/*
* Copyright (C) The MX4J Contributors.
* All rights reserved.
*
* This software is distributed under the terms of the MX4J License version 1.0.
* See the terms of the MX4J License in the documentation provided with this software.
*/
package mx4j.server;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.WeakHashMap;
import javax.management.DynamicMBean;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanNotificationInfo;
import javax.management.MBeanOperationInfo;
import javax.management.MBeanParameterInfo;
import javax.management.NotificationBroadcaster;
import javax.management.loading.MLet;
import mx4j.MBeanDescription;
import mx4j.MBeanDescriptionAdapter;
import mx4j.MX4JSystemKeys;
import mx4j.log.Log;
import mx4j.log.Logger;
import mx4j.util.Utils;
/**
* Introspector for MBeans. <p>
* Main purposes of this class are:
* <ul>
* <li> Given an mbean, gather all information regarding it into a {@link MBeanMetaData} instance, see {@link #introspect}
* <li> Given an introspected MBeanMetaData, decide if the MBean is compliant or not.
* <li> Act as a factory for {@link MBeanInvoker}s
* </ul>
* <p/>
* The following system properties are used to control this class' behavior:
* <ul>
* <li> mx4j.strict.mbean.interface, if set to 'no' then are treated as standard MBeans also classes that implement
* management interfaces beloging to different packages or that are inner classes; otherwise are treated as MBeans
* only classes that implement interfaces whose name if the fully qualified name of the MBean class + "MBean"
* <li> mx4j.mbean.invoker, if set to the qualified name of an implementation of the {@link MBeanInvoker} interface,
* then an instance of the class will be used to invoke methods on standard MBeans. By default the generated-on-the-fly
* MBeanInvoker is used; to revert to the version that uses reflection, for example,
* use mx4j.mbean.invoker = {@link CachingReflectionMBeanInvoker mx4j.server.CachingReflectionMBeanInvoker}
* </ul>
*
* @version $Revision: 1.34 $
*/
public class MBeanIntrospector
{
private static final MBeanDescriptionAdapter DEFAULT_DESCRIPTION = new MBeanDescriptionAdapter();
private static final MBeanConstructorInfo[] EMPTY_CONSTRUCTORS = new MBeanConstructorInfo[0];
private static final MBeanParameterInfo[] EMPTY_PARAMETERS = new MBeanParameterInfo[0];
private static final MBeanAttributeInfo[] EMPTY_ATTRIBUTES = new MBeanAttributeInfo[0];
private static final MBeanNotificationInfo[] EMPTY_NOTIFICATIONS = new MBeanNotificationInfo[0];
private static final MBeanOperationInfo[] EMPTY_OPERATIONS = new MBeanOperationInfo[0];
private boolean extendedMBeanInterfaces = false;
private boolean bcelAvailable = false;
private String mbeanInvokerClass = null;
private final WeakHashMap mbeanInfoCache = new WeakHashMap();
private final WeakHashMap mbeanInvokerCache = new WeakHashMap();
public MBeanIntrospector()
{
String strict = (String)AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
return System.getProperty(MX4JSystemKeys.MX4J_STRICT_MBEAN_INTERFACE);
}
});
if (strict != null && !Boolean.valueOf(strict).booleanValue())
{
extendedMBeanInterfaces = true;
}
// Try to see if BCEL classes are present
try
{
ClassLoader loader = getClass().getClassLoader();
if (loader == null) loader = Thread.currentThread().getContextClassLoader();
loader.loadClass("org.apache.bcelAvailable.generic.Type");
bcelAvailable = true;
}
catch (Throwable ignored)
{
}
// See if someone specified which MBean invoker to use
mbeanInvokerClass = (String)AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
return System.getProperty(MX4JSystemKeys.MX4J_MBEAN_INVOKER);
}
});
}
/**
* Introspect the given mbean, storing the results in the given metadata.
* It expects that the mbean field and the classloader field are not null
*
* @see #isMBeanCompliant
*/
public void introspect(MBeanMetaData metadata)
{
introspectType(metadata);
introspectMBeanInfo(metadata);
}
/**
* Returns whether the given already introspected metadata is compliant.
