/******************************************************************************* | |
* Copyright (c) 2008 - 2013 Oracle Corporation. 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. | |
* | |
* Contributors: | |
* Linda DeMichiel - Java Persistence 2.1 | |
* Linda DeMichiel - Java Persistence 2.0 | |
* | |
******************************************************************************/ | |
package javax.persistence; | |
/** | |
* 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. | |
* | |
* <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 | |
* <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 | |
} |