# Class RelationService

java.lang.Object
javax.management.NotificationBroadcasterSupport
javax.management.relation.RelationService

All Implemented Interfaces:
  `EventListener, MBeanRegistration, NotificationBroadcaster, NotificationEmitter, NotificationListener, RelationServiceMBean`

public class RelationService extends NotificationBroadcasterSupport implements RelationServiceMBean, MBeanRegistration, NotificationListener
The Relation Service is in charge of creating and deleting relation types and relations, of handling the consistency and of providing query mechanisms.

It implements the NotificationBroadcaster by extending NotificationBroadcasterSupport to send notifications when a relation is removed from it.

It implements the NotificationListener interface to be able to receive notifications concerning unregistration of MBeans referenced in relation roles and of relation MBeans.

It implements the MBeanRegistration interface to be able to retrieve its ObjectName and MBean Server.

Since:
  1.5

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `RelationService(boolean immediatePurgeFlag)`
  Constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addRelation(ObjectName relationObjectName)`
  Adds an MBean created by the user (and registered by him in the MBean Server) as a relation in the Relation Service.
  `void`
  `addRelationType(RelationType relationTypeObj)`
  Adds given object as a relation type.
  `Integer`
  `checkRoleReading(String roleName, String relationTypeName)`
  Checks if given Role can be read in a relation of the given type.
  `Integer`
  `checkRoleWriting(Role role, String relationTypeName, Boolean initFlag)`
  Checks if given Role can be set in a relation of given type.
  `void`
  `createRelation(String relationId, String relationTypeName, RoleList roleList)`
  Creates a simple relation (represented by a RelationSupport object) of given relation type, and adds it in the Relation Service.
  `void`
  `createRelationType(String relationTypeName, RoleInfo[] roleInfoArray)`
  Creates a relation type (a RelationTypeSupport object) with given role infos (provided by the RoleInfo objects), and adds it in the Relation Service.
  `Map<ObjectName, List<String>>`
  `findAssociatedMBeans(ObjectName mbeanName, String relationTypeName, String roleName)`
  Retrieves the MBeans associated to given one in a relation.
  `Map<String, List<String>>`
  `findReferencingRelations(ObjectName mbeanName, String relationTypeName, String roleName)`
  Retrieves the relations where a given MBean is referenced.
  `List<String>`
  `findRelationsOfType(String relationTypeName)`
  Returns the relation ids for relations of the given type.
  `List<String>`
  `getAllRelationIds()`
  Returns all the relation ids for all the relations handled by the Relation Service.
  `List<String>`
  `getAllRelationTypeNames()`
  Retrieves names of all known relation types.
  `RoleResult`
  `getAllRoles(String relationId)`
  Returns all roles present in the relation.
  `MBeanNotificationInfo[]`
  `getNotificationInfo()`
  Returns a NotificationInfo object containing the name of the Java class of the notification and the notification types sent.
  `boolean`
  `getPurgeFlag()`
  Returns the flag to indicate if when a notification is received for the unregistration of an MBean referenced in a relation, if an immediate "purge" of the relations (look for the relations no longer valid) has to be performed , or if that will be performed only when the purgeRelations method will be explicitly called.
  `Map<ObjectName, List<String>>`
  `getReferencedMBeans(String relationId)`
  Retrieves MBeans referenced in the various roles of the relation.
  `String`
  `getRelationTypeName(String relationId)`
  Returns name of associated relation type for given relation.
  `List<ObjectName>`
  `getRole(String relationId, String roleName)`
  Retrieves role value for given role name in given relation.
  `Integer`
  `getRoleCardinality(String relationId, String roleName)`
  Retrieves the number of MBeans currently referenced in the given role.
  `RoleInfo`
  `getRoleInfo(String relationTypeName, String roleInfoName)`
  Retrieves role info for given role name of a given relation type.
  `List<RoleInfo>`
  `getRoleInfos(String relationTypeName)`
  Retrieves list of role infos (RoleInfo objects) of a given relation type.
  `RoleResult`
  `getRoles(String relationId, String[] roleNameArray)`
  Retrieves values of roles with given names in given relation.
  `void`
  `handleNotification(Notification notif, Object handback)`
  Invoked when a JMX notification occurs.
  `Boolean`
  `hasRelation(String relationId)`
  Checks if there is a relation identified in Relation Service with given relation id.
  `void`
  `isActive()`
  Checks if the Relation Service is active.
  `String`
  `isRelation(ObjectName objectName)`
  Returns the relation id associated to the given ObjectName if the MBean has been added as a relation in the Relation Service.
  `ObjectName`
  `isRelationMBean(String relationId)`
  If the relation is represented by an MBean (created by the user and added as a relation in the Relation Service), returns the ObjectName of the MBean.
  `void`
  `postDeregister()`
  Allows the MBean to perform any operations needed after having been unregistered in the MBean server.
  `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.
  `void`
  `preDeregister()`
  Allows the MBean to perform any operations it needs before being unregistered by the MBean server.
  `ObjectName`
  `preRegister(MBeanServer server, ObjectName name)`
  Allows the MBean to perform any operations it needs before being registered in the MBean Server.
  `void`
  `purgeRelations()`
  Purges the relations.
  `void`
  `removeRelation(String relationId)`
  Removes given relation from the Relation Service.
  `void`
  `removeRelationType(String relationTypeName)`
  Removes given relation type from Relation Service.
  `void`
  `sendRelationCreationNotification(String relationId)`
  Sends a notification (RelationNotification) for a relation creation.
  `void`
  `sendRelationRemovalNotification(String relationId, List<ObjectName> unregMBeanList)`
  Sends a notification (RelationNotification) for a relation removal.
  `void`
  `sendRoleUpdateNotification(String relationId, Role newRole, List<ObjectName> oldValue)`
  Sends a notification (RelationNotification) for a role update in the given relation.
  `void`
  `setPurgeFlag(boolean purgeFlag)`
  Sets the flag to indicate if when a notification is received for the unregistration of an MBean referenced in a relation, if an immediate "purge" of the relations (look for the relations no longer valid) has to be performed , or if that will be performed only when the purgeRelations method will be explicitly called.
  `void`
  `setRole(String relationId, Role role)`
  Sets the given role in given relation.
  `RoleResult`
  `setRoles(String relationId, RoleList roleList)`
  Sets the given roles in given relation.
  `void`
  `updateRoleMap(String relationId, Role newRole, List<ObjectName> oldValue)`
  Handles update of the Relation Service role map for the update of given role in given relation.

