org.eclipse.persistence.internal.indirection.ContainerIndirectionPolicy Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation
Show all versions of eclipselink Show documentation
EclipseLink build based upon Git transaction f2b9fc5
/*
* Copyright (c) 1998, 2019 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.lang.reflect.Constructor;
import org.eclipse.persistence.exceptions.DescriptorException;
import org.eclipse.persistence.indirection.IndirectContainer;
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.security.PrivilegedAccessHelper;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
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.queries.ObjectLevelReadQuery;
import org.eclipse.persistence.queries.ReadQuery;
/**
* Purpose: Provide ability for developers to wrap ValueHolders (Basic Indirection)
* Responsibilities:
* - Wrap & un-wrap a ValueHolder within an IndirectContainer
*
- Reflectively instantiate the containers as required
*
* @see org.eclipse.persistence.indirection.IndirectContainer
* @author Doug Clarke (TOP)
* @since 2.5.0.5
*/
public class ContainerIndirectionPolicy extends BasicIndirectionPolicy {
private Class containerClass;
private String containerClassName;
private transient Constructor containerConstructor;
/**
* INTERNAL:
* Construct a new indirection policy.
*/
public ContainerIndirectionPolicy() {
super();
}
/**
* INTERNAL:
* Return a backup clone of the attribute.
*/
@Override
public Object backupCloneAttribute(Object attributeValue, Object clone, Object backup, UnitOfWorkImpl unitOfWork) {
IndirectContainer container = (IndirectContainer)attributeValue;
ValueHolderInterface valueHolder = container.getValueHolder();
ValueHolderInterface newValueHolder = (ValueHolderInterface)super.backupCloneAttribute(valueHolder, clone, backup, unitOfWork);
return buildContainer(newValueHolder);
}
/**
* Build a container with the initialized constructor.
*/
protected IndirectContainer buildContainer(final ValueHolderInterface valueHolder) {
try {
IndirectContainer container = null;
if (getContainerConstructor().getParameterTypes().length == 0) {
container = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> (IndirectContainer)PrivilegedAccessHelper.invokeConstructor(getContainerConstructor(), new Object[0])
);
container.setValueHolder(valueHolder);
} else {
container = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> (IndirectContainer)PrivilegedAccessHelper.invokeConstructor(getContainerConstructor(), new Object[] { valueHolder })
);
}
return container;
} catch (Exception exception) {
throw DescriptorException.invalidIndirectionPolicyOperation(this, "buildContainer constructor (" + getContainerConstructor() + ") Failed: " + exception);
}
}
/**
* 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 buildContainer(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) {
IndirectContainer container = (IndirectContainer)attributeValue;
ValueHolderInterface valueHolder = container.getValueHolder();
ValueHolderInterface newValueHolder = (ValueHolderInterface)super.cloneAttribute(valueHolder, original, cacheKey, clone, refreshCascade, cloningSession, buildDirectlyFromRow);
return buildContainer(newValueHolder);
}
/**
* 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();
}
}
/**
* Returns the Container class which implements IndirectContainer.
*/
public Class getContainerClass() {
return containerClass;
}
/**
* INTERNAL:
* Used by MW.
*/
public String getContainerClassName() {
if ((containerClassName == null) && (containerClass != null)) {
containerClassName = containerClass.getName();
}
return containerClassName;
}
/**
*
* @return java.lang.reflect.Constructor
*/
protected Constructor getContainerConstructor() {
return containerConstructor;
}
/**
* 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) {
ValueHolderInterface valueHolder = ((UnitOfWorkValueHolder)container.getValueHolder()).getWrappedValueHolder();
if ((valueHolder == null) && session.isRemoteUnitOfWork()) {
RemoteSessionController controller = ((RemoteUnitOfWork)session).getParentSessionController();
valueHolder = controller.getRemoteValueHolders().get(((UnitOfWorkValueHolder)container.getValueHolder()).getWrappedValueHolderRemoteID());
}
return buildContainer(valueHolder);
} 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 "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) {
return ((IndirectContainer)attribute).getValueHolder().getValue();
}
/**
* INTERNAL:
* Ensure the container class implements IndirectContainer and that it
* has a constructor which can be used.
