```
public interface ExternalReferencesInterface
```
The ExternalReferencesInterface is used by the governance team to define external references to elements within the governance program.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`String`	`createExternalReference(String userId, String anchorGUID, ExternalReferenceProperties properties)`	Create a definition of a external reference.
`void`	`deleteExternalReference(String userId, String externalReferenceGUID)`	Remove the definition of a external reference.
`List<ExternalReferenceElement>`	`findExternalReferencesById(String userId, String resourceId, int startFrom, int pageSize)`	Retrieve the list of external references for this resourceId.
`ExternalReferenceElement`	`getExternalReferenceByGUID(String userId, String externalReferenceGUID)`	Return information about a specific external reference.
`List<ExternalReferenceElement>`	`getExternalReferencesByURL(String userId, String url, int startFrom, int pageSize)`	Retrieve the list of external references for this URL.
`void`	`linkExternalReferenceToElement(String userId, String attachedToGUID, String externalReferenceGUID, ExternalReferenceLinkProperties linkProperties)`	Link an external reference to an object.
`List<ExternalReferenceElement>`	`retrieveAttachedExternalReferences(String userId, String attachedToGUID, int startFrom, int pageSize)`	Retrieve the list of external references attached to the supplied object.
`void`	`unlinkExternalReferenceFromElement(String userId, String attachedToGUID, String externalReferenceGUID)`	Remove the link between a external reference and an element.
`void`	`updateExternalReference(String userId, String externalReferenceGUID, boolean isMergeUpdate, ExternalReferenceProperties properties)`	Update the definition of a external reference.

Method Detail

createExternalReference
```
String createExternalReference(String userId,
                               String anchorGUID,
                               ExternalReferenceProperties properties)
                        throws InvalidParameterException,
                               UserNotAuthorizedException,
                               PropertyServerException
```
Create a definition of a external reference.

Parameters:

userId - calling user

anchorGUID - optional element to link the external reference to that will act as an anchor - that is, this external reference will be deleted when the element is deleted (once the external reference is linked to the anchor).

properties - properties for a external reference

Returns:

unique identifier of the external reference

Throws:

InvalidParameterException - qualifiedName or userId is null; qualifiedName is not unique

PropertyServerException - problem accessing property server

UserNotAuthorizedException - security access problem

updateExternalReference

void updateExternalReference(String userId,
                             String externalReferenceGUID,
                             boolean isMergeUpdate,
                             ExternalReferenceProperties properties)
                      throws InvalidParameterException,
                             UserNotAuthorizedException,
                             PropertyServerException

Update the definition of a external reference.

Parameters:: userId - calling user; externalReferenceGUID - unique identifier of external reference; isMergeUpdate - are unspecified properties unchanged (true) or replaced with null?; properties - properties to change
Throws:: InvalidParameterException - guid, qualifiedName or userId is null; qualifiedName is not unique; guid is not known; PropertyServerException - problem accessing property server; UserNotAuthorizedException - security access problem

deleteExternalReference

void deleteExternalReference(String userId,
                             String externalReferenceGUID)
                      throws InvalidParameterException,
                             UserNotAuthorizedException,
                             PropertyServerException

Remove the definition of a external reference.

Parameters:: userId - calling user; externalReferenceGUID - unique identifier of external reference
Throws:: InvalidParameterException - guid or userId is null; guid is not known; PropertyServerException - problem accessing property server; UserNotAuthorizedException - security access problem

linkExternalReferenceToElement

void linkExternalReferenceToElement(String userId,
                                    String attachedToGUID,
                                    String externalReferenceGUID,
                                    ExternalReferenceLinkProperties linkProperties)
                             throws InvalidParameterException,
                                    PropertyServerException,
                                    UserNotAuthorizedException

Link an external reference to an object.

