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:
-
defaultValue
defines the value returned bygetDefaultValue()
; -
minValue
defines the value returned bygetMinValue()
; -
maxValue
defines the value returned bygetMaxValue()
; -
legalValues
defines 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
legalValues
is present then neitherminValue
normaxValue
must be present; - if
defaultValue
is present then it must satisfy the constraints defined bylegalValues
,minValue
, ormaxValue
when any of these is also present; - if
minValue
andmaxValue
are both present thenminValue
must not be greater thanmaxValue
.
- Since:
- 1.5
- See Also:
- JMX Specification, version 1.4
Interface | Description |
---|---|
CompositeData | The |
CompositeDataView | A Java class can implement this interface to indicate how it is to be converted into a |
OpenMBeanAttributeInfo | Describes an attribute of an open MBean. |
OpenMBeanConstructorInfo | Describes a constructor of an Open MBean. |
OpenMBeanInfo | Describes an Open MBean: an Open MBean is recognized as such if its |
OpenMBeanOperationInfo | Describes an operation of an Open MBean. |
OpenMBeanParameterInfo | Describes a parameter used in one or more operations or constructors of an open MBean. |
TabularData | The |
Class | Description |
---|---|
ArrayType<T> | The |
CompositeDataInvocationHandler | An |
CompositeDataSupport | The |
CompositeType | The |
OpenMBeanAttributeInfoSupport | Describes an attribute of an open MBean. |
OpenMBeanConstructorInfoSupport | Describes a constructor of an Open MBean. |
OpenMBeanInfoSupport | The |
OpenMBeanOperationInfoSupport | Describes an operation of an Open MBean. |
OpenMBeanParameterInfoSupport | Describes a parameter used in one or more operations or constructors of an open MBean. |
OpenType<T> | The |
SimpleType<T> | The |
TabularDataSupport | The |
TabularType | The |
Exception | Description |
---|---|
InvalidKeyException | 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. |
InvalidOpenTypeException | This runtime exception is thrown to indicate that the open type of an open data value is not the one expected. |
KeyAlreadyExistsException | 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. |
OpenDataException | 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. |