javax.management

Class StandardMBean

Contents
  • All Implemented Interfaces:
    DynamicMBean, MBeanRegistration
    Direct Known Subclasses:
    StandardEmitterMBean

    public class StandardMBean
extends Object
implements DynamicMBean, MBeanRegistration

    An MBean whose management interface is determined by reflection on a Java interface.

    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.

    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...).

    This class also provides hooks that make it possible to supply custom descriptions and names for the MBeanInfo returned by the DynamicMBean interface.

    Using this class, an MBean can be created with any implementation class name Impl and with a management interface defined (as for current Standard MBeans) by any interface Intf, in one of two general ways:

    • Using the public constructor StandardMBean(impl,interface): 
           MBeanServer mbs;
     ...
     Impl impl = new Impl(...);
     StandardMBean mbean = new StandardMBean(impl, Intf.class, false);
     mbs.registerMBean(mbean, objectName);
    • Subclassing StandardMBean: 
           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);

    In either case, the class Impl must implement the interface Intf.

    Standard MBeans based on the naming relationship between implementation and interface classes are of course still available.

    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 false parameter to the constructor or super(...) invocation is instead true.

    Since:
    1.5

    • Constructor Detail

      • StandardMBean

        public StandardMBean(T implementation,
             Class<T> mbeanInterface)
              throws NotCompliantMBeanException

        Make a DynamicMBean out of the object implementation, using the specified mbeanInterface class.

        Type Parameters:
        T - Allows the compiler to check that implementation does indeed implement the class described by mbeanInterface. The compiler can only check this if mbeanInterface is a class literal such as MyMBean.class.
        Parameters:
        implementation - The implementation of this MBean.
        mbeanInterface - The Management Interface exported by this MBean's implementation. If null, then this object will use standard JMX design pattern to determine the management interface associated with the given implementation.
        Throws:
        IllegalArgumentException - if the given implementation is null.
        NotCompliantMBeanException - if the mbeanInterface does not follow JMX design patterns for Management Interfaces, or if the given implementation does not implement the specified interface.

      • StandardMBean

        protected StandardMBean(Class<?> mbeanInterface)
                 throws NotCompliantMBeanException

        Make a DynamicMBean out of this, using the specified mbeanInterface class.

        Calls this(this,mbeanInterface). This constructor is reserved to subclasses.

        Parameters:
        mbeanInterface - The Management Interface exported by this MBean.
        Throws:
        NotCompliantMBeanException - if the mbeanInterface does not follow JMX design patterns for Management Interfaces, or if this does not implement the specified interface.

      • StandardMBean

        public StandardMBean(T implementation,
             Class<T> mbeanInterface,
             boolean isMXBean)

        Make a DynamicMBean out of the object implementation, using the specified 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 StandardMBean(Object, Class), it does not throw NotCompliantMBeanException.

        Type Parameters:
        T - Allows the compiler to check that implementation does indeed implement the class described by mbeanInterface. The compiler can only check this if mbeanInterface is a class literal such as MyMBean.class.
        Parameters:
        implementation - The implementation of this MBean.
        mbeanInterface - The Management Interface exported by this MBean's implementation. If null, then this object will use standard JMX design pattern to determine the management interface associated with the given implementation.
        isMXBean - If true, the mbeanInterface parameter names an MXBean interface and the resultant MBean is an MXBean.
        Throws:
        IllegalArgumentException - if the given implementation is null, or if the mbeanInterface does not follow JMX design patterns for Management Interfaces, or if the given implementation does not implement the specified interface.
        Since:
        1.6

      • StandardMBean

        protected StandardMBean(Class<?> mbeanInterface,
             boolean isMXBean)

        Make a DynamicMBean out of this, using the specified 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 StandardMBean(Object, Class), it does not throw NotCompliantMBeanException.

        Calls this(this, mbeanInterface, isMXBean). This constructor is reserved to subclasses.

