introspector.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)Introspector.java	1.90 06/01/23
 * 
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.jmx.mbeanserver;


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

import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.UndeclaredThrowableException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import javax.management.Descriptor;
import javax.management.DescriptorKey;
import javax.management.DynamicMBean;
import javax.management.ImmutableDescriptor;
import javax.management.MBeanInfo;
import javax.management.NotCompliantMBeanException;

/**
 * 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 VARIABLES
     * ------------------------------------------
     */

    private static final String attributeDescription =
	"Attribute exposed for management";
    private static final String operationDescription =
	"Operation exposed for management";
    private static final String constructorDescription =
	"Public constructor of the MBean";
    private static final String mbeanInfoDescription =
	"Information on the management interface of the MBean";
    

     /*
     * ------------------------------------------
     *  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. 
     *
     * @since.unbundled JMX RI 1.2
     **/
    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.
     *
     * @since.unbundled JMX RI 1.2
     **/
    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 {
        // 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;
        }
        final String msg =
            "MBean class " + mbeanClass.getName() + " does not implement " +
            "DynamicMBean, neither follows the Standard MBean conventions (" +
            mbeanException.toString() + ") nor the MXBean conventions (" +
            mxbeanException.toString() + ")";
        throw new NotCompliantMBeanException(msg);
    }

    public static DynamicMBean makeDynamicMBean(Object mbean)
        throws NotCompliantMBeanException {
        if (mbean instanceof DynamicMBean)
            return (DynamicMBean) mbean;
        final Class mbeanClass = mbean.getClass();
        Class c = null;
        try {
            c = 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 = 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) return new MXBeanSupport(mbean, c);
        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)
	    throws NotCompliantMBeanException {
	MXBeanIntrospector.getInstance().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();
        PerInterface<?> perInterface = introspector.getPerInterface(mbeanInterface);
        return introspector.getClassMBeanInfo(baseClass, perInterface);