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/*
 * Copyright (c) 1998, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Oracle - initial API and implementation from Oracle TopLink
package org.eclipse.persistence.internal.indirection;

import java.util.*;
import org.eclipse.persistence.descriptors.changetracking.*;
import org.eclipse.persistence.mappings.*;
import org.eclipse.persistence.queries.*;
import org.eclipse.persistence.indirection.*;
import org.eclipse.persistence.sessions.remote.*;
import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.internal.descriptors.*;
import org.eclipse.persistence.internal.queries.*;
import org.eclipse.persistence.internal.sessions.remote.*;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.internal.identitymaps.CacheKey;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.internal.sessions.MergeManager;
import org.eclipse.persistence.internal.sessions.UnitOfWorkImpl;

/**
 * 

Purpose

: * 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; /** PERF: Cache the mappings container policy. */ protected ContainerPolicy containerPolicy; /** * IndirectList and IndirectSet can be configured not to instantiate the list from the * database when you add and remove from them. IndirectList defaults to this behavior. When * Set to true, the collection associated with this TransparentIndirection will be setup so as * not to instantiate for adds and removes. The weakness of this setting for an IndirectSet is * that when the set is not instantiated, if a duplicate element is added, it will not be * detected until commit time. */ protected Boolean useLazyInstantiation; /** * INTERNAL: * Construct a new indirection policy. */ public TransparentIndirectionPolicy() { super(); } /** * INTERNAL: * Return a backup clone of the attribute. */ @Override 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) { ValueHolderInterface containerValueHolder = container.getValueHolder(); // CR#2852176 Use a BackupValueHolder to handle replacing of the original. BackupValueHolder backupValueHolder = new BackupValueHolder(containerValueHolder); if (containerValueHolder instanceof UnitOfWorkValueHolder) { ((UnitOfWorkValueHolder) containerValueHolder).setBackupValueHolder(backupValueHolder); } return this.buildIndirectContainer(backupValueHolder); } /** * Construct and return an instance of the specified * indirect container class. */ protected IndirectContainer buildIndirectContainer() { IndirectContainer container = null; //3732 if (defaultContainerSize != null) { container = (IndirectContainer)getContainerPolicy().containerInstance(getDefaultContainerSize()); } else { container = (IndirectContainer)getContainerPolicy().containerInstance(); } if (container instanceof IndirectCollection){ if (this.useLazyInstantiation != null){ ((IndirectCollection)container).setUseLazyInstantiation(this.useLazyInstantiation.booleanValue()); } } return container; } /** * Return a new IndirectContainer with the specified value holder. */ protected Object buildIndirectContainer(ValueHolderInterface valueHolder) { IndirectContainer result = buildIndirectContainer(); result.setValueHolder(valueHolder); return result; } /** * 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. */ @Override public Object buildIndirectObject(ValueHolderInterface valueHolder){ return buildIndirectContainer(valueHolder); } /** * 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. */ @Override public Object cloneAttribute(Object attributeValue, Object original, CacheKey cacheKey, Object clone, Integer refreshCascade, AbstractSession cloningSession, boolean buildDirectlyFromRow) { ValueHolderInterface valueHolder = null; Object container = null; IndirectList indirectList = null; IndirectContainer indirectContainer = null; if (attributeValue instanceof IndirectContainer) { indirectContainer = (IndirectContainer)attributeValue; valueHolder = indirectContainer.getValueHolder(); if (indirectContainer instanceof IndirectList) { indirectList = (IndirectList)indirectContainer; } } if (!buildDirectlyFromRow && cloningSession.isUnitOfWork() && ((UnitOfWorkImpl)cloningSession).