org.eclipse.persistence.descriptors

Class VersionLockingPolicy

java.lang.Object

org.eclipse.persistence.descriptors.VersionLockingPolicy

All Implemented Interfaces:

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

Direct Known Subclasses:

TimestampLockingPolicy

public class VersionLockingPolicy
extends java.lang.Object
implements org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy, java.io.Serializable

Purpose: Used to allow a single version number to be used for optimistic locking.

Since:

TOPLink/Java 2.0

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

Fields

Modifier and Type	Field and Description
static int	IN_CACHE
static int	IN_OBJECT

Constructor Summary

Constructors

Constructor and Description
VersionLockingPolicy() PUBLIC: Create a new VersionLockingPolicy.
VersionLockingPolicy(org.eclipse.persistence.internal.helper.DatabaseField field) PUBLIC: Create a new VersionLockingPolicy.
VersionLockingPolicy(java.lang.String fieldName) PUBLIC: Create a new VersionLockingPolicy.

Method Summary

Methods

Modifier and Type	Method and Description
void	addLockFieldsToUpdateRow(org.eclipse.persistence.internal.sessions.AbstractRecord databaseRow, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Add update fields for template row.
void	addLockValuesToTranslationRow(ObjectLevelModifyQuery query) INTERNAL: This method adds the lock value to the translation row of the passed in query. depending on the storage flag, the value is either retrieved from the cache of the object.
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.
Expression	buildUpdateExpression(org.eclipse.persistence.internal.helper.DatabaseTable table, Expression mainExpression, org.eclipse.persistence.internal.sessions.AbstractRecord row, org.eclipse.persistence.internal.sessions.AbstractRecord row2) INTERNAL: When given an expression, this method will return a new expression with the optimistic locking values included.
java.lang.Object	clone() INTERNAL: Clone the policy
int	compareWriteLockValues(java.lang.Object value1, java.lang.Object value2) INTERNAL: This method compares two writeLockValues.
java.lang.Object	getBaseValue() INTERNAL: This is the base value that is older than all other values, it is used in the place of null in some situations.
org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange	getLockOnChangeMode() ADVANCED: returns the LockOnChange mode for this policy.
java.lang.Object	getNewLockValue(ModifyQuery query) INTERNAL: This method gets the write lock value from either the cache or the object stored in the query.
java.lang.Object	getValueToPutInCache(org.eclipse.persistence.internal.sessions.AbstractRecord row, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Return the value that should be stored in the identity map.
int	getVersionDifference(java.lang.Object currentValue, java.lang.Object domainObject, java.lang.Object primaryKeys, org.eclipse.persistence.internal.sessions.AbstractSession session) PUBLIC: Return the number of versions different between these objects.
AbstractDirectMapping	getVersionMapping() INTERNAL: Returns the mapping that will be used to access the version value from an object.
org.eclipse.persistence.internal.helper.DatabaseField	getWriteLockField() INTERNAL: Return the write lock field.
java.lang.String	getWriteLockFieldName() PUBLIC: Return the field name of the field that stores the write lock value.
Expression	getWriteLockUpdateExpression(ExpressionBuilder builder, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Retrun an expression that updates the write lock
java.lang.Object	getWriteLockValue(java.lang.Object domainObject, java.lang.Object primaryKey, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: This method will return the optimistic lock value for the object
void	initialize(org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: It is responsible for initializing the policy;
void	initializeProperties() INTERNAL: It is responsible for initializing the policy properties;
boolean	isCascaded() PUBLIC: Return true if the policy uses cascade locking.
boolean	isNewerVersion(org.eclipse.persistence.internal.sessions.AbstractRecord databaseRow, java.lang.Object domainObject, java.lang.Object primaryKey, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Compares the value from the row and from the object (or cache).
boolean	isNewerVersion(java.lang.Object firstLockFieldValue, java.lang.Object secondWriteLockFieldValue) INTERNAL: Compares two values.
boolean	isNewerVersion(java.lang.Object currentValue, java.lang.Object domainObject, java.lang.Object primaryKey, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Compares the value with the value from the object (or cache).
boolean	isStoredInCache() PUBLIC: Return true if the lock value is stored in the cache.
boolean	isStoredInObject() PUBLIC: Return true if the lock value is stored in the object.
void	mergeIntoParentCache(org.eclipse.persistence.internal.identitymaps.CacheKey unitOfWorkCacheKey, org.eclipse.persistence.internal.identitymaps.CacheKey parentSessionCacheKey) INTERNAL: This method should merge changes from the parent into the child.
void	mergeIntoParentCache(org.eclipse.persistence.internal.sessions.UnitOfWorkImpl uow, java.lang.Object primaryKey, java.lang.Object object) INTERNAL: Only applicable when the value is stored in the cache.
void	setDescriptor(ClassDescriptor descriptor) INTERNAL:
void	setIsCascaded(boolean isCascaded) PUBLIC: Set whether to use cascade locking on the policy.
void	setIsStoredInCache(boolean isStoredInCache) PUBLIC: Set whether to store the lock in the cache or in the object.
void	setLockOnChangeMode(org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange lockOnChangeMode) ADVANCED: Sets the LockOnChange mode for this policy.
void	setupWriteFieldsForInsert(ObjectLevelModifyQuery query) INTERNAL: This method must be included in any locking policy.
void	setWriteLockField(org.eclipse.persistence.internal.helper.DatabaseField writeLockField) ADVANCED: Set the write lock field.
void	setWriteLockFieldName(java.lang.String writeLockFieldName) PUBLIC: Set the write lock field name.
boolean	shouldUpdateVersionOnMappingChange() INTERNAL: Returns true if the policy has been set to set an optimistic read lock when any mapping changes.
boolean	shouldUpdateVersionOnOwnedMappingChange() INTERNAL: Returns true if the policy has been set to set an optimistic read lock when a owning mapping changes.
void	storeInCache() PUBLIC: Configure the version lock value to be stored in the cache.
void	storeInObject() PUBLIC: Configure the version lock value to be stored in the object.
boolean	supportsWriteLockValuesComparison() INTERNAL: Indicates that compareWriteLockValues method is supported by the policy.
void	updateObjectWithWriteValue(ObjectLevelModifyQuery query, java.lang.Object lockValue)
void	updateRowAndObjectForUpdate(ObjectLevelModifyQuery query, java.lang.Object domainObject) INTERNAL: This method updates the modify row, and the domain object with the new lock value.
void	validateDelete(int rowCount, java.lang.Object object, DeleteObjectQuery query) INTERNAL: Check the row count for lock failure.
void	validateUpdate(int rowCount, java.lang.Object object, WriteObjectQuery query) INTERNAL: Check the row count for lock failure.
void	writeLockValueIntoRow(ObjectLevelModifyQuery query, java.lang.Object domainObject) INTERNAL: This method updates the modify row with the old lock value.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