* Must be called after {@link #introspect}
*/
public boolean isMBeanCompliant(MBeanMetaData metadata)
{
return isMBeanClassCompliant(metadata) && isMBeanTypeCompliant(metadata) && isMBeanInfoCompliant(metadata);
}
/**
* Used by the test cases, invoked via reflection, keep it private.
* Introspect the mbean and returns if it's compliant
*/
private boolean testCompliance(MBeanMetaData metadata)
{
introspect(metadata);
return isMBeanCompliant(metadata);
}
private boolean isMBeanClassCompliant(MBeanMetaData metadata)
{
// No requirements on the implementation (can be abstract, non public and no accessible constructors)
// but the management interface must be public
Logger logger = getLogger();
if (metadata.getMBeanInterface() != null)
{
boolean isPublic = Modifier.isPublic(metadata.getMBeanInterface().getModifiers());
if (!isPublic && logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean interface is not public");
return isPublic;
}
return true;
}
private boolean isMBeanTypeCompliant(MBeanMetaData metadata)
{
Logger logger = getLogger();
if (metadata.isMBeanStandard() && metadata.isMBeanDynamic())
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean is both standard and dynamic");
return false;
}
if (!metadata.isMBeanStandard() && !metadata.isMBeanDynamic())
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean is not standard nor dynamic");
return false;
}
return true;
}
private boolean isMBeanInfoCompliant(MBeanMetaData metadata)
{
Logger logger = getLogger();
MBeanInfo info = metadata.getMBeanInfo();
if (info == null)
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBeanInfo is null");
return false;
}
if (info.getClassName() == null)
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBeanInfo.getClassName() is null");
return false;
}
return true;
}
private void introspectType(MBeanMetaData metadata)
{
// Some information is already provided (StandardMBean)
if (metadata.isMBeanStandard())
{
introspectStandardMBean(metadata);
return;
}
if (metadata.getMBean() instanceof DynamicMBean)
{
metadata.setMBeanDynamic(true);
return;
}
else
{
metadata.setMBeanDynamic(false);
// Continue and see if it's a plain standard MBean
}
// We have a plain standard MBean, introspect it
introspectStandardMBean(metadata);
}
private void introspectStandardMBean(MBeanMetaData metadata)
{
Class management = metadata.getMBeanInterface();
if (management != null)
{
// Be sure the MBean implements the management interface
if (management.isInstance(metadata.getMBean()))
{
metadata.setMBeanInvoker(createInvoker(metadata));
return;
}
else
{
// Not compliant, reset the values
metadata.setMBeanStandard(false);
metadata.setMBeanInterface(null);
metadata.setMBeanInvoker(null);
return;
}
}
else
{
Class cls = metadata.getMBean().getClass();
for (Class c = cls; c != null; c = c.getSuperclass())
{
Class[] intfs = c.getInterfaces();
for (int i = 0; i < intfs.length; ++i)
{
Class intf = intfs[i];
if (implementsMBean(c.getName(), intf.getName()))
{
// OK, found the MBean interface for this class
metadata.setMBeanStandard(true);
metadata.setMBeanInterface(intf);
metadata.setMBeanInvoker(createInvoker(metadata));
return;
}
}
}
// Management interface not found, it's not compliant, reset the values
metadata.setMBeanStandard(false);
metadata.setMBeanInterface(null);
metadata.setMBeanInvoker(null);
}
}
private void introspectMBeanInfo(MBeanMetaData metadata)
{
if (metadata.isMBeanDynamic())
{
metadata.setMBeanInfo(getDynamicMBeanInfo(metadata));
}
else if (metadata.isMBeanStandard())
{
metadata.setMBeanInfo(createStandardMBeanInfo(metadata));
}
else
{
// Not a valid MBean, reset the MBeanInfo: this will cause an exception later
metadata.setMBeanInfo(null);
}
}
private MBeanInfo getDynamicMBeanInfo(MBeanMetaData metadata)
{
Logger logger = getLogger();
MBeanInfo info = null;
try
{
info = ((DynamicMBean)metadata.getMBean()).getMBeanInfo();
}
