rmi/CORBA/PortableRemoteObjectDelegateImpl.java

/* PortableRemoteObjectDelegateImpl.java --
   Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
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this exception to your version of the library, but you are not
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package gnu.javax.rmi.CORBA;

import gnu.CORBA.SimpleDelegate;
import gnu.CORBA.Unexpected;
import gnu.CORBA.Poa.LocalDelegate;
import gnu.CORBA.Poa.ORB_1_4;
import gnu.CORBA.Poa.AOM;

import java.rmi.NoSuchObjectException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.RMIClassLoader;

import javax.rmi.CORBA.PortableRemoteObjectDelegate;
import javax.rmi.CORBA.Stub;
import javax.rmi.CORBA.Tie;
import javax.rmi.CORBA.Util;

import org.omg.CORBA.BAD_PARAM;
import org.omg.CORBA.ORB;
import org.omg.CORBA.portable.Delegate;
import org.omg.CORBA.portable.ObjectImpl;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.POAHelper;
import org.omg.PortableServer.Servant;
import org.omg.PortableServer.POAManagerPackage.State;

/**
 * Implements PortableRemoteObjectDelegate.
 *
 * @author Wu Gansha (gansha.wu@intel.com) (stub)
 * @author Audrius Meskauskas (AudriusA@Bioinformatics.org) (implementation)
 */
public class PortableRemoteObjectDelegateImpl
  implements PortableRemoteObjectDelegate
{
  /**
   * <p>
   * Makes the remote object <code>a_target</code> ready for remote
   * communication using the same communications runtime as for the passed
   * <code>a_source</code> parameter. The a_target is connected to the same
   * ORB (and, if applicable, to the same POA) as the a_source.
   *
   * @param a_target the target to connect to ORB, must be an instance of either
   * {@link ObjectImpl} (Stubs and old-style ties) or {@link Servant} (POA-bases
   * ties).
   *
   * @param a_source the object, providing the connection information, must be
   * an instance of either {@link ObjectImpl} (Stubs and old-style ties) or
   * {@link Servant} (POA-bases ties).
   *
   * @throws RemoteException if the target is already connected to another ORB.
   */
  public void connect(Remote a_target, Remote a_source)
    throws RemoteException
  {
    ORB orb = null;
    POA poa = null;
    boolean ok = false;

    try
      {
        if (a_source instanceof Servant)
          {
            Servant s = (Servant) a_source;
            orb = s._orb();
            poa = s._poa();
            ok = true;
          }

        if (!ok && a_source instanceof ObjectImpl)
          {
            ObjectImpl o = (ObjectImpl) a_source;
            orb = o._orb();
            ok = true;
            try
              {
                if (orb instanceof ORB_1_4)
                  {
                    // POA information available.
                    ORB_1_4 xorb = (ORB_1_4) orb;
                    Delegate d = o._get_delegate();

                    if (d instanceof LocalDelegate)
                      {
                        LocalDelegate l = (LocalDelegate) d;
                        poa = l.poa;
                      }
                    else if (d instanceof SimpleDelegate)
                      {
                        byte[] ior_key = ((SimpleDelegate) d).getIor().key;
                        AOM.Obj ref = xorb.rootPOA.findIorKey(ior_key);
                        if (ref != null)
                          poa = ref.poa;
                      }
                  }
              }
            catch (Exception ex)
              {
                // OK, POA info is not available, but as ORB is available, we
                // will connect in a default way.
              }
          }
      }
    catch (Exception ex)
      {
        RuntimeException rex = new RuntimeException("Unable to get info from "
          + a_source);
        rex.initCause(ex);
        throw rex;
      }

    if (!ok && a_source instanceof Tie)
      {
        Tie t = (Tie) a_source;
        orb = t.orb();
        poa = null;
        ok = true;
      }

    if (orb == null)
      throw new RemoteException("Unable to determine ORB from " + a_source);

    if (a_target instanceof Stub)
      {
        StubDelegateImpl.connect((Stub) a_target, orb, poa);
      }
    else if (a_target instanceof Servant)
      {
        try
          {
            if (poa == null)
              {
                poa = POAHelper.narrow(orb.resolve_initial_references("RootPOA"));
                // Activate if not active.
                if (poa.the_POAManager().get_state().value() == State._HOLDING)
                  poa.the_POAManager().activate();
              }
            poa.servant_to_reference((Servant) a_target);
          }
        catch (Exception ex)
          {
            throw new Unexpected(ex);
          }
      }
    else if (a_target instanceof org.omg.CORBA.Object)
      {
        // Connect as object.
        orb.connect((org.omg.CORBA.Object) a_target);
      }
    else if (a_target instanceof Tie)
      {
        // We avoid calling this because it will aways connect to the root poa.
        ((Tie) a_target).orb(orb);
      }
  }