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) && (! valueHolder.isInstantiated()) && (((DatabaseValueHolder) valueHolder).getSession() == null) && (! ((DatabaseValueHolder) valueHolder).isSerializedRemoteUnitOfWorkValueHolder())) { throw DescriptorException.attemptToRegisterDeadIndirection(original, this.mapping); } if (this.mapping.getRelationshipPartner() == null) { container = this.mapping.buildCloneForPartObject(attributeValue, original, cacheKey, clone, cloningSession, refreshCascade, false, false); } else { if (indirectContainer == null) { 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. DatabaseValueHolder newValueHolder = this.mapping.createCloneValueHolder(valueHolder, original, clone, row, cloningSession, buildDirectlyFromRow); container = buildIndirectContainer(newValueHolder); Object cloneCollection = this.mapping.buildCloneForPartObject(attributeValue, original, cacheKey, clone, cloningSession, refreshCascade, false, false); newValueHolder.privilegedSetValue(cloneCollection); newValueHolder.setInstantiated(); } } else { if (indirectContainer == null) { valueHolder = new ValueHolder(attributeValue); } AbstractRecord row = null; if (valueHolder instanceof DatabaseValueHolder) { row = ((DatabaseValueHolder)valueHolder).getRow(); } DatabaseValueHolder uowValueHolder = this.mapping.createCloneValueHolder(valueHolder, original, clone, row, cloningSession, buildDirectlyFromRow); if ((indirectContainer == null) || !buildDirectlyFromRow) { container = buildIndirectContainer(uowValueHolder); } else { // PERF: If building from rows inside uow, there is no original, // so just use the already built indirect collection. indirectContainer.setValueHolder(uowValueHolder); container = indirectContainer; } } if (cloningSession.isUnitOfWork()){ // Set the change listener. if ((this.mapping.getDescriptor().getObjectChangePolicy().isObjectChangeTrackingPolicy()) && (((ChangeTracker)clone)._persistence_getPropertyChangeListener() != null) && (container instanceof CollectionChangeTracker) ) { ((CollectionChangeTracker)container).setTrackedAttributeName(this.mapping.getAttributeName()); ((CollectionChangeTracker)container)._persistence_setPropertyChangeListener(((ChangeTracker)clone)._persistence_getPropertyChangeListener()); } if (indirectList != null) { ((IndirectList)container).setIsListOrderBrokenInDb(indirectList.isListOrderBrokenInDb()); } } 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. */ @Override public Object 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. */ @Override public AbstractRecord extractReferenceRow(Object referenceObject) { if (this.objectIsInstantiated(referenceObject)) { return null; } else { return ((DatabaseValueHolder)((IndirectContainer)referenceObject).getValueHolder()).getRow(); } } /** * 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. */ @Override public void fixObjectReferences(Object object, Map objectDescriptors, Map processedObjects, ObjectLevelReadQuery query, DistributedSession session) { Object container = getMapping().getAttributeValueFromObject(object); if (container instanceof IndirectContainer && ((((IndirectContainer) container).getValueHolder() instanceof RemoteValueHolder)) ) { RemoteValueHolder valueHolder = (RemoteValueHolder)((IndirectContainer)container).getValueHolder(); valueHolder.setSession(session); valueHolder.setMapping(getMapping()); if ((!query.shouldMaintainCache()) && ((!query.shouldCascadeParts()) || (query.shouldCascadePrivateParts() && (!this.mapping.isPrivateOwned())))) { valueHolder.setQuery(null); } else { valueHolder.setQuery(query); } // set to uninstantiated since no objects are serialized past remote value holders valueHolder.setUninstantiated(); } else { this.mapping.fixRealObjectReferences(object, objectDescriptors, processedObjects, query, session); } } /** * 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() { if (this.containerPolicy == null) { this.containerPolicy = getCollectionMapping().getContainerPolicy(); } return this.containerPolicy; } /** * 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. */ @Override public Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject, AbstractSession session) { IndirectContainer container = (IndirectContainer)unitOfWorkIndirectionObject; if (container.getValueHolder() instanceof UnitOfWorkValueHolder) { return buildIndirectContainer((ValueHolderInterface) getOriginalValueHolder(unitOfWorkIndirectionObject, session)); } else { return container; } } /** * INTERNAL: * Return the original indirection object for a unit of work indirection object. */ @Override public Object getOriginalIndirectionObjectForMerge(Object unitOfWorkIndirectionObject, AbstractSession session) { IndirectContainer container = (IndirectContainer) getOriginalIndirectionObject(unitOfWorkIndirectionObject, session); DatabaseValueHolder holder = (DatabaseValueHolder)container.getValueHolder(); if (holder != null && holder.getSession()!