J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2002-2006 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 java.util.prefs; |
| 27 | |
| 28 | import java.util.*; |
| 29 | import java.io.*; |
| 30 | import javax.xml.parsers.*; |
| 31 | import javax.xml.transform.*; |
| 32 | import javax.xml.transform.dom.*; |
| 33 | import javax.xml.transform.stream.*; |
| 34 | import org.xml.sax.*; |
| 35 | import org.w3c.dom.*; |
| 36 | |
| 37 | /** |
| 38 | * XML Support for java.util.prefs. Methods to import and export preference |
| 39 | * nodes and subtrees. |
| 40 | * |
| 41 | * @author Josh Bloch and Mark Reinhold |
| 42 | * @see Preferences |
| 43 | * @since 1.4 |
| 44 | */ |
| 45 | class XmlSupport { |
| 46 | // The required DTD URI for exported preferences |
| 47 | private static final String PREFS_DTD_URI = |
| 48 | "http://java.sun.com/dtd/preferences.dtd"; |
| 49 | |
| 50 | // The actual DTD corresponding to the URI |
| 51 | private static final String PREFS_DTD = |
| 52 | "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + |
| 53 | |
| 54 | "<!-- DTD for preferences -->" + |
| 55 | |
| 56 | "<!ELEMENT preferences (root) >" + |
| 57 | "<!ATTLIST preferences" + |
| 58 | " EXTERNAL_XML_VERSION CDATA \"0.0\" >" + |
| 59 | |
| 60 | "<!ELEMENT root (map, node*) >" + |
| 61 | "<!ATTLIST root" + |
| 62 | " type (system|user) #REQUIRED >" + |
| 63 | |
| 64 | "<!ELEMENT node (map, node*) >" + |
| 65 | "<!ATTLIST node" + |
| 66 | " name CDATA #REQUIRED >" + |
| 67 | |
| 68 | "<!ELEMENT map (entry*) >" + |
| 69 | "<!ATTLIST map" + |
| 70 | " MAP_XML_VERSION CDATA \"0.0\" >" + |
| 71 | "<!ELEMENT entry EMPTY >" + |
| 72 | "<!ATTLIST entry" + |
| 73 | " key CDATA #REQUIRED" + |
| 74 | " value CDATA #REQUIRED >" ; |
| 75 | /** |
| 76 | * Version number for the format exported preferences files. |
| 77 | */ |
| 78 | private static final String EXTERNAL_XML_VERSION = "1.0"; |
| 79 | |
| 80 | /* |
| 81 | * Version number for the internal map files. |
| 82 | */ |
| 83 | private static final String MAP_XML_VERSION = "1.0"; |
| 84 | |
| 85 | /** |
| 86 | * Export the specified preferences node and, if subTree is true, all |
| 87 | * subnodes, to the specified output stream. Preferences are exported as |
| 88 | * an XML document conforming to the definition in the Preferences spec. |
| 89 | * |
| 90 | * @throws IOException if writing to the specified output stream |
| 91 | * results in an <tt>IOException</tt>. |
| 92 | * @throws BackingStoreException if preference data cannot be read from |
| 93 | * backing store. |
| 94 | * @throws IllegalStateException if this node (or an ancestor) has been |
| 95 | * removed with the {@link #removeNode()} method. |
| 96 | */ |
| 97 | static void export(OutputStream os, final Preferences p, boolean subTree) |
| 98 | throws IOException, BackingStoreException { |
| 99 | if (((AbstractPreferences)p).isRemoved()) |
| 100 | throw new IllegalStateException("Node has been removed"); |
| 101 | Document doc = createPrefsDoc("preferences"); |
| 102 | Element preferences = doc.getDocumentElement() ; |
| 103 | preferences.setAttribute("EXTERNAL_XML_VERSION", EXTERNAL_XML_VERSION); |
| 104 | Element xmlRoot = (Element) |
| 105 | preferences.appendChild(doc.createElement("root")); |
| 106 | xmlRoot.setAttribute("type", (p.isUserNode() ? "user" : "system")); |
| 107 | |
| 108 | // Get bottom-up list of nodes from p to root, excluding root |
| 109 | List ancestors = new ArrayList(); |
| 110 | |
| 111 | for (Preferences kid = p, dad = kid.parent(); dad != null; |
| 112 | kid = dad, dad = kid.parent()) { |
| 113 | ancestors.add(kid); |
| 114 | } |
| 115 | Element e = xmlRoot; |
| 116 | for (int i=ancestors.size()-1; i >= 0; i--) { |
| 117 | e.appendChild(doc.createElement("map")); |
| 118 | e = (Element) e.appendChild(doc.createElement("node")); |
| 119 | e.setAttribute("name", ((Preferences)ancestors.get(i)).name()); |
| 120 | } |
| 121 | putPreferencesInXml(e, doc, p, subTree); |
| 122 | |
| 123 | writeDoc(doc, os); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Put the preferences in the specified Preferences node into the |
| 128 | * specified XML element which is assumed to represent a node |
