/*

 * Copyright (c) 2009, 2012, 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.

 */

package com.sun.jmx.remote.internal;

import java.util.Properties;

import java.io.IOException;

import java.rmi.Remote;

import java.rmi.NoSuchObjectException;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * A helper class for RMI-IIOP and CORBA APIs.

 */

public final class IIOPHelper {

    private IIOPHelper() { }

    // loads IIOPProxy implementation class if available

    private static final String IMPL_CLASS =

        "com.sun.jmx.remote.protocol.iiop.IIOPProxyImpl";

    private static final IIOPProxy proxy =

        AccessController.doPrivileged(new PrivilegedAction<IIOPProxy>() {

            public IIOPProxy run() {

                try {

                    Class<?> c = Class.forName(IMPL_CLASS, true,

                                               IIOPHelper.class.getClassLoader());

                    return (IIOPProxy)c.newInstance();

                } catch (ClassNotFoundException cnf) {

                    return null;

                } catch (InstantiationException e) {

                    throw new AssertionError(e);

                } catch (IllegalAccessException e) {

                    throw new AssertionError(e);

                }

            }});

    /**

     * Returns true if RMI-IIOP and CORBA is available.

     */

    public static boolean isAvailable() {

        return proxy != null;

    }

    private static void ensureAvailable() {

        if (proxy == null)

            throw new AssertionError("Should not here");

    }

    /**

     * Returns true if the given object is a Stub.

     */

    public static boolean isStub(Object obj) {

        return (proxy == null) ? false : proxy.isStub(obj);

    }

    /**

     * Returns the Delegate to which the given Stub delegates.

     */

    public static Object getDelegate(Object stub) {

        ensureAvailable();

        return proxy.getDelegate(stub);

    }

    /**

     * Sets the Delegate for a given Stub.

     */

    public static void setDelegate(Object stub, Object delegate) {

        ensureAvailable();

        proxy.setDelegate(stub, delegate);

    }

    /**

     * Returns the ORB associated with the given stub

     *

     * @throws  UnsupportedOperationException

     *          if the object does not support the operation that

     *          was invoked

     */

    public static Object getOrb(Object stub) {

        ensureAvailable();

        return proxy.getOrb(stub);

    }

    /**

     * Connects the Stub to the given ORB.

     */

    public static void connect(Object stub, Object orb)

        throws IOException

    {

        if (proxy == null)

            throw new IOException("Connection to ORB failed, RMI/IIOP not available");

        proxy.connect(stub, orb);

    }

    /**

     * Returns true if the given object is an ORB.

     */

    public static boolean isOrb(Object obj) {

        return (proxy == null) ? false : proxy.isOrb(obj);

    }

    /**

     * Creates, and returns, a new ORB instance.

     */

    public static Object createOrb(String[] args, Properties props)

        throws IOException

    {

        if (proxy == null)

            throw new IOException("ORB initialization failed, RMI/IIOP not available");

        return proxy.createOrb(args, props);

    }

    /**

     * Converts a string, produced by the object_to_string method, back

     * to a CORBA object reference.

     */

    public static Object stringToObject(Object orb, String str) {

        ensureAvailable();

        return proxy.stringToObject(orb, str);

    }

    /**

     * Converts the given CORBA object reference to a string.

     */

    public static String objectToString(Object orb, Object obj) {

        ensureAvailable();

        return proxy.objectToString(orb, obj);

    }

    /**

     * Checks to ensure that an object of a remote or abstract interface

     * type can be cast to a desired type.

     */

    public static <T> T narrow(Object narrowFrom, Class<T> narrowTo) {

        ensureAvailable();

        return proxy.narrow(narrowFrom, narrowTo);

    }

    /**

     * Makes a server object ready to receive remote calls

     */

    public static void exportObject(Remote obj) throws IOException {

        if (proxy == null)

            throw new IOException("RMI object cannot be exported, RMI/IIOP not available");

        proxy.exportObject(obj);

    }

    /**

     * Deregisters a server object from the runtime.

     */

    public static void unexportObject(Remote obj) throws IOException {

        if (proxy == null)

            throw new NoSuchObjectException("Object not exported");

        proxy.unexportObject(obj);

    }

    /**

     * Returns a stub for the given server object.

     */

    public static Remote toStub(Remote obj) throws IOException {

        if (proxy == null)

            throw new NoSuchObjectException("Object not exported");

        return proxy.toStub(obj);

    }

}