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org.eclipse.persistence.descriptors
Class SelectedFieldsLockingPolicy

java.lang.Object
org.eclipse.persistence.descriptors.FieldsLockingPolicy
org.eclipse.persistence.descriptors.SelectedFieldsLockingPolicy

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy

public class SelectedFieldsLockingPolicy

extends FieldsLockingPolicy

Purpose: An implementation of the OptimisticLockingPolicy interface. This policy compares selected fields in the WHERE clause when doing an update or a delete. If any field has been changed, an optimistic locking exception will be thrown. Note that the fields specified must be mapped and not be primary keys.

NOTE: This policy can only be used inside a unit of work.

Since:

TopLink 2.5

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy

org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange

Field Summary

protected java.util.Vector	lockFields
protected java.util.Map	lockFieldsByTable

Fields inherited from class org.eclipse.persistence.descriptors.FieldsLockingPolicy

allNonPrimaryKeyFields, descriptor

Constructor Summary

SelectedFieldsLockingPolicy()
PUBLIC: Create a new selected fields locking policy.

Method Summary

void	addLockFieldName(java.lang.String fieldName) PUBLIC: Add a fieldname to lock on.
void	addLockValuesToTranslationRow(ObjectLevelModifyQuery query) INTERNAL: Values to be included in the locking mechanism are added to the translation row.
protected java.util.Vector	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 lock fields to compare based on the passed in table.
java.util.Vector	getLockFields() INTERNAL: Returns the lock fields
protected java.util.Vector	getLockFields(org.eclipse.persistence.internal.helper.DatabaseTable table) INTERNAL: returns the lock fields based on the passed in table
protected java.util.Map	getLockFieldsByTable() INTERNAL: returns the lock fields
void	initialize(org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: It is responsible for initializing the policy;
void	setLockFieldNames(java.util.Vector lockFieldNames) PUBLIC: Set the field names to lock on.
void	setLockFields(java.util.Map lockFieldsByTable) INTERNAL: Used to set the field names to be used in this policy.
protected void	setLockFields(java.util.Vector lockFields) INTERNAL: Sets the lock fields
protected void	setLockFieldsByTable(java.util.Map lockFieldsByTable) INTERNAL: Used to set the field names to be used in this policy.

Methods inherited from class org.eclipse.persistence.descriptors.FieldsLockingPolicy

addLockFieldsToUpdateRow, buildAllNonPrimaryKeyFields, buildDeleteExpression, buildExpression, buildUpdateExpression, clone, compareWriteLockValues, getAllNonPrimaryKeyFields, getAllNonPrimaryKeyFields, getBaseValue, getLockOnChangeMode, getValueToPutInCache, getVersionDifference, getWriteLockField, getWriteLockUpdateExpression, getWriteLockValue, 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

Field Detail

lockFieldsByTable

protected java.util.Map lockFieldsByTable

lockFields

protected java.util.Vector lockFields

Constructor Detail

SelectedFieldsLockingPolicy

public SelectedFieldsLockingPolicy()

PUBLIC: Create a new selected fields locking policy. A field locking policy is based on locking on the specified 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.

Method Detail

addLockFieldName

public void addLockFieldName(java.lang.String fieldName)

PUBLIC: Add a fieldname to lock on. All fields in this list will be compared when Updating if the value of any of the fields does not match the value in memory, an OptimisticLockException will be thrown. Note: An Automatic update will not be done on this field, only a comparison occurs.

addLockValuesToTranslationRow

public void addLockValuesToTranslationRow(ObjectLevelModifyQuery query)
                                   throws DatabaseException

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

Throws:

DatabaseException

getFieldsToCompare

protected java.util.Vector 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 lock fields to compare based on the passed in table.

Specified by:

getFieldsToCompare in class FieldsLockingPolicy

getLockFields

public java.util.Vector getLockFields()

INTERNAL: Returns the lock fields

getLockFields

protected java.util.Vector getLockFields(org.eclipse.persistence.internal.helper.DatabaseTable table)

INTERNAL: returns the lock fields based on the passed in table

getLockFieldsByTable

protected java.util.Map getLockFieldsByTable()

INTERNAL: returns the lock fields

initialize

public void initialize(org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: It is responsible for initializing the policy;

Specified by:

initialize in interface org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy

Overrides:

initialize in class FieldsLockingPolicy

setLockFieldNames

public void setLockFieldNames(java.util.Vector lockFieldNames)

PUBLIC: Set the field names to lock on. All fields in this list will be compared when Updating. If the value of any of the fields does not match the value in memory, an OptimisticLockException will be thrown. Note: An Automatic update will not be done on this field, only a comparison occurs.

setLockFields

public void setLockFields(java.util.Map lockFieldsByTable)

INTERNAL: Used to set the field names to be used in this policy.

setLockFields

protected void setLockFields(java.util.Vector lockFields)

INTERNAL: Sets the lock fields

setLockFieldsByTable

protected void setLockFieldsByTable(java.util.Map lockFieldsByTable)

INTERNAL: Used to set the field names to be used in this policy.

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