|
| |
|
| java.lang.Object
 org.jboss.ejb.plugins.lock.BeanLockSupport
org.jboss.ejb.plugins.lock.NoLock
org.jboss.ejb.plugins.lock.JDBCOptimisticLock
| JDBCOptimisticLock | | final public class JDBCOptimisticLock extends NoLock (Code) | | This class is an optmistic lock implementation.
It locks tableFields and their values during transaction.
Locked tableFields and their values are added to the WHERE clause of the
UPDATE SQL statement when entity is stored.
The following strategies are supported:
- fixed group of tableFields
Fixed group of tableFields is used for locking . The tableFields and their values are
locked at the beginning of a transaction. The group name must match
one of the entity's load-group-name.
- modified strategy
The tableFields that were modified during transaction are used as lock.
All entity's field values are locked at the beginning of the transaction.
The tableFields are locked only after its actual change.
- read strategy
The tableFields that were read/modified during transaction.
All entity's field values are locked at the beginning of the transaction.
The tableFields are locked only after they were accessed.
- version-column strategy
This adds additional version field of type java.lang.Long. Each update
of the entity will increase the version value by 1.
- timestamp-column strategy
Adds additional timestamp column of type java.util.Date. Each update
of the entity will set the field to the current time.
- key-generator column strategy
Adds additional column. The type is defined by user. The key generator
is used to set the next value.
Note: all optimistic locking related code should be rewritten when in the
new CMP design.
Note2: done.
author:
Alex Loubyansky
version:
$Revision: 57209 $ |
|
|
|