org.eclipse.persistence.internal.indirection.ProxyIndirectionHandler Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation
EclipseLink build based upon Git transaction f2b9fc5
There is a newer version: 5.0.0-B03
/*
 * Copyright (c) 1998, 2018 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 java.io.Serializable;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.InvocationTargetException;
import java.security.AccessController;
import java.security.PrivilegedActionException;

import org.eclipse.persistence.exceptions.ValidationException;
import org.eclipse.persistence.indirection.ValueHolderInterface;
import org.eclipse.persistence.internal.security.PrivilegedAccessHelper;
import org.eclipse.persistence.internal.security.PrivilegedGetClassLoaderForClass;
import org.eclipse.persistence.internal.security.PrivilegedMethodInvoker;
import org.eclipse.persistence.exceptions.QueryException;

/**
 * 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.
     */
    public Object invoke(Object proxy, Method m, 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 {
                        if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                            String toString = (String)AccessController.doPrivileged(new PrivilegedMethodInvoker(m, valueHolder.getValue(), args));
                            result = "{ " + toString + " }";
                        }else{
                            String toString = (String)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 {
                    if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                        result = AccessController.doPrivileged(new PrivilegedMethodInvoker(m, value, args));
                    }else{
                        result = 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(Class anInterface, Class[] interfaces, ValueHolderInterface valueHolder) {
        ClassLoader classLoader = null;
        if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
            try{
                classLoader = AccessController.doPrivileged(new PrivilegedGetClassLoaderForClass(anInterface));
            }catch (PrivilegedActionException ex){
                throw (RuntimeException) ex.getCause();
            }
        }else{
            classLoader = 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;
    }
}