && m.value());

    }

    /**

     * Try to find the MBean interface corresponding to the class aName

     * - i.e. <i>aName</i>MBean, from within aClass and its superclasses.

     **/

    private static <T> Class<? super T> findMBeanInterface(

            Class<T> aClass, String aName) {

        Class<? super T> current = aClass;

        while (current != null) {

            final Class<?>[] interfaces = current.getInterfaces();

            final int len = interfaces.length;

            for (int i=0;i<len;i++)  {

                Class<? super T> inter = Util.cast(interfaces[i]);

                inter = implementsMBean(inter, aName);

                if (inter != null) return inter;

            }

            current = current.getSuperclass();

        }

        return null;

    }

    public static String descriptionForElement(AnnotatedElement elmt) {

        if (elmt == null)

            return null;

        Description d = elmt.getAnnotation(Description.class);

        if (d == null)

            return null;

        return d.value();

    }

    public static String descriptionForParameter(

            Annotation[] parameterAnnotations) {

        for (Annotation a : parameterAnnotations) {

            if (a instanceof Description)

                return ((Description) a).value();

        }

        return null;

    }

    public static String nameForParameter(

            Annotation[] parameterAnnotations) {

        for (Annotation a : parameterAnnotations) {

            Class<? extends Annotation> ac = a.annotationType();

            // You'd really have to go out of your way to have more than

            // one @Name annotation, so we don't check for that.

            if (ac.getSimpleName().equals("Name")) {

                try {

                    Method value = ac.getMethod("value");

                    if (value.getReturnType() == String.class &&

                            value.getParameterTypes().length == 0) {

                        return (String) value.invoke(a);

                    }

                } catch (Exception e) {

                    MBEANSERVER_LOGGER.log(

                            Level.WARNING,

                            "Unexpected exception getting @" + ac.getName(),

                            e);

                }

            }