/******************************************************************************* | |
* 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.descriptors; | |
import java.lang.reflect.*; | |
import java.security.AccessController; | |
import java.security.PrivilegedActionException; | |
import org.eclipse.persistence.internal.helper.*; | |
import org.eclipse.persistence.exceptions.*; | |
import org.eclipse.persistence.internal.sessions.AbstractRecord; | |
import org.eclipse.persistence.sessions.Session; | |
import org.eclipse.persistence.sessions.Record; | |
import org.eclipse.persistence.internal.security.*; | |
/** | |
* <p><b>Purpose</b>: | |
* Used to allow complex inheritance support. Typically class indicators are used to define inheritance in the database, | |
* however in complex cases the class type may be determined through another mechanism. | |
* The method calls a static method on the descriptor class to determine the class to use for the database row. | |
* | |
* @see org.eclipse.persistence.descriptors.InheritancePolicy#setClassExtractor(ClassExtrator) | |
*/ | |
public class MethodClassExtractor extends ClassExtractor { | |
protected transient ClassDescriptor descriptor; | |
protected String classExtractionMethodName; | |
protected transient Method classExtractionMethod; | |
/** | |
* INTERNAL: | |
* Return all the classExtractionMethod | |
*/ | |
public Method getClassExtractionMethod() { | |
return classExtractionMethod; | |
} | |
/** | |
* PUBLIC: | |
* A class extraction method can be registered with the descriptor to override the default inheritance mechanism. | |
* This allows for the class indicator field to not be used, and a user defined one instead. | |
* The method registered must be a static method on the class that the descriptor is for, | |
* the method must take DatabaseRow as argument, and must return the class to use for that row. | |
* This method will be used to decide which class to instantiate when reading from the database. | |
* It is the application's responsibility to populate any typing information in the database required | |
* to determine the class from the row. | |
* If this method is used then the class indicator field and mapping cannot be used, | |
* also the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly. | |
*/ | |
public String getClassExtractionMethodName() { | |
return classExtractionMethodName; | |
} | |
/** | |
* INTERNAL: | |
*/ | |
protected void setClassExtractionMethod(Method classExtractionMethod) { | |
this.classExtractionMethod = classExtractionMethod; | |
} | |
/** | |
* PUBLIC: | |
* A class extraction method can be registered with the descriptor to override the default inheritance mechanism. | |
* This allows for the class indicator field to not be used, and a user defined one instead. | |
* The method registered must be a static method on the class that the descriptor is for, | |
* the method must take DatabaseRow as argument, and must return the class to use for that row. | |
* This method will be used to decide which class to instantiate when reading from the database. | |
* It is the application's responsibility to populate any typing information in the database required | |
* to determine the class from the row. | |
* If this method is used then the class indicator field and mapping cannot be used, | |
* also the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly. | |
*/ | |
public void setClassExtractionMethodName(String staticClassClassExtractionMethod) { | |
this.classExtractionMethodName = staticClassClassExtractionMethod; | |
} | |
/** | |
* INTERNAL: | |
* Setup the default classExtractionMethod, or if one was specified by the user make sure it is valid. | |
*/ | |
public void initialize(ClassDescriptor descriptor, Session session) throws DescriptorException { | |
setDescriptor(descriptor); | |
Class[] declarationParameters = new Class[1]; | |
declarationParameters[0] = ClassConstants.DatabaseRow_Class; | |
try { | |
setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters)); | |
} catch (NoSuchMethodException ignore) { | |
declarationParameters[0] = ClassConstants.Record_Class; | |
try { | |
setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters)); | |
} catch (NoSuchMethodException exception) { | |
throw DescriptorException.noSuchMethodWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception); | |
} | |
} catch (SecurityException exception) { | |
throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception); | |
} | |
// CR#2818667 Ensure the method is static. | |
if (!Modifier.isStatic(getClassExtractionMethod().getModifiers())) { | |
throw DescriptorException.classExtractionMethodMustBeStatic(getClassExtractionMethodName(), descriptor); | |
} | |
} | |
/** | |
* INTERNAL | |
* Extract/compute the class from the database row and return the class. | |
* Map is used as the public interface to database row, the key is the field name, | |
* the value is the database value. | |
*/ | |
public Class extractClassFromRow(Record row, org.eclipse.persistence.sessions.Session session) { | |
Class classForRow; | |
try { | |
Object[] arguments = new Object[1]; | |
arguments[0] = row; | |
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){ | |
try { | |
classForRow = (Class)AccessController.doPrivileged(new PrivilegedMethodInvoker(getClassExtractionMethod(), null, arguments)); | |
} catch (PrivilegedActionException exception) { | |
Exception throwableException = exception.getException(); | |
if (throwableException instanceof IllegalAccessException) { | |
throw DescriptorException.illegalAccessWhileInvokingRowExtractionMethod((AbstractRecord)row, getClassExtractionMethod(), getDescriptor(), throwableException); | |
} else { | |
throw DescriptorException.targetInvocationWhileInvokingRowExtractionMethod((AbstractRecord)row, getClassExtractionMethod(), getDescriptor(), throwableException); | |
} | |
} | |
} else { | |
classForRow = (Class)PrivilegedAccessHelper.invokeMethod(getClassExtractionMethod(), null, arguments); | |
} | |
} catch (IllegalAccessException exception) { | |
throw DescriptorException.illegalAccessWhileInvokingRowExtractionMethod((AbstractRecord)row, getClassExtractionMethod(), getDescriptor(), exception); | |
} catch (InvocationTargetException exception) { | |
throw DescriptorException.targetInvocationWhileInvokingRowExtractionMethod((AbstractRecord)row, getClassExtractionMethod(), getDescriptor(), exception); | |
} | |
return classForRow; | |
} | |
/** | |
* INTERNAL: | |
* Return the descriptor. | |
*/ | |
protected ClassDescriptor getDescriptor() { | |
return descriptor; | |
} | |
/** | |
* INTERNAL: | |
* Set the descriptor. | |
*/ | |
protected void setDescriptor(ClassDescriptor descriptor) { | |
this.descriptor = descriptor; | |
} | |
} |