  ### Methods declared in class NotificationBroadcasterSupport

  `addNotificationListener, handleNotification, removeNotificationListener, removeNotificationListener, sendNotification`
  Modifier and Type
  Method
  Description
  `void`
  `addNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback)`
  Adds a listener.
  `protected void`
  `handleNotification(NotificationListener listener, Notification notif, Object handback)`
  This method is called by `sendNotification` for each listener in order to send the notification to that listener.
  `void`
  `removeNotificationListener(NotificationListener listener)`
  Removes a listener from this MBean.
  `void`
  `removeNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback)`
  Removes a listener from this MBean.
  `void`
  `sendNotification(Notification notification)`
  Sends a notification.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  Creates and returns a copy of this object.
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `Object`.
  `int`
  `hashCode()`
  Returns a hash code value for this object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `String`
  `toString()`
  Returns a string representation of the object.
  `final void`
  `wait()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `final void`
  `wait(long timeoutMillis)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
  `final void`
  `wait(long timeoutMillis, int nanos)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

- ## Constructor Details

  - ### RelationService

    public RelationService(boolean immediatePurgeFlag)
    Constructor.
    Parameters:
      `immediatePurgeFlag` - flag to indicate when a notification is received for the unregistration of an MBean referenced in a relation, if an immediate "purge" of the relations (look for the relations no longer valid) has to be performed , or if that will be performed only when the purgeRelations method will be explicitly called.

      true is immediate purge.

- ## Method Details

  - ### isActive

    public void isActive() throws RelationServiceNotRegisteredException
    Checks if the Relation Service is active. Current condition is that the Relation Service must be registered in the MBean Server
    Specified by:
      `isActive` in interface `RelationServiceMBean`
    Throws:
      `RelationServiceNotRegisteredException` - if it is not registered

  - ### preRegister

    public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception
    Description copied from interface: `MBeanRegistration`
    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.
    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:
      `Exception` - This exception will be caught by the MBean Server and re-thrown as an `MBeanRegistrationException`.

