/******************************************************************************* | |
* Copyright (c) 1998, 2013 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 v1.0 and Eclipse Distribution License v. 1.0 | |
* which accompanies this distribution. | |
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html | |
* and the Eclipse Distribution License is available at | |
* http://www.eclipse.org/org/documents/edl-v10.php. | |
* | |
* Contributors: | |
* Oracle - initial API and implementation from Oracle TopLink | |
******************************************************************************/ | |
package org.eclipse.persistence.internal.indirection; | |
import java.rmi.server.ObjID; | |
import java.util.*; | |
import org.eclipse.persistence.mappings.DatabaseMapping.WriteType; | |
import org.eclipse.persistence.queries.*; | |
import org.eclipse.persistence.sessions.remote.DistributedSession; | |
import org.eclipse.persistence.indirection.*; | |
import org.eclipse.persistence.exceptions.*; | |
import org.eclipse.persistence.internal.descriptors.*; | |
import org.eclipse.persistence.internal.helper.*; | |
import org.eclipse.persistence.internal.identitymaps.CacheKey; | |
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.internal.sessions.AbstractRecord; | |
import org.eclipse.persistence.internal.sessions.AbstractSession; | |
import org.eclipse.persistence.internal.sessions.MergeManager; | |
import org.eclipse.persistence.internal.sessions.UnitOfWorkImpl; | |
/** | |
* <h2>Purpose</h2>: | |
* BasicIndirectionPolicy implements the behavior necessary for a | |
* a ForeignReferenceMapping (or TransformationMapping) to | |
* use ValueHolders to delay the reading of objects from the database | |
* until they are actually needed. | |
* | |
* @see ForeignReferenceMapping | |
* @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. | |
*/ | |
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 | |
ValueHolder result = new ValueHolder(); | |
// delay instantiation until absolutely necessary | |
if ((!(valueHolder instanceof UnitOfWorkValueHolder)) || valueHolder.isInstantiated()) { | |
result.setValue(super.backupCloneAttribute(valueHolder.getValue(), clone, backup, unitOfWork)); | |
} else { | |
((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. | |
*/ | |
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. | |
*/ | |
public Object cloneAttribute(Object attributeValue, Object original, CacheKey cacheKey, Object clone, Integer refreshCascade, AbstractSession cloningSession, boolean buildDirectlyFromRow) { | |
ValueHolderInterface valueHolder = (ValueHolderInterface) attributeValue; | |
ValueHolderInterface 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) | |
&& (! ((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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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 | |
* @param attributeValue | |
* @return | |
* @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, | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
public Object nullValueFromRow() { | |
return new ValueHolder(); | |
} | |
/** | |
* INTERNAL: | |
* Return whether the specified object is instantiated. | |
*/ | |
public boolean objectIsInstantiated(Object object) { | |
return ((ValueHolderInterface)object).isInstantiated(); | |
} | |
/** | |
* INTERNAL: | |
* Return whether the specified object can be instantiated without database access. | |
*/ | |
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. | |
*/ | |
public void setRealAttributeValueInObject(Object target, Object attributeValue) { | |
ValueHolderInterface holder = (ValueHolderInterface)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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
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. | |
*/ | |
public Object valueFromRow(Object object) { | |
return new ValueHolder(object); | |
} | |
} |