javax.persistence.PessimisticLockScope Maven / Gradle / Ivy
// $Id: $
// EJB3 Specification Copyright 2004-2009 Sun Microsystems, Inc.
package javax.persistence;
/**
* Defines the values of the javax.persistence.lock.scope
* property for pessimistic locking. This property may be passed as
* an argument to the methods of the {@link EntityManager},
* {@link Query}, and {@link TypedQuery} interfaces that
* allow lock modes to be specified or used with the
* {@link NamedQuery} annotation.
*
* @since Java Persistence 2.0
*/
public enum PessimisticLockScope {
/**
* This value defines the default behavior for pessimistic locking.
*
* The persistence provider must lock the database row(s) that
* correspond to the non-collection-valued persistent state of
* that instance. If a joined inheritance strategy is used, or if
* the entity is otherwise mapped to a secondary table, this
* entails locking the row(s) for the entity instance in the
* additional table(s). Entity relationships for which the locked
* entity contains the foreign key will also be locked, but not
* the state of the referenced entities (unless those entities are
* explicitly locked). Element collections and relationships for
* which the entity does not contain the foreign key (such as
* relationships that are mapped to join tables or unidirectional
* one-to-many relationships for which the target entity contains
* the foreign key) will not be locked by default.
*/
NORMAL,
/**
* In addition to the behavior for
* PessimisticLockScope.NORMAL, element collections
* and relationships owned by the entity that are contained in
* join tables will be locked if the
* javax.persistence.lock.scope property is specified
* with a value of PessimisticLockScope.EXTENDED.
* The state of entities referenced by such relationships will not
* be locked (unless those entities are explicitly locked).
* Locking such a relationship or element collection generally locks only
* the rows in the join table or collection table for that
* relationship or collection. This means that phantoms will be
* possible.
*/
EXTENDED
}