gcc/libjava/classpath/org/omg/PortableServer/Servant.java

/* Servant.java --
   Copyright (C) 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
the Free Software Foundation; either version 2, or (at your option)
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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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permission to link this library with independent modules to produce an
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this exception to your version of the library, but you are not
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exception statement from your version. */


package org.omg.PortableServer;

import org.omg.CORBA.BAD_OPERATION;
import org.omg.CORBA.BAD_INV_ORDER;
import org.omg.CORBA.NO_IMPLEMENT;
import org.omg.CORBA.OBJECT_NOT_EXIST;
import org.omg.CORBA.ORB;
import org.omg.PortableServer.POAPackage.ServantNotActive;
import org.omg.PortableServer.POAPackage.WrongPolicy;
import org.omg.PortableServer.portable.Delegate;

import gnu.CORBA.Minor;
import gnu.CORBA.Poa.ORB_1_4;
import gnu.CORBA.Poa.gnuPOA;

/**
 * <p>
 * The servant is responsible for handling the method invocation on the
 * target object. It can be one servant per object, or the same servant can
 * support several (possibly all) objects, associated with the given POA.
 * </p> <p>
 * Till JDK 1.3 inclusive, a typical IDL to java compiler generates an
 * implementation base (name pattern _*ImplBase.java) that is derived from the
 * {@link org.omg.CORBA.portable.ObjectImpl}. Since JDK 1.4 the implementation
 * base is derived from the Servant, also having a different name pattern
 * (*POA.java). This suffix may be confusing, as the servant itself is
 * <i>not</i> POA nor it is derived from it.
 * </p><p>
 * In both cases, the implementation base also inherits an interface, containing
 * definitions of the application specific methods. The application programmer
 * writes a child of the implementation base, implementing these methods
 * for the application-specific functionality. The ObjectImpl is connected
 * directly to the ORB. The Servant is connected to POA that can be obtained
 * from the ORB.
 * </p><p>
 * If the servant is connected to more than one object, the exact object
 * being currently served can be identified with {@link #_object_id}.
 * </p><p>
 * The derivativ of Servant, being directly connected to serve requests,
 * must inherit either from {@link org.omg.CORBA.portable.InvokeHandler}
 * or from {@link org.omg.PortableServer.DynamicImplementation}).
 * </p><p>
 * The Servant type is a CORBA <code>native</code> type.
 * </p>
 *
 * @see POA#servant_to_reference(Servant)
 *
 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
 */
public abstract class Servant
{
  /**
   * The delegate, where calls to some Servant methods are forwarded.
   */
  private Delegate delegate;

  /**
   * Get the repository ids of all interfaces, supported by the
   * CORBA object, identified by the passed Id. In the typical code the
   * passed parameters are ignored, returning an array of repository ids,
   * supported by the servant implementation.
   *
   * @param poa a POA of the given object.
   * @param object_ID the object Id of the given object.
   *
   * @return an array, containing the repository ids.
   */
  public abstract String[] _all_interfaces(POA poa, byte[] object_ID);

  /**
   * Get the delegate, where calls to some Servant methods are forwarded.
   */
  public final Delegate _get_delegate()
  {
    if (delegate == null) {
      throw new BAD_INV_ORDER
        ("The Servant has not been associated with an ORBinstance");
    }
    return delegate;
  }

  /**
  * Get the interface repository definition <code>InterfaceDef</code> for this
  * Object. By default, forwards request to the delegate.
  *
  * @specnote The interface repository is officially not implemented up till
  * JDK 1.5 inclusive. The delegate throws NO_IMPLEMENT, always.
  */
  public org.omg.CORBA.Object _get_interface_def()
  {
    throw new NO_IMPLEMENT();
  }

  /**
  * Checks if the passed servant is an instance of the given CORBA IDL type.
  * By default, forwards the requet to the delegate.
  *
  * @param repository_id a repository ID, representing an IDL type for that the
  * servant must be checked.
  *
  * @return true if the servant is an instance of the given type, false
  * otherwise.
  */
  public boolean _is_a(String repository_id)
  {
    return delegate.is_a(this, repository_id);
  }