        Parameters:
        mbeanInterface - The Management Interface exported by this MBean.
        isMXBean - If true, the mbeanInterface parameter names an MXBean interface and the resultant MBean is an MXBean.
        Throws:
        IllegalArgumentException - if the mbeanInterface does not follow JMX design patterns for Management Interfaces, or if this does not implement the specified interface.
        Since:
        1.6

    • Method Detail

      • setImplementation

        public void setImplementation(Object implementation)
                       throws NotCompliantMBeanException

        Replace the implementation object wrapped in this object.

        Parameters:
        implementation - The new implementation of this Standard MBean (or MXBean). The implementation object must implement the Standard MBean (or MXBean) interface that was supplied when this StandardMBean was constructed.
        Throws:
        IllegalArgumentException - if the given implementation is null.
        NotCompliantMBeanException - if the given implementation does not implement the Standard MBean (or MXBean) interface that was supplied at construction.
        See Also:
        getImplementation()

      • getImplementation

        public Object getImplementation()
        Get the implementation of this Standard MBean (or MXBean).
        Returns:
        The implementation of this Standard MBean (or MXBean).
        See Also:
        setImplementation(java.lang.Object)

      • getMBeanInterface

        public final Class<?> getMBeanInterface()
        Get the Management Interface of this Standard MBean (or MXBean).
        Returns:
        The management interface of this Standard MBean (or MXBean).

      • getImplementationClass

        public Class<?> getImplementationClass()
        Get the class of the implementation of this Standard MBean (or MXBean).
        Returns:
        The class of the implementation of this Standard MBean (or MXBean).

      • invoke

        public Object invoke(String actionName,
            Object[] params,
            String[] signature)
              throws MBeanException,
                     ReflectionException
        Description copied from interface: DynamicMBean
        Allows an action to be invoked on the Dynamic MBean.
        Specified by:
        invoke in interface DynamicMBean
        Parameters:
        actionName - The name of the action to be invoked.
        params - An array containing the parameters to be set when the action is invoked.
        signature - An array containing the signature of the action. The class objects will be loaded through the same class loader as the one used for loading the MBean on which the action is invoked.
        Returns:
        The object returned by the action, which represents the result of invoking the action on the MBean specified.
        Throws:
        MBeanException - Wraps a java.lang.Exception thrown by the MBean's invoked method.
        ReflectionException - Wraps a java.lang.Exception thrown while trying to invoke the method

      • getMBeanInfo

        public MBeanInfo getMBeanInfo()
        Get the MBeanInfo for this MBean.

        This method implements DynamicMBean.getMBeanInfo().

        This method first calls getCachedMBeanInfo() in order to retrieve the cached MBeanInfo for this MBean, if any. If the MBeanInfo returned by getCachedMBeanInfo() is not null, then it is returned.
        Otherwise, this method builds a default MBeanInfo for this MBean, using the Management Interface specified for this MBean.

        While building the MBeanInfo, this method calls the customization hooks that make it possible for subclasses to supply their custom descriptions, parameter names, etc...
        Finally, it calls cacheMBeanInfo() in order to cache the new MBeanInfo.

        Specified by:
        getMBeanInfo in interface DynamicMBean
        Returns:
        The cached MBeanInfo for that MBean, if not null, or a newly built MBeanInfo if none was cached.

      • getClassName

        protected String getClassName(MBeanInfo info)
        Customization hook: Get the className that will be used in the MBeanInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom class name. The default implementation returns info.getClassName().
        Parameters:
        info - The default MBeanInfo derived by reflection.
        Returns:
        the class name for the new MBeanInfo.

      • getDescription

        protected String getDescription(MBeanInfo info)
        Customization hook: Get the description that will be used in the MBeanInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom MBean description. The default implementation returns info.getDescription().
        Parameters:
        info - The default MBeanInfo derived by reflection.
        Returns:
        the description for the new MBeanInfo.

      • getDescription

        protected String getDescription(MBeanAttributeInfo info)
        Customization hook: Get the description that will be used in the MBeanAttributeInfo returned by this MBean.

        Subclasses may redefine this method in order to supply their custom description. The default implementation returns getDescription((MBeanFeatureInfo) info).

        Parameters:
        info - The default MBeanAttributeInfo derived by reflection.
        Returns:
        the description for the given MBeanAttributeInfo.

