Module org.eclipse.persistence.core

Package org.eclipse.persistence.internal.indirection

Class ProxyIndirectionPolicy

java.lang.Object

org.eclipse.persistence.internal.indirection.IndirectionPolicy

org.eclipse.persistence.internal.indirection.BasicIndirectionPolicy

org.eclipse.persistence.internal.indirection.ProxyIndirectionPolicy

All Implemented Interfaces:

Serializable, Cloneable

public class ProxyIndirectionPolicy
extends BasicIndirectionPolicy

ProxyIndirectionPolicy

Define the behavior for Proxy Indirection.

Proxy Indirection uses the Proxy and InvocationHandler features of JDK 1.3 to provide "transparent indirection" for 1:1 relationships. In order to use Proxy Indirection:

• The target class must implement at least one public interface
• The attribute on the source class must be typed as that public interface

In this policy, proxy objects are returned during object creation. When a message other than toString is called on the proxy the real object data is retrieved from the database.

Since:

TopLink 3.0

See Also:

• ProxyIndirectionHandler
• Serialized Form

Field Summary

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

mapping

Constructor Summary

Constructors

Constructor	Description
ProxyIndirectionPolicy()
ProxyIndirectionPolicy(Class<?>[] targetInterfaces)

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	cloneAttribute(Object attributeValue, Object original, CacheKey cacheKey, Object clone, Integer refreshCascade, AbstractSession cloningSession, boolean buildDirectlyFromRow)	INTERNAL: Return a clone of the attribute.
AbstractRecord	extractReferenceRow(Object referenceObject)	INTERNAL: Return the reference row for the reference object.
void	fixObjectReferences(Object object, Map<Object,ObjectDescriptor> objectDescriptors, Map<Object,Object> 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	getRealAttributeValueFromObject(Object obj, Object object)	INTERNAL: Return the "real" attribute value, as opposed to any wrapper.
static Object	getValueFromProxy(Object value)	INTERNAL: Given a proxy object, trigger the indirection and return the actual object represented by the proxy.
boolean	hasTargetInterfaces()	INTERNAL: Return if targetInterfaces is not empty.
void	initialize()	INTERNAL: Nothing required.
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.
boolean	isValidType(Class<?> attributeType)	INTERNAL: Verify that a class type is valid to use for the proxy.
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 "real" value of the attribute to attributeValue.
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 attribute type is correct for the indirection policy.
void	validateGetMethodReturnType(Class<?> returnType, IntegrityChecker checker)	INTERNAL: Verify that the return type of the attribute's get method is correct for the indirection policy.
void	validateSetMethodParameterType(Class<?> parameterType, IntegrityChecker checker)	INTERNAL: Verify that the parameter type of the attribute's set method 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, 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.BasicIndirectionPolicy

buildIndirectObject, extractPrimaryKeyForReferenceObject, getOriginalIndirectionObjectForMerge, getOriginalValueHolder, getValueFromRemoteValueHolder, setSourceObject, typeIsValid, valueFromQuery

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

buildCascadeQuery, clone, getCollectionMapping, getForeignReferenceMapping, getMapping, getOneToOneMapping, getTransformationMapping, 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 Details

ProxyIndirectionPolicy

public ProxyIndirectionPolicy(Class<?>[] targetInterfaces)

ProxyIndirectionPolicy

public ProxyIndirectionPolicy()

Method Details

initialize

public void initialize()

INTERNAL: Nothing required.

Overrides:

initialize in class IndirectionPolicy

reset

public void reset(Object target)

Reset the wrapper used to store the value.

Overrides:

reset in class BasicIndirectionPolicy

hasTargetInterfaces

public boolean hasTargetInterfaces()

INTERNAL: Return if targetInterfaces is not empty.

valueFromRow

public Object valueFromRow(Object object)

INTERNAL: Return the value to be stored in the object's attribute. This will be a proxy object.

Overrides:

valueFromRow in class BasicIndirectionPolicy

valueFromQuery

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

INTERNAL: Return the value to be stored in the object's attribute. This will be a proxy object.

Overrides:

valueFromQuery in class BasicIndirectionPolicy

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.

Overrides:

valueFromMethod in class BasicIndirectionPolicy

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 batch query. * NOTE: Currently not supported anyway.

Overrides:

valueFromBatchQuery in class BasicIndirectionPolicy

objectIsInstantiated

public boolean objectIsInstantiated(Object object)

INTERNAL: Return whether the specified object is instantiated.

Overrides:

objectIsInstantiated in class BasicIndirectionPolicy

objectIsEasilyInstantiated

public boolean objectIsEasilyInstantiated(Object object)

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

Overrides:

objectIsEasilyInstantiated in class BasicIndirectionPolicy

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.

Overrides:

nullValueFromRow in class BasicIndirectionPolicy

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.

Overrides:

mergeRemoteValueHolder in class BasicIndirectionPolicy

getRealAttributeValueFromObject

public Object getRealAttributeValueFromObject(Object obj,
 Object object)

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

Overrides:

getRealAttributeValueFromObject in class BasicIndirectionPolicy

getValueFromProxy

public static Object getValueFromProxy(Object value)

INTERNAL: Given a proxy object, trigger the indirection and return the actual object represented by the proxy.

setRealAttributeValueInObject

public void setRealAttributeValueInObject(Object target,
 Object attributeValue)

INTERNAL: Set the "real" value of the attribute to attributeValue.

Overrides:

setRealAttributeValueInObject in class BasicIndirectionPolicy

getOriginalIndirectionObject

public Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject,
 AbstractSession session)

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

Overrides:

getOriginalIndirectionObject in class BasicIndirectionPolicy

fixObjectReferences

public void fixObjectReferences(Object object,
 Map<Object,ObjectDescriptor> objectDescriptors,
 Map<Object,Object> 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.

Overrides:

fixObjectReferences in class BasicIndirectionPolicy

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.

Overrides:

extractReferenceRow in class BasicIndirectionPolicy

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.

Overrides:

cloneAttribute in class BasicIndirectionPolicy

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.

backupCloneAttribute

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

INTERNAL: Return a backup clone of the attribute.

Overrides:

backupCloneAttribute in class BasicIndirectionPolicy

iterateOnAttributeValue

public void iterateOnAttributeValue(DescriptorIterator iterator,
 Object attributeValue)

INTERNAL: Iterate over the specified attribute value.

Overrides:

iterateOnAttributeValue in class BasicIndirectionPolicy

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 non-null and implement some public interface.

Overrides:

validateAttributeOfInstantiatedObject in class BasicIndirectionPolicy

validateDeclaredAttributeType

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

INTERNAL: Verify that attribute type 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 contained in targetInterfaces.

Overrides:

validateDeclaredAttributeType in class BasicIndirectionPolicy

Throws:

DescriptorException

validateGetMethodReturnType

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

INTERNAL: Verify that the return type of the attribute's get method 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 a public interface.

Overrides:

validateGetMethodReturnType in class BasicIndirectionPolicy

Throws:

DescriptorException

validateSetMethodParameterType

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

INTERNAL: Verify that the parameter type of the attribute's set method 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 a public interface.

Overrides:

validateSetMethodParameterType in class BasicIndirectionPolicy

Throws:

DescriptorException

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 BasicIndirectionPolicy

See Also:

• validateAttributeOfInstantiatedObject(Object attributeValue)

isValidType

public boolean isValidType(Class<?> attributeType)

INTERNAL: Verify that a class type is valid to use for the proxy. The class must be one of the interfaces in targetInterfaces.