IN_CACHE

public static final int IN_CACHE

See Also:

Constant Field Values

IN_OBJECT

public static final int IN_OBJECT

See Also:

Constant Field Values

Constructor Detail

VersionLockingPolicy

public VersionLockingPolicy()

PUBLIC: Create a new VersionLockingPolicy. Defaults to storing the lock value in the cache.

VersionLockingPolicy

public VersionLockingPolicy(java.lang.String fieldName)

PUBLIC: Create a new VersionLockingPolicy. Defaults to storing the lock value in the cache.

Parameters:

fieldName - specifies the field name for the write lock field.

VersionLockingPolicy

public VersionLockingPolicy(org.eclipse.persistence.internal.helper.DatabaseField field)

PUBLIC: Create a new VersionLockingPolicy. Defaults to storing the lock value in the cache.

Parameters:

field - the write lock field.

Method Detail

addLockFieldsToUpdateRow

public void addLockFieldsToUpdateRow(org.eclipse.persistence.internal.sessions.AbstractRecord databaseRow,
                            org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: Add update fields for template row. These are any unmapped fields required to write in an update.

Specified by:

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

addLockValuesToTranslationRow

public void addLockValuesToTranslationRow(ObjectLevelModifyQuery query)

INTERNAL: This method adds the lock value to the translation row of the passed in query. depending on the storage flag, the value is either retrieved from the cache of the object.

Specified by:

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

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.

Specified by:

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

buildUpdateExpression

public Expression buildUpdateExpression(org.eclipse.persistence.internal.helper.DatabaseTable table,
                               Expression mainExpression,
                               org.eclipse.persistence.internal.sessions.AbstractRecord row,
                               org.eclipse.persistence.internal.sessions.AbstractRecord row2)

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 an update call.

