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package oracle.toplink.essentials.internal.indirection;
import java.util.*;
import oracle.toplink.essentials.mappings.*;
import oracle.toplink.essentials.queryframework.*;
import oracle.toplink.essentials.indirection.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.internal.descriptors.*;
import oracle.toplink.essentials.internal.queryframework.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.internal.sessions.AbstractRecord;
import oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl;
import oracle.toplink.essentials.internal.sessions.AbstractSession;
/**
* <h2>Purpose</h2>:
* TransparentIndirectionPolicy implements the behavior necessary for a
* a CollectionMapping to use
* IndirectContainers to delay the reading of objects from the database
* until they are actually needed.
*
* @see CollectionMapping
* @see IndirectContainer
* @author Big Country
* @since TOPLink/Java 2.5
*/
public class TransparentIndirectionPolicy extends IndirectionPolicy {
//3732
protected static Integer defaultContainerSize;
/**
* INTERNAL:
* Construct a new indirection policy.
*/
public TransparentIndirectionPolicy() {
super();
}
/**
* INTERNAL:
* Return a backup clone of the attribute.
*/
public Object backupCloneAttribute(Object attributeValue, Object clone, Object backup, UnitOfWorkImpl unitOfWork) {
// delay instantiation until absolutely necessary
if ((!(attributeValue instanceof IndirectContainer)) || objectIsInstantiated(attributeValue)) {
return super.backupCloneAttribute(attributeValue, clone, backup, unitOfWork);
} else {
return buildBackupClone((IndirectContainer)attributeValue);
}
}
/**
* INTERNAL:
* Return a backup clone of a clone container that has not been
* read from the database yet.
* This is used by the indirection policy to hook together a UOW
* clone with its backup clone - only when the clone (the working
* copy returned to the user) instantiates its contents from the
* database will these contents be copied to the backup clone.
*/
protected Object buildBackupClone(IndirectContainer container) {
UnitOfWorkValueHolder containerValueHolder = (UnitOfWorkValueHolder)container.getValueHolder();
// CR#2852176 Use a BackupValueHolder to handle replacing of the original.
BackupValueHolder backupValueHolder = new BackupValueHolder(containerValueHolder);
containerValueHolder.setBackupValueHolder(backupValueHolder);
return this.buildIndirectContainer(backupValueHolder);
}
/**
* Construct and return an instance of the specified
* indirect container class.
*/
protected IndirectContainer buildIndirectContainer() {
//3732
if (defaultContainerSize != null) {
return (IndirectContainer)getContainerPolicy().containerInstance(getDefaultContainerSize());
} else {
return (IndirectContainer)getContainerPolicy().containerInstance();
}
}
/**
* Return a new IndirectContainer with the specified value holder.
*/
protected Object buildIndirectContainer(ValueHolderInterface valueHolder) {
IndirectContainer result = buildIndirectContainer();
result.setValueHolder(valueHolder);
return result;
}
/**
* Return a clone of the attribute.
* @param 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.
*/
public Object cloneAttribute(Object attributeValue, Object original, Object clone, UnitOfWorkImpl unitOfWork, boolean buildDirectlyFromRow) {
ValueHolderInterface valueHolder = null;
Object container = null;
if (attributeValue instanceof IndirectContainer) {
valueHolder = ((IndirectContainer)attributeValue).getValueHolder();
}
if (!buildDirectlyFromRow && unitOfWork.isOriginalNewObject(original)) {
// CR#3156435 Throw a meaningful exception if a serialized/dead value holder is detected.
// This can occur if an existing serialized object is attempt to be registered as new.
if ((valueHolder instanceof DatabaseValueHolder)
&& (! ((DatabaseValueHolder) valueHolder).isInstantiated())
&& (((DatabaseValueHolder) valueHolder).getSession() == null)
&& (! ((DatabaseValueHolder) valueHolder).isSerializedRemoteUnitOfWorkValueHolder())) {
throw DescriptorException.attemptToRegisterDeadIndirection(original, getMapping());
}
if (getMapping().getRelationshipPartner() == null) {
container = getMapping().buildCloneForPartObject(attributeValue, original, clone, unitOfWork, false);
} else {
if (!(attributeValue instanceof IndirectContainer)) {
valueHolder = new ValueHolder(attributeValue);
}
AbstractRecord row = null;
if (valueHolder instanceof DatabaseValueHolder) {
row = ((DatabaseValueHolder)valueHolder).getRow();
}
//If a new object is being cloned then we must build a new UOWValueHolder
// this is so that new clones can also have their relationships managed
// here the code instantiates the valueholder in a privledged manner because a
// UOWValueHolder will assume the objects in the collection are existing if the valueholder
// Goes through it's own instantiation process.
