JEAN stands for Java Entity Attribute Network.
Java is the programming language used for JEAN. This does not make much difference to an average user, except to note that it means that the program will run unchanged on virtually every type of computer. It does make a difference however to system builders; JEAN comes with an API (Application Programmers Interface) so that JEAN may be incorporated as a component in larger systems. Java is also one of the major languages used in the World Wide Web, so JEAN may be used in web applications.
The Oxford Dictionary defines entity as "A thing's existence, as opposed to its qualities or relations."
Entities are just items, which can be virtually anything that you can find on a computer network. The word object has a specific meaning in computing so we use the word entity to indicate that we can deal with just about everything. Because
the entities are connected in a network the term node is often used interchangeably with entity.
JEAN recognises three types of entity:
Catalogs which are used to classify groups and items,
Groups which are used to group items together either permanently or temporarily, and
Items which are either the actual items of interest in this collection, or which represent and point to the actual items of interest.
An item may be in a number of groups and/or a number of categories.
Attributes are, as described above, properties of the entities that we are interested in, these can be things like names, dates of acquisition or descriptions. JEAN has a rich variety of attribute types; some types are simply to hold values, some point to files, some reference other JEAN entities. When a JEAN application is being designed the major design effort is to decide the types of attributes that each entity will have; Categories, Groups and Items can all have their own sets of attributes defined.
JEAN entities are linked together to form a Network. The structure that is used for a JEAN Catalog is known as a DAG (Directed Acyclic Graph). This is similiar to the familiar tree shown in, for example, an Explorer window, the difference being that any entity can have more than one container as opposed to a file which can only be in one folder. An item may be in a number of groups, or a number of categories.
One of the visual components of JEAN is the Catalog which looks like a tree, however as your application expands you will find that the same item in the Catalog can be reached by a number of different paths.