Package org.eclipse.persistence.internal.indirection

Class BasicIndirectionPolicy

java.lang.Object

org.eclipse.persistence.internal.indirection.IndirectionPolicy

org.eclipse.persistence.internal.indirection.BasicIndirectionPolicy

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

ContainerIndirectionPolicy, ProxyIndirectionPolicy, WeavedObjectBasicIndirectionPolicy

public class BasicIndirectionPolicy
extends IndirectionPolicy

Purpose

: BasicIndirectionPolicy implements the behavior necessary for a a org.eclipse.persistence.mappings.ForeignReferenceMapping (or TransformationMapping) to use ValueHolders to delay the reading of objects from the database until they are actually needed.

Since:

TOPLink/Java 2.5

Author:

Mike Norman

See Also:

Serialized Form

Field Summary

Fields inherited from class org.eclipse.persistence.internal.indirection.IndirectionPolicy

mapping

Constructor Summary

Constructors

Constructor	Description
BasicIndirectionPolicy()	INTERNAL: Construct a new indirection policy.

Method Summary

Modifier and Type	Method	Description
Object	backupCloneAttribute(Object attributeValue, Object clone, Object backup, UnitOfWorkImpl unitOfWork)	INTERNAL: Return a backup clone of the attribute.
Object	buildIndirectObject(ValueHolderInterface valueHolder)	INTERNAL: This method can be used when an Indirection Object is required to be built from a provided ValueHolderInterface object.
Object	cloneAttribute(Object attributeValue, Object original, CacheKey cacheKey, Object clone, Integer refreshCascade, AbstractSession cloningSession, boolean buildDirectlyFromRow)	INTERNAL: Return a clone of the attribute.
Object	extractPrimaryKeyForReferenceObject(Object referenceObject, AbstractSession session)	INTERNAL: Return the primary key for the reference object (i.e.
AbstractRecord	extractReferenceRow(Object referenceObject)	INTERNAL: Return the reference row for the reference object.
void	fixObjectReferences(Object object, Map objectDescriptors, Map processedObjects, ObjectLevelReadQuery query, DistributedSession session)	INTERNAL: An object has been serialized from the server to the client.
Object	getOriginalIndirectionObject(Object unitOfWorkIndirectionObject, AbstractSession session)	INTERNAL: Return the original indirection object for a unit of work indirection object.
Object	getOriginalIndirectionObjectForMerge(Object unitOfWorkIndirectionObject, AbstractSession session)	INTERNAL: Return the original indirection object for a unit of work indirection object.
Object	getOriginalValueHolder(Object unitOfWorkIndirectionObject, AbstractSession session)	INTERNAL: Return the original valueHolder object.
Object	getRealAttributeValueFromObject(Object object, Object attribute)	INTERNAL: Return the "real" attribute value, as opposed to any wrapper.
Object	getValueFromRemoteValueHolder(RemoteValueHolder remoteValueHolder)	INTERNAL: Extract and return the appropriate value from the specified remote value holder.
boolean	isAttributeValueFullyBuilt(Object attributeValue)	INTERNAL: The method validateAttributeOfInstantiatedObject(Object attributeValue) fixes the value of the attributeValue in cases where it is null and indirection requires that it contain some specific data structure.
void	iterateOnAttributeValue(DescriptorIterator iterator, Object attributeValue)	INTERNAL: Iterate over the specified attribute value,
void	mergeRemoteValueHolder(Object clientSideDomainObject, Object serverSideDomainObject, MergeManager mergeManager)	INTERNAL Replace the client value holder with the server value holder, after copying some of the settings from the client value holder.
Object	nullValueFromRow()	INTERNAL: Return the null value of the appropriate attribute.
boolean	objectIsEasilyInstantiated(Object object)	INTERNAL: Return whether the specified object can be instantiated without database access.
boolean	objectIsInstantiated(Object object)	INTERNAL: Return whether the specified object is instantiated.
void	reset(Object target)	Reset the wrapper used to store the value.
void	setRealAttributeValueInObject(Object target, Object attributeValue)	INTERNAL: Set the value of the appropriate attribute of target to attributeValue.
void	setSourceObject(Object sourceObject, Object attributeValue)	INTERNAL: set the source object into QueryBasedValueHolder.
protected boolean	typeIsValid(Class attributeType)	INTERNAL: Return whether the type is appropriate for the indirection policy.
Object	validateAttributeOfInstantiatedObject(Object attributeValue)	INTERNAL: Verify that the value of the attribute within an instantiated object is of the appropriate type for the indirection policy.
void	validateDeclaredAttributeType(Class attributeType, IntegrityChecker checker)	INTERNAL: Verify that attributeType is correct for the indirection policy.
void	validateGetMethodReturnType(Class returnType, IntegrityChecker checker)	INTERNAL: Verify that getter returnType is correct for the indirection policy.
void	validateSetMethodParameterType(Class parameterType, IntegrityChecker checker)	INTERNAL: Verify that setter parameterType is correct for the indirection policy.
Object	valueFromBatchQuery(ReadQuery batchQuery, AbstractRecord row, ObjectLevelReadQuery originalQuery, CacheKey parentCacheKey)	INTERNAL: Return the value to be stored in the object's attribute.
Object	valueFromMethod(Object object, AbstractRecord row, AbstractSession session)	INTERNAL: Return the value to be stored in the object's attribute.
Object	valueFromQuery(ReadQuery query, AbstractRecord row, Object sourceObject, AbstractSession session)	INTERNAL: Return the value to be stored in the object's attribute.
Object	valueFromQuery(ReadQuery query, AbstractRecord row, AbstractSession session)	INTERNAL: Return the value to be stored in the object's attribute.
Object	valueFromRow(Object object)	INTERNAL: Return the value to be stored in the object's attribute.

