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Java example source code file (StandardMBean.java)
This example Java source code file (StandardMBean.java) is included in the alvinalexander.com
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The StandardMBean.java Java example source code
/*
* Copyright (c) 2002, 2008, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.management;
import static com.sun.jmx.defaults.JmxProperties.MISC_LOGGER;
import com.sun.jmx.mbeanserver.DescriptorCache;
import com.sun.jmx.mbeanserver.Introspector;
import com.sun.jmx.mbeanserver.MBeanSupport;
import com.sun.jmx.mbeanserver.MXBeanSupport;
import com.sun.jmx.mbeanserver.StandardMBeanSupport;
import com.sun.jmx.mbeanserver.Util;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.logging.Level;
import javax.management.openmbean.OpenMBeanAttributeInfo;
import javax.management.openmbean.OpenMBeanAttributeInfoSupport;
import javax.management.openmbean.OpenMBeanConstructorInfo;
import javax.management.openmbean.OpenMBeanConstructorInfoSupport;
import javax.management.openmbean.OpenMBeanOperationInfo;
import javax.management.openmbean.OpenMBeanOperationInfoSupport;
import javax.management.openmbean.OpenMBeanParameterInfo;
import javax.management.openmbean.OpenMBeanParameterInfoSupport;
/**
* <p>An MBean whose management interface is determined by reflection
* on a Java interface.</p>
*
* <p>This class brings more flexibility to the notion of Management
* Interface in the use of Standard MBeans. Straightforward use of
* the patterns for Standard MBeans described in the JMX Specification
* means that there is a fixed relationship between the implementation
* class of an MBean and its management interface (i.e., if the
* implementation class is Thing, the management interface must be
* ThingMBean). This class makes it possible to keep the convenience
* of specifying the management interface with a Java interface,
* without requiring that there be any naming relationship between the
* implementation and interface classes.</p>
*
* <p>By making a DynamicMBean out of an MBean, this class makes
* it possible to select any interface implemented by the MBean as its
* management interface, provided that it complies with JMX patterns
* (i.e., attributes defined by getter/setter etc...).</p>
*
* <p> This class also provides hooks that make it possible to supply
* custom descriptions and names for the {@link MBeanInfo} returned by
* the DynamicMBean interface.</p>
*
* <p>Using this class, an MBean can be created with any
* implementation class name <i>Impl and with a management
* interface defined (as for current Standard MBeans) by any interface
* <i>Intf, in one of two general ways:
*
* <ul>
*
* <li>Using the public constructor
* {@link #StandardMBean(java.lang.Object, java.lang.Class, boolean)
* StandardMBean(impl,interface)}:
* <pre>
* MBeanServer mbs;
* ...
* Impl impl = new Impl(...);
* StandardMBean mbean = new StandardMBean(impl, Intf.class, false);
* mbs.registerMBean(mbean, objectName);
* </pre>
*
* <li>Subclassing StandardMBean:
* <pre>
* public class Impl extends StandardMBean implements Intf {
* public Impl() {
* super(Intf.class, false);
* }
* // implement methods of Intf
* }
*
* [...]
*
* MBeanServer mbs;
* ....
* Impl impl = new Impl();
* mbs.registerMBean(impl, objectName);
* </pre>
*
* </ul>
*
* <p>In either case, the class Impl must implement the
* interface <i>Intf.
*
* <p>Standard MBeans based on the naming relationship between
* implementation and interface classes are of course still
* available.</p>
*
* <p>This class may also be used to construct MXBeans. The usage
* is exactly the same as for Standard MBeans except that in the
* examples above, the {@code false} parameter to the constructor or
* {@code super(...)} invocation is instead {@code true}.</p>
*
* @since 1.5
*/
public class StandardMBean implements DynamicMBean, MBeanRegistration {
private final static DescriptorCache descriptors =
DescriptorCache.getInstance(JMX.proof);
/**
* The DynamicMBean that wraps the MXBean or Standard MBean implementation.
**/
private volatile MBeanSupport<?> mbean;
/**
* The cached MBeanInfo.
**/
private volatile MBeanInfo cachedMBeanInfo;
/**
* Make a DynamicMBean out of <var>implementation, using the
* specified <var>mbeanInterface class.
* @param implementation The implementation of this MBean.
* If <code>null, and null implementation is allowed,
* then the implementation is assumed to be <var>this.
* @param mbeanInterface The Management Interface exported by this
* MBean's implementation. If <code>null, then this
* object will use standard JMX design pattern to determine
* the management interface associated with the given
* implementation.
* @param nullImplementationAllowed <code>true if a null
* implementation is allowed. If null implementation is allowed,
* and a null implementation is passed, then the implementation
* is assumed to be <var>this.
* @exception IllegalArgumentException if the given
* <var>implementation is null, and null is not allowed.