Parameters:: userId - the name of the calling user.; attachedToGUID - object linked to external references.; linkProperties - description for the reference from the perspective of the object that the reference is being attached to.; externalReferenceGUID - unique identifier (guid) of the external reference details.
Throws:: InvalidParameterException - problem with the GUID or the external references are not correctly specified, or are null.; PropertyServerException - the server is not available.; UserNotAuthorizedException - the calling user is not authorized to issue the call.

unlinkExternalReferenceFromElement
```
void unlinkExternalReferenceFromElement(String userId,
                                        String attachedToGUID,
                                        String externalReferenceGUID)
                                 throws InvalidParameterException,
                                        PropertyServerException,
                                        UserNotAuthorizedException
```
Remove the link between a external reference and an element. If the element is its anchor, the external reference is removed.

Parameters:

userId - the name of the calling user.

attachedToGUID - object linked to external references.

externalReferenceGUID - identifier of the external reference.

Throws:

InvalidParameterException - problem with the GUID or the external references are not correctly specified, or are null.

PropertyServerException - the server is not available.

UserNotAuthorizedException - the calling user is not authorized to issue the call.

getExternalReferenceByGUID

ExternalReferenceElement getExternalReferenceByGUID(String userId,
                                                    String externalReferenceGUID)
                                             throws InvalidParameterException,
                                                    UserNotAuthorizedException,
                                                    PropertyServerException

Return information about a specific external reference.

Parameters:: userId - calling user; externalReferenceGUID - unique identifier for the external reference
Returns:: properties of the external reference
Throws:: InvalidParameterException - externalReferenceGUID or userId is null; PropertyServerException - problem accessing property server; UserNotAuthorizedException - security access problem

findExternalReferencesById

List<ExternalReferenceElement> findExternalReferencesById(String userId,
                                                          String resourceId,
                                                          int startFrom,
                                                          int pageSize)
                                                   throws InvalidParameterException,
                                                          PropertyServerException,
                                                          UserNotAuthorizedException

Retrieve the list of external references for this resourceId.

Parameters:: userId - the name of the calling user.; resourceId - unique reference id assigned by the resource owner (supports wildcards). This is the qualified name of the entity; startFrom - index of the list to start from (0 for start); pageSize - maximum number of elements to return.
Returns:: links to addition information.
Throws:: InvalidParameterException - guid invalid or the external references are not correctly specified, or are null.; PropertyServerException - the server is not available.; UserNotAuthorizedException - the calling user is not authorized to issue the call.

getExternalReferencesByURL

List<ExternalReferenceElement> getExternalReferencesByURL(String userId,
                                                          String url,
                                                          int startFrom,
                                                          int pageSize)
                                                   throws InvalidParameterException,
                                                          PropertyServerException,
                                                          UserNotAuthorizedException

Retrieve the list of external references for this URL.

Parameters:: userId - the name of the calling user.; url - URL of the external resource.; startFrom - index of the list to start from (0 for start); pageSize - maximum number of elements to return.
Returns:: links to addition information.
Throws:: InvalidParameterException - guid invalid or the external references are not correctly specified, or are null.; PropertyServerException - the server is not available.; UserNotAuthorizedException - the calling user is not authorized to issue the call.

retrieveAttachedExternalReferences

List<ExternalReferenceElement> retrieveAttachedExternalReferences(String userId,
                                                                  String attachedToGUID,
                                                                  int startFrom,
                                                                  int pageSize)
                                                           throws InvalidParameterException,
                                                                  PropertyServerException,
                                                                  UserNotAuthorizedException

Retrieve the list of external references attached to the supplied object.

Parameters:: userId - the name of the calling user.; attachedToGUID - object linked to external reference.; startFrom - index of the list to start from (0 for start); pageSize - maximum number of elements to return.
Returns:: links to addition information.
Throws:: InvalidParameterException - guid invalid or the external references are not correctly specified, or are null.; PropertyServerException - the server is not available.; UserNotAuthorizedException - the calling user is not authorized to issue the call.

Interface ExternalReferencesInterface