The {@code DiagnosticCommandMBean} is registered to the * {@linkplain java.lang.management.ManagementFactory#getPlatformMBeanServer * platform MBeanServer} as are other platform MBeans. * *
The {@link javax.management.ObjectName ObjectName} for uniquely identifying * the diagnostic MBean within an MBeanServer is: *
* {@code com.sun.management:type=DiagnosticCommand} ** *
This MBean is a {@link javax.management.DynamicMBean DynamicMBean} * and also a {@link javax.management.NotificationEmitter}. * The {@code DiagnosticCommandMBean} is generated at runtime and is subject to * modifications during the lifetime of the Java virtual machine. * * A diagnostic command is represented as an operation of * the {@code DiagnosticCommandMBean} interface. Each diagnostic command has: *
The diagnostic command name is always provided with the meta-data on the * operation in a field named {@code dcmd.name} (see below). * *
A diagnostic command may or may not support options or arguments. * All the operations return {@code String} and either take * no parameter for operations that do not support any option or argument, * or take a {@code String[]} parameter for operations that support at least * one option or argument. * Each option or argument must be stored in a single String. * Options or arguments split across several String instances are not supported. * *
The distinction between options and arguments: options are identified by * the option name while arguments are identified by their position in the * command line. Options and arguments are processed in the order of the array * passed to the invocation method. * *
Like any operation of a dynamic MBean, each of these operations is * described by {@link javax.management.MBeanOperationInfo MBeanOperationInfo} * instance. Here's the values returned by this object: *
The {@link javax.management.Descriptor Descriptor} * is a collection of fields containing additional * meta-data for a JMX element. A field is a name and an associated value. * The additional meta-data provided for an operation associated with a * diagnostic command are described in the table below: * *
| Name | Type | Description | *
|---|---|---|
| dcmd.name | String | *The original diagnostic command name (not the operation name) | *
| dcmd.description | String | *The diagnostic command description | *
| dcmd.help | String | *The full help message for this diagnostic command (same output as * the one produced by the 'help' command) | *
| dcmd.vmImpact | String | *The impact of the diagnostic command, * this value is the same as the one printed in the 'impact' * section of the help message of the diagnostic command, and it * is different from the getImpact() of the MBeanOperationInfo | *
| dcmd.enabled | boolean | *True if the diagnostic command is enabled, false otherwise | *
| dcmd.permissionClass | String | *Some diagnostic command might require a specific permission to be * executed, in addition to the MBeanPermission to invoke their * associated MBean operation. This field returns the fully qualified * name of the permission class or null if no permission is required * | *
| dcmd.permissionName | String | *The fist argument of the permission required to execute this * diagnostic command or null if no permission is required | *
| dcmd.permissionAction | String | *The second argument of the permission required to execute this * diagnostic command or null if the permission constructor has only * one argument (like the ManagementPermission) or if no permission * is required | *
| dcmd.arguments | Descriptor | *A Descriptor instance containing the descriptions of options and * arguments supported by the diagnostic command (see below) | *
The description of parameters (options or arguments) of a diagnostic * command is provided within a Descriptor instance. In this Descriptor, * each field name is a parameter name, and each field value is itself * a Descriptor instance. The fields provided in this second Descriptor * instance are described in the table below: * *
| Name | Type | Description | *
|---|---|---|
| dcmd.arg.name | String | *The name of the parameter | *
| dcmd.arg.type | String | *The type of the parameter. The returned String is the name of a type * recognized by the diagnostic command parser. These types are not * Java types and are implementation dependent. * | *
| dcmd.arg.description | String | *The parameter description | *
| dcmd.arg.isMandatory | boolean | *True if the parameter is mandatory, false otherwise | *
| dcmd.arg.isOption | boolean | *True if the parameter is an option, false if it is an argument | *
| dcmd.arg.isMultiple | boolean | *True if the parameter can be specified several times, false * otherwise | *
When the set of diagnostic commands currently supported by the Java * Virtual Machine is modified, the {@code DiagnosticCommandMBean} emits * a {@link javax.management.Notification} with a * {@linkplain javax.management.Notification#getType() type} of * * {@code "jmx.mbean.info.changed"} and a * {@linkplain javax.management.Notification#getUserData() userData} that * is the new {@code MBeanInfo}. * * @since 1.8 */ public interface DiagnosticCommandMBean extends DynamicMBean { }