**/
private <T> void construct(T implementation, Class mbeanInterface,
boolean nullImplementationAllowed,
boolean isMXBean)
throws NotCompliantMBeanException {
if (implementation == null) {
// Have to use (T)this rather than mbeanInterface.cast(this)
// because mbeanInterface might be null.
if (nullImplementationAllowed)
implementation = Util.<T>cast(this);
else throw new IllegalArgumentException("implementation is null");
}
if (isMXBean) {
if (mbeanInterface == null) {
mbeanInterface = Util.cast(Introspector.getMXBeanInterface(
implementation.getClass()));
}
this.mbean = new MXBeanSupport(implementation, mbeanInterface);
} else {
if (mbeanInterface == null) {
mbeanInterface = Util.cast(Introspector.getStandardMBeanInterface(
implementation.getClass()));
}
this.mbean =
new StandardMBeanSupport(implementation, mbeanInterface);
}
}
/**
* <p>Make a DynamicMBean out of the object
* <var>implementation, using the specified
* <var>mbeanInterface class.
*
* @param implementation The implementation of this MBean.
* @param mbeanInterface The Management Interface exported by this
* MBean's implementation. If <code>null, then this
* object will use standard JMX design pattern to determine
* the management interface associated with the given
* implementation.
* @param <T> Allows the compiler to check
* that {@code implementation} does indeed implement the class
* described by {@code mbeanInterface}. The compiler can only
* check this if {@code mbeanInterface} is a class literal such
* as {@code MyMBean.class}.
*
* @exception IllegalArgumentException if the given
* <var>implementation is null.
* @exception NotCompliantMBeanException if the <var>mbeanInterface
* does not follow JMX design patterns for Management Interfaces, or
* if the given <var>implementation does not implement the
* specified interface.
**/
public <T> StandardMBean(T implementation, Class mbeanInterface)
throws NotCompliantMBeanException {
construct(implementation, mbeanInterface, false, false);
}
/**
* <p>Make a DynamicMBean out of this, using the specified
* <var>mbeanInterface class.
*
* <p>Calls {@link #StandardMBean(java.lang.Object, java.lang.Class)
* this(this,mbeanInterface)}.
* This constructor is reserved to subclasses.</p>
*
* @param mbeanInterface The Management Interface exported by this
* MBean.
*
* @exception NotCompliantMBeanException if the <var>mbeanInterface
* does not follow JMX design patterns for Management Interfaces, or
* if <var>this does not implement the specified interface.
**/
protected StandardMBean(Class<?> mbeanInterface)
throws NotCompliantMBeanException {
construct(null, mbeanInterface, true, false);
}
/**
* <p>Make a DynamicMBean out of the object
* <var>implementation, using the specified
* <var>mbeanInterface class, and choosing whether the
* resultant MBean is an MXBean. This constructor can be used
* to make either Standard MBeans or MXBeans. Unlike the
* constructor {@link #StandardMBean(Object, Class)}, it
* does not throw NotCompliantMBeanException.</p>
*
* @param implementation The implementation of this MBean.
* @param mbeanInterface The Management Interface exported by this
* MBean's implementation. If <code>null, then this
* object will use standard JMX design pattern to determine
* the management interface associated with the given
* implementation.
* @param isMXBean If true, the {@code mbeanInterface} parameter
* names an MXBean interface and the resultant MBean is an MXBean.
* @param <T> Allows the compiler to check
* that {@code implementation} does indeed implement the class
* described by {@code mbeanInterface}. The compiler can only
* check this if {@code mbeanInterface} is a class literal such
* as {@code MyMBean.class}.
*
* @exception IllegalArgumentException if the given
* <var>implementation is null, or if the mbeanInterface
* does not follow JMX design patterns for Management Interfaces, or
* if the given <var>implementation does not implement the
* specified interface.
*
* @since 1.6
**/
public <T> StandardMBean(T implementation, Class mbeanInterface,
boolean isMXBean) {
try {
construct(implementation, mbeanInterface, false, isMXBean);
} catch (NotCompliantMBeanException e) {
throw new IllegalArgumentException(e);
}
}
/**
* <p>Make a DynamicMBean out of this, using the specified
* <var>mbeanInterface class, and choosing whether the resulting
* MBean is an MXBean. This constructor can be used
* to make either Standard MBeans or MXBeans. Unlike the
* constructor {@link #StandardMBean(Object, Class)}, it
* does not throw NotCompliantMBeanException.</p>
*
* <p>Calls {@link #StandardMBean(java.lang.Object, java.lang.Class, boolean)
* this(this, mbeanInterface, isMXBean)}.
* This constructor is reserved to subclasses.</p>
*
* @param mbeanInterface The Management Interface exported by this
* MBean.
* @param isMXBean If true, the {@code mbeanInterface} parameter
* names an MXBean interface and the resultant MBean is an MXBean.
*
* @exception IllegalArgumentException if the <var>mbeanInterface
* does not follow JMX design patterns for Management Interfaces, or
* if <var>this does not implement the specified interface.