= null){ holder.setSession(session); } return container; } /** * 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. */ @Override public Object getOriginalValueHolder(Object unitOfWorkIndirectionObject, AbstractSession session) { if (! (unitOfWorkIndirectionObject instanceof IndirectContainer)){ return new ValueHolder(); } IndirectContainer container = (IndirectContainer)unitOfWorkIndirectionObject; if (container.getValueHolder() instanceof WrappingValueHolder) { ValueHolderInterface valueHolder = ((WrappingValueHolder)container.getValueHolder()).getWrappedValueHolder(); if ((valueHolder == null) && session.isRemoteUnitOfWork()) { RemoteSessionController controller = ((RemoteUnitOfWork)session).getParentSessionController(); valueHolder = controller.getRemoteValueHolders().get(((UnitOfWorkValueHolder)container.getValueHolder()).getWrappedValueHolderRemoteID()); } if (!session.isProtectedSession()){ while (valueHolder instanceof WrappingValueHolder && ((WrappingValueHolder)valueHolder).getWrappedValueHolder() != null){ valueHolder = ((WrappingValueHolder)valueHolder).getWrappedValueHolder(); } } // EL bug 470161 if ((valueHolder != null) && (valueHolder instanceof DatabaseValueHolder)) { ((DatabaseValueHolder) valueHolder).releaseWrappedValueHolder(session); } return valueHolder; } else { return container.getValueHolder(); } } /** * INTERNAL: * Return the "real" attribute value, as opposed to any wrapper. * This will trigger the wrapper to instantiate the value. */ @Override public Object getRealAttributeValueFromObject(Object object, Object attribute) { // PERF: do not instantiate - this.getContainerPolicy().sizeFor(object);// forgive me for this hack: but we have to do something to trigger the database read return attribute; } /** * INTERNAL: * Trigger the instantiation of the value. */ @Override public void instantiateObject(Object object, Object attribute) { getContainerPolicy().sizeFor(attribute); } /** * 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 * @param attributeValue * @return * @see validateAttributeOfInstantiatedObject(Object attributeValue) */ @Override public boolean isAttributeValueFullyBuilt(Object attributeValue){ return attributeValue != null; } public Boolean getUseLazyInstantiation() { return useLazyInstantiation; } /** * INTERNAL: * Extract and return the appropriate value from the * specified remote value holder. */ @Override public Object getValueFromRemoteValueHolder(RemoteValueHolder remoteValueHolder) { Object result = remoteValueHolder.getServerIndirectionObject(); this.getContainerPolicy().sizeFor(result);// forgive me for this hack: but we have to do something to trigger the database read return result; } /** * 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. */ @Override 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: * set the source object into QueryBasedValueHolder. */ @Override public void setSourceObject(Object sourceObject, Object attributeValue) { if( attributeValue instanceof IndirectContainer) { ValueHolderInterface valueHolder = ((IndirectContainer)attributeValue).getValueHolder(); if (valueHolder instanceof QueryBasedValueHolder) { ((QueryBasedValueHolder)valueHolder).setSourceObject(sourceObject); } } } /** * ADVANCED: * IndirectList and IndirectSet can be configured not to instantiate the list from the * database when you add and remove from them. IndirectList defaults to this behavior. When * Set to true, the collection associated with this TransparentIndirection will be setup so as * not to instantiate for adds and removes. The weakness of this setting for an IndirectSet is * that when the set is not instantiated, if a duplicate element is added, it will not be * detected until commit time. */ @Override public void setUseLazyInstantiation(Boolean useLazyInstantiation) { this.useLazyInstantiation = useLazyInstantiation; } /** * ADVANCED: * IndirectList and IndirectSet can be configured not to instantiate the list from the * database when you add and remove from them. IndirectList defaults to this behavior. When * Set to true, the collection associated with this TransparentIndirection will be setup so as * not to instantiate for adds and removes. The weakness of this setting for an IndirectSet is * that when the set is not instantiated, if a duplicate element is added, it will not be * detected until commit time. */ @Override public Boolean shouldUseLazyInstantiation() { return useLazyInstantiation; } /** * INTERNAL: * Iterate over the specified attribute value. */ @Override 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 * Replace the client value holder with the server value holder, * after copying some of the settings from the client