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/*
 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
/*
 * Licensed Materials - Property of IBM
 * RMI-IIOP v1.0
 * Copyright IBM Corp. 1998 1999  All Rights Reserved
 *
 */

package javax.rmi;

import java.io.File;
import java.io.FileInputStream;
import java.net.MalformedURLException;
import java.rmi.NoSuchObjectException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.RMIClassLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Properties;

import javax.rmi.CORBA.GetPropertyAction;

import org.omg.CORBA.INITIALIZE;

/**
 * Server implementation objects may either inherit from javax.rmi.PortableRemoteObject or they may implement a remote
 * interface and then use the exportObject method to register themselves as a server object. The toStub method takes a
 * server implementation and returns a stub that can be used to access that server object. The connect method makes a
 * Remote object ready for remote communication. The unexportObject method is used to deregister a server object,
 * allowing it to become available for garbage collection. The narrow method takes an object reference or abstract
 * interface type and attempts to narrow it to conform to the given interface. If the operation is successful the result
 * will be an object of the specified type, otherwise an exception will be thrown.
 */
public class PortableRemoteObject
{

    private static javax.rmi.CORBA.PortableRemoteObjectDelegate proDelegate = null;

    private static final String PortableRemoteObjectClassKey = "javax.rmi.CORBA.PortableRemoteObjectClass";

    static
    {
        proDelegate = (javax.rmi.CORBA.PortableRemoteObjectDelegate) createDelegateIfSpecified(PortableRemoteObjectClassKey);
    }

    /**
     * Initializes the object by calling exportObject(this).
     * 
     * @exception RemoteException
     *                if export fails.
     */
    protected PortableRemoteObject() throws RemoteException
    {
        if (proDelegate != null)
        {
            PortableRemoteObject.exportObject((Remote) this);
        }
    }

    /**
     * Makes a server object ready to receive remote calls. Note that subclasses of PortableRemoteObject do not need to
     * call this method, as it is called by the constructor.
     * 
     * @param obj
     *            the server object to export.
     * @exception RemoteException
     *                if export fails.
     */
    public static void exportObject(Remote obj) throws RemoteException
    {

        // Let the delegate do everything, including error handling.
        if (proDelegate != null)
        {
            proDelegate.exportObject(obj);
        }
    }

    /**
     * Returns a stub for the given server object.
     * 
     * @param obj
     *            the server object for which a stub is required. Must either be a subclass of PortableRemoteObject or
     *            have been previously the target of a call to {@link #exportObject}.
     * @return the most derived stub for the object.
     * @exception NoSuchObjectException
     *                if a stub cannot be located for the given server object.
     */
    public static Remote toStub(Remote obj) throws NoSuchObjectException
    {

        if (proDelegate != null)
        {
            return proDelegate.toStub(obj);
        }
        return null;
    }

    /**
     * Deregisters a server object from the runtime, allowing the object to become available for garbage collection.
     * 
     * @param obj
     *            the object to unexport.
     * @exception NoSuchObjectException
     *                if the remote object is not currently exported.
     */
    public static void unexportObject(Remote obj) throws NoSuchObjectException
    {

        if (proDelegate != null)
        {
            proDelegate.unexportObject(obj);
        }

    }

    /**
     * Checks to ensure that an object of a remote or abstract interface type can be cast to a desired type.
     * 
     * @param narrowFrom
     *            the object to check.
     * @param narrowTo
     *            the desired type.
     * @return an object which can be cast to the desired type.
     * @throws ClassCastException
     *             if narrowFrom cannot be cast to narrowTo.
     */
    public static java.lang.Object narrow(java.lang.Object narrowFrom, java.lang.Class narrowTo)
            throws ClassCastException
    {

        if (proDelegate != null)
        {
            return proDelegate.narrow(narrowFrom, narrowTo);
        }
        return null;

    }

    /**
     * Makes a Remote object ready for remote communication. This normally happens implicitly when the object is sent or
     * received as an argument on a remote method call, but in some circumstances it is useful to perform this action by
     * making an explicit call. See the {@link javax.rmi.CORBA.Stub#connect} method for more information.
     * 
     * @param target
     *            the object to connect.
     * @param source
     *            a previously connected object.
     * @throws RemoteException
     *             if source is not connected or if target is already connected to a different
     *             ORB than source.
     */
    public static void connect(Remote target, Remote source) throws RemoteException
    {

        if (proDelegate != null)
        {
            proDelegate.connect(target, source);
        }

    }

    // Same code as in javax.rmi.CORBA.Util. Can not be shared because they
    // are in different packages and the visibility needs to be package for
    // security reasons. If you know a better solution how to share this code
    // then remove it from here.
    private static Object createDelegateIfSpecified(String classKey)
    {
        String className = (String) AccessController.doPrivileged(new GetPropertyAction(classKey));
        if (className == null)
        {
            Properties props = getORBPropertiesFile();
            if (props != null)
            {
                className = props.getProperty(classKey);
            }
        }
        if (className == null)
        {
            return new org.jboss.com.sun.corba.se.impl.javax.rmi.PortableRemoteObject();
        }

        try
        {
            return loadDelegateClass(className).newInstance();
        }
        catch (ClassNotFoundException ex)
        {
            INITIALIZE exc = new INITIALIZE("Cannot instantiate " + className);
            exc.initCause(ex);
            throw exc;
        }
        catch (Exception ex)
        {
            INITIALIZE exc = new INITIALIZE("Error while instantiating" + className);
            exc.initCause(ex);
            throw exc;
        }

    }

    private static Class loadDelegateClass(String className) throws ClassNotFoundException
    {
        try
        {
            return Class.forName(className, false, PortableRemoteObject.class.getClassLoader());
        }
        catch (ClassNotFoundException e)
        {
            // ignore, then try RMIClassLoader
        }
        try
        {
            return RMIClassLoader.loadClass((String) null, className);
        }
        catch (MalformedURLException e)
        {
            String msg = "Could not load " + className + ": " + e.toString();
            ClassNotFoundException exc = new ClassNotFoundException(msg);
            throw exc;
        }
    }

    /**
     * Load the orb.properties file.
     */
    private static Properties getORBPropertiesFile()
    {
        return AccessController.doPrivileged(new GetORBPropertiesFileAction());
    }
}

class GetORBPropertiesFileAction implements PrivilegedAction
{
    private boolean debug = false;

    public GetORBPropertiesFileAction()
    {
    }

    private String getSystemProperty(final String name)
    {
        // This will not throw a SecurityException because this
        // class was loaded from rt.jar using the bootstrap classloader.
        String propValue = AccessController.doPrivileged(new PrivilegedAction()
        {
            public String run()
            {
                return System.getProperty(name);
            }
        });

        return propValue;
    }

    private void getPropertiesFromFile(Properties props, String fileName)
    {
        try
        {
            File file = new File(fileName);
            if (!file.exists())
                return;

            FileInputStream in = new FileInputStream(file);

            try
            {
                props.load(in);
            }
            finally
            {
                in.close();
            }
        }
        catch (Exception exc)
        {
            if (debug)
                System.out.println("ORB properties file " + fileName + " not found: " + exc);
        }
    }

    public Properties run()
    {
        Properties defaults = new Properties();

        String javaHome = getSystemProperty("java.home");
        String fileName = javaHome + File.separator + "lib" + File.separator + "orb.properties";

        getPropertiesFromFile(defaults, fileName);
        Properties results = new Properties(defaults);

        String userHome = getSystemProperty("user.home");
        fileName = userHome + File.separator + "orb.properties";

        getPropertiesFromFile(results, fileName);
        return results;
    }
}