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1: /* Resolver.java -- 2: Copyright (C) 1999,2000,2001 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: package gnu.xml.util; 39: 40: import java.io.File; 41: import java.io.IOException; 42: import java.util.Dictionary; 43: 44: import org.xml.sax.EntityResolver; 45: import org.xml.sax.InputSource; 46: import org.xml.sax.SAXException; 47: 48: /** 49: * Utility implementation of a SAX resolver, which can be used to improve 50: * network utilization of SAX based XML components. It does this by 51: * supporting local caches of external entities. 52: * SAX parsers <em>should</em> use such local caches when possible. 53: * 54: * @see XCat 55: */ 56: public class Resolver implements EntityResolver, Cloneable 57: { 58: /** 59: * Updates a dictionary used to map PUBLIC identifiers to file names, 60: * so that it uses the mappings in a specified directory. 61: * 62: * @param mappings Array of string pairs, where the first member 63: * of each pair is a PUBLIC identifier and the second is the 64: * name of a file, relative to the specified directory. 65: * @param directory File holding the specified files. 66: */ 67: public static void addDirectoryMapping ( 68: Dictionary table, 69: String mappings [][], 70: File directory 71: ) throws IOException 72: { 73: for (int i = 0; i < mappings.length; i++) { 74: File file = new File (directory, mappings [i][1]); 75: String temp; 76: 77: if (!file.exists ()) // ?? log a warning ?? 78: continue; 79: 80: temp = fileToURL (file); 81: table.put (mappings [i][0], temp); 82: } 83: } 84: 85: // FIXME: these *URL routines don't quite belong here, except 86: // that they're all in the same spirit of making it easy to 87: // use local filesystem URIs with XML parsers. 88: 89: /** 90: * Provides the URL for a named file, without relying on the JDK 1.2 91: * {@link java.io.File#toURL File.toURL}() utility method. 92: * 93: * @param filename the file name to convert. Relative file names 94: * are resolved the way the JVM resolves them (current to the 95: * process-global current working directory). 96: * 97: * @exception IOException if the file does not exist 98: */ 99: public static String fileNameToURL (String filename) 100: throws IOException 101: { 102: return fileToURL (new File (filename)); 103: } 104: 105: /** 106: * Provides the URL for a file, without relying on the JDK 1.2 107: * {@link java.io.File#toURL File.toURL}() utility method. 108: * 109: * @param f the file to convert. Relative file names 110: * are resolved the way the JVM resolves them (current to the 111: * process-global current working directory). 112: * 113: * @exception IOException if the file does not exist 114: */ 115: public static String fileToURL (File f) 116: throws IOException 117: { 118: String temp; 119: 120: // NOTE: the javax.xml.parsers.DocumentBuilder and 121: // javax.xml.transform.stream.StreamSource versions 122: // of this don't have this test. Some JVM versions 123: // don't report this error sanely through URL code. 124: if (!f.exists ()) 125: throw new IOException ("no such file: " + f.getName ()); 126: 127: // FIXME: getAbsolutePath() seems buggy; I'm seeing components 128: // like "/foo/../" which are clearly not "absolute" 129: // and should have been resolved with the filesystem. 130: 131: // Substituting "/" would be wrong, "foo" may have been 132: // symlinked ... the URL code will make that change 133: // later, so that things can get _really_ broken! 134: 135: temp = f.getAbsolutePath (); 136: 137: if (File.separatorChar != '/') 138: temp = temp.replace (File.separatorChar, '/'); 139: if (!temp.startsWith ("/")) 140: temp = "/" + temp; 141: if (!temp.endsWith ("/") && f.isDirectory ()) 142: temp = temp + "/"; 143: return "file:" + temp; 144: } 145: 146: 147: /** 148: * Returns a URL string. Note that if a malformed URL is provided, or 149: * the parameter names a nonexistent file, the resulting URL may be 150: * malformed. 