value holder. */ @Override public void mergeRemoteValueHolder(Object clientSideDomainObject, Object serverSideDomainObject, MergeManager mergeManager) { // This will always be a transparent with a remote. IndirectContainer serverContainer = (IndirectContainer)getMapping().getAttributeValueFromObject(serverSideDomainObject); RemoteValueHolder serverValueHolder = (RemoteValueHolder)serverContainer.getValueHolder(); mergeClientIntoServerValueHolder(serverValueHolder, mergeManager); getMapping().setAttributeValueInObject(clientSideDomainObject, serverContainer); } /** * 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. */ @Override public Object nullValueFromRow() { throw DescriptorException.invalidUseOfTransparentIndirection(this.getMapping()); } /** * INTERNAL: * Return whether the specified object is instantiated. */ @Override public boolean objectIsInstantiated(Object object) { if (object instanceof IndirectContainer) { return ((IndirectContainer)object).isInstantiated(); } else { return true;// it must be a "real" collection } } /** * INTERNAL: * Return whether the specified object can be instantiated without database access. */ @Override public boolean objectIsEasilyInstantiated(Object object) { if (object instanceof IndirectContainer) { ValueHolderInterface valueHolder = ((IndirectContainer)object).getValueHolder(); if (valueHolder instanceof DatabaseValueHolder) { return ((DatabaseValueHolder)valueHolder).isEasilyInstantiated(); } } return true; } /** * INTERNAL: * Return whether the specified object is instantiated, or if it has changes. */ @Override public boolean objectIsInstantiatedOrChanged(Object object) { return objectIsInstantiated(object) || ((object instanceof IndirectCollection) && ((IndirectCollection)object).hasDeferredChanges()); } /** * ADVANCED: * Set the size to of container to create. Default to using default constructor. */ public static void setDefaultContainerSize(int defaultSize) { //3732 defaultContainerSize = Integer.valueOf(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. */ @Override 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. */ @Override 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 inefficient to initialize. if (attributeValue == null) { return buildIndirectContainer(); } 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. */ @Override 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. */ @Override public void validateDeclaredAttributeType(Class attributeType, IntegrityChecker checker) throws DescriptorException { super.validateDeclaredAttributeType(attributeType, checker); if (!this.typeIsValid(attributeType)) { checker.handleError(DescriptorException.attributeAndMappingWithTransparentIndirectionMismatch(this.getMapping(), attributeType, 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. */ @Override public void validateGetMethodReturnType(Class returnType, IntegrityChecker checker) throws DescriptorException { super.validateGetMethodReturnType(returnType, checker); if (!this.typeIsValid(returnType)) { checker.handleError(DescriptorException.returnAndMappingWithTransparentIndirectionMismatch(this.getMapping(), returnType, 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. */ @Override public void validateSetMethodParameterType(Class parameterType, IntegrityChecker checker) throws DescriptorException { super.validateSetMethodParameterType(parameterType, checker); if (!this.typeIsValid(parameterType)) { checker.handleError(DescriptorException.parameterAndMappingWithTransparentIndirectionMismatch(this.getMapping(), parameterType, 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 the batchQuery. * In this case, wrap the query in an IndirectContainer for later invocation. */ @Override public Object valueFromBatchQuery(ReadQuery batchQuery, AbstractRecord row, ObjectLevelReadQuery originalQuery, CacheKey parentCacheKey) { return this.buildIndirectContainer(new BatchValueHolder(batchQuery, row, getForeignReferenceMapping(), originalQuery, parentCacheKey)); } /** * 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. */ @Override 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. */ @Override 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). */ @Override public Object valueFromQuery(ReadQuery query, AbstractRecord row, Object object, AbstractSession session) { return this.buildIndirectContainer(new QueryBasedValueHolder(query, object, 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. */ @Override public Object valueFromRow(Object object) { return object; } }




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