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Diffstat (limited to 'libjava/classpath/gnu/xml/util/Resolver.java')
| -rw-r--r-- | libjava/classpath/gnu/xml/util/Resolver.java | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/xml/util/Resolver.java b/libjava/classpath/gnu/xml/util/Resolver.java new file mode 100644 index 000000000..b16f9617f --- /dev/null +++ b/libjava/classpath/gnu/xml/util/Resolver.java @@ -0,0 +1,263 @@ +/* Resolver.java -- + Copyright (C) 1999,2000,2001 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.xml.util; + +import java.io.File; +import java.io.IOException; +import java.util.Dictionary; + +import org.xml.sax.EntityResolver; +import org.xml.sax.InputSource; +import org.xml.sax.SAXException; + +/** + * Utility implementation of a SAX resolver, which can be used to improve + * network utilization of SAX based XML components. It does this by + * supporting local caches of external entities. + * SAX parsers <em>should</em> use such local caches when possible. + * + * @see XCat + */ +public class Resolver implements EntityResolver, Cloneable +{ + /** + * Updates a dictionary used to map PUBLIC identifiers to file names, + * so that it uses the mappings in a specified directory. + * + * @param mappings Array of string pairs, where the first member + * of each pair is a PUBLIC identifier and the second is the + * name of a file, relative to the specified directory. + * @param directory File holding the specified files. + */ + public static void addDirectoryMapping ( + Dictionary table, + String mappings [][], + File directory + ) throws IOException + { + for (int i = 0; i < mappings.length; i++) { + File file = new File (directory, mappings [i][1]); + String temp; + + if (!file.exists ()) // ?? log a warning ?? + continue; + + temp = fileToURL (file); + table.put (mappings [i][0], temp); + } + } + + // FIXME: these *URL routines don't quite belong here, except + // that they're all in the same spirit of making it easy to + // use local filesystem URIs with XML parsers. + + /** + * Provides the URL for a named file, without relying on the JDK 1.2 + * {@link java.io.File#toURL File.toURL}() utility method. + * + * @param filename the file name to convert. Relative file names + * are resolved the way the JVM resolves them (current to the + * process-global current working directory). + * + * @exception IOException if the file does not exist + */ + public static String fileNameToURL (String filename) + throws IOException + { + return fileToURL (new File (filename)); + } + + /** + * Provides the URL for a file, without relying on the JDK 1.2 + * {@link java.io.File#toURL File.toURL}() utility method. + * + * @param f the file to convert. Relative file names + * are resolved the way the JVM resolves them (current to the + * process-global current working directory). + * + * @exception IOException if the file does not exist + */ + public static String fileToURL (File f) + throws IOException + { + String temp; + + // NOTE: the javax.xml.parsers.DocumentBuilder and + // javax.xml.transform.stream.StreamSource versions + // of this don't have this test. Some JVM versions + // don't report this error sanely through URL code. + if (!f.exists ()) + throw new IOException ("no such file: " + f.getName ()); + + // FIXME: getAbsolutePath() seems buggy; I'm seeing components + // like "/foo/../" which are clearly not "absolute" + // and should have been resolved with the filesystem. + + // Substituting "/" would be wrong, "foo" may have been + // symlinked ... the URL code will make that change + // later, so that things can get _really_ broken! + + temp = f.getAbsolutePath (); + + if (File.separatorChar != '/') + temp = temp.replace (File.separatorChar, '/'); + if (!temp.startsWith ("/")) + temp = "/" + temp; + if (!temp.endsWith ("/") && f.isDirectory ()) + temp = temp + "/"; + return "file:" + temp; + } + + + /** + * Returns a URL string. Note that if a malformed URL is provided, or + * the parameter names a nonexistent file, the resulting URL may be + * malformed. + * + * @param fileOrURL If this is the name of a file which exists, + * then its URL is returned. Otherwise the argument is returned. + */ + public static String getURL (String fileOrURL) + { + try { + return fileNameToURL (fileOrURL); + } catch (Exception e) { + return fileOrURL; + } + } + + + + // note: cloneable, this is just copied; unguarded against mods + private Dictionary pubidMapping; + + /** + * Constructs a resolver which understands how to map PUBLIC identifiers + * to other URIs, typically for local copies of standard DTD components. + * + * @param dict maps PUBLIC identifiers to URIs. This is not + * copied; subsequent modifications will be reported through the + * resolution operations. + */ + public Resolver (Dictionary dict) + { pubidMapping = dict; } + + + // FIXME: want notion of a "system default" resolver, presumably + // loaded with all sorts of useful stuff. At the same time need + // a notion of resolver chaining (failure --> next) so that subsystems + // can set up things that won't interfere with other ones. + + /** + * This parses most MIME content type strings that have <em>charset=...</em> + * encoding declarations to and returns the specified encoding. This + * conforms to RFC 3023, and is useful when constructing InputSource + * objects from URLConnection objects or other objects using MIME + * content typing. + * + * @param contentType the MIME content type that will be parsed; must + * not be null. + * @return the appropriate encoding, or null if the content type is + * not text and there's no <code>charset=...</code> attribute + */ + static public String getEncoding (String contentType) + { + // currently a dumb parsing algorithm that works "mostly" and handles + // ..anything...charset=ABC + // ..anything...charset=ABC;otherAttr=DEF + // ..anything...charset=ABC (comment);otherAttr=DEF + // ..anything...charset= "ABC" (comment);otherAttr=DEF + + int temp; + String encoding; + String defValue = null; + + if (contentType.startsWith ("text/")) + defValue = contentType.startsWith ("text/html") + ? "ISO-8859-1" : "US-ASCII"; + + // Assumes 'charset' is only an attribute name, not part + // of a value, comment, or other attribute name + // ALSO assumes no escaped values like "\;" or "\)" + if ((temp = contentType.indexOf ("charset")) != -1) { + // strip out everything up to '=' ... + temp = contentType.indexOf ('=', temp); + if (temp == -1) + return defValue; + encoding = contentType.substring (temp + 1); + // ... and any subsequent attributes + if ((temp = encoding.indexOf (';')) != -1) + encoding = encoding.substring (0, temp); + // ... and any comments after value + if ((temp = encoding.indexOf ('(')) != -1) + encoding = encoding.substring (0, temp); + // ... then whitespace, and any (double) quotes + encoding = encoding.trim (); + if (encoding.charAt (0) == '"') + encoding = encoding.substring (1, encoding.length () - 1); + } else + encoding = defValue; + return encoding; + } + + + /** + * Uses a local dictionary of public identifiers to resolve URIs, + * normally with the goal of minimizing network traffic or latencies. + */ + public InputSource resolveEntity (String publicId, String systemId) + throws IOException, SAXException + { + InputSource retval = null; + String uri; + + if (publicId != null + && ((uri = (String) pubidMapping.get (publicId)) != null)) { + retval = new InputSource (uri); + retval.setPublicId (publicId); + } + + // Could do URN resolution here + + // URL resolution always done by parser + + // FIXME: chain to "next" resolver + + return retval; + } +} |