http://www.avaje.org/persistence-api: Packaging parent for Avaje OSS projects.
  • Rob Bygrave 
/*
 * Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.  The Eclipse Public License is available
 * at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
 * is available at http://www.eclipse.org/org/documents/edl-v10.php.
 */
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 EntityManager, Query, and TypedQuery interfaces that allow lock modes to be specified or used with the NamedQuery annotation. 
Since:Java Persistence 2.0
/**
 * Defines the values of the <code>javax.persistence.lock.scope</code> 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.

/**
   * This value defines the default behavior for pessimistic locking.
   * <p>
   * 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.

/**
   * In addition to the behavior for <code>PessimisticLockScope.NORMAL</code>, element collections and
   * relationships owned by the entity that are contained in join tables will be locked if the
   * <code>javax.persistence.lock.scope</code> property is specified with a value of
   * <code>PessimisticLockScope.EXTENDED</code>. 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
}