catch (Exception x)
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("getMBeanInfo threw: " + x.toString());
}
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Dynamic MBeanInfo is: " + info);
if (info == null)
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBeanInfo cannot be null");
return null;
}
return info;
}
private MBeanInfo createStandardMBeanInfo(MBeanMetaData metadata)
{
synchronized (mbeanInfoCache)
{
MBeanInfo info = (MBeanInfo)mbeanInfoCache.get(metadata.getMBean().getClass());
if (info != null) return info;
}
// This is a non-standard extension: description for standard MBeans
MBeanDescription description = createMBeanDescription(metadata);
MBeanConstructorInfo[] ctors = createMBeanConstructorInfo(metadata, description);
if (ctors == null) return null;
MBeanAttributeInfo[] attrs = createMBeanAttributeInfo(metadata, description);
if (attrs == null) return null;
MBeanOperationInfo[] opers = createMBeanOperationInfo(metadata, description);
if (opers == null) return null;
MBeanNotificationInfo[] notifs = createMBeanNotificationInfo(metadata);
if (notifs == null) return null;
MBeanInfo info = new MBeanInfo(metadata.getMBean().getClass().getName(), description.getMBeanDescription(), attrs, ctors, opers, notifs);
synchronized (mbeanInfoCache)
{
// Overwrite if already present, we've been unlucky
mbeanInfoCache.put(metadata.getMBean().getClass(), info);
}
return info;
}
private MBeanDescription createMBeanDescription(MBeanMetaData metadata)
{
// TODO: PERFORMANCE: looking up the MBeanDescription is a real performance hotspot for MBean registration
// TODO: PERFORMANCE: simply remarking the lookup yields to a 3.5x speedup (from 14 s to 4 s for 20k MBeans)
// TODO: PERFORMANCE: consider using a system property to disable lookup, and/or caching the lookup.
// This is a non-standard extension
Logger logger = getLogger();
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Looking for standard MBean description...");
// Use full qualified name only
String descrClassName = metadata.getMBeanInterface().getName() + "Description";
// Try to load the class
try
{
Class descrClass = null;
ClassLoader loader = metadata.getClassLoader();
if (loader == null) loader = Thread.currentThread().getContextClassLoader();
// Optimize lookup of the description class in case of MLets: we lookup the description class
// only in the classloader of the mbean, not in the whole CLR (since MLets delegates to the CLR)
if (loader.getClass() == MLet.class)
descrClass = ((MLet)loader).loadClass(descrClassName, null);
else
descrClass = loader.loadClass(descrClassName);
Object descrInstance = descrClass.newInstance();
if (descrInstance instanceof MBeanDescription)
{
MBeanDescription description = (MBeanDescription)descrInstance;
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Found provided standard MBean description: " + description);
return description;
}
}
catch (ClassNotFoundException ignored)
{
}
catch (InstantiationException ignored)
{
}
catch (IllegalAccessException ignored)
{
}
MBeanDescription description = DEFAULT_DESCRIPTION;
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Cannot find standard MBean description, using default: " + description);
return description;
}
private MBeanOperationInfo[] createMBeanOperationInfo(MBeanMetaData metadata, MBeanDescription description)
{
ArrayList operations = new ArrayList();
Method[] methods = metadata.getMBeanInterface().getMethods();
for (int j = 0; j < methods.length; ++j)
{
Method method = methods[j];
if (!Utils.isAttributeGetter(method) && !Utils.isAttributeSetter(method))
{
String descr = description == null ? null : description.getOperationDescription(method);
Class[] params = method.getParameterTypes();
int paramsNumber = params.length;
MBeanParameterInfo[] paramsInfo = paramsNumber == 0 ? EMPTY_PARAMETERS : new MBeanParameterInfo[paramsNumber];