  /**
   * Narrow the given object to the instance of the given class. The currently
   * supported narrowing types are:
   *
   * 1. Simple widening conversion.<br>
   * 2. ObjectImpl -> RMI interface.<br>
   * 3. ObjectImpl -> ObjectImpl.<br>
   * 4. Tie -> Remote (implementation)<br>
   * 5. Remote (implementation) -> Tie.<br>
   *
   * The narrowing has sense only for derived classes.
   */
  public Object narrow(Object narrowFrom, Class narrowTo)
    throws ClassCastException
  {
    if (narrowTo == null)
      throw new ClassCastException("Can't narrow to null class");
    else if (narrowFrom == null)
      return null;
    else
    // Simple narrowing case.
    if (narrowTo.isAssignableFrom(narrowFrom.getClass()))
      return narrowFrom;
    else if (narrowTo.isInterface() || narrowFrom instanceof ObjectImpl)
      {
        // Narrow CORBA object to passed interface.

        String interf = narrowTo.getName();
        String stubClassName;

        stubClassName = getStubClassName(interf);

        try
          {
            // Replace the interface class by the stub class.
            narrowTo = Util.loadClass(stubClassName, null,
              narrowTo.getClassLoader());
          }
        catch (ClassNotFoundException e)
          {
            ClassCastException cex = new ClassCastException("Class not found: "
              + stubClassName);
            cex.initCause(e);
            throw cex;
          }
      }
    else if (narrowFrom instanceof Tie)
      {
        // Try to substitute the return tie target as a return value.
        Remote target = ((Tie) narrowFrom).getTarget();
        if (target != null && narrowTo.isAssignableFrom(target.getClass()))
          return target;
      }

    Object narrowed;
    try
      {
        narrowed = narrowTo.newInstance();
      }
    catch (Exception e)
      {
        ClassCastException cex = new ClassCastException("Cannot instantiate "
          + narrowTo.getName());
        cex.initCause(e);
        throw cex;
      }

    if (narrowed instanceof ObjectImpl)
      {
        // This also works for the instances of the Stub.
        ObjectImpl target = (ObjectImpl) narrowed;
        // Set the delegate, as is done in *Helper.narrow(..).
        target._set_delegate(((ObjectImpl) narrowFrom)._get_delegate());
      }
    else if (narrowed instanceof Tie && narrowFrom instanceof Remote)
      {
        // Try to set the narrowing object as a target for the Tie.
        ((Tie) narrowed).setTarget((Remote) narrowFrom);
      }
    else
      throw new ClassCastException("Narrowing of " + narrowFrom.getClass()
        + " to " + narrowTo + " is either not possible or not implemented.");

    return narrowed;
  }

  /**
   * Get the Stub class name for the name, representing the given interface.
   */
  static String getStubClassName(String interf)
  {
    String stubClassName;
    int p = interf.lastIndexOf('.');

    if (p < 0)
      // The interface is defined in the default package.
      stubClassName = "_" + interf + "_Stub";
    else
      stubClassName = interf.substring(0, p + 1) + "_"
        + interf.substring(p + 1) + "_Stub";
    return stubClassName;
  }

  /**
   * Get stub for the given implementation, searching by class name pattern. The
   * found stub must implement Remote for this method to succeed.
   */
  public Remote toStub(Remote ObjImpl)
    throws NoSuchObjectException
  {
    String icn = ObjImpl.getClass().getName();
    if (!icn.endsWith("Impl"))
      throw new BAD_PARAM("Invalid class name '" + icn
        + "', must end with 'Impl'");

    String sn = "_" + icn.substring(0, icn.length() - "Impl".length())
      + "_Stub";

    Class stubClass;
    Object o_stub;

    try
      {
        stubClass = RMIClassLoader.loadClass(sn);
        o_stub = stubClass.newInstance();
      }
    catch (Exception e)
      {
        NoSuchObjectException n = new NoSuchObjectException(sn);
        n.initCause(e);
        throw n;
      }

    if (!Remote.class.isAssignableFrom(stubClass))
      throw new ClassCastException(stubClass.getName()
        + " exists but cannot be returned as it does not inherit from "
        + Remote.class.getName());

    return (Remote) o_stub;
  }

  /**
   * If the object tie is no longer in use, disconnet it from the orb.
   */
  public void unexportObject(Remote obj)
    throws NoSuchObjectException
  {
    Util.unexportObject(obj);
  }

  /**
   * Find or create a tie for this target and mark it as being used by the given
   * object.
   */
  public void exportObject(Remote obj)
    throws RemoteException
  {
    if (obj instanceof Stub)
      Util.registerTarget(StubDelegateImpl.getTieFromStub((Stub) obj), obj);
    else if (obj instanceof Tie)
      {
        Tie t = (Tie) obj;
        Util.registerTarget(t, null);
      }
  }

}