/*
* @(#)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);
}
/**
* 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 Class getStandardMBeanInterface(Class baseClass)
throws NotCompliantMBeanException {
Class current = baseClass;
Class 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 Class getMXBeanInterface(Class baseClass)
throws NotCompliantMBeanException {
try {
return MXBeanSupport.findMXBeanInterface(baseClass);
} catch (Exception e) {
throw throwException(baseClass,e);
}
}
/*
* ------------------------------------------
* 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;
}
current = current.getSuperclass();
}
return null;
}
public static Descriptor descriptorForElement(final AnnotatedElement elmt) {
if (elmt == null)
return ImmutableDescriptor.EMPTY_DESCRIPTOR;
final Annotation[] annots = elmt.getAnnotations();
return descriptorForAnnotations(annots);
}
public static Descriptor descriptorForAnnotations(Annotation[] annots) {
if (annots.length == 0)
return ImmutableDescriptor.EMPTY_DESCRIPTOR;
Map<String, Object> descriptorMap = new HashMap<String, Object>();
for (Annotation a : annots) {
Class<? extends Annotation> c = a.annotationType();
Method[] elements = c.getMethods();
for (Method element : elements) {
DescriptorKey key = element.getAnnotation(DescriptorKey.class);
if (key != null) {
String name = key.value();
Object value;
try {
value = element.invoke(a);
} catch (RuntimeException e) {
// we don't expect this - except for possibly
// security exceptions?
// RuntimeExceptions shouldn't be "UndeclaredThrowable".
// anyway...
//
throw e;
} catch (Exception e) {
// we don't expect this
throw new UndeclaredThrowableException(e);
}
value = annotationToField(value);
Object oldValue = descriptorMap.put(name, value);
if (oldValue != null && !equals(oldValue, value)) {
final String msg =
"Inconsistent values for descriptor field " + name +
" from annotations: " + value + " :: " + oldValue;
throw new IllegalArgumentException(msg);
}
}
}
}
if (descriptorMap.isEmpty())
return ImmutableDescriptor.EMPTY_DESCRIPTOR;
else
return new ImmutableDescriptor(descriptorMap);
}
/**
* Throws a NotCompliantMBeanException or a SecurityException.
* @param notCompliant the class which was under examination
* @param cause the raeson why NotCompliantMBeanException should
* be thrown.
* @return nothing - this method always throw an exception.
* The return type makes it possible to write
* <pre> throw throwException(clazz,cause); </pre>
* @throws SecurityException - if cause is a SecurityException
* @throws NotCompliantMBeanException otherwise.
**/
static NotCompliantMBeanException throwException(Class<?> notCompliant,
Throwable cause)
throws NotCompliantMBeanException, SecurityException {
if (cause instanceof SecurityException)
throw (SecurityException) cause;
if (cause instanceof NotCompliantMBeanException)
throw (NotCompliantMBeanException)cause;
final String classname =
(notCompliant==null)?"null class":notCompliant.getName();
final String reason =
(cause==null)?"Not compliant":cause.getMessage();
final NotCompliantMBeanException res =
new NotCompliantMBeanException(classname+": "+reason);
res.initCause(cause);
throw res;
}
// Convert a value from an annotation element to a descriptor field value
// E.g. with @interface Foo {class value()} an annotation @Foo(String.class)
// will produce a Descriptor field value "java.lang.String"
private static Object annotationToField(Object x) {
// An annotation element cannot have a null value but never mind
if (x == null)
return null;
if (x instanceof Number || x instanceof String ||
x instanceof Character || x instanceof Boolean ||
x instanceof String[])
return x;
// Remaining possibilities: array of primitive (e.g. int[]),
// enum, class, array of enum or class.
Class<?> c = x.getClass();
if (c.isArray()) {
if (c.getComponentType().isPrimitive())
return x;
Object[] xx = (Object[]) x;
String[] ss = new String[xx.length];
for (int i = 0; i < xx.length; i++)
ss[i] = (String) annotationToField(xx[i]);
return ss;
}
if (x instanceof Class)
return ((Class<?>) x).getName();
if (x instanceof Enum)
return ((Enum) x).name();
// The only other possibility is that the value is another
// annotation, or that the language has evolved since this code
// was written. We don't allow for either of those currently.
throw new IllegalArgumentException("Illegal type for annotation " +
"element: " + x.getClass().getName());
}
// This must be consistent with the check for duplicate field values in
// ImmutableDescriptor.union. But we don't expect to be called very
// often so this inefficient check should be enough.
private static boolean equals(Object x, Object y) {
return Arrays.deepEquals(new Object[] {x}, new Object[] {y});
}
/**
* Returns the XXMBean interface or null if no such interface exists
*
* @param c The interface to be tested
* @param clName The name of the class implementing this interface
*/
private static Class implementsMBean(Class c, String clName) {
String clMBeanName = clName + "MBean";
if (c.getName().equals(clMBeanName)) {
return c;
}
Class current = c;
Class[] interfaces = c.getInterfaces();
for (int i = 0;i < interfaces.length; i++) {
if (interfaces[i].getName().equals(clMBeanName))
return interfaces[i];
}
return null;
}
}
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