| /* |
| * Copyright (c) 1998, 2021 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.rmi.server.ObjID; |
| import java.util.Map; |
| |
| import org.eclipse.persistence.exceptions.DescriptorException; |
| import org.eclipse.persistence.exceptions.IntegrityChecker; |
| import org.eclipse.persistence.indirection.ValueHolder; |
| import org.eclipse.persistence.indirection.ValueHolderInterface; |
| import org.eclipse.persistence.internal.descriptors.DescriptorIterator; |
| import org.eclipse.persistence.internal.helper.ClassConstants; |
| 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; |
| import org.eclipse.persistence.internal.sessions.remote.RemoteSessionController; |
| import org.eclipse.persistence.internal.sessions.remote.RemoteUnitOfWork; |
| import org.eclipse.persistence.internal.sessions.remote.RemoteValueHolder; |
| import org.eclipse.persistence.mappings.DatabaseMapping.WriteType; |
| import org.eclipse.persistence.queries.ObjectLevelReadQuery; |
| import org.eclipse.persistence.queries.ReadObjectQuery; |
| import org.eclipse.persistence.queries.ReadQuery; |
| import org.eclipse.persistence.sessions.remote.DistributedSession; |
| |
| /** |
| * <h2>Purpose</h2>: |
| * BasicIndirectionPolicy implements the behavior necessary for a |
| * a <code>org.eclipse.persistence.mappings.ForeignReferenceMapping</code> (or TransformationMapping) to |
| * use ValueHolders to delay the reading of objects from the database |
| * until they are actually needed. |
| * |
| * @author Mike Norman |
| * @since TOPLink/Java 2.5 |
| */ |
| public class BasicIndirectionPolicy extends IndirectionPolicy { |
| |
| /** |
| * INTERNAL: |
| * Construct a new indirection policy. |
| */ |
| public BasicIndirectionPolicy() { |
| super(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return a backup clone of the attribute. |
| */ |
| @Override |
| public Object backupCloneAttribute(Object attributeValue, Object clone, Object backup, UnitOfWorkImpl unitOfWork) { |
| //no need to check if the attribute is a valueholder because closeAttribute |
| // should always be called first |
| ValueHolderInterface<?> valueHolder = (ValueHolderInterface)attributeValue;// cast the value |
| ValueHolderInterface<Object> result = null; |
| // delay instantiation until absolutely necessary |
| if ((!(valueHolder instanceof UnitOfWorkValueHolder)) || valueHolder.isInstantiated()) { |
| result = new ValueHolder<>(); |
| result.setValue(super.backupCloneAttribute(valueHolder.getValue(), clone, backup, unitOfWork)); |
| } else { |
| // Backup value holder will be instantiated when uow vh is, to get original value, |
| // backup must also know about the uow vh, in case it needs to get its value. |
| result = new BackupValueHolder(valueHolder); |
| ((UnitOfWorkValueHolder)valueHolder).setBackupValueHolder(result); |
| } |
| |
| 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 valueHolder; |
| } |
| |
| /** |
| * INTERNAL: |
| * 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 = (ValueHolderInterface<?>) attributeValue; |
| ValueHolderInterface<Object> result; |
| |
| 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) { |
| result = new ValueHolder<>(); |
| result.setValue(this.mapping.buildCloneForPartObject(valueHolder.getValue(), original, null, clone, cloningSession, refreshCascade, false, false)); |
| } else { |
| //if I have a relationship partner trigger the indirection so that the value will be inserted |
| // because of this call the entire tree should be recursively cloned |
| AbstractRecord row = null; |
| if (valueHolder instanceof DatabaseValueHolder) { |
| row = ((DatabaseValueHolder)valueHolder).getRow(); |
| } |
| result = this.mapping.createCloneValueHolder(valueHolder, original, clone, row, cloningSession, buildDirectlyFromRow); |
| |
| Object newObject = this.mapping.buildCloneForPartObject(valueHolder.getValue(), original, cacheKey, clone, cloningSession, refreshCascade, false, false); |
| ((UnitOfWorkValueHolder)result).privilegedSetValue(newObject); |