151: * 152: * @param fileOrURL If this is the name of a file which exists, 153: * then its URL is returned. Otherwise the argument is returned. 154: */ 155: public static String getURL (String fileOrURL) 156: { 157: try { 158: return fileNameToURL (fileOrURL); 159: } catch (Exception e) { 160: return fileOrURL; 161: } 162: } 163: 164: 165: 166: // note: cloneable, this is just copied; unguarded against mods 167: private Dictionary pubidMapping; 168: 169: /** 170: * Constructs a resolver which understands how to map PUBLIC identifiers 171: * to other URIs, typically for local copies of standard DTD components. 172: * 173: * @param dict maps PUBLIC identifiers to URIs. This is not 174: * copied; subsequent modifications will be reported through the 175: * resolution operations. 176: */ 177: public Resolver (Dictionary dict) 178: { pubidMapping = dict; } 179: 180: 181: // FIXME: want notion of a "system default" resolver, presumably 182: // loaded with all sorts of useful stuff. At the same time need 183: // a notion of resolver chaining (failure --> next) so that subsystems 184: // can set up things that won't interfere with other ones. 185: 186: /** 187: * This parses most MIME content type strings that have <em>charset=...</em> 188: * encoding declarations to and returns the specified encoding. This 189: * conforms to RFC 3023, and is useful when constructing InputSource 190: * objects from URLConnection objects or other objects using MIME 191: * content typing. 192: * 193: * @param contentType the MIME content type that will be parsed; must 194: * not be null. 195: * @return the appropriate encoding, or null if the content type is 196: * not text and there's no <code>charset=...</code> attribute 197: */ 198: static public String getEncoding (String contentType) 199: { 200: // currently a dumb parsing algorithm that works "mostly" and handles 201: // ..anything...charset=ABC 202: // ..anything...charset=ABC;otherAttr=DEF 203: // ..anything...charset=ABC (comment);otherAttr=DEF 204: // ..anything...charset= "ABC" (comment);otherAttr=DEF 205: 206: int temp; 207: String encoding; 208: String defValue = null; 209: 210: if (contentType.startsWith ("text/")) 211: defValue = contentType.startsWith ("text/html") 212: ? "ISO-8859-1" : "US-ASCII"; 213: 214: // Assumes 'charset' is only an attribute name, not part 215: // of a value, comment, or other attribute name 216: // ALSO assumes no escaped values like "\;" or "\)" 217: if ((temp = contentType.indexOf ("charset")) != -1) { 218: // strip out everything up to '=' ... 219: temp = contentType.indexOf ('=', temp); 220: if (temp == -1) 221: return defValue; 222: encoding = contentType.substring (temp + 1); 223: // ... and any subsequent attributes 224: if ((temp = encoding.indexOf (';')) != -1) 225: encoding = encoding.substring (0, temp); 226: // ... and any comments after value 227: if ((temp = encoding.indexOf ('(')) != -1) 228: encoding = encoding.substring (0, temp); 229: // ... then whitespace, and any (double) quotes 230: encoding = encoding.trim (); 231: if (encoding.charAt (0) == '"') 232: encoding = encoding.substring (1, encoding.length () - 1); 233: } else 234: encoding = defValue; 235: return encoding; 236: } 237: 238: 239: /** 240: * Uses a local dictionary of public identifiers to resolve URIs, 241: * normally with the goal of minimizing network traffic or latencies. 242: */ 243: public InputSource resolveEntity (String publicId, String systemId) 244: throws IOException, SAXException 245: { 246: InputSource retval = null; 247: String uri; 248: 249: if (publicId != null 250: && ((uri = (String) pubidMapping.get (publicId)) != null)) { 251: retval = new InputSource (uri); 252: retval.setPublicId (publicId); 253: } 254: 255: // Could do URN resolution here 256: 257: // URL resolution always done by parser 258: 259: // FIXME: chain to "next" resolver 260: 261: return retval; 262: } 263: }