J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2004 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.naming; |
| 27 | |
| 28 | import java.util.Vector; |
| 29 | import java.util.Enumeration; |
| 30 | |
| 31 | /** |
| 32 | * This class represents a reference to an object that is found outside of |
| 33 | * the naming/directory system. |
| 34 | *<p> |
| 35 | * Reference provides a way of recording address information about |
| 36 | * objects which themselves are not directly bound to the naming/directory system. |
| 37 | *<p> |
| 38 | * A Reference consists of an ordered list of addresses and class information |
| 39 | * about the object being referenced. |
| 40 | * Each address in the list identifies a communications endpoint |
| 41 | * for the same conceptual object. The "communications endpoint" |
| 42 | * is information that indicates how to contact the object. It could |
| 43 | * be, for example, a network address, a location in memory on the |
| 44 | * local machine, another process on the same machine, etc. |
| 45 | * The order of the addresses in the list may be of significance |
| 46 | * to object factories that interpret the reference. |
| 47 | *<p> |
| 48 | * Multiple addresses may arise for |
| 49 | * various reasons, such as replication or the object offering interfaces |
| 50 | * over more than one communication mechanism. The addresses are indexed |
| 51 | * starting with zero. |
| 52 | *<p> |
| 53 | * A Reference also contains information to assist in creating an instance |
| 54 | * of the object to which this Reference refers. It contains the class name |
| 55 | * of that object, and the class name and location of the factory to be used |
| 56 | * to create the object. |
| 57 | * The class factory location is a space-separated list of URLs representing |
| 58 | * the class path used to load the factory. When the factory class (or |
| 59 | * any class or resource upon which it depends) needs to be loaded, |
| 60 | * each URL is used (in order) to attempt to load the class. |
| 61 | *<p> |
| 62 | * A Reference instance is not synchronized against concurrent access by multiple |
| 63 | * threads. Threads that need to access a single Reference concurrently should |
| 64 | * synchronize amongst themselves and provide the necessary locking. |
| 65 | * |
| 66 | * @author Rosanna Lee |
| 67 | * @author Scott Seligman |
| 68 | * |
| 69 | * @see RefAddr |
| 70 | * @see StringRefAddr |
| 71 | * @see BinaryRefAddr |
| 72 | * @since 1.3 |
| 73 | */ |
| 74 | |
| 75 | /*<p> |
| 76 | * The serialized form of a Reference object consists of the class |
| 77 | * name of the object being referenced (a String), a Vector of the |
| 78 | * addresses (each a RefAddr), the name of the class factory (a |
| 79 | * String), and the location of the class factory (a String). |
| 80 | */ |
| 81 | |
| 82 | |
| 83 | public class Reference implements Cloneable, java.io.Serializable { |
| 84 | /** |
| 85 | * Contains the fully-qualified name of the class of the object to which |
| 86 | * this Reference refers. |
| 87 | * @serial |
| 88 | * @see java.lang.Class#getName |
| 89 | */ |
| 90 | protected String className; |
| 91 | /** |
| 92 | * Contains the addresses contained in this Reference. |
| 93 | * Initialized by constructor. |
| 94 | * @serial |
| 95 | */ |
| 96 | protected Vector<RefAddr> addrs = null; |
| 97 | |
| 98 | /** |
| 99 | * Contains the name of the factory class for creating |
| 100 | * an instance of the object to which this Reference refers. |
| 101 | * Initialized to null. |
| 102 | * @serial |
| 103 | */ |
| 104 | protected String classFactory = null; |
| 105 | |
| 106 | /** |
| 107 | * Contains the location of the factory class. |
| 108 | * Initialized to null. |
| 109 | * @serial |
| 110 | */ |
| 111 | protected String classFactoryLocation = null; |
| 112 | |
| 113 | /** |
| 114 | * Constructs a new reference for an object with class name 'className'. |
| 115 | * Class factory and class factory location are set to null. |
| 116 | * The newly created reference contains zero addresses. |
| 117 | * |
| 118 | * @param className The non-null class name of the object to which |
| 119 | * this reference refers. |
| 120 | */ |
| 121 | public Reference(String className) { |
| 122 | this.className = className; |
| 123 | addrs = new Vector(); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Constructs a new reference for an object with class name 'className' and |
| 128 | * an address. |
| 129 | * Class factory and class factory location are set to null. |
| 130 | * |
| 131 | * @param className The non-null class name of the object to |
| 132 | * which this reference refers. |
| 133 | * @param addr The non-null address of the object. |
| 134 | */ |
| 135 | public Reference(String className, RefAddr addr) { |
| 136 | this.className = className; |
| 137 | addrs = new Vector(); |
| 138 | addrs.addElement(addr); |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * Constructs a new reference for an object with class name 'className', |
