001 /* Servant.java --
002 Copyright (C) 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package org.omg.PortableServer;
040
041 import org.omg.CORBA.BAD_OPERATION;
042 import org.omg.CORBA.BAD_INV_ORDER;
043 import org.omg.CORBA.NO_IMPLEMENT;
044 import org.omg.CORBA.OBJECT_NOT_EXIST;
045 import org.omg.CORBA.ORB;
046 import org.omg.PortableServer.POAPackage.ServantNotActive;
047 import org.omg.PortableServer.POAPackage.WrongPolicy;
048 import org.omg.PortableServer.portable.Delegate;
049
050 import gnu.CORBA.Minor;
051 import gnu.CORBA.Poa.ORB_1_4;
052 import gnu.CORBA.Poa.gnuPOA;
053
054 /**
055 * <p>
056 * The servant is responsible for handling the method invocation on the
057 * target object. It can be one servant per object, or the same servant can
058 * support several (possibly all) objects, associated with the given POA.
059 * </p> <p>
060 * Till JDK 1.3 inclusive, a typical IDL to java compiler generates an
061 * implementation base (name pattern _*ImplBase.java) that is derived from the
062 * {@link org.omg.CORBA.portable.ObjectImpl}. Since JDK 1.4 the implementation
063 * base is derived from the Servant, also having a different name pattern
064 * (*POA.java). This suffix may be confusing, as the servant itself is
065 * <i>not</i> POA nor it is derived from it.
066 * </p><p>
067 * In both cases, the implementation base also inherits an interface, containing
068 * definitions of the application specific methods. The application programmer
069 * writes a child of the implementation base, implementing these methods
070 * for the application-specific functionality. The ObjectImpl is connected
071 * directly to the ORB. The Servant is connected to POA that can be obtained
072 * from the ORB.
073 * </p><p>
074 * If the servant is connected to more than one object, the exact object
075 * being currently served can be identified with {@link #_object_id}.
076 * </p><p>
077 * The derivativ of Servant, being directly connected to serve requests,
078 * must inherit either from {@link org.omg.CORBA.portable.InvokeHandler}
079 * or from {@link org.omg.PortableServer.DynamicImplementation}).
080 * </p><p>
081 * The Servant type is a CORBA <code>native</code> type.
082 * </p>
083 *
084 * @see POA#servant_to_reference(Servant)
085 *
086 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
087 */
088 public abstract class Servant
089 {
090 /**
091 * The delegate, where calls to some Servant methods are forwarded.
092 */
093 private Delegate delegate;
094
095 /**
096 * Get the repository ids of all interfaces, supported by the
097 * CORBA object, identified by the passed Id. In the typical code the
098 * passed parameters are ignored, returning an array of repository ids,
099 * supported by the servant implementation.
100 *
101 * @param poa a POA of the given object.
102 * @param object_ID the object Id of the given object.
103 *
104 * @return an array, containing the repository ids.
105 */
106 public abstract String[] _all_interfaces(POA poa, byte[] object_ID);
107
108 /**
109 * Get the delegate, where calls to some Servant methods are forwarded.
110 */
111 public final Delegate _get_delegate()
112 {
113 if (delegate == null) {
114 throw new BAD_INV_ORDER
115 ("The Servant has not been associated with an ORBinstance");
116 }
117 return delegate;
118 }
119
120 /**
121 * Get the interface repository definition <code>InterfaceDef</code> for this
122 * Object. By default, forwards request to the delegate.
123 *
124 * @specnote The interface repository is officially not implemented up till
125 * JDK 1.5 inclusive. The delegate throws NO_IMPLEMENT, always.
126 */
127 public org.omg.CORBA.Object _get_interface_def()
128 {
129 throw new NO_IMPLEMENT();
130 }
131
132 /**
133 * Checks if the passed servant is an instance of the given CORBA IDL type.
134 * By default, forwards the requet to the delegate.
135 *
136 * @param repository_id a repository ID, representing an IDL type for that the
137 * servant must be checked.
138 *
139 * @return true if the servant is an instance of the given type, false
140 * otherwise.
141 */
142 public boolean _is_a(String repository_id)
143 {
144 return delegate.is_a(this, repository_id);
145 }
146
147 /**
148 * Determines if the server object for this reference has already
149 * been destroyed. By default, forwards request to the delegate.