  - ### postRegister

    public void postRegister(Boolean registrationDone)
    Description copied from interface: `MBeanRegistration`
    Allows the MBean to perform any operations needed after having been registered in the MBean server or after the registration has failed.

    If the implementation of this method throws a `RuntimeException` or an `Error`, the MBean Server will rethrow those inside a `RuntimeMBeanException` or `RuntimeErrorException`, respectively. However, throwing an exception in `postRegister` will not change the state of the MBean: if the MBean was already registered (`registrationDone` is `true`), the MBean will remain registered.

    This might be confusing for the code calling `createMBean()` or `registerMBean()`, as such code might assume that MBean registration has failed when such an exception is raised. Therefore it is recommended that implementations of `postRegister` do not throw Runtime Exceptions or Errors if it can be avoided.

    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.

  - ### preDeregister

    public void preDeregister() throws Exception
    Description copied from interface: `MBeanRegistration`
    Allows the MBean to perform any operations it needs before being unregistered by the MBean server.
    Specified by:
      `preDeregister` in interface `MBeanRegistration`
    Throws:
      `Exception` - This exception will be caught by the MBean server and re-thrown as an `MBeanRegistrationException`.

  - ### postDeregister

    public void postDeregister()
    Description copied from interface: `MBeanRegistration`
    Allows the MBean to perform any operations needed after having been unregistered in the MBean server.

    If the implementation of this method throws a `RuntimeException` or an `Error`, the MBean Server will rethrow those inside a `RuntimeMBeanException` or `RuntimeErrorException`, respectively. However, throwing an exception in `postDeregister` will not change the state of the MBean: the MBean was already successfully deregistered and will remain so.

    This might be confusing for the code calling `unregisterMBean()`, as it might assume that MBean deregistration has failed. Therefore it is recommended that implementations of `postDeregister` do not throw Runtime Exceptions or Errors if it can be avoided.

    Specified by:
      `postDeregister` in interface `MBeanRegistration`

  - ### getPurgeFlag

    public boolean getPurgeFlag()
    Returns the flag to indicate if when a notification is received for the unregistration of an MBean referenced in a relation, if an immediate "purge" of the relations (look for the relations no longer valid) has to be performed , or if that will be performed only when the purgeRelations method will be explicitly called.

    true is immediate purge.

    Specified by:
      `getPurgeFlag` in interface `RelationServiceMBean`
    Returns:
      true if purges are automatic.
    See Also:
      - `setPurgeFlag(boolean)`

  - ### setPurgeFlag

    public void setPurgeFlag(boolean purgeFlag)
    Sets the flag to indicate if when a notification is received for the unregistration of an MBean referenced in a relation, if an immediate "purge" of the relations (look for the relations no longer valid) has to be performed , or if that will be performed only when the purgeRelations method will be explicitly called.

    true is immediate purge.

    Specified by:
      `setPurgeFlag` in interface `RelationServiceMBean`
    Parameters:
      `purgeFlag` - flag
    See Also:
      - `getPurgeFlag()`

  - ### createRelationType

    public void createRelationType(String relationTypeName, RoleInfo[] roleInfoArray) throws IllegalArgumentException, InvalidRelationTypeException
    Creates a relation type (a RelationTypeSupport object) with given role infos (provided by the RoleInfo objects), and adds it in the Relation Service.
    Specified by:
      `createRelationType` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeName` - name of the relation type
      `roleInfoArray` - array of role infos
    Throws:
      `IllegalArgumentException` - if null parameter
      `InvalidRelationTypeException` - If:

      - there is already a relation type with that name

      - the same name has been used for two different role infos

      - no role info provided

      - one null role info provided

  - ### addRelationType

    public void addRelationType(RelationType relationTypeObj) throws IllegalArgumentException, InvalidRelationTypeException
    Adds given object as a relation type. The object is expected to implement the RelationType interface.
    Specified by:
      `addRelationType` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeObj` - relation type object (implementing the RelationType interface)
    Throws:
      `IllegalArgumentException` - if null parameter or if `relationTypeObj.getRelationTypeName()` returns null.
      `InvalidRelationTypeException` - if:

      - the same name has been used for two different roles

      - no role info provided

      - one null role info provided

      - there is already a relation type with that name

  - ### getAllRelationTypeNames

    public List<String> getAllRelationTypeNames()
    Retrieves names of all known relation types.
    Specified by:
      `getAllRelationTypeNames` in interface `RelationServiceMBean`
    Returns:
      ArrayList of relation type names (Strings)

  - ### getRoleInfos

    public List<RoleInfo> getRoleInfos(String relationTypeName) throws IllegalArgumentException, RelationTypeNotFoundException
    Retrieves list of role infos (RoleInfo objects) of a given relation type.
    Specified by:
      `getRoleInfos` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeName` - name of relation type
    Returns:
      ArrayList of RoleInfo.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - if there is no relation type with that name.

  - ### getRoleInfo

    public RoleInfo getRoleInfo(String relationTypeName, String roleInfoName) throws IllegalArgumentException, RelationTypeNotFoundException, RoleInfoNotFoundException
    Retrieves role info for given role name of a given relation type.
    Specified by:
      `getRoleInfo` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeName` - name of relation type
      `roleInfoName` - name of role
    Returns:
      RoleInfo object.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - if the relation type is not known in the Relation Service
      `RoleInfoNotFoundException` - if the role is not part of the relation type.

  - ### removeRelationType

    public void removeRelationType(String relationTypeName) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationTypeNotFoundException
    Removes given relation type from Relation Service.

    The relation objects of that type will be removed from the Relation Service.

    Specified by:
      `removeRelationType` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeName` - name of the relation type to be removed
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - If there is no relation type with that name

  - ### createRelation

    public void createRelation(String relationId, String relationTypeName, RoleList roleList) throws RelationServiceNotRegisteredException, IllegalArgumentException, RoleNotFoundException, InvalidRelationIdException, RelationTypeNotFoundException, InvalidRoleValueException
    Creates a simple relation (represented by a RelationSupport object) of given relation type, and adds it in the Relation Service.

    Roles are initialized according to the role list provided in parameter. The ones not initialized in this way are set to an empty ArrayList of ObjectNames.

    A RelationNotification, with type RELATION_BASIC_CREATION, is sent.

    Specified by:
      `createRelation` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation identifier, to identify uniquely the relation inside the Relation Service
      `relationTypeName` - name of the relation type (has to be created in the Relation Service)
      `roleList` - role list to initialize roles of the relation (can be null).
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter, except the role list which can be null if no role initialization
      `RoleNotFoundException` - if a value is provided for a role that does not exist in the relation type
      `InvalidRelationIdException` - if relation id already used
      `RelationTypeNotFoundException` - if relation type not known in Relation Service
      `InvalidRoleValueException` - if:

      - the same role name is used for two different roles

      - the number of referenced MBeans in given value is less than expected minimum degree

      - the number of referenced MBeans in provided value exceeds expected maximum degree

      - one referenced MBean in the value is not an Object of the MBean class expected for that role

      - an MBean provided for that role does not exist

  - ### addRelation

    public void addRelation(ObjectName relationObjectName) throws IllegalArgumentException, RelationServiceNotRegisteredException, NoSuchMethodException, InvalidRelationIdException, InstanceNotFoundException, InvalidRelationServiceException, RelationTypeNotFoundException, RoleNotFoundException, InvalidRoleValueException
    Adds an MBean created by the user (and registered by him in the MBean Server) as a relation in the Relation Service.

    To be added as a relation, the MBean must conform to the following:

    - implement the Relation interface

    - have for RelationService ObjectName the ObjectName of current Relation Service

    - have a relation id unique and unused in current Relation Service

    - have for relation type a relation type created in the Relation Service

    - have roles conforming to the role info provided in the relation type.