      • getDescription

        protected String getDescription(MBeanConstructorInfo info)
        Customization hook: Get the description that will be used in the MBeanConstructorInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom description. The default implementation returns getDescription((MBeanFeatureInfo) info).
        Parameters:
        info - The default MBeanConstructorInfo derived by reflection.
        Returns:
        the description for the given MBeanConstructorInfo.

      • getDescription

        protected String getDescription(MBeanConstructorInfo ctor,
                    MBeanParameterInfo param,
                    int sequence)
        Customization hook: Get the description that will be used for the sequence MBeanParameterInfo of the MBeanConstructorInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom description. The default implementation returns param.getDescription().
        Parameters:
        ctor - The default MBeanConstructorInfo derived by reflection.
        param - The default MBeanParameterInfo derived by reflection.
        sequence - The sequence number of the parameter considered ("0" for the first parameter, "1" for the second parameter, etc...).
        Returns:
        the description for the given MBeanParameterInfo.

      • getParameterName

        protected String getParameterName(MBeanConstructorInfo ctor,
                      MBeanParameterInfo param,
                      int sequence)
        Customization hook: Get the name that will be used for the sequence MBeanParameterInfo of the MBeanConstructorInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom parameter name. The default implementation returns param.getName().
        Parameters:
        ctor - The default MBeanConstructorInfo derived by reflection.
        param - The default MBeanParameterInfo derived by reflection.
        sequence - The sequence number of the parameter considered ("0" for the first parameter, "1" for the second parameter, etc...).
        Returns:
        the name for the given MBeanParameterInfo.

      • getDescription

        protected String getDescription(MBeanOperationInfo info)
        Customization hook: Get the description that will be used in the MBeanOperationInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom description. The default implementation returns getDescription((MBeanFeatureInfo) info).
        Parameters:
        info - The default MBeanOperationInfo derived by reflection.
        Returns:
        the description for the given MBeanOperationInfo.

      • getImpact

        protected int getImpact(MBeanOperationInfo info)
        Customization hook: Get the impact flag of the operation that will be used in the MBeanOperationInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom impact flag. The default implementation returns info.getImpact().
        Parameters:
        info - The default MBeanOperationInfo derived by reflection.
        Returns:
        the impact flag for the given MBeanOperationInfo.

      • getParameterName

        protected String getParameterName(MBeanOperationInfo op,
                      MBeanParameterInfo param,
                      int sequence)
        Customization hook: Get the name that will be used for the sequence MBeanParameterInfo of the MBeanOperationInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom parameter name. The default implementation returns param.getName().
        Parameters:
        op - The default MBeanOperationInfo derived by reflection.
        param - The default MBeanParameterInfo derived by reflection.
        sequence - The sequence number of the parameter considered ("0" for the first parameter, "1" for the second parameter, etc...).
        Returns:
        the name to use for the given MBeanParameterInfo.

      • getDescription

        protected String getDescription(MBeanOperationInfo op,
                    MBeanParameterInfo param,
                    int sequence)
        Customization hook: Get the description that will be used for the sequence MBeanParameterInfo of the MBeanOperationInfo returned by this MBean.
        Subclasses may redefine this method in order to supply their custom description. The default implementation returns param.getDescription().
        Parameters:
        op - The default MBeanOperationInfo derived by reflection.
        param - The default MBeanParameterInfo derived by reflection.
        sequence - The sequence number of the parameter considered ("0" for the first parameter, "1" for the second parameter, etc...).
        Returns:
        the description for the given MBeanParameterInfo.

      • getConstructors

        protected MBeanConstructorInfo[] getConstructors(MBeanConstructorInfo[] ctors,
                                     Object impl)
        Customization hook: Get the MBeanConstructorInfo[] that will be used in the MBeanInfo returned by this MBean.
        By default, this method returns null if the wrapped implementation is not 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 MBeanServer.createMBean(...).
        Otherwise, if the wrapped implementation is this, ctors is returned.
        Subclasses may redefine this method in order to modify this behavior, if needed.
        Parameters:
        ctors - The default MBeanConstructorInfo[] derived by reflection.
        impl - The wrapped implementation. If null is passed, the wrapped implementation is ignored and ctors is returned.
        Returns:
        the MBeanConstructorInfo[] for the new MBeanInfo.