for (int k = 0; k < paramsNumber; ++k)
{
Class param = params[k];
String paramName = description == null ? null : description.getOperationParameterName(method, k);
String paramDescr = description == null ? null : description.getOperationParameterDescription(method, k);
paramsInfo[k] = new MBeanParameterInfo(paramName, param.getName(), paramDescr);
}
MBeanOperationInfo info = new MBeanOperationInfo(method.getName(), descr, paramsInfo, method.getReturnType().getName(), MBeanOperationInfo.UNKNOWN);
operations.add(info);
}
}
int opersNumber = operations.size();
return opersNumber == 0 ? EMPTY_OPERATIONS : (MBeanOperationInfo[])operations.toArray(new MBeanOperationInfo[opersNumber]);
}
private MBeanAttributeInfo[] createMBeanAttributeInfo(MBeanMetaData metadata, MBeanDescription description)
{
Logger logger = getLogger();
HashMap attributes = new HashMap();
HashMap getterNames = new HashMap();
Method[] methods = metadata.getMBeanInterface().getMethods();
for (int j = 0; j < methods.length; ++j)
{
Method method = methods[j];
if (Utils.isAttributeGetter(method))
{
String name = method.getName();
boolean isIs = name.startsWith("is");
String attribute = null;
if (isIs)
attribute = name.substring(2);
else
attribute = name.substring(3);
String descr = description == null ? null : description.getAttributeDescription(attribute);
MBeanAttributeInfo info = (MBeanAttributeInfo)attributes.get(attribute);
if (info != null)
{
// JMX spec does not allow overloading attributes.
// If an attribute with the same name already exists the MBean is not compliant
if (!info.getType().equals(method.getReturnType().getName()))
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean is not compliant: has overloaded attribute " + attribute);
return null;
}
else
{
// They return the same value,
if (getterNames.get(name) != null)
{
// This is the case of an attribute being present in multiple interfaces
// Ignore all but the first, since they resolve to the same method anyways
continue;
}
// there is a chance that one is a get-getter and one is a is-getter
// for a boolean attribute. In this case, the MBean is not compliant.
if (info.isReadable())
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean is not compliant: has overloaded attribute " + attribute);
return null;
}
// MBeanAttributeInfo is already present due to a setter method, just update its readability
info = new MBeanAttributeInfo(attribute, info.getType(), info.getDescription(), true, info.isWritable(), isIs);
}
}
else
{
info = new MBeanAttributeInfo(attribute, method.getReturnType().getName(), descr, true, false, isIs);
}
// Replace if exists
attributes.put(attribute, info);
getterNames.put(name, method);
}
else if (Utils.isAttributeSetter(method))
{
String name = method.getName();
String attribute = name.substring(3);
String descr = description == null ? null : description.getAttributeDescription(attribute);
MBeanAttributeInfo info = (MBeanAttributeInfo)attributes.get(attribute);
if (info != null)
{
// JMX spec does not allow overloading attributes.
// If an attribute with the same name already exists the MBean is not compliant
if (!info.getType().equals(method.getParameterTypes()[0].getName()))
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("MBean is not compliant: has overloaded attribute " + attribute);
return null;
}
else
{
// MBeanAttributeInfo is already present due to a getter method, just update its writability
info = new MBeanAttributeInfo(info.getName(), info.getType(), info.getDescription(), info.isReadable(), true, info.isIs());
}
}
else
{
info = new MBeanAttributeInfo(attribute, method.getParameterTypes()[0].getName(), descr, false, true, false);
}
// Replace if exists
attributes.put(attribute, info);
}
}
int size = attributes.size();
return size == 0 ? EMPTY_ATTRIBUTES : (MBeanAttributeInfo[])attributes.values().toArray(new MBeanAttributeInfo[size]);
}