*
* @since 1.6
**/
protected StandardMBean(Class<?> mbeanInterface, boolean isMXBean) {
try {
construct(null, mbeanInterface, true, isMXBean);
} catch (NotCompliantMBeanException e) {
throw new IllegalArgumentException(e);
}
}
/**
* <p>Replace the implementation object wrapped in this object.
*
* @param implementation The new implementation of this Standard MBean
* (or MXBean). The <code>implementation object must implement
* the Standard MBean (or MXBean) interface that was supplied when this
* <code>StandardMBean was constructed.
*
* @exception IllegalArgumentException if the given
* <var>implementation is null.
*
* @exception NotCompliantMBeanException if the given
* <var>implementation does not implement the
* Standard MBean (or MXBean) interface that was
* supplied at construction.
*
* @see #getImplementation
**/
public void setImplementation(Object implementation)
throws NotCompliantMBeanException {
if (implementation == null)
throw new IllegalArgumentException("implementation is null");
if (isMXBean()) {
this.mbean = new MXBeanSupport(implementation,
Util.<Classcast(getMBeanInterface()));
} else {
this.mbean = new StandardMBeanSupport(implementation,
Util.<Classcast(getMBeanInterface()));
}
}
/**
* Get the implementation of this Standard MBean (or MXBean).
* @return The implementation of this Standard MBean (or MXBean).
*
* @see #setImplementation
**/
public Object getImplementation() {
return mbean.getResource();
}
/**
* Get the Management Interface of this Standard MBean (or MXBean).
* @return The management interface of this Standard MBean (or MXBean).
**/
public final Class<?> getMBeanInterface() {
return mbean.getMBeanInterface();
}
/**
* Get the class of the implementation of this Standard MBean (or MXBean).
* @return The class of the implementation of this Standard MBean (or MXBean).
**/
public Class<?> getImplementationClass() {
return mbean.getResource().getClass();
}
// ------------------------------------------------------------------
// From the DynamicMBean interface.
// ------------------------------------------------------------------
public Object getAttribute(String attribute)
throws AttributeNotFoundException,
MBeanException,
ReflectionException {
return mbean.getAttribute(attribute);
}
// ------------------------------------------------------------------
// From the DynamicMBean interface.
// ------------------------------------------------------------------
public void setAttribute(Attribute attribute)
throws AttributeNotFoundException,
InvalidAttributeValueException,
MBeanException,
ReflectionException {
mbean.setAttribute(attribute);
}
// ------------------------------------------------------------------
// From the DynamicMBean interface.
// ------------------------------------------------------------------
public AttributeList getAttributes(String[] attributes) {
return mbean.getAttributes(attributes);
}
// ------------------------------------------------------------------
// From the DynamicMBean interface.
// ------------------------------------------------------------------
public AttributeList setAttributes(AttributeList attributes) {
return mbean.setAttributes(attributes);
}
// ------------------------------------------------------------------
// From the DynamicMBean interface.
// ------------------------------------------------------------------
public Object invoke(String actionName, Object params[], String signature[])
throws MBeanException, ReflectionException {
return mbean.invoke(actionName, params, signature);
}
/**
* Get the {@link MBeanInfo} for this MBean.
* <p>
* This method implements
* {@link javax.management.DynamicMBean#getMBeanInfo()
* DynamicMBean.getMBeanInfo()}.
* <p>
* This method first calls {@link #getCachedMBeanInfo()} in order to
* retrieve the cached MBeanInfo for this MBean, if any. If the
* MBeanInfo returned by {@link #getCachedMBeanInfo()} is not null,
* then it is returned.<br>
* Otherwise, this method builds a default MBeanInfo for this MBean,
* using the Management Interface specified for this MBean.
* <p>
* While building the MBeanInfo, this method calls the customization
* hooks that make it possible for subclasses to supply their custom
* descriptions, parameter names, etc...<br>
* Finally, it calls {@link #cacheMBeanInfo(javax.management.MBeanInfo)
* cacheMBeanInfo()} in order to cache the new MBeanInfo.
* @return The cached MBeanInfo for that MBean, if not null, or a
* newly built MBeanInfo if none was cached.