Methods inherited from class org.eclipse.persistence.internal.indirection.IndirectionPolicy

buildCascadeQuery, clone, getCollectionMapping, getForeignReferenceMapping, getMapping, getOneToOneMapping, getTransformationMapping, initialize, instantiateObject, isWeavedObjectBasicIndirectionPolicy, mergeClientIntoServerValueHolder, objectIsInstantiatedOrChanged, setMapping, setRealAttributeValueInObject, setUseLazyInstantiation, shouldUseLazyInstantiation, usesIndirection, usesTransparentIndirection, validateContainerPolicy, validateDeclaredAttributeTypeForCollection, validateGetMethodReturnTypeForCollection, validateSetMethodParameterTypeForCollection

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicIndirectionPolicy

public BasicIndirectionPolicy()

INTERNAL: Construct a new indirection policy.

Method Detail

backupCloneAttribute

public Object backupCloneAttribute(Object attributeValue,
                                   Object clone,
                                   Object backup,
                                   UnitOfWorkImpl unitOfWork)

INTERNAL: Return a backup clone of the attribute.

Overrides:

backupCloneAttribute in class IndirectionPolicy

buildIndirectObject

public Object buildIndirectObject(ValueHolderInterface valueHolder)

INTERNAL: This method can be used when an Indirection Object is required to be built from a provided ValueHolderInterface object. This may be used for custom value holder types. Certain policies like the TransparentIndirectionPolicy may wrap the valueholder in another object.

Specified by:

buildIndirectObject in class IndirectionPolicy

cloneAttribute

public Object cloneAttribute(Object attributeValue,
                             Object original,
                             CacheKey cacheKey,
                             Object clone,
                             Integer refreshCascade,
                             AbstractSession cloningSession,
                             boolean buildDirectlyFromRow)

INTERNAL: Return a clone of the attribute.

Specified by:

cloneAttribute in class IndirectionPolicy

Parameters:

buildDirectlyFromRow - indicates that we are building the clone directly from a row as opposed to building the original from the row, putting it in the shared cache, and then cloning the original.

extractPrimaryKeyForReferenceObject

public Object extractPrimaryKeyForReferenceObject(Object referenceObject,
                                                  AbstractSession session)

INTERNAL: Return the primary key for the reference object (i.e. the object object referenced by domainObject and specified by mapping). This key will be used by a RemoteValueHolder.