    Specified by:
      `addRelation` in interface `RelationServiceMBean`
    Parameters:
      `relationObjectName` - ObjectName of the relation MBean to be added.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `NoSuchMethodException` - If the MBean does not implement the Relation interface
      `InvalidRelationIdException` - if:

      - no relation identifier in MBean

      - the relation identifier is already used in the Relation Service

      `InstanceNotFoundException` - if the MBean for given ObjectName has not been registered
      `InvalidRelationServiceException` - if:

      - no Relation Service name in MBean

      - the Relation Service name in the MBean is not the one of the current Relation Service

      `RelationTypeNotFoundException` - if:

      - no relation type name in MBean

      - the relation type name in MBean does not correspond to a relation type created in the Relation Service

      `InvalidRoleValueException` - if:

      - the number of referenced MBeans in a role is less than expected minimum degree

      - the number of referenced MBeans in a role exceeds expected maximum degree

      - one referenced MBean in the value is not an Object of the MBean class expected for that role

      - an MBean provided for a role does not exist

      `RoleNotFoundException` - if a value is provided for a role that does not exist in the relation type

  - ### isRelationMBean

    public ObjectName isRelationMBean(String relationId) throws IllegalArgumentException, RelationNotFoundException
    If the relation is represented by an MBean (created by the user and added as a relation in the Relation Service), returns the ObjectName of the MBean.
    Specified by:
      `isRelationMBean` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id identifying the relation
    Returns:
      ObjectName of the corresponding relation MBean, or null if the relation is not an MBean.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - there is no relation associated to that id

  - ### isRelation

    public String isRelation(ObjectName objectName) throws IllegalArgumentException
    Returns the relation id associated to the given ObjectName if the MBean has been added as a relation in the Relation Service.
    Specified by:
      `isRelation` in interface `RelationServiceMBean`
    Parameters:
      `objectName` - ObjectName of supposed relation
    Returns:
      relation id (String) or null (if the ObjectName is not a relation handled by the Relation Service)
    Throws:
      `IllegalArgumentException` - if null parameter

  - ### hasRelation

    public Boolean hasRelation(String relationId) throws IllegalArgumentException
    Checks if there is a relation identified in Relation Service with given relation id.
    Specified by:
      `hasRelation` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id identifying the relation
    Returns:
      boolean: true if there is a relation, false else
    Throws:
      `IllegalArgumentException` - if null parameter

  - ### getAllRelationIds

    public List<String> getAllRelationIds()
    Returns all the relation ids for all the relations handled by the Relation Service.
    Specified by:
      `getAllRelationIds` in interface `RelationServiceMBean`
    Returns:
      ArrayList of String

  - ### checkRoleReading

    public Integer checkRoleReading(String roleName, String relationTypeName) throws IllegalArgumentException, RelationTypeNotFoundException
    Checks if given Role can be read in a relation of the given type.
    Specified by:
      `checkRoleReading` in interface `RelationServiceMBean`
    Parameters:
      `roleName` - name of role to be checked
      `relationTypeName` - name of the relation type
    Returns:
      an Integer wrapping an integer corresponding to possible problems represented as constants in RoleUnresolved:

      - 0 if role can be read

      - integer corresponding to RoleStatus.NO_ROLE_WITH_NAME

      - integer corresponding to RoleStatus.ROLE_NOT_READABLE

    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - if the relation type is not known in the Relation Service

  - ### checkRoleWriting

    public Integer checkRoleWriting(Role role, String relationTypeName, Boolean initFlag) throws IllegalArgumentException, RelationTypeNotFoundException
    Checks if given Role can be set in a relation of given type.
    Specified by:
      `checkRoleWriting` in interface `RelationServiceMBean`
    Parameters:
      `role` - role to be checked
      `relationTypeName` - name of relation type
      `initFlag` - flag to specify that the checking is done for the initialization of a role, write access shall not be verified.
    Returns:
      an Integer wrapping an integer corresponding to possible problems represented as constants in RoleUnresolved:

