Source for org.omg.PortableServer.Servant

   1: /* Servant.java --
   2:    Copyright (C) 2005 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package org.omg.PortableServer;
  40: 
  41: import org.omg.CORBA.BAD_OPERATION;
  42: import org.omg.CORBA.NO_IMPLEMENT;
  43: import org.omg.CORBA.OBJECT_NOT_EXIST;
  44: import org.omg.CORBA.ORB;
  45: import org.omg.PortableServer.POAPackage.ServantNotActive;
  46: import org.omg.PortableServer.POAPackage.WrongPolicy;
  47: import org.omg.PortableServer.portable.Delegate;
  48: import gnu.CORBA.Poa.ORB_1_4;
  49: import gnu.CORBA.Poa.gnuPOA;
  50: 
  51: /**
  52:  * <p>
  53:  * The servant is responsible for handling the method invocation on the
  54:  * target object. It can be one servant per object, or the same servant can
  55:  * support several (possibly all) objects, associated with the given POA.
  56:  * </p> <p>
  57:  * Till JDK 1.3 inclusive, a typical IDL to java compiler generates an
  58:  * implementation base (name pattern _*ImplBase.java) that is derived from the
  59:  * {@link org.omg.CORBA.portable.ObjectImpl}. Since JDK 1.4 the implementation
  60:  * base is derived from the Servant, also having a different name pattern
  61:  * (*POA.java). This suffix may be confusing, as the servant itself is
  62:  * <i>not</i> POA nor it is derived from it.
  63:  * </p><p>
  64:  * In both cases, the implementation base also inherits an interface, containing
  65:  * definitions of the application specific methods. The application programmer
  66:  * writes a child of the implementation base, implementing these methods
  67:  * for the application-specific functionality. The ObjectImpl is connected
  68:  * directly to the ORB. The Servant is connected to POA that can be obtained
  69:  * from the ORB.
  70:  * </p><p>
  71:  * If the servant is connected to more than one object, the exact object
  72:  * being currently served can be identified with {@link #_object_id}.
  73:  * </p><p>
  74:  * The derivativ of Servant, being directly connected to serve requests,
  75:  * must inherit either from {@link org.omg.CORBA.portable.InvokeHandler}
  76:  * or from {@link org.omg.PortableServer.DynamicImplementation}).
  77:  * </p><p>
  78:  * The Servant type is a CORBA <code>native</code> type.
  79:  * </p>
  80:  *
  81:  * @see POA.servant_to_reference(Servant)
  82:  *
  83:  * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
  84:  */
  85: public abstract class Servant
  86: {
  87:   /**
  88:    * The delegate, where calls to some Servant methods are forwarded.
  89:    */
  90:   private Delegate delegate;
  91: 
  92:   /**
  93:    * Get the repository ids of all interfaces, supported by the
  94:    * CORBA object, identified by the passed Id. In the typical code the
  95:    * passed parameters are ignored, returning an array of repository ids,
  96:    * supported by the servant implementation.
  97:    *
  98:    * @param poa a POA of the given object.
  99:    * @param object_ID the object Id of the given object.
 100:    *
 101:    * @return an array, containing the repository ids.
 102:    */
 103:   public abstract String[] _all_interfaces(POA poa, byte[] object_ID);
 104: 
 105:   /**
 106:    * Get the delegate, where calls to some Servant methods are forwarded.
 107:    */
 108:   public final Delegate _get_delegate()
 109:   {
 110:     return delegate;
 111:   }
 112: 
 113:   /**
 114:   * Get the interface repository definition <code>InterfaceDef</code> for this
 115:   * Object. By default, forwards request to the delegate.
 116:   *
 117:   * @specnote The interface repository is officially not implemented up till
 118:   * JDK 1.5 inclusive. The delegate throws NO_IMPLEMENT, always.
 119:   */
 120:   public org.omg.CORBA.Object _get_interface_def()
 121:   {
 122:     throw new NO_IMPLEMENT();
 123:   }
 124: 
 125:   /**
 126:   * Checks if the passed servant is an instance of the given CORBA IDL type.
 127:   * By default, forwards the requet to the delegate.
 128:   *
 129:   * @param a_servant a servant to check.
 130:   * @param an_id a repository ID, representing an IDL type for that the
 131:   * servant must be checked.
 132:   *
 133:   * @return true if the servant is an instance of the given type, false
 134:   * otherwise.
 135:   */
 136:   public boolean _is_a(String repository_id)
 137:   {
 138:     return delegate.is_a(this, repository_id);
 139:   }
 140: 
 141:   /**
 142:    * Determines if the server object for this reference has already
 143:    * been destroyed. By default, forwards request to the delegate.
 144:    *
 145:    * @return true if the object has been destroyed, false otherwise.
