public String getDocument(@PathParam("entityType") final String entityType, @PathParam("entityId") final Long entityId,
@PathParam("documentId") final Long documentId, @Context final UriInfo uriInfo) {
this.context.authenticatedUser().validateHasReadPermission(this.SystemEntityType);
final DocumentData documentData = this.documentReadPlatformService.retrieveDocument(entityType, entityId, documentId);
final ApiRequestJsonSerializationSettings settings = this.apiRequestParameterHelper.process(uriInfo.getQueryParameters());
return this.toApiJsonSerializer.serialize(settings, documentData, this.RESPONSE_DATA_PARAMETERS);
}