class RelationshipDeletionHandler extends DeletionHandler {

    @Override
    public String allowDeleteRelationshipType( RelationshipType relationshipType )
    {
        Collection<Relationship> relationships = relationshipService.getRelationshipsByRelationshipType( relationshipType );

        return relationships.isEmpty() ? null : ERROR;
    }

    public  RelationshipDeletionHandler( RelationshipService relationshipService );

}