/*******************************************************************************
* Copyright (c) 1998, 2008 Oracle. 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.lang.reflect.*;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import org.eclipse.persistence.queries.*;
import org.eclipse.persistence.indirection.*;
import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.internal.descriptors.*;
import org.eclipse.persistence.internal.sessions.remote.*;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.internal.security.PrivilegedAccessHelper;
import org.eclipse.persistence.internal.security.PrivilegedGetConstructorFor;
import org.eclipse.persistence.internal.security.PrivilegedInvokeConstructor;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.internal.sessions.UnitOfWorkImpl;
/**
* <b>Purpose</b>: Provide ability for developers to wrap ValueHolders (Basic Indirection)<p>
* <b>Responsibilities</b>:<ul>
* <li>Wrap & un-wrap a ValueHolder within an IndirectContainer
* <li>Reflectivly instantiate the containers as required
* </ul>
* @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 Constructor containerConstructor;
/**
* INTERNAL:
* Construct a new indirection policy.
*/
public ContainerIndirectionPolicy() {
super();
}
/**
* INTERNAL:
* Return a backup clone of the attribute.
*/
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 conatiner with the initialized constructor.
* @see initializeContainer
*/
protected IndirectContainer buildContainer(ValueHolderInterface valueHolder) {
try {
IndirectContainer container = null;
if (getContainerConstructor().getParameterTypes().length == 0) {
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
container = (IndirectContainer)AccessController.doPrivileged(new PrivilegedInvokeConstructor(getContainerConstructor(), new Object[0]));
}else{
container = (IndirectContainer)PrivilegedAccessHelper.invokeConstructor(getContainerConstructor(), new Object[0]);
}
container.setValueHolder(valueHolder);
} else {
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
container = (IndirectContainer)AccessController.doPrivileged(new PrivilegedInvokeConstructor(getContainerConstructor(), new Object[] { valueHolder }));
}else{
container = (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.
*/
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.
*/
public Object cloneAttribute(Object attributeValue, Object original, Object clone, UnitOfWorkImpl unitOfWork, boolean buildDirectlyFromRow) {
IndirectContainer container = (IndirectContainer)attributeValue;
ValueHolderInterface valueHolder = container.getValueHolder();
ValueHolderInterface newValueHolder = (ValueHolderInterface)super.cloneAttribute(valueHolder, original, clone, unitOfWork, 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.
*/
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.
*/
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 = (ValueHolderInterface)controller.getRemoteValueHolders().get(((UnitOfWorkValueHolder)container.getValueHolder()).getWrappedValueHolderRemoteID());
}
return buildContainer(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) {
return ((IndirectContainer)attribute).getValueHolder().getValue();
}
/**
* INTERNAL:
* Ensure the container class implements IndirectContainer and that it
* has a constructor which can be used.
*/
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 {
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
try{
this.containerConstructor = (Constructor)AccessController.doPrivileged(new PrivilegedGetConstructorFor(getContainerClass(), new Class[] { ClassConstants.ValueHolderInterface_Class }, false));
}catch (PrivilegedActionException ex){
if (ex.getCause() instanceof NoSuchMethodException){
throw (NoSuchMethodException) ex.getCause();
}
throw (RuntimeException)ex.getCause();
}
}else{
this.containerConstructor = PrivilegedAccessHelper.getConstructorFor(getContainerClass(), new Class[] { ClassConstants.ValueHolderInterface_Class }, false);
}
return;
} catch (NoSuchMethodException nsme) {// DO NOTHING, exception thrown at end
}
// Try to find the default constructor
try {
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
try{
this.containerConstructor = (Constructor)AccessController.doPrivileged(new PrivilegedGetConstructorFor(getContainerClass(), new Class[0], false));
}catch (PrivilegedActionException ex){
if (ex.getCause() instanceof NoSuchMethodException){
throw (NoSuchMethodException) ex.getCause();
}
throw (RuntimeException)ex.getCause();
}
}else{
this.containerConstructor = PrivilegedAccessHelper.getConstructorFor(getContainerClass(), new Class[0], false);
}
return;
} catch (NoSuchMethodException nsme) {// DO NOTHING, exception thrown at end
}
// If no constructor is found then we throw an initialization exception
throw DescriptorException.noConstructorIndirectionContainerClass(this, containerClass);
}
/**
* INTERNAL:
* Iterate over the specified attribute value,
*/
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.
*/
public Object nullValueFromRow() {
return buildContainer(new ValueHolder());
}
/**
* Reset the wrapper used to store the value.
*/
public void reset(Object target) {
getMapping().setAttributeValueInObject(target, buildContainer(new ValueHolder()));
}
/**
* INTERNAL:
* Return whether the specified object is instantiated.
*/
public boolean objectIsInstantiated(Object object) {
return ((IndirectContainer)object).getValueHolder().isInstantiated();
}
/**
* 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.
*/
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.
*/
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.
*/
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.
*/
public Object valueFromBatchQuery(ReadQuery batchQuery, AbstractRecord row, ObjectLevelReadQuery originalQuery) {
ValueHolderInterface valueHolder = (ValueHolderInterface)super.valueFromBatchQuery(batchQuery, row, originalQuery);
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.
*/
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.
*/
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.
*/
public Object valueFromRow(Object object) {
return buildContainer(new ValueHolder(object));
}
}