| 143 | * and the class name and location of the object's factory. |
| 144 | * |
| 145 | * @param className The non-null class name of the object to which |
| 146 | * this reference refers. |
| 147 | * @param factory The possibly null class name of the object's factory. |
| 148 | * @param factoryLocation |
| 149 | * The possibly null location from which to load |
| 150 | * the factory (e.g. URL) |
| 151 | * @see javax.naming.spi.ObjectFactory |
| 152 | * @see javax.naming.spi.NamingManager#getObjectInstance |
| 153 | */ |
| 154 | public Reference(String className, String factory, String factoryLocation) { |
| 155 | this(className); |
| 156 | classFactory = factory; |
| 157 | classFactoryLocation = factoryLocation; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Constructs a new reference for an object with class name 'className', |
| 162 | * the class name and location of the object's factory, and the address for |
| 163 | * the object. |
| 164 | * |
| 165 | * @param className The non-null class name of the object to |
| 166 | * which this reference refers. |
| 167 | * @param factory The possibly null class name of the object's factory. |
| 168 | * @param factoryLocation The possibly null location from which |
| 169 | * to load the factory (e.g. URL) |
| 170 | * @param addr The non-null address of the object. |
| 171 | * @see javax.naming.spi.ObjectFactory |
| 172 | * @see javax.naming.spi.NamingManager#getObjectInstance |
| 173 | */ |
| 174 | public Reference(String className, RefAddr addr, |
| 175 | String factory, String factoryLocation) { |
| 176 | this(className, addr); |
| 177 | classFactory = factory; |
| 178 | classFactoryLocation = factoryLocation; |
| 179 | } |
| 180 | |
| 181 | /** |
| 182 | * Retrieves the class name of the object to which this reference refers. |
| 183 | * |
| 184 | * @return The non-null fully-qualified class name of the object. |
| 185 | * (e.g. "java.lang.String") |
| 186 | */ |
| 187 | public String getClassName() { |
| 188 | return className; |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * Retrieves the class name of the factory of the object |
| 193 | * to which this reference refers. |
| 194 | * |
| 195 | * @return The possibly null fully-qualified class name of the factory. |
| 196 | * (e.g. "java.lang.String") |
| 197 | */ |
| 198 | public String getFactoryClassName() { |
| 199 | return classFactory; |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * Retrieves the location of the factory of the object |
| 204 | * to which this reference refers. |
| 205 | * If it is a codebase, then it is an ordered list of URLs, |
| 206 | * separated by spaces, listing locations from where the factory |
| 207 | * class definition should be loaded. |
| 208 | * |
| 209 | * @return The possibly null string containing the |
| 210 | * location for loading in the factory's class. |
| 211 | */ |
| 212 | public String getFactoryClassLocation() { |
| 213 | return classFactoryLocation; |
| 214 | } |
| 215 | |
| 216 | /** |
| 217 | * Retrieves the first address that has the address type 'addrType'. |
| 218 | * String.compareTo() is used to test the equality of the address types. |
| 219 | * |
| 220 | * @param addrType The non-null address type for which to find the address. |
| 221 | * @return The address in this reference with address type 'addrType; |
| 222 | * null if no such address exist. |
| 223 | */ |
| 224 | public RefAddr get(String addrType) { |
| 225 | int len = addrs.size(); |
| 226 | RefAddr addr; |
| 227 | for (int i = 0; i < len; i++) { |
| 228 | addr = (RefAddr) addrs.elementAt(i); |
| 229 | if (addr.getType().compareTo(addrType) == 0) |
| 230 | return addr; |
| 231 | } |
| 232 | return null; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Retrieves the address at index posn. |
| 237 | * @param posn The index of the address to retrieve. |
| 238 | * @return The address at the 0-based index posn. It must be in the |
| 239 | * range [0,getAddressCount()). |
| 240 | * @exception ArrayIndexOutOfBoundsException If posn not in the specified |
| 241 | * range. |
| 242 | */ |
| 243 | public RefAddr get(int posn) { |
| 244 | return ((RefAddr) addrs.elementAt(posn)); |
| 245 | } |
| 246 | |
| 247 | /** |
| 248 | * Retrieves an enumeration of the addresses in this reference. |
| 249 | * When addresses are added, changed or removed from this reference, |
| 250 | * its effects on this enumeration are undefined. |
| 251 | * |
| 252 | * @return An non-null enumeration of the addresses |
| 253 | * (<tt>RefAddr</tt>) in this reference. |
| 254 | * If this reference has zero addresses, an enumeration with |
| 255 | * zero elements is returned. |
| 256 | */ |
| 257 | public Enumeration<RefAddr> getAll() { |
| 258 | return addrs.elements(); |
| 259 | } |
| 260 | |
| 261 | /** |
| 262 | * Retrieves the number of addresses in this reference. |
| 263 | * |
| 264 | * @return The nonnegative number of addresses in this reference. |