| 129 | * in the specified XML document which is assumed to conform to |
| 130 | * PREFS_DTD. If subTree is true, create children of the specified |
| 131 | * XML node conforming to all of the children of the specified |
| 132 | * Preferences node and recurse. |
| 133 | * |
| 134 | * @throws BackingStoreException if it is not possible to read |
| 135 | * the preferences or children out of the specified |
| 136 | * preferences node. |
| 137 | */ |
| 138 | private static void putPreferencesInXml(Element elt, Document doc, |
| 139 | Preferences prefs, boolean subTree) throws BackingStoreException |
| 140 | { |
| 141 | Preferences[] kidsCopy = null; |
| 142 | String[] kidNames = null; |
| 143 | |
| 144 | // Node is locked to export its contents and get a |
| 145 | // copy of children, then lock is released, |
| 146 | // and, if subTree = true, recursive calls are made on children |
| 147 | synchronized (((AbstractPreferences)prefs).lock) { |
| 148 | // Check if this node was concurrently removed. If yes |
| 149 | // remove it from XML Document and return. |
| 150 | if (((AbstractPreferences)prefs).isRemoved()) { |
| 151 | elt.getParentNode().removeChild(elt); |
| 152 | return; |
| 153 | } |
| 154 | // Put map in xml element |
| 155 | String[] keys = prefs.keys(); |
| 156 | Element map = (Element) elt.appendChild(doc.createElement("map")); |
| 157 | for (int i=0; i<keys.length; i++) { |
| 158 | Element entry = (Element) |
| 159 | map.appendChild(doc.createElement("entry")); |
| 160 | entry.setAttribute("key", keys[i]); |
| 161 | // NEXT STATEMENT THROWS NULL PTR EXC INSTEAD OF ASSERT FAIL |
| 162 | entry.setAttribute("value", prefs.get(keys[i], null)); |
| 163 | } |
| 164 | // Recurse if appropriate |
| 165 | if (subTree) { |
| 166 | /* Get a copy of kids while lock is held */ |
| 167 | kidNames = prefs.childrenNames(); |
| 168 | kidsCopy = new Preferences[kidNames.length]; |
| 169 | for (int i = 0; i < kidNames.length; i++) |
| 170 | kidsCopy[i] = prefs.node(kidNames[i]); |
| 171 | } |
| 172 | // release lock |
| 173 | } |
| 174 | |
| 175 | if (subTree) { |
| 176 | for (int i=0; i < kidNames.length; i++) { |
| 177 | Element xmlKid = (Element) |
| 178 | elt.appendChild(doc.createElement("node")); |
| 179 | xmlKid.setAttribute("name", kidNames[i]); |
| 180 | putPreferencesInXml(xmlKid, doc, kidsCopy[i], subTree); |
| 181 | } |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * Import preferences from the specified input stream, which is assumed |
| 187 | * to contain an XML document in the format described in the Preferences |
| 188 | * spec. |
| 189 | * |
| 190 | * @throws IOException if reading from the specified output stream |
| 191 | * results in an <tt>IOException</tt>. |
| 192 | * @throws InvalidPreferencesFormatException Data on input stream does not |
| 193 | * constitute a valid XML document with the mandated document type. |
| 194 | */ |
| 195 | static void importPreferences(InputStream is) |
| 196 | throws IOException, InvalidPreferencesFormatException |
| 197 | { |
| 198 | try { |
| 199 | Document doc = loadPrefsDoc(is); |
| 200 | String xmlVersion = |
| 201 | doc.getDocumentElement().getAttribute("EXTERNAL_XML_VERSION"); |
| 202 | if (xmlVersion.compareTo(EXTERNAL_XML_VERSION) > 0) |
| 203 | throw new InvalidPreferencesFormatException( |
| 204 | "Exported preferences file format version " + xmlVersion + |
| 205 | " is not supported. This java installation can read" + |
| 206 | " versions " + EXTERNAL_XML_VERSION + " or older. You may need" + |
| 207 | " to install a newer version of JDK."); |
| 208 | |
| 209 | Element xmlRoot = (Element) doc.getDocumentElement(). |
| 210 | getChildNodes().item(0); |
| 211 | Preferences prefsRoot = |
| 212 | (xmlRoot.getAttribute("type").equals("user") ? |
| 213 | Preferences.userRoot() : Preferences.systemRoot()); |
| 214 | ImportSubtree(prefsRoot, xmlRoot); |
| 215 | } catch(SAXException e) { |
| 216 | throw new InvalidPreferencesFormatException(e); |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | /** |
| 221 | * Create a new prefs XML document. |
| 222 | */ |
| 223 | private static Document createPrefsDoc( String qname ) { |
| 224 | try { |
| 225 | DOMImplementation di = DocumentBuilderFactory.newInstance(). |