**/
public MBeanInfo getMBeanInfo() {
try {
final MBeanInfo cached = getCachedMBeanInfo();
if (cached != null) return cached;
} catch (RuntimeException x) {
if (MISC_LOGGER.isLoggable(Level.FINEST)) {
MISC_LOGGER.logp(Level.FINEST,
MBeanServerFactory.class.getName(), "getMBeanInfo",
"Failed to get cached MBeanInfo", x);
}
}
if (MISC_LOGGER.isLoggable(Level.FINER)) {
MISC_LOGGER.logp(Level.FINER,
MBeanServerFactory.class.getName(), "getMBeanInfo",
"Building MBeanInfo for " +
getImplementationClass().getName());
}
MBeanSupport<?> msupport = mbean;
final MBeanInfo bi = msupport.getMBeanInfo();
final Object impl = msupport.getResource();
final boolean immutableInfo = immutableInfo(this.getClass());
final String cname = getClassName(bi);
final String text = getDescription(bi);
final MBeanConstructorInfo[] ctors = getConstructors(bi,impl);
final MBeanAttributeInfo[] attrs = getAttributes(bi);
final MBeanOperationInfo[] ops = getOperations(bi);
final MBeanNotificationInfo[] ntfs = getNotifications(bi);
final Descriptor desc = getDescriptor(bi, immutableInfo);
final MBeanInfo nmbi = new MBeanInfo(
cname, text, attrs, ctors, ops, ntfs, desc);
try {
cacheMBeanInfo(nmbi);
} catch (RuntimeException x) {
if (MISC_LOGGER.isLoggable(Level.FINEST)) {
MISC_LOGGER.logp(Level.FINEST,
MBeanServerFactory.class.getName(), "getMBeanInfo",
"Failed to cache MBeanInfo", x);
}
}
return nmbi;
}
/**
* Customization hook:
* Get the className that will be used in the MBeanInfo returned by
* this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom class name. The default implementation returns
* {@link MBeanInfo#getClassName() info.getClassName()}.
* @param info The default MBeanInfo derived by reflection.
* @return the class name for the new MBeanInfo.
**/
protected String getClassName(MBeanInfo info) {
if (info == null) return getImplementationClass().getName();
return info.getClassName();
}
/**
* Customization hook:
* Get the description that will be used in the MBeanInfo returned by
* this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom MBean description. The default implementation returns
* {@link MBeanInfo#getDescription() info.getDescription()}.
* @param info The default MBeanInfo derived by reflection.
* @return the description for the new MBeanInfo.
**/
protected String getDescription(MBeanInfo info) {
if (info == null) return null;
return info.getDescription();
}
/**
* <p>Customization hook:
* Get the description that will be used in the MBeanFeatureInfo
* returned by this MBean.</p>
*
* <p>Subclasses may redefine this method in order to supply
* their custom description. The default implementation returns
* {@link MBeanFeatureInfo#getDescription()
* info.getDescription()}.</p>
*
* <p>This method is called by
* {@link #getDescription(MBeanAttributeInfo)},
* {@link #getDescription(MBeanOperationInfo)},
* {@link #getDescription(MBeanConstructorInfo)}.</p>
*
* @param info The default MBeanFeatureInfo derived by reflection.
* @return the description for the given MBeanFeatureInfo.
**/
protected String getDescription(MBeanFeatureInfo info) {
if (info == null) return null;
return info.getDescription();
}
/**
* Customization hook:
* Get the description that will be used in the MBeanAttributeInfo
* returned by this MBean.
*
* <p>Subclasses may redefine this method in order to supply their
* custom description. The default implementation returns {@link
* #getDescription(MBeanFeatureInfo)
* getDescription((MBeanFeatureInfo) info)}.
* @param info The default MBeanAttributeInfo derived by reflection.
* @return the description for the given MBeanAttributeInfo.
**/
protected String getDescription(MBeanAttributeInfo info) {
return getDescription((MBeanFeatureInfo)info);
}
/**
* Customization hook:
* Get the description that will be used in the MBeanConstructorInfo
* returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom description.
* The default implementation returns {@link
* #getDescription(MBeanFeatureInfo)
* getDescription((MBeanFeatureInfo) info)}.
* @param info The default MBeanConstructorInfo derived by reflection.
* @return the description for the given MBeanConstructorInfo.
**/
protected String getDescription(MBeanConstructorInfo info) {
return getDescription((MBeanFeatureInfo)info);
}
/**
* Customization hook:
* Get the description that will be used for the <var>sequence
* MBeanParameterInfo of the MBeanConstructorInfo returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom description. The default implementation returns
* {@link MBeanParameterInfo#getDescription() param.getDescription()}.
*
* @param ctor The default MBeanConstructorInfo derived by reflection.
* @param param The default MBeanParameterInfo derived by reflection.
* @param sequence The sequence number of the parameter considered
* ("0" for the first parameter, "1" for the second parameter,
* etc...).
* @return the description for the given MBeanParameterInfo.
**/
protected String getDescription(MBeanConstructorInfo ctor,
MBeanParameterInfo param,
int sequence) {
if (param == null) return null;
return param.getDescription();
}
/**
* Customization hook:
* Get the name that will be used for the <var>sequence
* MBeanParameterInfo of the MBeanConstructorInfo returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom parameter name. The default implementation returns
* {@link MBeanParameterInfo#getName() param.getName()}.
*
* @param ctor The default MBeanConstructorInfo derived by reflection.
* @param param The default MBeanParameterInfo derived by reflection.
* @param sequence The sequence number of the parameter considered
* ("0" for the first parameter, "1" for the second parameter,
* etc...).
* @return the name for the given MBeanParameterInfo.
