org.eclipse.persistence.mappings.converters.ClassInstanceConverter Maven / Gradle / Ivy
/*
* Copyright (c) 1998, 2024 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.mappings.converters;
import org.eclipse.persistence.exceptions.ConversionException;
import org.eclipse.persistence.internal.helper.ClassConstants;
import org.eclipse.persistence.internal.security.PrivilegedAccessHelper;
import org.eclipse.persistence.internal.security.PrivilegedNewInstanceFromClass;
import org.eclipse.persistence.mappings.DatabaseMapping;
import org.eclipse.persistence.mappings.foundation.AbstractDirectMapping;
import org.eclipse.persistence.sessions.Session;
import java.security.AccessController;
import java.security.PrivilegedActionException;
/**
* Purpose: Allows a class name to be converted to and from a new instance of the class.
*
* When using a ClassInstanceConverter, the database will store the Class name and the java object
* model will contain an instance of that class initialized with its default constructor
*
* @author James Sutherland
* @since OracleAS TopLink 10g (10.0.3)
*/
public class ClassInstanceConverter implements Converter {
protected DatabaseMapping mapping;
/**
* PUBLIC:
* Default constructor.
*/
public ClassInstanceConverter() {
}
/**
* INTERNAL:
* Convert the class name to a class, then create an instance of the class.
*/
@Override
public Object convertDataValueToObjectValue(Object fieldValue, Session session) {
Object attributeValue = null;
if (fieldValue != null) {
Class attributeClass = session.getDatasourcePlatform().convertObject(fieldValue, ClassConstants.CLASS);
try {
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
try {
attributeValue = AccessController.doPrivileged(new PrivilegedNewInstanceFromClass(attributeClass));
} catch (PrivilegedActionException exception) {
throw ConversionException.couldNotBeConverted(fieldValue, attributeClass, exception.getException());
}
} else {
attributeValue = PrivilegedAccessHelper.newInstanceFromClass(attributeClass);
}
} catch (Exception exception) {
throw ConversionException.couldNotBeConverted(fieldValue, attributeClass, exception);
}
}
return attributeValue;
}
/**
* INTERNAL:
* Convert to the field class.
*/
@Override
public Object convertObjectValueToDataValue(Object attributeValue, Session session) {
if (attributeValue == null) {
return null;
}
return attributeValue.getClass().getName();
}
/**
* INTERNAL:
* Set the mapping.
*/
@Override
public void initialize(DatabaseMapping mapping, Session session) {
this.mapping = mapping;
// CR#... Mapping must also have the field classification.
if (getMapping().isDirectToFieldMapping()) {
AbstractDirectMapping directMapping = (AbstractDirectMapping)getMapping();
// Allow user to specify field type to override computed value. (i.e. blob, nchar)
if (directMapping.getFieldClassification() == null) {
directMapping.setFieldClassification(ClassConstants.STRING);
}
}
}
/**
* INTERNAL:
* Return the mapping.
*/
protected DatabaseMapping getMapping() {
return mapping;
}
/**
* INTERNAL:
* If the converter converts the value to a non-atomic value, i.e.
* a value that can have its' parts changed without being replaced,
* then it must return false, serialization can be non-atomic.
*/
@Override
public boolean isMutable() {
return false;
}
}