Overrides:

extractPrimaryKeyForReferenceObject in class IndirectionPolicy

extractReferenceRow

public AbstractRecord extractReferenceRow(Object referenceObject)

INTERNAL: Return the reference row for the reference object. This allows the new row to be built without instantiating the reference object. Return null if the object has already been instantiated.

Specified by:

extractReferenceRow in class IndirectionPolicy

fixObjectReferences

public void fixObjectReferences(Object object,
                                Map objectDescriptors,
                                Map processedObjects,
                                ObjectLevelReadQuery query,
                                DistributedSession session)

INTERNAL: An object has been serialized from the server to the client. Replace the transient attributes of the remote value holders with client-side objects.

Specified by:

fixObjectReferences in class IndirectionPolicy

getOriginalIndirectionObject

public Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject,
                                           AbstractSession session)

INTERNAL: Return the original indirection object for a unit of work indirection object. This is used when building a new object from the unit of work when the original fell out of the cache.

Specified by:

getOriginalIndirectionObject in class IndirectionPolicy

getOriginalIndirectionObjectForMerge

public Object getOriginalIndirectionObjectForMerge(Object unitOfWorkIndirectionObject,
                                                   AbstractSession session)

INTERNAL: Return the original indirection object for a unit of work indirection object.

Overrides:

getOriginalIndirectionObjectForMerge in class IndirectionPolicy

getOriginalValueHolder

public Object getOriginalValueHolder(Object unitOfWorkIndirectionObject,
                                     AbstractSession session)

INTERNAL: Return the original valueHolder object. Access to the underlying valueholder may be required when serializing the valueholder or converting the valueHolder to another type.

Specified by:

getOriginalValueHolder in class IndirectionPolicy

reset

public void reset(Object target)

Reset the wrapper used to store the value.

Overrides:

reset in class IndirectionPolicy

getRealAttributeValueFromObject

public Object getRealAttributeValueFromObject(Object object,
                                              Object attribute)

INTERNAL: Return the "real" attribute value, as opposed to any wrapper. This will trigger the wrapper to instantiate the value.

Specified by:

getRealAttributeValueFromObject in class IndirectionPolicy

getValueFromRemoteValueHolder

public Object getValueFromRemoteValueHolder(RemoteValueHolder remoteValueHolder)

INTERNAL: Extract and return the appropriate value from the specified remote value holder.

Specified by:

getValueFromRemoteValueHolder in class IndirectionPolicy

isAttributeValueFullyBuilt

public boolean isAttributeValueFullyBuilt(Object attributeValue)

INTERNAL: The method validateAttributeOfInstantiatedObject(Object attributeValue) fixes the value of the attributeValue in cases where it is null and indirection requires that it contain some specific data structure. Return whether this will happen. This method is used to help determine if indirection has been triggered

Overrides:

isAttributeValueFullyBuilt in class IndirectionPolicy

Parameters:

attributeValue -

Returns:

See Also:

validateAttributeOfInstantiatedObject(java.lang.Object)

iterateOnAttributeValue

public void iterateOnAttributeValue(DescriptorIterator iterator,
                                    Object attributeValue)

INTERNAL: Iterate over the specified attribute value,

Overrides:

iterateOnAttributeValue in class IndirectionPolicy

mergeRemoteValueHolder

public void mergeRemoteValueHolder(Object clientSideDomainObject,
                                   Object serverSideDomainObject,
                                   MergeManager mergeManager)

INTERNAL Replace the client value holder with the server value holder, after copying some of the settings from the client value holder.

Specified by:

mergeRemoteValueHolder in class IndirectionPolicy

nullValueFromRow

public Object nullValueFromRow()

INTERNAL: Return the null value of the appropriate attribute. That is, the field from the database is NULL, return what should be placed in the object's attribute as a result. In this case, return an empty ValueHolder.

Specified by:

nullValueFromRow in class IndirectionPolicy

objectIsInstantiated

public boolean objectIsInstantiated(Object object)

INTERNAL: Return whether the specified object is instantiated.