**/
protected String getParameterName(MBeanConstructorInfo ctor,
MBeanParameterInfo param,
int sequence) {
if (param == null) return null;
return param.getName();
}
/**
* Customization hook:
* Get the description that will be used in the MBeanOperationInfo
* returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom description. The default implementation returns
* {@link #getDescription(MBeanFeatureInfo)
* getDescription((MBeanFeatureInfo) info)}.
* @param info The default MBeanOperationInfo derived by reflection.
* @return the description for the given MBeanOperationInfo.
**/
protected String getDescription(MBeanOperationInfo info) {
return getDescription((MBeanFeatureInfo)info);
}
/**
* Customization hook:
* Get the <var>impact flag of the operation that will be used in
* the MBeanOperationInfo returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom impact flag. The default implementation returns
* {@link MBeanOperationInfo#getImpact() info.getImpact()}.
* @param info The default MBeanOperationInfo derived by reflection.
* @return the impact flag for the given MBeanOperationInfo.
**/
protected int getImpact(MBeanOperationInfo info) {
if (info == null) return MBeanOperationInfo.UNKNOWN;
return info.getImpact();
}
/**
* Customization hook:
* Get the name that will be used for the <var>sequence
* MBeanParameterInfo of the MBeanOperationInfo returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom parameter name. The default implementation returns
* {@link MBeanParameterInfo#getName() param.getName()}.
*
* @param op The default MBeanOperationInfo derived by reflection.
* @param param The default MBeanParameterInfo derived by reflection.
* @param sequence The sequence number of the parameter considered
* ("0" for the first parameter, "1" for the second parameter,
* etc...).
* @return the name to use for the given MBeanParameterInfo.
**/
protected String getParameterName(MBeanOperationInfo op,
MBeanParameterInfo param,
int sequence) {
if (param == null) return null;
return param.getName();
}
/**
* Customization hook:
* Get the description that will be used for the <var>sequence
* MBeanParameterInfo of the MBeanOperationInfo returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom description. The default implementation returns
* {@link MBeanParameterInfo#getDescription() param.getDescription()}.
*
* @param op The default MBeanOperationInfo derived by reflection.
* @param param The default MBeanParameterInfo derived by reflection.
* @param sequence The sequence number of the parameter considered
* ("0" for the first parameter, "1" for the second parameter,
* etc...).
* @return the description for the given MBeanParameterInfo.
**/
protected String getDescription(MBeanOperationInfo op,
MBeanParameterInfo param,
int sequence) {
if (param == null) return null;
return param.getDescription();
}
/**
* Customization hook:
* Get the MBeanConstructorInfo[] that will be used in the MBeanInfo
* returned by this MBean.
* <br>
* By default, this method returns <code>null if the wrapped
* implementation is not <var>this. Indeed, if the wrapped
* implementation is not this object itself, it will not be possible
* to recreate a wrapped implementation by calling the implementation
* constructors through <code>MBeanServer.createMBean(...).
* Otherwise, if the wrapped implementation is <var>this,
* <var>ctors is returned.
* <br>
* Subclasses may redefine this method in order to modify this
* behavior, if needed.
* @param ctors The default MBeanConstructorInfo[] derived by reflection.
* @param impl The wrapped implementation. If <code>null is
* passed, the wrapped implementation is ignored and
* <var>ctors is returned.
* @return the MBeanConstructorInfo[] for the new MBeanInfo.
**/
protected MBeanConstructorInfo[]
getConstructors(MBeanConstructorInfo[] ctors, Object impl) {
if (ctors == null) return null;
if (impl != null && impl != this) return null;
return ctors;
}
/**
* Customization hook:
* Get the MBeanNotificationInfo[] that will be used in the MBeanInfo
* returned by this MBean.
* <br>
* Subclasses may redefine this method in order to supply their
* custom notifications.
* @param info The default MBeanInfo derived by reflection.
* @return the MBeanNotificationInfo[] for the new MBeanInfo.
**/
MBeanNotificationInfo[] getNotifications(MBeanInfo info) {
return null;
}
/**
* <p>Get the Descriptor that will be used in the MBeanInfo
* returned by this MBean.</p>
*
* <p>Subclasses may redefine this method in order to supply
* their custom descriptor.</p>
*
* <p>The default implementation of this method returns a Descriptor
* that contains at least the field {@code interfaceClassName}, with
* value {@link #getMBeanInterface()}.getName(). It may also contain
* the field {@code immutableInfo}, with a value that is the string
* {@code "true"} if the implementation can determine that the
* {@code MBeanInfo} returned by {@link #getMBeanInfo()} will always
* be the same. It may contain other fields: fields defined by the
* JMX specification must have appropriate values, and other fields
* must follow the conventions for non-standard field names.</p>
*
* @param info The default MBeanInfo derived by reflection.
* @return the Descriptor for the new MBeanInfo.