150 *
151 * @return true if the object has been destroyed, false otherwise.
152 */
153 public boolean _non_existent()
154 {
155 return delegate.non_existent(this);
156 }
157
158 /**
159 * Returns the ORB that is directly associated with the given servant.
160 * In this implementation, the method is overridden to return
161 */
162 public final ORB _orb()
163 {
164 return delegate.orb(this);
165 }
166
167 /**
168 * Returns the root POA of the ORB instance, associated with this servant.
169 * It is the same POA that would be returned by resolving the initial
170 * reference "RootPOA" for that orb. By default, forwards request to the
171 * delegate.
172 *
173 * @see ORB#resolve_initial_references
174 */
175 public POA _default_POA()
176 {
177 return delegate == null ? null : delegate.default_POA(this);
178 }
179
180 /**
181 * Return the invocation target object identifier as a byte array.
182 * This is typically used when the same servant serves multiple objects,
183 * and the object id can encapsulated the whole description of the
184 * object.
185 *
186 * This method returns correct values even when the same
187 * servant serves several objects in parallel threads. The ORB maintains the
188 * thread to invocation data map for all calls that are currently being
189 * processed.
190 */
191 public final byte[] _object_id()
192 {
193 if (delegate != null)
194 return delegate.object_id(this);
195 else
196 throw new OBJECT_NOT_EXIST();
197 }
198
199 /**
200 * Get POA that is directly associated with the given servant.
201 * By default, forwards request to the delegate.
202 */
203 public final POA _poa()
204 {
205 return delegate.poa(this);
206 }
207
208 /**
209 * Set the delegate for this servant.
210 */
211 public final void _set_delegate(Delegate a_delegate)
212 {
213 delegate = a_delegate;
214 }
215
216 /**
217 * Obtains the CORBA object reference that is a current invocation target for
218 * the given servant. This is important when the same servant serves
219 * multiple objects. If the servant is not yet connected to the passed
220 * orb, the method will try to connect it to that orb on POA, returned
221 * by the method {@link #_default_POA}. That method can be overridden to
222 * get poa where the object must be automatically connected when
223 * calling this method.
224 *
225 * @param an_orb the ORB with relate to that the object is requested.
226 */
227 public final org.omg.CORBA.Object _this_object(ORB an_orb)
228 {
229 if (delegate != null)
230 return delegate.this_object(this);
231 else
232 {
233 if (an_orb instanceof ORB_1_4)
234 {
235 ORB_1_4 m_orb = (ORB_1_4) an_orb;
236
237 gnuPOA dp = (gnuPOA) _default_POA();
238 if (dp == null)
239 dp = m_orb.rootPOA;
240
241 try
242 {
243 return dp.servant_to_reference(this);
244 }
245 catch (WrongPolicy unexp)
246 {
247 BAD_OPERATION bad = new BAD_OPERATION();
248 bad.minor = Minor.Policy;
249 bad.initCause(unexp);
250 throw bad;
251 }
252 catch (ServantNotActive ex)
253 {
254 try
255 {
256 return dp.id_to_reference(dp.activate_object(this));
257 }
258 catch (Exception unexp)
259 {
260 unexp.initCause(ex);
261
262 BAD_OPERATION bad = new BAD_OPERATION();
263 bad.minor = Minor.Activation;
264 bad.initCause(unexp);
265 throw bad;
266 }
267 }
268 }
269 }
270 throw new OBJECT_NOT_EXIST();
271 }
272
273 /**
274 * Obtains the CORBA object reference that is a current invocation target for
275 * the given servant. This is important when the same servant serves
276 * multiple objects. This method required the servant to be connected
277 * to a single orb, and a delegate set.
278 *
279 * This method returns correct values even when the same
280 * servant serves several objects in parallel threads. The ORB maintains the
281 * thread to invocation data map for all calls that are currently being
282 * processed.
283 */
284 public final org.omg.CORBA.Object _this_object()
285 {
286 if (delegate != null)
287 return _this_object(_orb());
288 else
289 {
290 POA def = _default_POA();
291 if (def instanceof gnuPOA)
292 return _this_object(((gnuPOA) def).orb());
293 }
294 throw new OBJECT_NOT_EXIST();
295 }
296 }