UnitOfWorkValueHolder newValueHolder = this.getMapping().createUnitOfWorkValueHolder(valueHolder, original, clone, row, unitOfWork, buildDirectlyFromRow);
container = buildIndirectContainer(newValueHolder);
Object cloneCollection = getMapping().buildCloneForPartObject(attributeValue, original, clone, unitOfWork, false);
newValueHolder.privilegedSetValue(cloneCollection);
newValueHolder.setInstantiated();
}
} else {
if (!(attributeValue instanceof IndirectContainer)) {
valueHolder = new ValueHolder(attributeValue);
}
AbstractRecord row = null;
if (valueHolder instanceof DatabaseValueHolder) {
row = ((DatabaseValueHolder)valueHolder).getRow();
}
container = buildIndirectContainer(getMapping().createUnitOfWorkValueHolder(valueHolder, original, clone, row, unitOfWork, buildDirectlyFromRow));
}
return container;
}
/**
* INTERNAL:
* Return whether the container policy is valid for the indirection policy.
* In this case, the container policy MUST be configured
* for an IndirectContainer.
*/
protected boolean containerPolicyIsValid() {
if (Helper.classImplementsInterface(this.getContainerClass(), ClassConstants.IndirectContainer_Class)) {
return true;
}
return false;
}
/**
* 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.
* OneToOneMappings should not be using transparent direction.
*/
public Vector extractPrimaryKeyForReferenceObject(Object referenceObject, AbstractSession session) {
throw DescriptorException.invalidUseOfTransparentIndirection(this.getMapping());
}
/**
* 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.
*/
public AbstractRecord extractReferenceRow(Object referenceObject) {
if (this.objectIsInstantiated(referenceObject)) {
return null;
} else {
return ((DatabaseValueHolder)((IndirectContainer)referenceObject).getValueHolder()).getRow();
}
}
/**
* INTERNAL:
* Return the container class for the mapping.
*/
protected Class getContainerClass() {
return this.getContainerPolicy().getContainerClass();
}
/**
* INTERNAL:
* Return the container policy for the mapping.
*/
protected ContainerPolicy getContainerPolicy() {
return this.getCollectionMapping().getContainerPolicy();
}
/**
* INTERNAL:
* Return the the size to of container to create. Default to using default constructor.
*/
protected static int getDefaultContainerSize() {
//3732
return defaultContainerSize.intValue();
}
/**
* INTERNAL:
* Return the original indirection object for a unit of work indirection object.
*/
public Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject, AbstractSession session) {
IndirectContainer container = (IndirectContainer)unitOfWorkIndirectionObject;
if (container.getValueHolder() instanceof UnitOfWorkValueHolder) {
ValueHolderInterface valueHolder = ((UnitOfWorkValueHolder)container.getValueHolder()).getWrappedValueHolder();
return buildIndirectContainer(valueHolder);
} else {
return container;
}
}
/**
* INTERNAL:
* Return the "real" attribute value, as opposed to any wrapper.
* This will trigger the wrapper to instantiate the value.
*/
public Object getRealAttributeValueFromObject(Object object, Object attribute) {
this.getContainerPolicy().sizeFor(attribute);// forgive me for this hack: but we have to do something to trigger the database read
return attribute;
}
/**
* INTERNAL:
* Set the value of the appropriate attribute of target to attributeValue.
* If the Target has yet to be instantiated then we need to instantiate the target to ensure that
* the backup clone is instantiated for comparison.
*/
public void setRealAttributeValueInObject(Object target, Object attributeValue) {
/*
Bug 3573808 - do NOT trigger the valueholder; SPECj benchmark
deadlocks in this method.
Re-ran the original testcase IndirectContainerTestDatabase
testMergeCloneWithSerializedTransparentIndirection
and it passes without triggering the valueholder. MWN
//cr 3788
// Trigger the valueholder when setting the value in an object
Object object = this.getMapping().getAttributeValueFromObject(target);
if (object instanceof IndirectContainer){
((IndirectContainer)object).getValueHolder().getValue();
}
*/
super.setRealAttributeValueInObject(target, attributeValue);
}
/**
* INTERNAL:
* Iterate over the specified attribute value.
*/
public void iterateOnAttributeValue(DescriptorIterator iterator, Object attributeValue) {
if (attributeValue instanceof IndirectContainer) {
iterator.iterateIndirectContainerForMapping((IndirectContainer)attributeValue, this.getMapping());
} else {// it must be a "real" collection
super.iterateOnAttributeValue(iterator, attributeValue);
}
}
/**
* 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.
* OneToOneMappings should not be using transparent direction.
*/
public Object nullValueFromRow() {
throw DescriptorException.invalidUseOfTransparentIndirection(this.getMapping());
}
/**
* INTERNAL:
* Return whether the specified object is instantiated.
*/
public boolean objectIsInstantiated(Object object) {
if (object instanceof IndirectContainer) {
return ((IndirectContainer)object).isInstantiated();
} else {
return true;// it must be a "real" collection
}
}
/**
* ADVANCED:
* Set the size to of container to create. Default to using default constructor.