| 265 | */ |
| 266 | public int size() { |
| 267 | return addrs.size(); |
| 268 | } |
| 269 | |
| 270 | /** |
| 271 | * Adds an address to the end of the list of addresses. |
| 272 | * |
| 273 | * @param addr The non-null address to add. |
| 274 | */ |
| 275 | public void add(RefAddr addr) { |
| 276 | addrs.addElement(addr); |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * Adds an address to the list of addresses at index posn. |
| 281 | * All addresses at index posn or greater are shifted up |
| 282 | * the list by one (away from index 0). |
| 283 | * |
| 284 | * @param posn The 0-based index of the list to insert addr. |
| 285 | * @param addr The non-null address to add. |
| 286 | * @exception ArrayIndexOutOfBoundsException If posn not in the specified |
| 287 | * range. |
| 288 | */ |
| 289 | public void add(int posn, RefAddr addr) { |
| 290 | addrs.insertElementAt(addr, posn); |
| 291 | } |
| 292 | |
| 293 | /** |
| 294 | * Deletes the address at index posn from the list of addresses. |
| 295 | * All addresses at index greater than posn are shifted down |
| 296 | * the list by one (towards index 0). |
| 297 | * |
| 298 | * @param posn The 0-based index of in address to delete. |
| 299 | * @return The address removed. |
| 300 | * @exception ArrayIndexOutOfBoundsException If posn not in the specified |
| 301 | * range. |
| 302 | */ |
| 303 | public Object remove(int posn) { |
| 304 | Object r = addrs.elementAt(posn); |
| 305 | addrs.removeElementAt(posn); |
| 306 | return r; |
| 307 | } |
| 308 | |
| 309 | /** |
| 310 | * Deletes all addresses from this reference. |
| 311 | */ |
| 312 | public void clear() { |
| 313 | addrs.setSize(0); |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * Determines whether obj is a reference with the same addresses |
| 318 | * (in same order) as this reference. |
| 319 | * The addresses are checked using RefAddr.equals(). |
| 320 | * In addition to having the same addresses, the Reference also needs to |
| 321 | * have the same class name as this reference. |
| 322 | * The class factory and class factory location are not checked. |
| 323 | * If obj is null or not an instance of Reference, null is returned. |
| 324 | * |
| 325 | * @param obj The possibly null object to check. |
| 326 | * @return true if obj is equal to this reference; false otherwise. |
| 327 | */ |
| 328 | public boolean equals(Object obj) { |
| 329 | if ((obj != null) && (obj instanceof Reference)) { |
| 330 | Reference target = (Reference)obj; |
| 331 | // ignore factory information |
| 332 | if (target.className.equals(this.className) && |
| 333 | target.size() == this.size()) { |
| 334 | Enumeration mycomps = getAll(); |
| 335 | Enumeration comps = target.getAll(); |
| 336 | while (mycomps.hasMoreElements()) |
| 337 | if (!(mycomps.nextElement().equals(comps.nextElement()))) |
| 338 | return false; |
| 339 | return true; |
| 340 | } |
| 341 | } |
| 342 | return false; |
| 343 | } |
| 344 | |
| 345 | /** |
| 346 | * Computes the hash code of this reference. |
| 347 | * The hash code is the sum of the hash code of its addresses. |
| 348 | * |
| 349 | * @return A hash code of this reference as an int. |
| 350 | */ |
| 351 | public int hashCode() { |
| 352 | int hash = className.hashCode(); |
| 353 | for (Enumeration e = getAll(); e.hasMoreElements();) |
| 354 | hash += e.nextElement().hashCode(); |
| 355 | return hash; |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * Generates the string representation of this reference. |
| 360 | * The string consists of the class name to which this reference refers, |
| 361 | * and the string representation of each of its addresses. |
| 362 | * This representation is intended for display only and not to be parsed. |
| 363 | * |
| 364 | * @return The non-null string representation of this reference. |
| 365 | */ |
| 366 | public String toString() { |
| 367 | StringBuffer buf = new StringBuffer("Reference Class Name: " + |
| 368 | className + "\n"); |
| 369 | int len = addrs.size(); |
| 370 | for (int i = 0; i < len; i++) |
| 371 | buf.append(get(i).toString()); |
| 372 | |
| 373 | return buf.toString(); |
| 374 | } |
| 375 | |
| 376 | /** |
| 377 | * Makes a copy of this reference using its class name |
| 378 | * list of addresses, class factory name and class factory location. |
| 379 | * Changes to the newly created copy does not affect this Reference |
| 380 | * and vice versa. |
| 381 | */ |
| 382 | public Object clone() { |
| 383 | Reference r = new Reference(className, classFactory, classFactoryLocation); |
| 384 | Enumeration<RefAddr> a = getAll(); |
| 385 | r.addrs = new Vector(); |
| 386 | |
| 387 | while (a.hasMoreElements()) |
| 388 | r.addrs.addElement(a.nextElement()); |
| 389 | return r; |
| 390 | } |
| 391 | /** |
| 392 | * Use serialVersionUID from JNDI 1.1.1 for interoperability |
| 393 | */ |
| 394 | private static final long serialVersionUID = -1673475790065791735L; |
| 395 | }; |