      - 0 if role can be set

      - integer corresponding to RoleStatus.NO_ROLE_WITH_NAME

      - integer for RoleStatus.ROLE_NOT_WRITABLE

      - integer for RoleStatus.LESS_THAN_MIN_ROLE_DEGREE

      - integer for RoleStatus.MORE_THAN_MAX_ROLE_DEGREE

      - integer for RoleStatus.REF_MBEAN_OF_INCORRECT_CLASS

      - integer for RoleStatus.REF_MBEAN_NOT_REGISTERED

    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - if unknown relation type

  - ### sendRelationCreationNotification

    public void sendRelationCreationNotification(String relationId) throws IllegalArgumentException, RelationNotFoundException
    Sends a notification (RelationNotification) for a relation creation. The notification type is:

    - RelationNotification.RELATION_BASIC_CREATION if the relation is an object internal to the Relation Service

    - RelationNotification.RELATION_MBEAN_CREATION if the relation is a MBean added as a relation.

    The source object is the Relation Service itself.

    It is called in Relation Service createRelation() and addRelation() methods.

    Specified by:
      `sendRelationCreationNotification` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation identifier of the updated relation
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if there is no relation for given relation id

  - ### sendRoleUpdateNotification

    public void sendRoleUpdateNotification(String relationId, Role newRole, List<ObjectName> oldValue) throws IllegalArgumentException, RelationNotFoundException
    Sends a notification (RelationNotification) for a role update in the given relation. The notification type is:

    - RelationNotification.RELATION_BASIC_UPDATE if the relation is an object internal to the Relation Service

    - RelationNotification.RELATION_MBEAN_UPDATE if the relation is a MBean added as a relation.

    The source object is the Relation Service itself.

    It is called in relation MBean setRole() (for given role) and setRoles() (for each role) methods (implementation provided in RelationSupport class).

    It is also called in Relation Service setRole() (for given role) and setRoles() (for each role) methods.

    Specified by:
      `sendRoleUpdateNotification` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation identifier of the updated relation
      `newRole` - new role (name and new value)
      `oldValue` - old role value (List of ObjectName objects)
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if there is no relation for given relation id

  - ### sendRelationRemovalNotification

    public void sendRelationRemovalNotification(String relationId, List<ObjectName> unregMBeanList) throws IllegalArgumentException, RelationNotFoundException
    Sends a notification (RelationNotification) for a relation removal. The notification type is:

    - RelationNotification.RELATION_BASIC_REMOVAL if the relation is an object internal to the Relation Service

    - RelationNotification.RELATION_MBEAN_REMOVAL if the relation is a MBean added as a relation.

    The source object is the Relation Service itself.

    It is called in Relation Service removeRelation() method.

    Specified by:
      `sendRelationRemovalNotification` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation identifier of the updated relation
      `unregMBeanList` - List of ObjectNames of MBeans expected to be unregistered due to relation removal (can be null)
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if there is no relation for given relation id

  - ### updateRoleMap

    public void updateRoleMap(String relationId, Role newRole, List<ObjectName> oldValue) throws IllegalArgumentException, RelationServiceNotRegisteredException, RelationNotFoundException
    Handles update of the Relation Service role map for the update of given role in given relation.

    It is called in relation MBean setRole() (for given role) and setRoles() (for each role) methods (implementation provided in RelationSupport class).

    It is also called in Relation Service setRole() (for given role) and setRoles() (for each role) methods.

    To allow the Relation Service to maintain the consistency (in case of MBean unregistration) and to be able to perform queries, this method must be called when a role is updated.

    Specified by:
      `updateRoleMap` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation identifier of the updated relation
      `newRole` - new role (name and new value)
      `oldValue` - old role value (List of ObjectName objects)
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `RelationNotFoundException` - if no relation for given id.

  - ### removeRelation

    public void removeRelation(String relationId) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationNotFoundException
    Removes given relation from the Relation Service.

    A RelationNotification notification is sent, its type being:

    - RelationNotification.RELATION_BASIC_REMOVAL if the relation was only internal to the Relation Service

    - RelationNotification.RELATION_MBEAN_REMOVAL if the relation is registered as an MBean.

    For MBeans referenced in such relation, nothing will be done,

    Specified by:
      `removeRelation` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id of the relation to be removed
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation corresponding to given relation id

  - ### purgeRelations

    public void purgeRelations() throws RelationServiceNotRegisteredException
    Purges the relations.

