+++ /dev/null
-// XMLReaderFactory.java - factory for creating a new reader.
-// http://www.saxproject.org
-// Written by David Megginson
-// and by David Brownell
-// NO WARRANTY! This class is in the Public Domain.
-// $Id: XMLReaderFactory.java,v 1.10 2002/04/22 01:00:13 dbrownell Exp $
-
-package org.xml.sax.helpers;
-import java.io.BufferedReader;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import org.xml.sax.XMLReader;
-import org.xml.sax.SAXException;
-
-
-/**
- * Factory for creating an XML reader.
- *
- * <blockquote>
- * <em>This module, both source code and documentation, is in the
- * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
- * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
- * for further information.
- * </blockquote>
- *
- * <p>This class contains static methods for creating an XML reader
- * from an explicit class name, or based on runtime defaults:</p>
- *
- * <pre>
- * try {
- * XMLReader myReader = XMLReaderFactory.createXMLReader();
- * } catch (SAXException e) {
- * System.err.println(e.getMessage());
- * }
- * </pre>
- *
- * <p><strong>Note to Distributions bundled with parsers:</strong>
- * You should modify the implementation of the no-arguments
- * <em>createXMLReader</em> to handle cases where the external
- * configuration mechanisms aren't set up. That method should do its
- * best to return a parser when one is in the class path, even when
- * nothing bound its class name to <code>org.xml.sax.driver</code> so
- * those configuration mechanisms would see it.</p>
- *
- * @since SAX 2.0
- * @author David Megginson, David Brownell
- * @version 2.0.1 (sax2r2)
- */
-final public class XMLReaderFactory
-{
- /**
- * Private constructor.
- *
- * <p>This constructor prevents the class from being instantiated.</p>
- */
- private XMLReaderFactory ()
- {
- }
-
- private static final String property = "org.xml.sax.driver";
-
- /**
- * Attempt to create an XMLReader from system defaults.
- * In environments which can support it, the name of the XMLReader
- * class is determined by trying each these options in order, and
- * using the first one which succeeds:</p> <ul>
- *
- * <li>If the system property <code>org.xml.sax.driver</code>
- * has a value, that is used as an XMLReader class name. </li>
- *
- * <li>The JAR "Services API" is used to look for a class name
- * in the <em>META-INF/services/org.xml.sax.driver</em> file in
- * jarfiles available to the runtime.</li>
- *
- * <li> SAX parser distributions are strongly encouraged to provide
- * a default XMLReader class name that will take effect only when
- * previous options (on this list) are not successful.</li>
- *
- * <li>Finally, if {@link ParserFactory#makeParser()} can
- * return a system default SAX1 parser, that parser is wrapped in
- * a {@link ParserAdapter}. (This is a migration aid for SAX1
- * environments, where the <code>org.xml.sax.parser</code> system
- * property will often be usable.) </li>
- *
- * </ul>
- *
- * <p> In environments such as small embedded systems, which can not
- * support that flexibility, other mechanisms to determine the default
- * may be used. </p>
- *
- * <p>Note that many Java environments allow system properties to be
- * initialized on a command line. This means that <em>in most cases</em>
- * setting a good value for that property ensures that calls to this
- * method will succeed, except when security policies intervene.
- * This will also maximize application portability to older SAX
- * environments, with less robust implementations of this method.
- * </p>
- *
- * @return A new XMLReader.
- * @exception org.xml.sax.SAXException If no default XMLReader class
- * can be identified and instantiated.
- * @see #createXMLReader(java.lang.String)
- */
- public static XMLReader createXMLReader ()
- throws SAXException
- {
- String className = null;
- ClassLoader loader = NewInstance.getClassLoader ();
-
- // 1. try the JVM-instance-wide system property
- try { className = System.getProperty (property); }
- catch (RuntimeException e) { /* normally fails for applets */ }
-
- // 2. if that fails, try META-INF/services/
- if (className == null) {
- try {
- String service = "META-INF/services/" + property;
- InputStream in;
- BufferedReader reader;
-
- if (loader == null)
- in = ClassLoader.getSystemResourceAsStream (service);
- else
- in = loader.getResourceAsStream (service);
-
- if (in != null) {
- reader = new BufferedReader (
- new InputStreamReader (in, "UTF8"));
- className = reader.readLine ();
- in.close ();
- }
- } catch (Exception e) {
- }
- }
-
- // 3. Distro-specific fallback
- if (className == null) {
-// BEGIN DISTRIBUTION-SPECIFIC
-
- // EXAMPLE:
- // className = "com.example.sax.XmlReader";
- // or a $JAVA_HOME/jre/lib/*properties setting...
-
-// END DISTRIBUTION-SPECIFIC
- }
-
- // do we know the XMLReader implementation class yet?
- if (className != null)
- return loadClass (loader, className);
-
- // 4. panic -- adapt any SAX1 parser
- try {
- return new ParserAdapter (ParserFactory.makeParser ());
- } catch (Exception e) {
- throw new SAXException ("Can't create default XMLReader; "
- + "is system property org.xml.sax.driver set?");
- }
- }
-
-
- /**
- * Attempt to create an XML reader from a class name.
- *
- * <p>Given a class name, this method attempts to load
- * and instantiate the class as an XML reader.</p>
- *
- * <p>Note that this method will not be usable in environments where
- * the caller (perhaps an applet) is not permitted to load classes
- * dynamically.</p>
- *
- * @return A new XML reader.
- * @exception org.xml.sax.SAXException If the class cannot be
- * loaded, instantiated, and cast to XMLReader.
- * @see #createXMLReader()
- */
- public static XMLReader createXMLReader (String className)
- throws SAXException
- {
- return loadClass (NewInstance.getClassLoader (), className);
- }
-
- private static XMLReader loadClass (ClassLoader loader, String className)
- throws SAXException
- {
- try {
- return (XMLReader) NewInstance.newInstance (loader, className);
- } catch (ClassNotFoundException e1) {
- throw new SAXException("SAX2 driver class " + className +
- " not found", e1);
- } catch (IllegalAccessException e2) {
- throw new SAXException("SAX2 driver class " + className +
- " found but cannot be loaded", e2);
- } catch (InstantiationException e3) {
- throw new SAXException("SAX2 driver class " + className +
- " loaded but cannot be instantiated (no empty public constructor?)",
- e3);
- } catch (ClassCastException e4) {
- throw new SAXException("SAX2 driver class " + className +
- " does not implement XMLReader", e4);
- }
- }
-}
git://source.jalview.org / jalview.git / blobdiff