Annotea Object Identification

Like other Annotea objects, the bookmark and the topic objects have their own identification URI. This URI ensures that Annotea objects retain their identity globally even when objects are merged together from different data stores, or moved to another location along with a bookmark file, or sent to another user by e-mail. Not all users have their own Web domains. Therefore, the current Annotea Ubimarks implementation uses URIs that are unique UUIDs, such as “urn:uid:025f3d84-57bd-11da-924db619a79a047d”. The UUIDs can be easily created without owning a Web domain. Resolving the objects content based on the UUID would need more work, but that is not usually a problem. Alternatively, the user can choose HTTP addresses in her own domain with date info by defining an URI path, for instance, “http://mydomain.org/AnnoteaURI/”. Similarly, a bookmark server can create URIs. If the URI changes in the server or for some other reason, the correspondence between two Annotea objects can be defined by using the owl:sameAs property

Bookmark and Topic Properties

Annotea does not define all bookmark and topic properties by itself. It uses properties from well known vocabularies, such as Dublin Core. Applications already familiar with these properties know how to deal with them also in Annotea object context without any extra processing.RDF for a sample bookmark and a topic is presented in Figure 1. Bookmarks and topics have many common properties with other Annotea objects. For instance, the objects can have a title (dc:title), a longer description (dc:description), information about their author (dc:creator and foaf:maker), the creation date (a:created), the modification date (dc:date), and links to other related information (RDFS:seeAlso)