private MBeanNotificationInfo[] createMBeanNotificationInfo(MBeanMetaData metadata)
{
MBeanNotificationInfo[] notifs = null;
Object mbean = metadata.getMBean();
if (mbean instanceof NotificationBroadcaster)
{
notifs = ((NotificationBroadcaster)mbean).getNotificationInfo();
}
if (notifs == null || notifs.length == 0) notifs = EMPTY_NOTIFICATIONS;
return notifs;
}
private MBeanConstructorInfo[] createMBeanConstructorInfo(MBeanMetaData metadata, MBeanDescription descrs)
{
Class mbeanClass = metadata.getMBean().getClass();
Constructor[] ctors = mbeanClass.getConstructors();
int ctorsNumber = ctors.length;
MBeanConstructorInfo[] constructors = ctorsNumber == 0 ? EMPTY_CONSTRUCTORS : new MBeanConstructorInfo[ctorsNumber];
for (int i = 0; i < ctorsNumber; ++i)
{
Constructor constructor = ctors[i];
String descr = descrs == null ? null : descrs.getConstructorDescription(constructor);
Class[] params = constructor.getParameterTypes();
int paramsNumber = params.length;
MBeanParameterInfo[] paramsInfo = paramsNumber == 0 ? EMPTY_PARAMETERS : new MBeanParameterInfo[paramsNumber];
for (int j = 0; j < paramsNumber; ++j)
{
Class param = params[j];
String paramName = descrs == null ? null : descrs.getConstructorParameterName(constructor, j);
String paramDescr = descrs == null ? null : descrs.getConstructorParameterDescription(constructor, j);
paramsInfo[j] = new MBeanParameterInfo(paramName, param.getName(), paramDescr);
}
String ctorName = constructor.getName();
MBeanConstructorInfo info = new MBeanConstructorInfo(ctorName, descr, paramsInfo);
constructors[i] = info;
}
return constructors;
}
private boolean implementsMBean(String clsName, String intfName)
{
if (intfName.equals(clsName + "MBean")) return true;
if (extendedMBeanInterfaces)
{
// Check also that the may be in different packages and/or inner classes
// Trim packages
int clsDot = clsName.lastIndexOf('.');
if (clsDot > 0) clsName = clsName.substring(clsDot + 1);
int intfDot = intfName.lastIndexOf('.');
if (intfDot > 0) intfName = intfName.substring(intfDot + 1);
// Try again
if (intfName.equals(clsName + "MBean")) return true;
// Trim inner classes
int clsDollar = clsName.lastIndexOf('$');
if (clsDollar > 0) clsName = clsName.substring(clsDollar + 1);
int intfDollar = intfName.lastIndexOf('$');
if (intfDollar > 0) intfName = intfName.substring(intfDollar + 1);
// Try again
if (intfName.equals(clsName + "MBean")) return true;
}
// Give up
return false;
}
private MBeanInvoker createInvoker(MBeanMetaData metadata)
{
MBeanInvoker invoker = null;
synchronized (mbeanInvokerCache)
{
invoker = (MBeanInvoker)mbeanInvokerCache.get(metadata.getMBeanInterface());
if (invoker != null) return invoker;
}
Logger logger = getLogger();
if (mbeanInvokerClass != null)
{
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Custom MBeanInvoker class is: " + mbeanInvokerClass);
try
{
invoker = (MBeanInvoker)Thread.currentThread().getContextClassLoader().loadClass(mbeanInvokerClass).newInstance();
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Using custom MBeanInvoker: " + invoker);
}
catch (Exception x)
{
if (logger.isEnabledFor(Logger.DEBUG)) logger.debug("Cannot instantiate custom MBeanInvoker, using default", x);
}
}
if (invoker == null)
{
if (bcelAvailable)
{
invoker = BCELMBeanInvoker.create(metadata);
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Using default BCEL MBeanInvoker for MBean " + metadata.getObjectName() + ", " + invoker);
}
else
{
invoker = new CachingReflectionMBeanInvoker();
if (logger.isEnabledFor(Logger.TRACE)) logger.trace("Using default Reflection MBeanInvoker for MBean " + metadata.getObjectName() + ", " + invoker);
}
}
synchronized (mbeanInvokerCache)
{
// Overwrite if already present: we've been unlucky
mbeanInvokerCache.put(metadata.getMBeanInterface(), invoker);
}
return invoker;
}
private Logger getLogger()
{
return Log.getLogger(getClass().getName());
}
}