Specified by:

objectIsInstantiated in class IndirectionPolicy

objectIsEasilyInstantiated

public boolean objectIsEasilyInstantiated(Object object)

INTERNAL: Return whether the specified object can be instantiated without database access.

Specified by:

objectIsEasilyInstantiated in class IndirectionPolicy

setRealAttributeValueInObject

public void setRealAttributeValueInObject(Object target,
                                          Object attributeValue)

INTERNAL: Set the value of the appropriate attribute of target to attributeValue. In this case, place the value inside the target's ValueHolder.

Overrides:

setRealAttributeValueInObject in class IndirectionPolicy

setSourceObject

public void setSourceObject(Object sourceObject,
                            Object attributeValue)

INTERNAL: set the source object into QueryBasedValueHolder. Used only by transparent indirection.

Overrides:

setSourceObject in class IndirectionPolicy

typeIsValid

protected boolean typeIsValid(Class attributeType)

INTERNAL: Return whether the type is appropriate for the indirection policy. In this case, the attribute type MUST be ValueHolderInterface.

validateAttributeOfInstantiatedObject

public Object validateAttributeOfInstantiatedObject(Object attributeValue)

INTERNAL: Verify that the value of the attribute within an instantiated object is of the appropriate type for the indirection policy. In this case, the attribute must be non-null and it must be a ValueHolderInterface. If the value is null return a new indirection object to be used for the attribute.

Overrides:

validateAttributeOfInstantiatedObject in class IndirectionPolicy

validateDeclaredAttributeType

public void validateDeclaredAttributeType(Class attributeType,
                                          IntegrityChecker checker)
                                   throws DescriptorException

INTERNAL: Verify that attributeType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker. In this case, the attribute type MUST be ValueHolderInterface.

Overrides:

validateDeclaredAttributeType in class IndirectionPolicy

Throws:

DescriptorException

validateGetMethodReturnType

public void validateGetMethodReturnType(Class returnType,
                                        IntegrityChecker checker)
                                 throws DescriptorException

INTERNAL: Verify that getter returnType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker. In this case, the return type MUST be ValueHolderInterface.

Overrides:

validateGetMethodReturnType in class IndirectionPolicy

Throws:

DescriptorException

validateSetMethodParameterType

public void validateSetMethodParameterType(Class parameterType,
                                           IntegrityChecker checker)
                                    throws DescriptorException

INTERNAL: Verify that setter parameterType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker. In this case, the parameter type MUST be ValueHolderInterface.

Overrides:

validateSetMethodParameterType in class IndirectionPolicy

Throws:

DescriptorException

valueFromBatchQuery

public Object valueFromBatchQuery(ReadQuery batchQuery,
                                  AbstractRecord row,
                                  ObjectLevelReadQuery originalQuery,
                                  CacheKey parentCacheKey)

INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the batchQuery. In this case, wrap the query in a ValueHolder for later invocation.

Specified by:

valueFromBatchQuery in class IndirectionPolicy

valueFromMethod

public Object valueFromMethod(Object object,
                              AbstractRecord row,
                              AbstractSession session)

INTERNAL: Return the value to be stored in the object's attribute. This value is determined by invoking the appropriate method on the object and passing it the row and session. In this case, wrap the row in a ValueHolder for later use.

Specified by:

valueFromMethod in class IndirectionPolicy

valueFromQuery

public Object valueFromQuery(ReadQuery query,
                             AbstractRecord row,
                             Object sourceObject,
                             AbstractSession session)

INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the query. In this case, wrap the query in a ValueHolder for later invocation.

Specified by:

valueFromQuery in class IndirectionPolicy

valueFromQuery

public Object valueFromQuery(ReadQuery query,
                             AbstractRecord row,
                             AbstractSession session)

INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the query. In this case, wrap the query in a ValueHolder for later invocation.

Specified by:

valueFromQuery in class IndirectionPolicy

valueFromRow

public Object valueFromRow(Object object)

INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the row. In this case, simply wrap the object in a ValueHolder.

Specified by:

valueFromRow in class IndirectionPolicy