      • getCachedMBeanInfo

        protected MBeanInfo getCachedMBeanInfo()
        Customization hook: Return the MBeanInfo cached for this object.

        Subclasses may redefine this method in order to implement their own caching policy. The default implementation stores one MBeanInfo object per instance.

        Returns:
        The cached MBeanInfo, or null if no MBeanInfo is cached.
        See Also:
        cacheMBeanInfo(MBeanInfo)

      • cacheMBeanInfo

        protected void cacheMBeanInfo(MBeanInfo info)
        Customization hook: cache the MBeanInfo built for this object.

        Subclasses may redefine this method in order to implement their own caching policy. The default implementation stores info in this instance. A subclass can define other policies, such as not saving info (so it is reconstructed every time getMBeanInfo() is called) or sharing a unique MBeanInfo object when several StandardMBean instances have equal MBeanInfo values.

        Parameters:
        info - the new MBeanInfo to cache. Any previously cached value is discarded. This parameter may be null, in which case there is no new cached value.

      • preRegister

        public ObjectName preRegister(MBeanServer server,
                     ObjectName name)
                       throws Exception

        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.

        The default implementation of this method returns the name parameter. It does nothing else for Standard MBeans. For MXBeans, it records the MBeanServer and ObjectName parameters so they can be used to translate inter-MXBean references.

        It is good practice for a subclass that overrides this method to call the overridden method via super.preRegister(...). This is necessary if this object is an MXBean that is referenced by attributes or operations in other MXBeans.

        Specified by:
        preRegister in interface MBeanRegistration
        Parameters:
        server - The MBean server in which the MBean will be registered.
        name - The object name of the MBean. This name is null if the name parameter to one of the createMBean or registerMBean methods in the MBeanServer interface is null. In that case, this method must return a non-null ObjectName for the new MBean.
        Returns:
        The name under which the MBean is to be registered. This value must not be null. If the name parameter is not null, it will usually but not necessarily be the returned value.
        Throws:
        IllegalArgumentException - if this is an MXBean and name is null.
        InstanceAlreadyExistsException - if this is an MXBean and it has already been registered under another name (in this MBean Server or another).
        Exception - no other checked exceptions are thrown by this method but Exception is declared so that subclasses can override the method and throw their own exceptions.
        Since:
        1.6

      • postRegister

        public void postRegister(Boolean registrationDone)

        Allows the MBean to perform any operations needed after having been registered in the MBean server or after the registration has failed.

        The default implementation of this method does nothing for Standard MBeans. For MXBeans, it undoes any work done by preRegister if registration fails.

        It is good practice for a subclass that overrides this method to call the overridden method via super.postRegister(...). This is necessary if this object is an MXBean that is referenced by attributes or operations in other MXBeans.

        Specified by:
        postRegister in interface MBeanRegistration
        Parameters:
        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

      • preDeregister

        public void preDeregister()
                   throws Exception

        Allows the MBean to perform any operations it needs before being unregistered by the MBean server.

        The default implementation of this method does nothing.

        It is good practice for a subclass that overrides this method to call the overridden method via super.preDeregister(...).

        Specified by:
        preDeregister in interface MBeanRegistration
        Throws:
        Exception - no checked exceptions are throw by this method but Exception is declared so that subclasses can override this method and throw their own exceptions.
        Since:
        1.6

      • postDeregister

        public void postDeregister()

        Allows the MBean to perform any operations needed after having been unregistered in the MBean server.

        The default implementation of this method does nothing for Standard MBeans. For MXBeans, it removes any information that was recorded by the preRegister method.

        It is good practice for a subclass that overrides this method to call the overridden method via super.postRegister(...). This is necessary if this object is an MXBean that is referenced by attributes or operations in other MXBeans.

        Specified by:
        postDeregister in interface MBeanRegistration
        Since:
        1.6

Document created the 11/06/2005, last modified the 04/03/2020
Source of the printed document:https://www.gaudry.be/en/java-api-rf-javax/management/standardmbean.html

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