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1: /* PortableRemoteObject.java -- 2: Copyright (C) 2004, 2004, 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 javax.rmi; 40: 41: import gnu.javax.rmi.CORBA.DelegateFactory; 42: 43: import org.omg.CORBA.BAD_PARAM; 44: import org.omg.CORBA.ORB; 45: import org.omg.CORBA.portable.ObjectImpl; 46: import org.omg.PortableServer.POA; 47: import org.omg.PortableServer.Servant; 48: 49: import java.rmi.NoSuchObjectException; 50: import java.rmi.Remote; 51: import java.rmi.RemoteException; 52: 53: import javax.rmi.CORBA.PortableRemoteObjectDelegate; 54: import javax.rmi.CORBA.Stub; 55: import javax.rmi.CORBA.Tie; 56: import javax.rmi.CORBA.Util; 57: 58: /** 59: * <p> 60: * An utility class for RMI/IDL server side object implementations. Server side 61: * implementation objects may inherit from this class, but this is not 62: * mandatory, as the needed methds are static. Server side implementations may 63: * choose to inherit from {@link ObjectImpl} or {@link Servant} instead. 64: * </p> 65: * <p> 66: * The functionality of methods in this class is forwarded to the enclosed 67: * PortableRemoteObjectDelegate. This delegate can be altered by setting the 68: * system property "javax.rmi.CORBA.PortableRemoteObjectClass" to the name of 69: * the alternative class that must implement 70: * {@link PortableRemoteObjectDelegate}. 71: * </p> 72: * 73: * @author Audrius Meskauskas (AudriusA@Bioinformatics.org) 74: */ 75: public class PortableRemoteObject 76: { 77: /** 78: * A delegate where the functionality is forwarded. 79: */ 80: static PortableRemoteObjectDelegate delegate = (PortableRemoteObjectDelegate) DelegateFactory.getInstance(DelegateFactory.PORTABLE_REMOTE_OBJECT); 81: 82: /** 83: * The protected constructor calls {@link exportObject} (this). 84: * 85: * @throws RemoteException if the exportObject(this) throws one. 86: */ 87: protected PortableRemoteObject() 88: throws RemoteException 89: { 90: exportObject((Remote) this); 91: } 92: 93: /** 94: * <p> 95: * Makes the remote object <code>a_target</code> ready for remote 96: * communication using the same communications runtime as for the passed 97: * <code>a_source</code> parameter. The a_target is connected to the same 98: * ORB (and, if applicable, to the same {@link POA}) as the a_source. 99: * 100: * @param target the target to connect to ORB, must be an instance of either 101: * {@link ObjectImpl} (Stubs and old-style ties) or {@link Tie}. 102: * 103: * @param source the object, providing the connection information, must be 104: * an instance of either {@link ObjectImpl} (Stubs and old-style ties) or 105: * {@link Servant} (the next-generation Ties supporting {@link POA}). 106: * 107: * @throws RemoteException if the target is already connected to another ORB. 108: */ 109: public static void connect(Remote target, Remote source) 110: throws RemoteException 111: { 112: delegate.connect(target, source); 113: } 114: 115: /** 116: * <p> 117: * Makes a server object ready for remote calls. The subclasses of 118: * PortableRemoteObject do not need to call this method, as it is called by 119: * the constructor. 120: * </p> 121: * <p> 122: * This method only creates a tie object and caches it for future usage. The 123: * created tie does not have a delegate or an ORB associated. 124: * </p> 125: * 126: * @param object the object to export. 127: * 128: * @throws RemoteException if export fails due any reason. 129: */ 130: public static void exportObject(Remote object) 131: throws RemoteException 132: { 133: delegate.exportObject(object); 134: } 135: 136: /** 137: * Narrows the passed object to conform to the given interface or IDL type. In 138: * RMI-IIOP, this method replaces the narrow(org.omg.CORBA.Object) method that 139: * was present in the CORBA Helpers. This method frequently returns different 140: * instance and cannot be replaced by the direct cast. The typical narrowing 141: * cases (all supported by GNU Classpath) are: 142: * <ul> 143: * <li>A CORBA object (for instance, returned by the 144: * {@link ORB#string_to_object} or from the naming service) can be narrowed 145: * into interface, derived from Remote. The method will try to locate an 146: * appropriate {@link Stub} by the name pattern (_*_Stub). If the object being 147: * narrowed is connected to an ORB, the returned instance will inherit that 148: * connection, representing the same remote (or local) object, but now with 149: * the possibility to invoke remote methods. </li> 150: * <li>A CORBA object may be directly narrowed into the appropriate 151: * {@link Stub} class, if it is and passed as a second parameter. This allows 152: * to use non-standard stubs without parameterless constructors.</li> 153: * <li>Any two classes, derived from the {@link ObjectImpl} (may be Stub's) 154: * can be narrowed one into another (a delegate is transferred). </li> 155: * <li>An implementation of Remote can be narrowed into {@link Tie} that can 156: * later connected to an ORB, making the methods accessible remotely. The 157: * Remote being narrowed normally provides a local implementation, but you can 158: * also narrow remote Stub, creating "forwarding Tie".</li> 159: * <li>null is narrowed into null regardless of the second parameter.</li> 160: * <li>A {@link Tie} can be narrowed into Remote, representing the 161: * implementation for this Tie (if one is set).</li> 162: * </ul> 163: * 164: * @param object the object like CORBA Object, Stub or Remote that must be 165: * narrowed to the given interface. 166: * 167: * @param narrowToInstaceOf the class of the interface to that the object must 168: * be narrowed. 169: * 170: * @return On success, an object of type narrowTo or null, if narrowFrom = 171: * null. 172: * 173: * @throws ClassCastException if no narrowing is possible. 174: */ 175: public static Object narrow(Object object, Class narrowToInstaceOf) 176: throws ClassCastException 177: { 178: return delegate.narrow(object, narrowToInstaceOf); 179: } 180: 181: /** 182: * <p> 183: * Takes a server implementation object (name pattern *imp) and returns a stub 184: * object that can be used to access that server object (target), name 185: * (pattern _*_Stub). 186: * 187: * The returned stub is not connected to any ORB and must be explicitly 188: * connected using {@link #connect}. 189: * </p> 190: * <p> 191: * The method signature prevents it from returning stubs that does not 192: * implement Remote (ClassCastException will be thrown). 193: * </p> 194: * 195: * @param target a server side object implementation. 196: * @return a stub object that can be used to access that server object. 197: * 198: * @throws NoSuchObjectException if a stub class cannot be located by supposed 199: * name pattern, or an instance of stub fails to be instantiated. 200: * 201: * @throws ClassCastException if the stub class can be located, but it does 202: * not inherit from Remote. 203: * 204: * @throws BAD_PARAM if the name of the passed class does not match the 205: * implementation name pattern (does not end by 'Impl'). 206: */ 207: public static Remote toStub(Remote targetImpl) 208: throws NoSuchObjectException 209: { 210: return delegate.toStub(targetImpl); 211: } 212: 213: /** 214: * Deregister a currently exported server object from the ORB runtimes. The 215: * object to becomes available for garbage collection. This is usually 216: * impemented via {@link Util#unexportObject} 217: * 218: * @param object the object to unexport. 219: * 220: * @throws NoSuchObjectException if the passed object is not currently 221: * exported. 222: */ 223: public static void unexportObject(Remote object) 224: throws NoSuchObjectException 225: { 226: delegate.unexportObject(object); 227: } 228: }