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org.eclipse.persistence.descriptors
Class ChangedFieldsLockingPolicy
java.lang.Object
org.eclipse.persistence.descriptors.FieldsLockingPolicy
org.eclipse.persistence.descriptors.ChangedFieldsLockingPolicy
- All Implemented Interfaces:
- java.io.Serializable, java.lang.Cloneable, org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy
-
public class ChangedFieldsLockingPolicy
- extends FieldsLockingPolicy
Purpose: An implementation of the OptimisticLockingPolicy interface. This policy compares only the changed fields in the WHERE clause when doing an update. If any field has been changed, an optimistic locking exception will be thrown. A delete will only compare the primary key.
NOTE: This policy can only be used inside a unit of work.
- Since:
- TopLink 2.1
- Author:
- Peter Krogh
- See Also:
- Serialized Form
Nested classes/interfaces inherited from interface org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy |
org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange |
Method Summary |
void |
addLockValuesToTranslationRow(ObjectLevelModifyQuery query)
INTERNAL: Values to be included in the locking mechanism are added to the translation row. |
Expression |
buildDeleteExpression(org.eclipse.persistence.internal.helper.DatabaseTable table, Expression mainExpression, org.eclipse.persistence.internal.sessions.AbstractRecord row)
INTERNAL: When given an expression, this method will return a new expression with the optimistic locking values included. |
protected java.util.List<org.eclipse.persistence.internal.helper.DatabaseField> |
getFieldsToCompare(org.eclipse.persistence.internal.helper.DatabaseTable table, org.eclipse.persistence.internal.sessions.AbstractRecord transRow, org.eclipse.persistence.internal.sessions.AbstractRecord modifyRow)
INTERNAL: Returns the fields that should be compared in the where clause. |
Methods inherited from class org.eclipse.persistence.descriptors.FieldsLockingPolicy |
addLockFieldsToUpdateRow, buildAllNonPrimaryKeyFields, buildExpression, buildUpdateExpression, clone, compareWriteLockValues, getAllNonPrimaryKeyFields, getAllNonPrimaryKeyFields, getBaseValue, getLockOnChangeMode, getValueToPutInCache, getVersionDifference, getWriteLockField, getWriteLockUpdateExpression, getWriteLockValue, initialize, initializeProperties, isCascaded, isNewerVersion, isNewerVersion, isPrimaryKey, isStoredInCache, mergeIntoParentCache, setAllNonPrimaryKeyFields, setDescriptor, setLockOnChangeMode, setupWriteFieldsForInsert, shouldUpdateVersionOnMappingChange, shouldUpdateVersionOnOwnedMappingChange, supportsWriteLockValuesComparison, updateRowAndObjectForUpdate, validateDelete, validateUpdate, verifyUsage |
Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
ChangedFieldsLockingPolicy
public ChangedFieldsLockingPolicy()
- PUBLIC: Create a new changed fields locking policy. This locking policy is based on locking on all changed fields by comparing with their previous values to detect field-level collisions. Note: the unit of work must be used for all updates when using field locking. Without a unit of work, there is no way for to know what the original values were without the back up clone in the unit of work.
addLockValuesToTranslationRow
public void addLockValuesToTranslationRow(ObjectLevelModifyQuery query)
- INTERNAL: Values to be included in the locking mechanism are added to the translation row. For changed fields the normal build row is ok as only changed fields matter.
-
- Specified by:
addLockValuesToTranslationRow
in interface org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy
- Specified by:
addLockValuesToTranslationRow
in class FieldsLockingPolicy
buildDeleteExpression
public Expression buildDeleteExpression(org.eclipse.persistence.internal.helper.DatabaseTable table,
Expression mainExpression,
org.eclipse.persistence.internal.sessions.AbstractRecord row)
- INTERNAL: When given an expression, this method will return a new expression with the optimistic locking values included. The values are taken from the passed in database row. This expression will be used in a delete call. No new criteria will be added for changed fields.
-
- Specified by:
buildDeleteExpression
in interface org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy
- Overrides:
buildDeleteExpression
in class FieldsLockingPolicy
getFieldsToCompare
protected java.util.List<org.eclipse.persistence.internal.helper.DatabaseField> getFieldsToCompare(org.eclipse.persistence.internal.helper.DatabaseTable table,
org.eclipse.persistence.internal.sessions.AbstractRecord transRow,
org.eclipse.persistence.internal.sessions.AbstractRecord modifyRow)
- INTERNAL: Returns the fields that should be compared in the where clause. In this case, it is only the fields that were changed.
-
- Specified by:
getFieldsToCompare
in class FieldsLockingPolicy
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