*/
Descriptor getDescriptor(MBeanInfo info, boolean immutableInfo) {
ImmutableDescriptor desc;
if (info == null ||
info.getDescriptor() == null ||
info.getDescriptor().getFieldNames().length == 0) {
final String interfaceClassNameS =
"interfaceClassName=" + getMBeanInterface().getName();
final String immutableInfoS =
"immutableInfo=" + immutableInfo;
desc = new ImmutableDescriptor(interfaceClassNameS, immutableInfoS);
desc = descriptors.get(desc);
} else {
Descriptor d = info.getDescriptor();
Map<String,Object> fields = new HashMap();
for (String fieldName : d.getFieldNames()) {
if (fieldName.equals("immutableInfo")) {
// Replace immutableInfo as the underlying MBean/MXBean
// could already implement NotificationBroadcaster and
// return immutableInfo=true in its MBeanInfo.
fields.put(fieldName, Boolean.toString(immutableInfo));
} else {
fields.put(fieldName, d.getFieldValue(fieldName));
}
}
desc = new ImmutableDescriptor(fields);
}
return desc;
}
/**
* Customization hook:
* Return the MBeanInfo cached for this object.
*
* <p>Subclasses may redefine this method in order to implement their
* own caching policy. The default implementation stores one
* {@link MBeanInfo} object per instance.
*
* @return The cached MBeanInfo, or null if no MBeanInfo is cached.
*
* @see #cacheMBeanInfo(MBeanInfo)
**/
protected MBeanInfo getCachedMBeanInfo() {
return cachedMBeanInfo;
}
/**
* Customization hook:
* cache the MBeanInfo built for this object.
*
* <p>Subclasses may redefine this method in order to implement
* their own caching policy. The default implementation stores
* <code>info in this instance. A subclass can define
* other policies, such as not saving <code>info (so it is
* reconstructed every time {@link #getMBeanInfo()} is called) or
* sharing a unique {@link MBeanInfo} object when several
* <code>StandardMBean instances have equal {@link
* MBeanInfo} values.
*
* @param info the new <code>MBeanInfo to cache. Any
* previously cached value is discarded. This parameter may be
* null, in which case there is no new cached value.
**/
protected void cacheMBeanInfo(MBeanInfo info) {
cachedMBeanInfo = info;
}
private boolean isMXBean() {
return mbean.isMXBean();
}
private static <T> boolean identicalArrays(T[] a, T[] b) {
if (a == b)
return true;
if (a == null || b == null || a.length != b.length)
return false;
for (int i = 0; i < a.length; i++) {
if (a[i] != b[i])
return false;
}
return true;
}
private static <T> boolean equal(T a, T b) {
if (a == b)
return true;
if (a == null || b == null)
return false;
return a.equals(b);
}
private static MBeanParameterInfo
customize(MBeanParameterInfo pi,
String name,
String description) {
if (equal(name, pi.getName()) &&
equal(description, pi.getDescription()))
return pi;
else if (pi instanceof OpenMBeanParameterInfo) {
OpenMBeanParameterInfo opi = (OpenMBeanParameterInfo) pi;
return new OpenMBeanParameterInfoSupport(name,
description,
opi.getOpenType(),
pi.getDescriptor());
} else {
return new MBeanParameterInfo(name,
pi.getType(),
description,
pi.getDescriptor());
}
}
private static MBeanConstructorInfo
customize(MBeanConstructorInfo ci,
String description,
MBeanParameterInfo[] signature) {
if (equal(description, ci.getDescription()) &&
identicalArrays(signature, ci.getSignature()))
return ci;
if (ci instanceof OpenMBeanConstructorInfo) {
OpenMBeanParameterInfo[] oparams =
paramsToOpenParams(signature);
return new OpenMBeanConstructorInfoSupport(ci.getName(),
description,
oparams,
ci.getDescriptor());
} else {
return new MBeanConstructorInfo(ci.getName(),
description,
signature,
ci.getDescriptor());
}
}
private static MBeanOperationInfo
customize(MBeanOperationInfo oi,
String description,
MBeanParameterInfo[] signature,
int impact) {
if (equal(description, oi.getDescription()) &&
identicalArrays(signature, oi.getSignature()) &&
impact == oi.getImpact())
return oi;
if (oi instanceof OpenMBeanOperationInfo) {
OpenMBeanOperationInfo ooi = (OpenMBeanOperationInfo) oi;
OpenMBeanParameterInfo[] oparams =
paramsToOpenParams(signature);
return new OpenMBeanOperationInfoSupport(oi.getName(),
description,
oparams,
ooi.getReturnOpenType(),
impact,
oi.getDescriptor());
} else {
return new MBeanOperationInfo(oi.getName(),
description,
signature,
oi.getReturnType(),
impact,
oi.getDescriptor());
}
}
private static MBeanAttributeInfo
customize(MBeanAttributeInfo ai,
String description) {
if (equal(description, ai.getDescription()))
return ai;
if (ai instanceof OpenMBeanAttributeInfo) {
OpenMBeanAttributeInfo oai = (OpenMBeanAttributeInfo) ai;
return new OpenMBeanAttributeInfoSupport(ai.getName(),
description,
oai.getOpenType(),
ai.isReadable(),
ai.isWritable(),
ai.isIs(),
ai.getDescriptor());
} else {
return new MBeanAttributeInfo(ai.getName(),