 146:    */
 147:   public boolean _non_existent()
 148:   {
 149:     return delegate.non_existent(this);
 150:   }
 151: 
 152:   /**
 153:   * Returns the ORB that is directly associated with the given servant.
 154:   * In this implementation, the method is overridden to return
 155:   */
 156:   public final ORB _orb()
 157:   {
 158:     return delegate.orb(this);
 159:   }
 160: 
 161:   /**
 162:    * Returns the root POA of the ORB instance, associated with this servant.
 163:    * It is the same POA that would be returned by resolving the initial
 164:    * reference "RootPOA" for that orb. By default, forwards request to the
 165:    * delegate.
 166:    *
 167:    * @see ORB.resolve_initial_references
 168:    */
 169:   public POA _default_POA()
 170:   {
 171:     return delegate == null ? null : delegate.default_POA(this);
 172:   }
 173: 
 174:   /**
 175:   * Return the invocation target object identifier as a byte array.
 176:   * This is typically used when the same servant serves multiple objects,
 177:   * and the object id can encapsulated the whole description of the
 178:   * object.
 179:   *
 180:   * This method returns correct values even when the same
 181:   * servant serves several objects in parallel threads. The ORB maintains the
 182:   * thread to invocation data map for all calls that are currently being
 183:   * processed.
 184:   */
 185:   public final byte[] _object_id()
 186:   {
 187:     if (delegate != null)
 188:       return delegate.object_id(this);
 189:     else
 190:       throw new OBJECT_NOT_EXIST();
 191:   }
 192: 
 193:   /**
 194:   * Get POA that is directly associated with the given servant.
 195:   * By default, forwards request to the delegate.
 196:   */
 197:   public final POA _poa()
 198:   {
 199:     return delegate.poa(this);
 200:   }
 201: 
 202:   /**
 203:   * Set the delegate for this servant.
 204:   */
 205:   public final void _set_delegate(Delegate a_delegate)
 206:   {
 207:     delegate = a_delegate;
 208:   }
 209: 
 210:   /**
 211:   * Obtains the CORBA object reference that is a current invocation target for
 212:   * the given servant. This is important when the same servant serves
 213:   * multiple objects. If the servant is not yet connected to the passed
 214:   * orb, the method will try to connect it to that orb on POA, returned
 215:   * by the method {@link _default_POA}. That method can be overridden to
 216:   * get poa where the object must be automatically connected when
 217:   * calling this method.
 218:   *
 219:   * @param an_orb the ORB with relate to that the object is requested.
 220:   */
 221:   public final org.omg.CORBA.Object _this_object(ORB an_orb)
 222:   {
 223:     if (delegate != null)
 224:       return delegate.this_object(this);
 225:     else
 226:       {
 227:         if (an_orb instanceof ORB_1_4)
 228:           {
 229:             ORB_1_4 m_orb = (ORB_1_4) an_orb;
 230: 
 231:             gnuPOA dp = (gnuPOA) _default_POA();
 232:             if (dp == null)
 233:               dp = m_orb.rootPOA;
 234: 
 235:             try
 236:               {
 237:                 return dp.servant_to_reference(this);
 238:               }
 239:             catch (WrongPolicy unexp)
 240:               {
 241:                 BAD_OPERATION bad = new BAD_OPERATION();
 242:                 bad.initCause(unexp);
 243:                 throw bad;
 244:               }
 245:             catch (ServantNotActive ex)
 246:               {
 247:                 try
 248:                   {
 249:                     return dp.id_to_reference(dp.activate_object(this));
 250:                   }
 251:                 catch (Exception unexp)
 252:                   {
 253:                     unexp.initCause(ex);
 254: 
 255:                     BAD_OPERATION bad = new BAD_OPERATION();
 256:                     bad.initCause(unexp);
 257:                     throw bad;
 258:                   }
 259:               }
 260:           }
 261:       }
 262:     throw new OBJECT_NOT_EXIST();
 263:   }
 264: 
 265:   /**
 266:   * Obtains the CORBA object reference that is a current invocation target for
 267:   * the given servant. This is important when the same servant serves
 268:   * multiple objects. This method required the servant to be connected
 269:   * to a single orb, and a delegate set.
 270:   *
 271:   * This method returns correct values even when the same
 272:   * servant serves several objects in parallel threads. The ORB maintains the
 273:   * thread to invocation data map for all calls that are currently being
 274:   * processed.
 275:   */
 276:   public final org.omg.CORBA.Object _this_object()
 277:   {
 278:     if (delegate != null)
 279:       return _this_object(_orb());
 280:     else
 281:       {
 282:         POA def = _default_POA();
 283:         if (def instanceof gnuPOA)
 284:           return _this_object(((gnuPOA) def).orb());
 285:       }
 286:     throw new OBJECT_NOT_EXIST();
 287:   }