The following table lists the core JCR interfaces and the corresponding Jackrabbit implementation classes found in this package.
| JCR interface | Implementation class |
|---|---|
| {@link javax.jcr.Repository Repository} | {@link org.apache.jackrabbit.core.RepositoryImpl RepositoryImpl} |
| {@link javax.jcr.Session Session} | {@link org.apache.jackrabbit.core.SessionImpl SessionImpl} |
| {@link javax.jcr.Workspace Workspace} | {@link org.apache.jackrabbit.core.WorkspaceImpl WorkspaceImpl} |
| {@link javax.jcr.Item Item} | {@link org.apache.jackrabbit.core.ItemImpl ItemImpl} |
| {@link javax.jcr.Property Property} | {@link org.apache.jackrabbit.core.PropertyImpl PropertyImpl} |
| {@link javax.jcr.Node Node} | {@link org.apache.jackrabbit.core.NodeImpl NodeImpl} |
A Jackrabbit repository instance can be created using the static {@link org.apache.jackrabbit.core.RepositoryImpl#create(org.apache.jackrabbit.core.config.RepositoryConfig) RepositoryImpl.create(RepositoryConfig)} method. Classes in the {@link org.apache.jackrabbit.core.jndi org.apache.jackrabbit.core.jndi} package provide a mechanism for binding a Jackrabbit repository in a JNDI directory context.
A SessionImpl instance is created upon successfully login to the
Repository (see Repository#login(Credentials, String)).
A Session is always tied to the Workspace
specified in the Repository#login(Credentials, String) call. A
workspace represents a persistent tree of repository items (i.e. Nodes
and Propertys). The items in a workspace are 'visible' to all
sessions accessing it (subject to their access rights, of course).
A WorkspaceImpl instance represents a specifc workspace as
seen by the session that accesses it.
Every repository item is uniquely identified by its ItemId. The id
of a node (NodeId) consists of the node's uuid. The id of a property
(PropertyId) consists of the parent node's uuid and the
name of the property.
Every SessionImpl instance has its own ItemManager.
The per-session instance of ItemManager acts as item factory (i.e.
it creates NodeImpl and PropertyImpl instances) and
provides item access by item id and item caching.
The data (or state) of an item is represented by the following classes in the
subpackage state:
There's one SharedItemStateManager for every workspace.
It provides item state caching and it guarantees that there's only one
(persistent) item state instance for any distinct item id in that workspace.
Every session has its own SessionItemStateManager that consists
of the session's TransientItemStateManager and the workspace's
SharedItemStateManager.
Each item (i.e. NodeImpl and PropertyImpl) instance
is holding an ItemState instance. When e.g. a session is modifying
a property by changing the property's value, a new transient item state
is created by the session's TransientItemStateManager. This
transient state is actually wrapping the (old) shared state (copy on write).
The PropertyImpl's state is then replaced by the new transient state.
Transient (i.e. unsaved) modifications are 'session-local', i.e. they are not visible to other sessions. When the modifications are saved they become instantly visible to all sessions accessing the same workspace.