  /**
   * Determines if the server object for this reference has already
   * been destroyed. By default, forwards request to the delegate.
   *
   * @return true if the object has been destroyed, false otherwise.
   */
  public boolean _non_existent()
  {
    return delegate.non_existent(this);
  }

  /**
  * Returns the ORB that is directly associated with the given servant.
  * In this implementation, the method is overridden to return
  */
  public final ORB _orb()
  {
    return delegate.orb(this);
  }

  /**
   * Returns the root POA of the ORB instance, associated with this servant.
   * It is the same POA that would be returned by resolving the initial
   * reference "RootPOA" for that orb. By default, forwards request to the
   * delegate.
   *
   * @see ORB#resolve_initial_references
   */
  public POA _default_POA()
  {
    return delegate == null ? null : delegate.default_POA(this);
  }

  /**
  * Return the invocation target object identifier as a byte array.
  * This is typically used when the same servant serves multiple objects,
  * and the object id can encapsulated the whole description of the
  * object.
  *
  * This method returns correct values even when the same
  * servant serves several objects in parallel threads. The ORB maintains the
  * thread to invocation data map for all calls that are currently being
  * processed.
  */
  public final byte[] _object_id()
  {
    if (delegate != null)
      return delegate.object_id(this);
    else
      throw new OBJECT_NOT_EXIST();
  }

  /**
  * Get POA that is directly associated with the given servant.
  * By default, forwards request to the delegate.
  */
  public final POA _poa()
  {
    return delegate.poa(this);
  }

  /**
  * Set the delegate for this servant.
  */
  public final void _set_delegate(Delegate a_delegate)
  {
    delegate = a_delegate;
  }

  /**
  * Obtains the CORBA object reference that is a current invocation target for
  * the given servant. This is important when the same servant serves
  * multiple objects. If the servant is not yet connected to the passed
  * orb, the method will try to connect it to that orb on POA, returned
  * by the method {@link #_default_POA}. That method can be overridden to
  * get poa where the object must be automatically connected when
  * calling this method.
  *
  * @param an_orb the ORB with relate to that the object is requested.
  */
  public final org.omg.CORBA.Object _this_object(ORB an_orb)
  {
    if (delegate != null)
      return delegate.this_object(this);
    else
      {
        if (an_orb instanceof ORB_1_4)
          {
            ORB_1_4 m_orb = (ORB_1_4) an_orb;

            gnuPOA dp = (gnuPOA) _default_POA();
            if (dp == null)
              dp = m_orb.rootPOA;

            try
              {
                return dp.servant_to_reference(this);
              }
            catch (WrongPolicy unexp)
              {
                BAD_OPERATION bad = new BAD_OPERATION();
                bad.minor = Minor.Policy;
                bad.initCause(unexp);
                throw bad;
              }
            catch (ServantNotActive ex)
              {
                try
                  {
                    return dp.id_to_reference(dp.activate_object(this));
                  }
                catch (Exception unexp)
                  {
                    unexp.initCause(ex);

                    BAD_OPERATION bad = new BAD_OPERATION();
                    bad.minor = Minor.Activation;
                    bad.initCause(unexp);
                    throw bad;
                  }
              }
          }
      }
    throw new OBJECT_NOT_EXIST();
  }

  /**
  * Obtains the CORBA object reference that is a current invocation target for
  * the given servant. This is important when the same servant serves
  * multiple objects. This method required the servant to be connected
  * to a single orb, and a delegate set.
  *
  * This method returns correct values even when the same
  * servant serves several objects in parallel threads. The ORB maintains the
  * thread to invocation data map for all calls that are currently being
  * processed.
  */
  public final org.omg.CORBA.Object _this_object()
  {
    if (delegate != null)
      return _this_object(_orb());
    else
      {
        POA def = _default_POA();
        if (def instanceof gnuPOA)
          return _this_object(((gnuPOA) def).orb());
      }
    throw new OBJECT_NOT_EXIST();
  }
}