Package javax.management.openmbean
Provides the open data types and Open MBean descriptor classes. An Open MBean is an MBean where the types of attributes and of operation parameters and return values are built using a small set of predefined Java classes. Open MBeans facilitate operation with remote management programs that do not necessarily have access to application-specific types, including non-Java programs.
Every MBean has an MBeanInfo with information about the MBean itself, and its
attributes, operations, constructors, and notifications. In an
Open MBean, this MBeanInfo implements the OpenMBeanInfo
interface, usually by being an instance of OpenMBeanInfoSupport.
The attribute information returned by MBeanInfo.getAttributes for an Open MBean is an array of
objects implementing OpenMBeanAttributeInfo, usually instances of OpenMBeanAttributeInfoSupport. In addition to the usual
information about attributes, an
OpenMBeanAttributeInfo specifies the OpenType of the attribute.
The possible OpenType values are predefined, which
is what ensures that remote managers will understand them.
Similar remarks apply to the parameter types of operations and constructors, and to the return types of operations.
There is a distinction between an attribute's Java language
type, as returned by getType(), and
its OpenType, as returned by getOpenType(). For example, if the Java language type is
java.lang.String, the OpenType will be
SimpleType.String. If the Java language type is CompositeData, the
OpenType will be a CompositeType that
describes the items in the CompositeData instances
for the attribute.
Default values and constraints
In Open MBeans, attributes and parameters can have default values
and/or constraints associated with them in the
OpenMBeanAttributeInfo or OpenMBeanParameterInfo.
There are two ways to specify these constraints. Either the
values are directly specified as parameters to one of the
constructors of OpenMBeanAttributeInfoSupport or
OpenMBeanParameterInfoSupport, for example
OpenMBeanParameterInfoSupport(String, String, OpenType, Object, Object[]); or the values are
specified in a Descriptor given
as a parameter to one of the constructors.
When a Descriptor is used, the fields of interest are
these:
defaultValuedefines the value returned bygetDefaultValue();minValuedefines the value returned bygetMinValue();maxValuedefines the value returned bygetMaxValue();legalValuesdefines the values returned bygetLegalValues().
For defaultValue, minValue, and
maxValue, the associated value must either be of the Java type
corresponding to openType, or be a string that can be
converted into that type. The conversion uses the static method
valueOf(String) if it finds one; otherwise a constructor
with a single String parameter if it finds one; otherwise
it fails.
For legalValues, the associated value must be either
an array or a Set, and the elements of the array or set
must be convertible as described for defaultValue etc.
The following conditions must be met for these fields:
- the values must be of the appropriate type, or be strings that can be converted to the appropriate type as explained above;
- if
legalValuesis present then neitherminValuenormaxValuemust be present; - if
defaultValueis present then it must satisfy the constraints defined bylegalValues,minValue, ormaxValuewhen any of these is also present; - if
minValueandmaxValueare both present thenminValuemust not be greater thanmaxValue.
- Since:
- 1.5
- See Also:
-
ClassDescriptionArrayType<T>The
ArrayTypeclass is the open type class whose instances describe all open data values which are n-dimensional arrays of open data values.TheCompositeDatainterface specifies the behavior of a specific type of complex open data objects which represent composite data structures.AnInvocationHandlerthat forwards getter methods to aCompositeData.TheCompositeDataSupportclass is the open data class which implements theCompositeDatainterface.A Java class can implement this interface to indicate how it is to be converted into aCompositeDataby the MXBean framework.TheCompositeTypeclass is the open type class whose instances describe the types ofCompositeDatavalues.This runtime exception is thrown to indicate that a method parameter which was expected to be an item name of a composite data or a row index of a tabular data is not valid.This runtime exception is thrown to indicate that the open type of an open data value is not the one expected.This runtime exception is thrown to indicate that the index of a row to be added to a tabular data instance is already used to refer to another row in this tabular data instance.This checked exception is thrown when an open type, an open data or an open MBean metadata info instance could not be constructed because one or more validity constraints were not met.Describes an attribute of an open MBean.Describes an attribute of an open MBean.Describes a constructor of an Open MBean.Describes a constructor of an Open MBean.Describes an Open MBean: an Open MBean is recognized as such if itsgetMBeanInfo()method returns an instance of a class which implements theOpenMBeanInfointerface, typicallyOpenMBeanInfoSupport.TheOpenMBeanInfoSupportclass describes the management information of an open MBean: it is a subclass ofMBeanInfo, and it implements theOpenMBeanInfointerface.Describes an operation of an Open MBean.Describes an operation of an Open MBean.Describes a parameter used in one or more operations or constructors of an open MBean.Describes a parameter used in one or more operations or constructors of an open MBean.OpenType<T>TheOpenTypeclass is the parent abstract class of all classes which describe the actual open type of open data values.SimpleType<T>TheSimpleTypeclass is the open type class whose instances describe all open data values which are neither arrays, norCompositeDatavalues, norTabularDatavalues.TheTabularDatainterface specifies the behavior of a specific type of complex open data objects which represent tabular data structures.TheTabularDataSupportclass is the open data class which implements theTabularDataand theMapinterfaces, and which is internally based on a hash map data structure.TheTabularTypeclass is the open type class whose instances describe the types ofTabularDatavalues.