| ((UnitOfWorkValueHolder)result).setInstantiated(); |
| } |
| } else { |
| AbstractRecord row = null; |
| if (valueHolder instanceof DatabaseValueHolder) { |
| row = ((DatabaseValueHolder)valueHolder).getRow(); |
| } |
| result = this.mapping.createCloneValueHolder(valueHolder, original, clone, row, cloningSession, buildDirectlyFromRow); |
| } |
| return result; |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public Object extractPrimaryKeyForReferenceObject(Object referenceObject, AbstractSession session) { |
| if (objectIsEasilyInstantiated(referenceObject)) { |
| return super.extractPrimaryKeyForReferenceObject(((ValueHolderInterface)referenceObject).getValue(), session); |
| } else { |
| return getOneToOneMapping().extractPrimaryKeysForReferenceObjectFromRow(extractReferenceRow(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. |
| */ |
| @Override |
| public AbstractRecord extractReferenceRow(Object referenceObject) { |
| if (this.objectIsInstantiated(referenceObject)) { |
| return null; |
| } else { |
| return ((DatabaseValueHolder)referenceObject).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 attributeValue = this.mapping.getAttributeValueFromObject(object); |
| //bug 4147755 if it is not a Remote Valueholder then treat as if there was no VH... |
| if (attributeValue instanceof RemoteValueHolder){ |
| RemoteValueHolder rvh = (RemoteValueHolder)this.mapping.getAttributeValueFromObject(object); |
| rvh.setSession(session); |
| rvh.setMapping(this.mapping); |
| |
| if ((!query.shouldMaintainCache()) && ((!query.shouldCascadeParts()) || (query.shouldCascadePrivateParts() && (!this.mapping.isPrivateOwned())))) { |
| rvh.setQuery(null); |
| } else { |
| rvh.setQuery(query); |
| } |
| |
| // set to uninstantiated since no objects are serialized past remote value holders |
| rvh.setUninstantiated(); |
| }else{ |
| this.mapping.fixRealObjectReferences(object, objectDescriptors, processedObjects, query, 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. |
| */ |
| @Override |
| public Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject, AbstractSession session) { |
| return this.getOriginalValueHolder(unitOfWorkIndirectionObject, session); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the original indirection object for a unit of work indirection object. |
| */ |
| @Override |
| public Object getOriginalIndirectionObjectForMerge(Object unitOfWorkIndirectionObject, AbstractSession session) { |
| DatabaseValueHolder holder = (DatabaseValueHolder)getOriginalIndirectionObject(unitOfWorkIndirectionObject, session); |
| if (holder != null && holder.getSession()!= null){ |
| holder.setSession(session); |
| } |
| return holder; |
| } |
| |
| /** |
| * 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 UnitOfWorkValueHolder) |
| && (((UnitOfWorkValueHolder)unitOfWorkIndirectionObject).getRemoteUnitOfWork() != null)) { |
| ValueHolderInterface<?> valueHolder = ((UnitOfWorkValueHolder) unitOfWorkIndirectionObject).getWrappedValueHolder(); |
| if (valueHolder == null) { |
| // For remote session the original value holder is transient, |
| // so the value must be found in the registry or created. |
| RemoteUnitOfWork remoteUnitOfWork = (RemoteUnitOfWork)((UnitOfWorkValueHolder)unitOfWorkIndirectionObject).getRemoteUnitOfWork(); |
| RemoteSessionController controller = remoteUnitOfWork.getParentSessionController(); |
| ObjID id = ((UnitOfWorkValueHolder) unitOfWorkIndirectionObject).getWrappedValueHolderRemoteID(); |
| if (id != null) { |
| // This value holder may be on the server, or the client, |
| // on the server, the controller should exists, so can lock up in it, |
| // on the client, the id should be enough to create a new remote value holder. |
| if (controller != null) { |
| valueHolder = controller.getRemoteValueHolders().get(id); |
| } else if (session.isRemoteSession()) { |
| valueHolder = new RemoteValueHolder(id); |
| ((RemoteValueHolder)valueHolder).setSession(session); |