ai.getType(),
description,
ai.isReadable(),
ai.isWritable(),
ai.isIs(),
ai.getDescriptor());
}
}
private static OpenMBeanParameterInfo[]
paramsToOpenParams(MBeanParameterInfo[] params) {
if (params instanceof OpenMBeanParameterInfo[])
return (OpenMBeanParameterInfo[]) params;
OpenMBeanParameterInfo[] oparams =
new OpenMBeanParameterInfoSupport[params.length];
System.arraycopy(params, 0, oparams, 0, params.length);
return oparams;
}
// ------------------------------------------------------------------
// Build the custom MBeanConstructorInfo[]
// ------------------------------------------------------------------
private MBeanConstructorInfo[]
getConstructors(MBeanInfo info, Object impl) {
final MBeanConstructorInfo[] ctors =
getConstructors(info.getConstructors(), impl);
if (ctors == null)
return null;
final int ctorlen = ctors.length;
final MBeanConstructorInfo[] nctors = new MBeanConstructorInfo[ctorlen];
for (int i=0; i<ctorlen; i++) {
final MBeanConstructorInfo c = ctors[i];
final MBeanParameterInfo[] params = c.getSignature();
final MBeanParameterInfo[] nps;
if (params != null) {
final int plen = params.length;
nps = new MBeanParameterInfo[plen];
for (int ii=0;ii<plen;ii++) {
MBeanParameterInfo p = params[ii];
nps[ii] = customize(p,
getParameterName(c,p,ii),
getDescription(c,p,ii));
}
} else {
nps = null;
}
nctors[i] =
customize(c, getDescription(c), nps);
}
return nctors;
}
// ------------------------------------------------------------------
// Build the custom MBeanOperationInfo[]
// ------------------------------------------------------------------
private MBeanOperationInfo[] getOperations(MBeanInfo info) {
final MBeanOperationInfo[] ops = info.getOperations();
if (ops == null)
return null;
final int oplen = ops.length;
final MBeanOperationInfo[] nops = new MBeanOperationInfo[oplen];
for (int i=0; i<oplen; i++) {
final MBeanOperationInfo o = ops[i];
final MBeanParameterInfo[] params = o.getSignature();
final MBeanParameterInfo[] nps;
if (params != null) {
final int plen = params.length;
nps = new MBeanParameterInfo[plen];
for (int ii=0;ii<plen;ii++) {
MBeanParameterInfo p = params[ii];
nps[ii] = customize(p,
getParameterName(o,p,ii),
getDescription(o,p,ii));
}
} else {
nps = null;
}
nops[i] = customize(o, getDescription(o), nps, getImpact(o));
}
return nops;
}
// ------------------------------------------------------------------
// Build the custom MBeanAttributeInfo[]
// ------------------------------------------------------------------
private MBeanAttributeInfo[] getAttributes(MBeanInfo info) {
final MBeanAttributeInfo[] atts = info.getAttributes();
if (atts == null)
return null; // should not happen
final MBeanAttributeInfo[] natts;
final int attlen = atts.length;
natts = new MBeanAttributeInfo[attlen];
for (int i=0; i<attlen; i++) {
final MBeanAttributeInfo a = atts[i];
natts[i] = customize(a, getDescription(a));
}
return natts;
}
/**
* <p>Allows the MBean to perform any operations it needs before
* being registered in the MBean server. If the name of the MBean
* is not specified, the MBean can provide a name for its
* registration. If any exception is raised, the MBean will not be
* registered in the MBean server.</p>
*
* <p>The default implementation of this method returns the {@code name}
* parameter. It does nothing else for
* Standard MBeans. For MXBeans, it records the {@code MBeanServer}
* and {@code ObjectName} parameters so they can be used to translate
* inter-MXBean references.</p>
*
* <p>It is good practice for a subclass that overrides this method
* to call the overridden method via {@code super.preRegister(...)}.
* This is necessary if this object is an MXBean that is referenced
* by attributes or operations in other MXBeans.</p>
*
* @param server The MBean server in which the MBean will be registered.
*
* @param name The object name of the MBean. This name is null if
* the name parameter to one of the <code>createMBean or
* <code>registerMBean methods in the {@link MBeanServer}
* interface is null. In that case, this method must return a
* non-null ObjectName for the new MBean.
*
* @return The name under which the MBean is to be registered.
* This value must not be null. If the <code>name
* parameter is not null, it will usually but not necessarily be
* the returned value.
*
* @throws IllegalArgumentException if this is an MXBean and
* {@code name} is null.
*
* @throws InstanceAlreadyExistsException if this is an MXBean and
* it has already been registered under another name (in this
* MBean Server or another).
*
* @throws Exception no other checked exceptions are thrown by
* this method but {@code Exception} is declared so that subclasses
* can override the method and throw their own exceptions.