Specified by:

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

clone

public java.lang.Object clone()

INTERNAL: Clone the policy

Specified by:

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

Overrides:

clone in class java.lang.Object

supportsWriteLockValuesComparison

public boolean supportsWriteLockValuesComparison()

INTERNAL: Indicates that compareWriteLockValues method is supported by the policy.

Specified by:

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

compareWriteLockValues

public int compareWriteLockValues(java.lang.Object value1,
                         java.lang.Object value2)

INTERNAL: This method compares two writeLockValues. The writeLockValues should be non-null and of type Number. Returns: -1 if value1 is less (older) than value2; 0 if value1 equals value2; 1 if value1 is greater (newer) than value2. Throws: NullPointerException if the passed value is null; ClassCastException if the passed value is of a wrong type.

Specified by:

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

getBaseValue

public java.lang.Object getBaseValue()

INTERNAL: This is the base value that is older than all other values, it is used in the place of null in some situations.

Specified by:

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

getLockOnChangeMode

public org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange getLockOnChangeMode()

ADVANCED: returns the LockOnChange mode for this policy. This mode specifies if a Optimistic Write lock should be enforced on this entity when a set of mappings are changed. Unfortunately this locking policy can not enforce an optimistic write lock unless a FK or DTF field has changed so this type returns LockOnChange.NONE

Specified by:

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

getNewLockValue

public java.lang.Object getNewLockValue(ModifyQuery query)

INTERNAL: This method gets the write lock value from either the cache or the object stored in the query. It then returns the new incremented value.

getValueToPutInCache

public java.lang.Object getValueToPutInCache(org.eclipse.persistence.internal.sessions.AbstractRecord row,
                                    org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: Return the value that should be stored in the identity map. If the value is stored in the object, then return a null.

Specified by:

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

getVersionDifference

public int getVersionDifference(java.lang.Object currentValue,
                       java.lang.Object domainObject,
                       java.lang.Object primaryKeys,
                       org.eclipse.persistence.internal.sessions.AbstractSession session)

PUBLIC: Return the number of versions different between these objects.

Specified by:

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

Parameters:

currentValue - the new lock value

domainObject - the object containing the version to be compared to

primaryKeys - a vector containing the primary keys of the domainObject

session - the session to be used with the comparison

getWriteLockField

public org.eclipse.persistence.internal.helper.DatabaseField getWriteLockField()

INTERNAL: Return the write lock field.

Specified by:

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

getWriteLockFieldName

public java.lang.String getWriteLockFieldName()

PUBLIC: Return the field name of the field that stores the write lock value.

getWriteLockUpdateExpression

public Expression getWriteLockUpdateExpression(ExpressionBuilder builder,
                                      org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: Retrun an expression that updates the write lock

Specified by:

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

getWriteLockValue

public java.lang.Object getWriteLockValue(java.lang.Object domainObject,
                                 java.lang.Object primaryKey,
                                 org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: This method will return the optimistic lock value for the object

Specified by:

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

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

initializeProperties

public void initializeProperties()

INTERNAL: It is responsible for initializing the policy properties;

Specified by:

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

isCascaded

public boolean isCascaded()

PUBLIC: Return true if the policy uses cascade locking.

Specified by:

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

isNewerVersion

public boolean isNewerVersion(java.lang.Object currentValue,
                     java.lang.Object domainObject,
                     java.lang.Object primaryKey,
                     org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: Compares the value with the value from the object (or cache). Will return true if the currentValue is newer than the domainObject.

Specified by:

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

isNewerVersion

public boolean isNewerVersion(org.eclipse.persistence.internal.sessions.AbstractRecord databaseRow,
                     java.lang.Object domainObject,
                     java.lang.Object primaryKey,
                     org.eclipse.persistence.internal.sessions.AbstractSession session)

INTERNAL: Compares the value from the row and from the object (or cache). Will return true if the row is newer than the object.

Specified by:

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

isNewerVersion

public boolean isNewerVersion(java.lang.Object firstLockFieldValue,
                     java.lang.Object secondWriteLockFieldValue)

INTERNAL: Compares two values. Will return true if the firstLockFieldValue is newer than the secondWriteLockFieldValue.

isStoredInCache

public boolean isStoredInCache()

PUBLIC: Return true if the lock value is stored in the cache.

