introspector.java

JAVA的一些源码 JAVA2 STANDARD EDITION DEVELOPMENT KIT 5.0

/*
 * @(#)Introspector.java	1.68 03/12/19
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.jmx.mbeanserver;


// Java import
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;

// RI Import
import javax.management.IntrospectionException;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanOperationInfo;
import javax.management.MBeanParameterInfo;
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");
	}
    }
    
    /**
     * 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);
    }

    
    /**
     * 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
     */    
    static MBeanInfo testCompliance(final Class baseClass,
				    Class mbeanInterface) 
	    throws NotCompliantMBeanException {
	
	if (baseClass.isInterface()) 
	    throw new NotCompliantMBeanException(baseClass.getName() + 
						 " must be a class.");
	// ------------------------------ 
	// ------------------------------
	if (mbeanInterface == null)
	    // No interface specified: look for default MBean interface.
	    mbeanInterface = getStandardMBeanInterface(baseClass);
	else if (! mbeanInterface.isAssignableFrom(baseClass)) {
	    // specified interface not implemented by given class
	    final String msg =
		baseClass.getName() + " does not implement the " + 
		mbeanInterface.getName() + " interface";
	    throw new NotCompliantMBeanException(msg);
	} else if (! mbeanInterface.isInterface()) {
	    // Base class X, but XMBean is not an interface
	    final String msg =
		baseClass.getName() + ": " + mbeanInterface.getName() + 
		" is not an interface";
	    throw new NotCompliantMBeanException(msg);
	}


	if (mbeanInterface == null) {
	    // Error: MBean does not implement javax.management.DynamicMBean 
	    // nor MBean interface
	    final String baseClassName = baseClass.getName();
	    final String msg =
		baseClassName + " does not implement the " + baseClassName +
		"MBean interface or the DynamicMBean interface";
	    throw new NotCompliantMBeanException(msg);
	}
	
	final int mods = mbeanInterface.getModifiers();
	if (!Modifier.isPublic(mods)) 
	    throw new NotCompliantMBeanException(mbeanInterface.getName() + 
						 " implemented by " +
						 baseClass.getName() + 
						 " must be public");

	return (introspect(baseClass, mbeanInterface));
    }

    
    /**
     * 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 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 MBean implements the MBean or the Dynamic 
	// MBean interface
	if (isDynamic(baseClass)) return null;

	return getStandardMBeanInterface(baseClass);     
    }
    
    /**
     * 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 MBean. 
     *         Return <code>null</code> if no MBean interface is found.
     *         Does not check whether the MBean is a DynamicMBean.
     *
     */
    static Class getStandardMBeanInterface(Class baseClass) {

	// ------------------------------ 
	// ------------------------------
	
	Class current = baseClass;
	Class mbeanInterface = null;
	
	while (current != null) {
	    mbeanInterface = 
		findMBeanInterface(current, current.getName());
	    if (mbeanInterface != null) break;
	    current = current.getSuperclass();
	}
	return mbeanInterface;
    }

    /*
     * ------------------------------------------
     *  PRIVATE METHODS
     * ------------------------------------------
     */
    

    /**
     * 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 Class findMBeanInterface(Class aClass, String aName) {
	Class current = aClass;
	while (current != null) {
	    final Class[] interfaces = current.getInterfaces();   
	    final int len = interfaces.length;
	    for (int i=0;i<len;i++)  {	     
		final Class inter = 
		    implementsMBean(interfaces[i], aName);
		if (inter != null) return inter;