| 226 | newDocumentBuilder().getDOMImplementation(); |
| 227 | DocumentType dt = di.createDocumentType(qname, null, PREFS_DTD_URI); |
| 228 | return di.createDocument(null, qname, dt); |
| 229 | } catch(ParserConfigurationException e) { |
| 230 | throw new AssertionError(e); |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * Load an XML document from specified input stream, which must |
| 236 | * have the requisite DTD URI. |
| 237 | */ |
| 238 | private static Document loadPrefsDoc(InputStream in) |
| 239 | throws SAXException, IOException |
| 240 | { |
| 241 | DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); |
| 242 | dbf.setIgnoringElementContentWhitespace(true); |
| 243 | dbf.setValidating(true); |
| 244 | dbf.setCoalescing(true); |
| 245 | dbf.setIgnoringComments(true); |
| 246 | try { |
| 247 | DocumentBuilder db = dbf.newDocumentBuilder(); |
| 248 | db.setEntityResolver(new Resolver()); |
| 249 | db.setErrorHandler(new EH()); |
| 250 | return db.parse(new InputSource(in)); |
| 251 | } catch (ParserConfigurationException e) { |
| 252 | throw new AssertionError(e); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | /** |
| 257 | * Write XML document to the specified output stream. |
| 258 | */ |
| 259 | private static final void writeDoc(Document doc, OutputStream out) |
| 260 | throws IOException |
| 261 | { |
| 262 | try { |
| 263 | TransformerFactory tf = TransformerFactory.newInstance(); |
| 264 | try { |
| 265 | tf.setAttribute("indent-number", new Integer(2)); |
| 266 | } catch (IllegalArgumentException iae) { |
| 267 | //Ignore the IAE. Should not fail the writeout even the |
| 268 | //transformer provider does not support "indent-number". |
| 269 | } |
| 270 | Transformer t = tf.newTransformer(); |
| 271 | t.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, doc.getDoctype().getSystemId()); |
| 272 | t.setOutputProperty(OutputKeys.INDENT, "yes"); |
| 273 | //Transformer resets the "indent" info if the "result" is a StreamResult with |
| 274 | //an OutputStream object embedded, creating a Writer object on top of that |
| 275 | //OutputStream object however works. |
| 276 | t.transform(new DOMSource(doc), |
| 277 | new StreamResult(new BufferedWriter(new OutputStreamWriter(out, "UTF-8")))); |
| 278 | } catch(TransformerException e) { |
| 279 | throw new AssertionError(e); |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | /** |
| 284 | * Recursively traverse the specified preferences node and store |
| 285 | * the described preferences into the system or current user |
| 286 | * preferences tree, as appropriate. |
| 287 | */ |
| 288 | private static void ImportSubtree(Preferences prefsNode, Element xmlNode) { |
| 289 | NodeList xmlKids = xmlNode.getChildNodes(); |
| 290 | int numXmlKids = xmlKids.getLength(); |
| 291 | /* |
| 292 | * We first lock the node, import its contents and get |
| 293 | * child nodes. Then we unlock the node and go to children |
| 294 | * Since some of the children might have been concurrently |
| 295 | * deleted we check for this. |
| 296 | */ |
| 297 | Preferences[] prefsKids; |
| 298 | /* Lock the node */ |
| 299 | synchronized (((AbstractPreferences)prefsNode).lock) { |
| 300 | //If removed, return silently |
| 301 | if (((AbstractPreferences)prefsNode).isRemoved()) |
| 302 | return; |
| 303 | |
| 304 | // Import any preferences at this node |
| 305 | Element firstXmlKid = (Element) xmlKids.item(0); |
| 306 | ImportPrefs(prefsNode, firstXmlKid); |
| 307 | prefsKids = new Preferences[numXmlKids - 1]; |
| 308 | |
| 309 | // Get involved children |
| 310 | for (int i=1; i < numXmlKids; i++) { |
| 311 | Element xmlKid = (Element) xmlKids.item(i); |
| 312 | prefsKids[i-1] = prefsNode.node(xmlKid.getAttribute("name")); |
| 313 | } |
| 314 | } // unlocked the node |
| 315 | // import children |
| 316 | for (int i=1; i < numXmlKids; i++) |
| 317 | ImportSubtree(prefsKids[i-1], (Element)xmlKids.item(i)); |
| 318 | } |
| 319 | |
| 320 | /** |
| 321 | * Import the preferences described by the specified XML element |
| 322 | * (a map from a preferences document) into the specified |
| 323 | * preferences node. |
| 324 | */ |
