Defines the contract for objects which are able to manage the lifecycle of a Session associated with a well-defined "context" or "scope", providing the concrete implementation behind the notion of the current session.

The lifecycle of the context/scope is not specified by Hibernate, and varies depending on the nature of the program. The only hard restriction is that the scope must be single-threaded. On the other hand, since state tends to build up in the first-level cache of session, sessions should typically not be associated with long-lived scopes.

The most typical example of a scope with which a current session might be associated is the HTTP request context in a web application.

An implementation of this interface must:

• have a constructor accepting a single argument of type org.hibernate.engine.spi.SessionFactoryImplementor,
• be thread-safe,
• be fully serializable,
• guarantee that it destroys every session it creates, and
• ensure that each session it creates is the exclusive property of a single thread, since sessions contain fragile mutable state and are never considered thread-safe.

Every session factory has exactly one instance of this interface.

An implementation may be selected by setting the configuration property hibernate.current_session_context_class.