*/
public static void setDefaultContainerSize(int defaultSize) {
//3732
defaultContainerSize = new Integer(defaultSize);
}
/**
* INTERNAL:
* Return whether the type is appropriate for the indirection policy.
* In this case, the attribute type MUST be
* compatible with the one specified by the ContainerPolicy
* (i.e. either the container policy class is a subclass of the
* declared type [jdk1.1] or the container policy class implements
* the declared interface [jdk1.2]).
*/
protected boolean typeIsValid(Class declaredType) {
if (Helper.classIsSubclass(this.getContainerClass(), declaredType)) {
return true;
}
if (Helper.classImplementsInterface(this.getContainerClass(), declaredType)) {
return true;
}
return false;
}
/**
* INTERNAL:
* Return whether the indirection policy uses transparent indirection.
*/
public boolean usesTransparentIndirection(){
return true;
}
/**
* 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 at least a
* subclass or implementor of the container type.
* If the value is null return a new indirection object to be used for the attribute.
*/
public Object validateAttributeOfInstantiatedObject(Object attributeValue) {
// PERF: If the value is null, create a new value holder instance for the attribute value,
// this allows for indirection attributes to not be instantiated in the constructor as they
// are typically replaced when reading or cloning so is very inefficent to initialize.
if (attributeValue == null) {
return buildIndirectContainer();
}
if (!(this.getContainerPolicy().isValidContainer(attributeValue))) {
throw DescriptorException.indirectContainerInstantiationMismatch(attributeValue, this.getMapping());
}
return attributeValue;
}
/**
* INTERNAL:
* Verify that the container policy is compatible with the
* indirection policy. If it is incorrect, add an exception to the
* integrity checker.
*/
public void validateContainerPolicy(IntegrityChecker checker) throws DescriptorException {
super.validateContainerPolicy(checker);
if (!this.containerPolicyIsValid()) {
checker.handleError(DescriptorException.invalidContainerPolicyWithTransparentIndirection(this.getMapping(), this.getContainerPolicy()));
}
// Bug 2618982
if (getContainerPolicy().isMapPolicy() && ((((ForeignReferenceMapping)getMapping()).getRelationshipPartnerAttributeName() != null) || (getMapping().getRelationshipPartner() != null))) {
checker.handleError(DescriptorException.unsupportedTypeForBidirectionalRelationshipMaintenance(this.getMapping(), this.getContainerPolicy()));
}
}
/**
* 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
* compatible with the one specified by the ContainerPolicy.
*/
public void validateDeclaredAttributeType(Class attributeType, IntegrityChecker checker) throws DescriptorException {
super.validateDeclaredAttributeType(attributeType, checker);
if (!this.typeIsValid(attributeType)) {
checker.handleError(DescriptorException.attributeAndMappingWithTransparentIndirectionMismatch(this.getMapping(), this.validTypeName()));
}
}
/**
* 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 attribute type MUST be
* compatible with the one specified by the ContainerPolicy.
*/
public void validateGetMethodReturnType(Class returnType, IntegrityChecker checker) throws DescriptorException {
super.validateGetMethodReturnType(returnType, checker);
if (!this.typeIsValid(returnType)) {
checker.handleError(DescriptorException.returnAndMappingWithTransparentIndirectionMismatch(this.getMapping(), this.validTypeName()));
}
}
/**
* 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 attribute type MUST be
* compatible with the one specified by the ContainerPolicy.
*/
public void validateSetMethodParameterType(Class parameterType, IntegrityChecker checker) throws DescriptorException {
super.validateSetMethodParameterType(parameterType, checker);
if (!this.typeIsValid(parameterType)) {
checker.handleError(DescriptorException.parameterAndMappingWithTransparentIndirectionMismatch(this.getMapping(), this.validTypeName()));
}
}
/**
* INTERNAL:
* Return the type that is appropriate for the indirection policy.
*/
protected String validTypeName() {
return Helper.getShortClassName(this.getContainerClass());
}
/**
* 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.
* TransformationMappings should not be using transparent direction.
*/
public Object valueFromMethod(Object object, AbstractRecord row, AbstractSession session) {
throw DescriptorException.invalidUseOfTransparentIndirection(this.getMapping());
}
/**
* 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 an IndirectContainer for later invocation.
*/
public Object valueFromQuery(ReadQuery query, AbstractRecord row, AbstractSession session) {
return this.buildIndirectContainer(new QueryBasedValueHolder(query, row, session));
}
/**
* INTERNAL:
* A combination of valueFromQuery and valueFromRow(object).
* Sometimes the attribute is known (joining) but we still need to hang on
* to the query (pessimistic locking).
*/
public Object valueFromQuery(ReadQuery query, AbstractRecord row, Object object, AbstractSession session) {
return valueFromQuery(query, row, session);
}
/**
* INTERNAL:
* Return the value to be stored in the object's attribute.
* This allows wrapping of the real value, none is required for transparent.
*/
public Object valueFromRow(Object object) {
return object;
}
}
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