Distribution List handling
==========================

In order to use the existing distribution lists for the CardDAV interface, some
changes have been implemented regarding the distribution list handling. This
document describes those changes.


Terms and Definitions
---------------------

(a) Contact
A contact is a container object for addressbook-related properties. A contact is
uniquely identified by a combination of its context-, folder- and object-ID.

(b) Distribution List
A distribution list is a collection of address entries (members). Each address
entry represents either another Contact, or only an e-mail address and
optionally a name, a so called One-Off address entry.

(c) One-Off Address Entry
A One-Off address entry is an independant address, i.e. an address aentry that
does not represent another existing contact.

(d) Distribution List Member
A distribution list member is an address entry of a distribution list.


Usage of folder IDs
-------------------

Until now, only the context- and object-IDs were used by distribution lists to
identify a referenced contact. From now on, also the folder-ID is used. This is
necessary to support different contact storages in the future. Therefore, the
new field folder_id (type String) is introduced for the Distribution