Specified by:

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

isStoredInObject

public boolean isStoredInObject()

PUBLIC: Return true if the lock value is stored in the object.

getVersionMapping

public AbstractDirectMapping getVersionMapping()

INTERNAL: Returns the mapping that will be used to access the version value from an object.

mergeIntoParentCache

public void mergeIntoParentCache(org.eclipse.persistence.internal.sessions.UnitOfWorkImpl uow,
                        java.lang.Object primaryKey,
                        java.lang.Object object)

INTERNAL: Only applicable when the value is stored in the cache. Will merge with the parent unit of work.

Specified by:

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

mergeIntoParentCache

public void mergeIntoParentCache(org.eclipse.persistence.internal.identitymaps.CacheKey unitOfWorkCacheKey,
                        org.eclipse.persistence.internal.identitymaps.CacheKey parentSessionCacheKey)

INTERNAL: This method should merge changes from the parent into the child. #see this method in VersionLockingPolicy

Specified by:

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

setDescriptor

public void setDescriptor(ClassDescriptor descriptor)

INTERNAL:

Specified by:

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

setIsStoredInCache

public void setIsStoredInCache(boolean isStoredInCache)

PUBLIC: Set whether to store the lock in the cache or in the object.

Parameters:

isStoredInCache - set this to true if you would like to store lock in the cache and set it to false if you would like to store it in the object.

setIsCascaded

public void setIsCascaded(boolean isCascaded)

PUBLIC: Set whether to use cascade locking on the policy.

Parameters:

isCascaded - set this to true if you would like cascade the locking and set it to false if you would like no cascade locking.

setupWriteFieldsForInsert

public void setupWriteFieldsForInsert(ObjectLevelModifyQuery query)

INTERNAL: This method must be included in any locking policy. Put the initial writelock value into the modifyRow.

Specified by:

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

shouldUpdateVersionOnOwnedMappingChange

public boolean shouldUpdateVersionOnOwnedMappingChange()

INTERNAL: Returns true if the policy has been set to set an optimistic read lock when a owning mapping changes.

Specified by:

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

shouldUpdateVersionOnMappingChange

public boolean shouldUpdateVersionOnMappingChange()

INTERNAL: Returns true if the policy has been set to set an optimistic read lock when any mapping changes.

Specified by:

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

updateObjectWithWriteValue

public void updateObjectWithWriteValue(ObjectLevelModifyQuery query,
                              java.lang.Object lockValue)

setLockOnChangeMode

public void setLockOnChangeMode(org.eclipse.persistence.internal.descriptors.OptimisticLockingPolicy.LockOnChange lockOnChangeMode)

ADVANCED: Sets the LockOnChange mode for this policy. This mode specifies if a Optimistic Write lock should be enforced on this entity when set of mappings are changed.

Specified by:

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

setWriteLockField

public void setWriteLockField(org.eclipse.persistence.internal.helper.DatabaseField writeLockField)

ADVANCED: Set the write lock field. This can be used for advanced field types, such as XML nodes, or to set the field type.

setWriteLockFieldName

public void setWriteLockFieldName(java.lang.String writeLockFieldName)

PUBLIC: Set the write lock field name.

Parameters:

writeLockFieldName - the name of the field to lock against.

storeInCache

public void storeInCache()

PUBLIC: Configure the version lock value to be stored in the cache. This allows for the object not to require to store its version value as an attribute. Note: if using a stateless model where the object can be passed to a client and then later updated in a different transaction context, then the version lock value should not be stored in the cache, but in the object to ensure it is the correct value for that object. This is the default.

storeInObject

public void storeInObject()

PUBLIC: Configure the version lock value to be stored in the object. The object must define a mapping and an attribute to store the version value. Note: the value will be updated internally by EclipseLink and should not be updated by the application.

updateRowAndObjectForUpdate

public void updateRowAndObjectForUpdate(ObjectLevelModifyQuery query,
                               java.lang.Object domainObject)

INTERNAL: This method updates the modify row, and the domain object with the new lock value.

Specified by:

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

writeLockValueIntoRow

public void writeLockValueIntoRow(ObjectLevelModifyQuery query,
                         java.lang.Object domainObject)

INTERNAL: This method updates the modify row with the old lock value.

validateDelete

public void validateDelete(int rowCount,
                  java.lang.Object object,
                  DeleteObjectQuery query)

INTERNAL: Check the row count for lock failure.

Specified by:

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

validateUpdate

public void validateUpdate(int rowCount,
                  java.lang.Object object,
                  WriteObjectQuery query)

INTERNAL: Check the row count for lock failure.

Specified by:

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