*
* @since 1.6
*/
public ObjectName preRegister(MBeanServer server, ObjectName name)
throws Exception {
mbean.register(server, name);
return name;
}
/**
* <p>Allows the MBean to perform any operations needed after having been
* registered in the MBean server or after the registration has failed.</p>
*
* <p>The default implementation of this method does nothing for
* Standard MBeans. For MXBeans, it undoes any work done by
* {@link #preRegister preRegister} if registration fails.</p>
*
* <p>It is good practice for a subclass that overrides this method
* to call the overridden method via {@code super.postRegister(...)}.
* This is necessary if this object is an MXBean that is referenced
* by attributes or operations in other MXBeans.</p>
*
* @param registrationDone Indicates whether or not the MBean has
* been successfully registered in the MBean server. The value
* false means that the registration phase has failed.
*
* @since 1.6
*/
public void postRegister(Boolean registrationDone) {
if (!registrationDone)
mbean.unregister();
}
/**
* <p>Allows the MBean to perform any operations it needs before
* being unregistered by the MBean server.</p>
*
* <p>The default implementation of this method does nothing.
*
* <p>It is good practice for a subclass that overrides this method
* to call the overridden method via {@code super.preDeregister(...)}.</p>
*
* @throws Exception no checked exceptions are throw by this method
* but {@code Exception} is declared so that subclasses can override
* this method and throw their own exceptions.
*
* @since 1.6
*/
public void preDeregister() throws Exception {
}
/**
* <p>Allows the MBean to perform any operations needed after having been
* unregistered in the MBean server.</p>
*
* <p>The default implementation of this method does nothing for
* Standard MBeans. For MXBeans, it removes any information that
* was recorded by the {@link #preRegister preRegister} method.</p>
*
* <p>It is good practice for a subclass that overrides this method
* to call the overridden method via {@code super.postRegister(...)}.
* This is necessary if this object is an MXBean that is referenced
* by attributes or operations in other MXBeans.</p>
*
* @since 1.6
*/
public void postDeregister() {
mbean.unregister();
}
//
// MBeanInfo immutability
//
/**
* Cached results of previous calls to immutableInfo. This is
* a WeakHashMap so that we don't prevent a class from being
* garbage collected just because we know whether its MBeanInfo
* is immutable.
*/
private static final Map<Class mbeanInfoSafeMap =
new WeakHashMap<Class();
/**
* Return true if {@code subclass} is known to preserve the immutability
* of the {@code MBeanInfo}. The {@code subclass} is considered to have
* an immutable {@code MBeanInfo} if it does not override any of the
* getMBeanInfo, getCachedMBeanInfo, cacheMBeanInfo and getNotificationInfo
* methods.
*/
static boolean immutableInfo(Class<? extends StandardMBean> subclass) {
if (subclass == StandardMBean.class ||
subclass == StandardEmitterMBean.class)
return true;
synchronized (mbeanInfoSafeMap) {
Boolean safe = mbeanInfoSafeMap.get(subclass);
if (safe == null) {
try {
MBeanInfoSafeAction action =
new MBeanInfoSafeAction(subclass);
safe = AccessController.doPrivileged(action);
} catch (Exception e) { // e.g. SecurityException
/* We don't know, so we assume it isn't. */
safe = false;
}
mbeanInfoSafeMap.put(subclass, safe);
}
return safe;
}
}
static boolean overrides(Class<?> subclass, Class superclass,
String name, Class<?>... params) {
for (Class<?> c = subclass; c != superclass; c = c.getSuperclass()) {
try {
c.getDeclaredMethod(name, params);
return true;
} catch (NoSuchMethodException e) {
// OK: this class doesn't override it
}
}
return false;
}
private static class MBeanInfoSafeAction
implements PrivilegedAction<Boolean> {
private final Class<?> subclass;
MBeanInfoSafeAction(Class<?> subclass) {
this.subclass = subclass;
}
public Boolean run() {
// Check for "void cacheMBeanInfo(MBeanInfo)" method.
//
if (overrides(subclass, StandardMBean.class,
"cacheMBeanInfo", MBeanInfo.class))
return false;
// Check for "MBeanInfo getCachedMBeanInfo()" method.
//
if (overrides(subclass, StandardMBean.class,
"getCachedMBeanInfo", (Class<?>[]) null))
return false;
// Check for "MBeanInfo getMBeanInfo()" method.
//
if (overrides(subclass, StandardMBean.class,
"getMBeanInfo", (Class<?>[]) null))
return false;
// Check for "MBeanNotificationInfo[] getNotificationInfo()"
// method.
//
// This method is taken into account for the MBeanInfo
// immutability checks if and only if the given subclass is
// StandardEmitterMBean itself or can be assigned to
// StandardEmitterMBean.
//
if (StandardEmitterMBean.class.isAssignableFrom(subclass))
if (overrides(subclass, StandardEmitterMBean.class,
"getNotificationInfo", (Class<?>[]) null))
return false;
return true;
}
}
}
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