| } |
| } |
| if (valueHolder == null) { |
| // Must build a new value holder. |
| Object object = ((UnitOfWorkValueHolder) unitOfWorkIndirectionObject).getSourceObject(); |
| AbstractRecord row = this.mapping.getDescriptor().getObjectBuilder().buildRow(object, session, WriteType.UNDEFINED); |
| ReadObjectQuery query = new ReadObjectQuery(); |
| query.setSession(session); |
| valueHolder = (ValueHolderInterface) this.mapping.valueFromRow(row, null, query, true); |
| } |
| return valueHolder; |
| } |
| } |
| if (unitOfWorkIndirectionObject instanceof WrappingValueHolder) { |
| ValueHolderInterface<?> valueHolder = ((WrappingValueHolder)unitOfWorkIndirectionObject).getWrappedValueHolder(); |
| if (!session.isProtectedSession()){ |
| while (valueHolder instanceof WrappingValueHolder && ((WrappingValueHolder)valueHolder).getWrappedValueHolder() != null){ |
| valueHolder = ((WrappingValueHolder)valueHolder).getWrappedValueHolder(); |
| } |
| } |
| if ((valueHolder != null) && (valueHolder instanceof DatabaseValueHolder)) { |
| ((DatabaseValueHolder) valueHolder).releaseWrappedValueHolder(session); |
| } |
| return valueHolder; |
| } else { |
| return unitOfWorkIndirectionObject; |
| } |
| } |
| |
| /** |
| * Reset the wrapper used to store the value. |
| */ |
| @Override |
| public void reset(Object target) { |
| this.mapping.setAttributeValueInObject(target, new ValueHolder()); |
| } |
| |
| /** |
| * 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) { |
| if (attribute instanceof ValueHolderInterface) { |
| return ((ValueHolderInterface)attribute).getValue(); |
| } else { |
| return attribute; |
| } |
| } |
| |
| /** |
| * INTERNAL: |
| * Extract and return the appropriate value from the |
| * specified remote value holder. |
| */ |
| @Override |
| public Object getValueFromRemoteValueHolder(RemoteValueHolder remoteValueHolder) { |
| return remoteValueHolder.getValue(); |
| } |
| |
| /** |
| * 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 |
| * @see validateAttributeOfInstantiatedObject(Object attributeValue) |
| */ |
| @Override |
| public boolean isAttributeValueFullyBuilt(Object attributeValue){ |
| //Bug#413833 : If attributeValue is an instance of ValueHolder, |
| //it has not been built into the clone previously |
| return attributeValue != null && !(attributeValue instanceof ValueHolder && ((ValueHolder)attributeValue).isNewlyWeavedValueHolder()); |
| } |
| |
| /** |
| * INTERNAL: |
| * Iterate over the specified attribute value, |
| */ |
| @Override |
| public void iterateOnAttributeValue(DescriptorIterator iterator, Object attributeValue) { |
| iterator.iterateValueHolderForMapping((ValueHolderInterface)attributeValue, this.mapping); |
| } |
| |
| /** |
| * 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 remote value holder coming from the server, |
| RemoteValueHolder serverValueHolder = (RemoteValueHolder)this.mapping.getAttributeValueFromObject(serverSideDomainObject); |
| mergeClientIntoServerValueHolder(serverValueHolder, mergeManager); |
| |
| this.mapping.setAttributeValueInObject(clientSideDomainObject, serverValueHolder); |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public Object nullValueFromRow() { |
| return new ValueHolder(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return whether the specified object is instantiated. |
| */ |
| @Override |
| public boolean objectIsInstantiated(Object object) { |
| return ((ValueHolderInterface)object).isInstantiated(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return whether the specified object can be instantiated without database access. |
| */ |
| @Override |
| public boolean objectIsEasilyInstantiated(Object object) { |
| if (object instanceof DatabaseValueHolder) { |
| return ((DatabaseValueHolder)object).isEasilyInstantiated(); |
| } else { |
| return true; |
| } |
| } |
| |
| /** |
| * INTERNAL: |
| * Set the value of the appropriate attribute of target to attributeValue. |
| * In this case, place the value inside the target's ValueHolder. |
