Ch2 Architecture

Basic APIs

SessionFactory

• thread-safe

• immutable cache of compiled mapping

• for a single database

• multiple factories can be created for multiple database

• uses ConnectionProvider

• optionally maintains a second level cache of data that is reusable between transactions

Session

• single-threaded

• short-lived, represent a conversion

• wraps a JDBC connection

• factory for org.hibernate.Transaction (can span several transaction)

• maintains first level cache of persistent objects and collections

Persistent objects and collections

• short-lived single threaded

• contains persistent state and business function

• associated with exactly one Session

• once session is closed, it's detached and free to use

Transient and detached objects and collections

• either created and not persisted

• or obtained from a closed session

Transaction (org.hibernate.Transaction)

• single threaded, short-lived

• under-laying is JDBC, JTA or CORBA transaction

ConnectionProvider

• factory for, and pool of JDBC connection

• not exposed to application, can be extended

TransactionFactory

• not exposed, can be extended

ExtensionInterfaces

Contextual Session

SessionFactory.getCurrentSession()

• Configured by hibernate.current_session_context_class

  • configure full class name, or

  • three short names : "jta", "thread", "managed"

• JTA transactions

  • initially assuming using

  • defines the scope and context of current session

  • can use JTA interface to demarcate transactions

  • recommended for most applications, whether or not deployed in JEE container

  • if used in JEE container supporting CMT (container managed transaction), can use annotation

• Thread Local

  • (previously not recommended for production use)

• Managed Session

  • developer is responsible for bind and unbind

Use Hibernate Transaction API

• recommended if use plain Java SE without JTA