*/
@Override
public void initialize() {
// Verify that the provided class implements IndirectContainer
if (!ClassConstants.IndirectContainer_Class.isAssignableFrom(containerClass)) {
throw DescriptorException.invalidIndirectionContainerClass(this, containerClass);
}
// Try to find constructor which takes a ValueHolderInterface
try {
this.containerConstructor = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> PrivilegedAccessHelper.getConstructorFor(getContainerClass(), new Class[] { ClassConstants.ValueHolderInterface_Class }, false)
);
return;
// DO NOTHING, exception thrown at end
} catch (NoSuchMethodException nsme) {
// This indicates unexpected problem in the code
} catch (Exception ex) {
throw new RuntimeException(String.format(
"Invocation of %s constructior failed", getContainerClass().getName()), ex);
}
// Try to find the default constructor
try {
this.containerConstructor = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> PrivilegedAccessHelper.getConstructorFor(getContainerClass(), new Class[0], false)
);
return;
// DO NOTHING, exception thrown at end
} catch (NoSuchMethodException nsme) {
// This indicates unexpected problem in the code
} catch (Exception ex) {
throw new RuntimeException(String.format(
"Invocation of %s constructior failed", getContainerClass().getName()), ex);
}
// If no constructor is found then we throw an initialization exception
throw DescriptorException.noConstructorIndirectionContainerClass(this, containerClass);
}
/**
* 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 true;
}
/**
* INTERNAL:
* Iterate over the specified attribute value,
*/
@Override
public void iterateOnAttributeValue(DescriptorIterator iterator, Object attributeValue) {
super.iterateOnAttributeValue(iterator, ((IndirectContainer)attributeValue).getValueHolder());
}
/**
* 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 buildContainer(new ValueHolder());
}
/**
* Reset the wrapper used to store the value.
*/
@Override
public void reset(Object target) {
getMapping().setAttributeValueInObject(target, buildContainer(new ValueHolder()));
}
/**
* INTERNAL:
* Return whether the specified object is instantiated.
*/
@Override
public boolean objectIsInstantiated(Object object) {
return ((IndirectContainer)object).getValueHolder().isInstantiated();
}
/**
* INTERNAL:
* Return whether the specified object can be instantiated without database access.
*/
@Override
public boolean objectIsEasilyInstantiated(Object object) {
ValueHolderInterface valueHolder = ((IndirectContainer)object).getValueHolder();
if (valueHolder instanceof DatabaseValueHolder) {
return ((DatabaseValueHolder)valueHolder).isEasilyInstantiated();
} else {
return true;
}
}
/**
* Sets the Container class which implements IndirectContainer
*/
public void setContainerClass(Class containerClass) {
this.containerClass = containerClass;
}
/**
* Set the container classname for the MW
*/
public void setContainterClassName(String containerClassName) {
this.containerClassName = containerClassName;
}
/**
* 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) {
IndirectContainer container = (IndirectContainer)this.getMapping().getAttributeValueFromObject(target);
container.getValueHolder().setValue(attributeValue);
this.getMapping().setAttributeValueInObject(target, container);
}
/**
* INTERNAL:
* Return whether the type is appropriate for the indirection policy.
* In this case, the type must either be assignable from IndirectContainer or
* allow the conatinerClass to be assigned to it.
*/
@Override
protected boolean typeIsValid(Class attributeType) {
return ClassConstants.IndirectContainer_Class.isAssignableFrom(attributeType) || attributeType.isAssignableFrom(getContainerClass());
}
/**
* 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.
*/
@Override
public Object validateAttributeOfInstantiatedObject(Object attributeValue) {
if (!(getContainerClass().isInstance(attributeValue))) {
throw DescriptorException.valueHolderInstantiationMismatch(attributeValue, this.getMapping());
}
return attributeValue;
}
/**
* 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) {
ValueHolderInterface valueHolder = (ValueHolderInterface)super.valueFromBatchQuery(batchQuery, row, originalQuery, parentCacheKey);
return buildContainer(valueHolder);
}
/**
* 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) {
ValueHolderInterface valueHolder = (ValueHolderInterface)super.valueFromMethod(object, row, session);
return buildContainer(valueHolder);
}
/**
* 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) {
ValueHolderInterface valueHolder = (ValueHolderInterface)super.valueFromQuery(query, row, session);
return buildContainer(valueHolder);
}
/**
* 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 buildContainer(new ValueHolder(object));
}
}