org.eclipse.persistence.internal.indirection.ProxyIndirectionHandler 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.internal.indirection;
import org.eclipse.persistence.exceptions.QueryException;
import org.eclipse.persistence.exceptions.ValidationException;
import org.eclipse.persistence.indirection.ValueHolderInterface;
import org.eclipse.persistence.internal.security.PrivilegedAccessHelper;
import java.io.Serializable;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* ProxyIndirectionHandler
*
* Transparently handles EclipseLink indirection for 1:1 relationships through use of the Java Proxy framework
* in JDK 1.3. This class intercepts messages sent to the proxy object, and instantiates its internal
* ValueHolder when necessary.
*
* @see org.eclipse.persistence.internal.indirection.ProxyIndirectionPolicy
* @author Rick Barkhouse
* @since TopLink 3.0
*/
public class ProxyIndirectionHandler implements InvocationHandler, Serializable {
private ValueHolderInterface valueHolder;
// =====================================================================
/**
* INTERNAL:
*
* Just in here to allow for Serialization.
*/
public ProxyIndirectionHandler() {
}
// =====================================================================
/**
* INTERNAL:
*
* Store the value holder.
*/
private ProxyIndirectionHandler(ValueHolderInterface valueHolder) {
this.valueHolder = valueHolder;
}
// =====================================================================
/**
* INTERNAL:
*
* Handle the method calls on the proxy object.
*/
@Override
public Object invoke(final Object proxy, final Method m, final Object[] args) throws Throwable {
Object result = null;
try {
if ((!ValueHolderInterface.shouldToStringInstantiate) && m.getName().equals("toString")) {
if (valueHolder.isInstantiated()) {
if (valueHolder.getValue() == null) {
result = "null";
} else {
final String toString = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> PrivilegedAccessHelper.invokeMethod(m, valueHolder.getValue(), args)
);
result = "{ " + toString + " }";
}
} else {
result = "{ IndirectProxy: not instantiated }";
}
} else if (m.getName().equals("equals") && (valueHolder.getValue() == null) && (args[0] == null)) {
result = Boolean.TRUE;
} else {
Object value = valueHolder.getValue();
// CR2718
if (value == null) {
throw ValidationException.nullUnderlyingValueHolderValue(m.getName());
} else {
result = PrivilegedAccessHelper.callDoPrivilegedWithException(
() -> PrivilegedAccessHelper.invokeMethod(m, value, args)
);
}
}
} catch (InvocationTargetException e) {
throw e.getTargetException();
} catch (ValidationException e) {
// need to re-throw the validation exception
throw e;
} catch (Exception e) {
throw QueryException.unexpectedInvocation(e.getMessage());
}
return result;
}
// =====================================================================
/**
* INTERNAL:
*
* Utility method to create a new proxy object.
*/
public static Object newProxyInstance(final Class anInterface, final Class[] interfaces, final ValueHolderInterface valueHolder) {
final ClassLoader classLoader = PrivilegedAccessHelper.callDoPrivileged(
() -> PrivilegedAccessHelper.getClassLoaderForClass(anInterface)
);
return Proxy.newProxyInstance(classLoader, interfaces, new ProxyIndirectionHandler<>(valueHolder));
}
// =====================================================================
/**
* INTERNAL:
*
* Get the ValueHolder associated with this handler.
*/
public ValueHolderInterface getValueHolder() {
return this.valueHolder;
}
// =====================================================================
/**
* INTERNAL:
*
* Set the ValueHolder associated with this handler.
*/
public void setValueHolder(ValueHolderInterface value) {
this.valueHolder = value;
}
}