| */ |
| @Override |
| public void setRealAttributeValueInObject(Object target, Object attributeValue) { |
| ValueHolderInterface<Object> holder = (ValueHolderInterface<Object>)this.mapping.getAttributeValueFromObject(target); |
| if (holder == null) { |
| holder = new ValueHolder<>(attributeValue); |
| } else { |
| holder.setValue(attributeValue); |
| } |
| super.setRealAttributeValueInObject(target, holder); |
| } |
| |
| /** |
| * INTERNAL: |
| * set the source object into QueryBasedValueHolder. |
| * Used only by transparent indirection. |
| */ |
| @Override |
| public void setSourceObject(Object sourceObject, Object attributeValue) { |
| if (attributeValue instanceof QueryBasedValueHolder) { |
| ((QueryBasedValueHolder)attributeValue).setSourceObject(sourceObject); |
| } |
| } |
| |
| /** |
| * INTERNAL: |
| * Return whether the type is appropriate for the indirection policy. |
| * In this case, the attribute type MUST be ValueHolderInterface. |
| */ |
| protected boolean typeIsValid(Class attributeType) { |
| return attributeType == ClassConstants.ValueHolderInterface_Class || |
| attributeType == ClassConstants.WeavedAttributeValueHolderInterface_Class; |
| } |
| |
| /** |
| * 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. |
| */ |
| @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 new ValueHolder(); |
| } |
| if (!(attributeValue instanceof ValueHolderInterface)) { |
| throw DescriptorException.valueHolderInstantiationMismatch(attributeValue, this.mapping); |
| } |
| return attributeValue; |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public void validateDeclaredAttributeType(Class attributeType, IntegrityChecker checker) throws DescriptorException { |
| super.validateDeclaredAttributeType(attributeType, checker); |
| if (!this.typeIsValid(attributeType)) { |
| checker.handleError(DescriptorException.attributeAndMappingWithIndirectionMismatch(this.mapping)); |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public void validateGetMethodReturnType(Class returnType, IntegrityChecker checker) throws DescriptorException { |
| super.validateGetMethodReturnType(returnType, checker); |
| if (!this.typeIsValid(returnType)) { |
| checker.handleError(DescriptorException.returnAndMappingWithIndirectionMismatch(this.mapping)); |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public void validateSetMethodParameterType(Class parameterType, IntegrityChecker checker) throws DescriptorException { |
| super.validateSetMethodParameterType(parameterType, checker); |
| if (!this.typeIsValid(parameterType)) { |
| checker.handleError(DescriptorException.parameterAndMappingWithIndirectionMismatch(this.mapping)); |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public Object valueFromBatchQuery(ReadQuery batchQuery, AbstractRecord row, ObjectLevelReadQuery originalQuery, CacheKey parentCacheKey) { |
| return new BatchValueHolder(batchQuery, row, this.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. |
| * In this case, wrap the row in a ValueHolder for later use. |
| */ |
| @Override |
| public Object valueFromMethod(Object object, AbstractRecord row, AbstractSession session) { |
| return new TransformerBasedValueHolder(this.getTransformationMapping().getAttributeTransformer(), object, row, 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. |
| */ |
| @Override |
| public Object valueFromQuery(ReadQuery query, AbstractRecord row, Object sourceObject, AbstractSession session) { |
| return new QueryBasedValueHolder(query, sourceObject, row, 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. |
| */ |
| @Override |
| public Object valueFromQuery(ReadQuery query, AbstractRecord row, AbstractSession session) { |
| return new QueryBasedValueHolder(query, row, session); |
| } |
| |
| /** |
| * 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. |
| */ |
| @Override |
| public Object valueFromRow(Object object) { |
| return new ValueHolder<>(object); |
| } |
| } |