| 325 | private static void ImportPrefs(Preferences prefsNode, Element map) { |
| 326 | NodeList entries = map.getChildNodes(); |
| 327 | for (int i=0, numEntries = entries.getLength(); i < numEntries; i++) { |
| 328 | Element entry = (Element) entries.item(i); |
| 329 | prefsNode.put(entry.getAttribute("key"), |
| 330 | entry.getAttribute("value")); |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | /** |
| 335 | * Export the specified Map<String,String> to a map document on |
| 336 | * the specified OutputStream as per the prefs DTD. This is used |
| 337 | * as the internal (undocumented) format for FileSystemPrefs. |
| 338 | * |
| 339 | * @throws IOException if writing to the specified output stream |
| 340 | * results in an <tt>IOException</tt>. |
| 341 | */ |
| 342 | static void exportMap(OutputStream os, Map map) throws IOException { |
| 343 | Document doc = createPrefsDoc("map"); |
| 344 | Element xmlMap = doc.getDocumentElement( ) ; |
| 345 | xmlMap.setAttribute("MAP_XML_VERSION", MAP_XML_VERSION); |
| 346 | |
| 347 | for (Iterator i = map.entrySet().iterator(); i.hasNext(); ) { |
| 348 | Map.Entry e = (Map.Entry) i.next(); |
| 349 | Element xe = (Element) |
| 350 | xmlMap.appendChild(doc.createElement("entry")); |
| 351 | xe.setAttribute("key", (String) e.getKey()); |
| 352 | xe.setAttribute("value", (String) e.getValue()); |
| 353 | } |
| 354 | |
| 355 | writeDoc(doc, os); |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * Import Map from the specified input stream, which is assumed |
| 360 | * to contain a map document as per the prefs DTD. This is used |
| 361 | * as the internal (undocumented) format for FileSystemPrefs. The |
| 362 | * key-value pairs specified in the XML document will be put into |
| 363 | * the specified Map. (If this Map is empty, it will contain exactly |
| 364 | * the key-value pairs int the XML-document when this method returns.) |
| 365 | * |
| 366 | * @throws IOException if reading from the specified output stream |
| 367 | * results in an <tt>IOException</tt>. |
| 368 | * @throws InvalidPreferencesFormatException Data on input stream does not |
| 369 | * constitute a valid XML document with the mandated document type. |
| 370 | */ |
| 371 | static void importMap(InputStream is, Map m) |
| 372 | throws IOException, InvalidPreferencesFormatException |
| 373 | { |
| 374 | try { |
| 375 | Document doc = loadPrefsDoc(is); |
| 376 | Element xmlMap = doc.getDocumentElement(); |
| 377 | // check version |
| 378 | String mapVersion = xmlMap.getAttribute("MAP_XML_VERSION"); |
| 379 | if (mapVersion.compareTo(MAP_XML_VERSION) > 0) |
| 380 | throw new InvalidPreferencesFormatException( |
| 381 | "Preferences map file format version " + mapVersion + |
| 382 | " is not supported. This java installation can read" + |
| 383 | " versions " + MAP_XML_VERSION + " or older. You may need" + |
| 384 | " to install a newer version of JDK."); |
| 385 | |
| 386 | NodeList entries = xmlMap.getChildNodes(); |
| 387 | for (int i=0, numEntries=entries.getLength(); i<numEntries; i++) { |
| 388 | Element entry = (Element) entries.item(i); |
| 389 | m.put(entry.getAttribute("key"), entry.getAttribute("value")); |
| 390 | } |
| 391 | } catch(SAXException e) { |
| 392 | throw new InvalidPreferencesFormatException(e); |
| 393 | } |
| 394 | } |
| 395 | |
| 396 | private static class Resolver implements EntityResolver { |
| 397 | public InputSource resolveEntity(String pid, String sid) |
| 398 | throws SAXException |
| 399 | { |
| 400 | if (sid.equals(PREFS_DTD_URI)) { |
| 401 | InputSource is; |
| 402 | is = new InputSource(new StringReader(PREFS_DTD)); |
| 403 | is.setSystemId(PREFS_DTD_URI); |
| 404 | return is; |
| 405 | } |
| 406 | throw new SAXException("Invalid system identifier: " + sid); |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | private static class EH implements ErrorHandler { |
| 411 | public void error(SAXParseException x) throws SAXException { |
| 412 | throw x; |
| 413 | } |
| 414 | public void fatalError(SAXParseException x) throws SAXException { |
| 415 | throw x; |
| 416 | } |
| 417 | public void warning(SAXParseException x) throws SAXException { |
| 418 | throw x; |
| 419 | } |
| 420 | } |
| 421 | } |