    Depending on the purgeFlag value, this method is either called automatically when a notification is received for the unregistration of an MBean referenced in a relation (if the flag is set to true), or not (if the flag is set to false).

    In that case it is up to the user to call it to maintain the consistency of the relations. To be kept in mind that if an MBean is unregistered and the purge not done immediately, if the ObjectName is reused and assigned to another MBean referenced in a relation, calling manually this purgeRelations() method will cause trouble, as will consider the ObjectName as corresponding to the unregistered MBean, not seeing the new one.

    The behavior depends on the cardinality of the role where the unregistered MBean is referenced:

    - if removing one MBean reference in the role makes its number of references less than the minimum degree, the relation has to be removed.

    - if the remaining number of references after removing the MBean reference is still in the cardinality range, keep the relation and update it calling its handleMBeanUnregistration() callback.

    Specified by:
      `purgeRelations` in interface `RelationServiceMBean`
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server.

  - ### findReferencingRelations

    public Map<String, List<String>> findReferencingRelations(ObjectName mbeanName, String relationTypeName, String roleName) throws IllegalArgumentException
    Retrieves the relations where a given MBean is referenced.

    This corresponds to the CIM "References" and "ReferenceNames" operations.

    Specified by:
      `findReferencingRelations` in interface `RelationServiceMBean`
    Parameters:
      `mbeanName` - ObjectName of MBean
      `relationTypeName` - can be null; if specified, only the relations of that type will be considered in the search. Else all relation types are considered.
      `roleName` - can be null; if specified, only the relations where the MBean is referenced in that role will be returned. Else all roles are considered.
    Returns:
      an HashMap, where the keys are the relation ids of the relations where the MBean is referenced, and the value is, for each key, an ArrayList of role names (as an MBean can be referenced in several roles in the same relation).
    Throws:
      `IllegalArgumentException` - if null parameter

  - ### findAssociatedMBeans

    public Map<ObjectName, List<String>> findAssociatedMBeans(ObjectName mbeanName, String relationTypeName, String roleName) throws IllegalArgumentException
    Retrieves the MBeans associated to given one in a relation.

    This corresponds to CIM Associators and AssociatorNames operations.

    Specified by:
      `findAssociatedMBeans` in interface `RelationServiceMBean`
    Parameters:
      `mbeanName` - ObjectName of MBean
      `relationTypeName` - can be null; if specified, only the relations of that type will be considered in the search. Else all relation types are considered.
      `roleName` - can be null; if specified, only the relations where the MBean is referenced in that role will be considered. Else all roles are considered.
    Returns:
      an HashMap, where the keys are the ObjectNames of the MBeans associated to given MBean, and the value is, for each key, an ArrayList of the relation ids of the relations where the key MBean is associated to given one (as they can be associated in several different relations).
    Throws:
      `IllegalArgumentException` - if null parameter

  - ### findRelationsOfType

    public List<String> findRelationsOfType(String relationTypeName) throws IllegalArgumentException, RelationTypeNotFoundException
    Returns the relation ids for relations of the given type.
    Specified by:
      `findRelationsOfType` in interface `RelationServiceMBean`
    Parameters:
      `relationTypeName` - relation type name
    Returns:
      an ArrayList of relation ids.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationTypeNotFoundException` - if there is no relation type with that name.

  - ### getRole

    public List<ObjectName> getRole(String relationId, String roleName) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationNotFoundException, RoleNotFoundException
    Retrieves role value for given role name in given relation.
    Specified by:
      `getRole` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
      `roleName` - name of role
    Returns:
      the ArrayList of ObjectName objects being the role value
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation with given id
      `RoleNotFoundException` - if:

      - there is no role with given name

      or

      - the role is not readable.

