/******************************************************************************* | |
* 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.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.identitymaps.CacheKey; | |
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 transient 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, 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. | |
*/ | |
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 = 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. | |
*/ | |
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. | |
*/ | |
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: | |
* 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, | |
*/ | |
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(); | |
} | |
/** | |
* INTERNAL: | |
* Return whether the specified object can be instantiated without database access. | |
*/ | |
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. | |
*/ | |
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, 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. | |
*/ | |
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)); | |
} | |
} |