    See Also:
      - `setRole(String, Role)`

  - ### getRoles

    public RoleResult getRoles(String relationId, String[] roleNameArray) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationNotFoundException
    Retrieves values of roles with given names in given relation.
    Specified by:
      `getRoles` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
      `roleNameArray` - array of names of roles to be retrieved
    Returns:
      a RoleResult object, including a RoleList (for roles successfully retrieved) and a RoleUnresolvedList (for roles not retrieved).
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation with given id
    See Also:
      - `setRoles(String, RoleList)`

  - ### getAllRoles

    public RoleResult getAllRoles(String relationId) throws IllegalArgumentException, RelationNotFoundException, RelationServiceNotRegisteredException
    Returns all roles present in the relation.
    Specified by:
      `getAllRoles` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
    Returns:
      a RoleResult object, including a RoleList (for roles successfully retrieved) and a RoleUnresolvedList (for roles not readable).
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation for given id
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server

  - ### getRoleCardinality

    public Integer getRoleCardinality(String relationId, String roleName) throws IllegalArgumentException, RelationNotFoundException, RoleNotFoundException
    Retrieves the number of MBeans currently referenced in the given role.
    Specified by:
      `getRoleCardinality` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
      `roleName` - name of role
    Returns:
      the number of currently referenced MBeans in that role
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation with given id
      `RoleNotFoundException` - if there is no role with given name

  - ### setRole

    public void setRole(String relationId, Role role) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationNotFoundException, RoleNotFoundException, InvalidRoleValueException
    Sets the given role in given relation.

    Will check the role according to its corresponding role definition provided in relation's relation type

    The Relation Service will keep track of the change to keep the consistency of relations by handling referenced MBean deregistrations.

    Specified by:
      `setRole` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
      `role` - role to be set (name and new value)
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation with given id
      `RoleNotFoundException` - if the role does not exist or is not writable
      `InvalidRoleValueException` - if value provided for role is not valid:

      - the number of referenced MBeans in given value is less than expected minimum degree

      or

      - the number of referenced MBeans in provided value exceeds expected maximum degree

      or

      - one referenced MBean in the value is not an Object of the MBean class expected for that role

      or

      - an MBean provided for that role does not exist

    See Also:
      - `getRole(String, String)`

  - ### setRoles

    public RoleResult setRoles(String relationId, RoleList roleList) throws RelationServiceNotRegisteredException, IllegalArgumentException, RelationNotFoundException
    Sets the given roles in given relation.

    Will check the role according to its corresponding role definition provided in relation's relation type

    The Relation Service keeps track of the changes to keep the consistency of relations by handling referenced MBean deregistrations.

    Specified by:
      `setRoles` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
      `roleList` - list of roles to be set
    Returns:
      a RoleResult object, including a RoleList (for roles successfully set) and a RoleUnresolvedList (for roles not set).
    Throws:
      `RelationServiceNotRegisteredException` - if the Relation Service is not registered in the MBean Server
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation with given id
    See Also:
      - `getRoles(String, String[])`

  - ### getReferencedMBeans

    public Map<ObjectName, List<String>> getReferencedMBeans(String relationId) throws IllegalArgumentException, RelationNotFoundException
    Retrieves MBeans referenced in the various roles of the relation.
    Specified by:
      `getReferencedMBeans` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
    Returns:
      a HashMap mapping:

      ObjectName -> ArrayList of String (role names)

    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation for given relation id

  - ### getRelationTypeName

    public String getRelationTypeName(String relationId) throws IllegalArgumentException, RelationNotFoundException
    Returns name of associated relation type for given relation.
    Specified by:
      `getRelationTypeName` in interface `RelationServiceMBean`
    Parameters:
      `relationId` - relation id
    Returns:
      the name of the associated relation type.
    Throws:
      `IllegalArgumentException` - if null parameter
      `RelationNotFoundException` - if no relation for given relation id

  - ### handleNotification

    public void handleNotification(Notification notif, Object handback)
    Invoked when a JMX notification occurs. Currently handles notifications for unregistration of MBeans, either referenced in a relation role or being a relation itself.
    Specified by:
      `handleNotification` in interface `NotificationListener`
    Parameters:
      `notif` - The notification.
      `handback` - An opaque object which helps the listener to associate information regarding the MBean emitter (can be null).

  - ### getNotificationInfo

    public MBeanNotificationInfo[] getNotificationInfo()
    Returns a NotificationInfo object containing the name of the Java class of the notification and the notification types sent.
    Specified by:
      `getNotificationInfo` in interface `NotificationBroadcaster`
    Returns:
      the array of possible notifications.