- * This module, both source code and documentation, is in the - * Public Domain, and comes with NO WARRANTY. - *- * - *
This class contains static methods for creating an XML reader
- * from an explicit class name, or for creating an XML reader based
- * on the value of the org.xml.sax.driver system
- * property:
- * try {
- * XMLReader myReader = XMLReaderFactory.createXMLReader();
- * } catch (SAXException e) {
- * System.err.println(e.getMessage());
- * }
- *
- *
- * Note that these methods will not be usable in environments where - * system properties are not accessible or where the application or - * applet is not permitted to load classes dynamically.
- * - *Note to implementors: SAX implementations in specialized - * environments may replace this class with a different one optimized for the - * environment, as long as its method signatures remain the same.
- * - * @since SAX 2.0 - * @author David Megginson, - * sax@megginson.com - * @version 2.0 - * @see org.xml.sax.XMLReader - */ -final public class XMLReaderFactory -{ - - /** - * Private constructor. - * - *This constructor prevents the class from being instantiated.
- */ - private XMLReaderFactory () - { - } - - - /** - * Attempt to create an XML reader from a system property. - * - *This method uses the value of the system property - * "org.xml.sax.driver" as the full name of a Java class - * and tries to instantiate that class as a SAX2 - * XMLReader.
- * - *Note that many Java interpreters allow system properties - * to be specified on the command line.
- * - * @return A new XMLReader. - * @exception org.xml.sax.SAXException If the value of the - * "org.xml.sax.driver" system property is null, - * or if the class cannot be loaded and instantiated. - * @see #createXMLReader(java.lang.String) - */ - public static XMLReader createXMLReader () - throws SAXException - { - String className = System.getProperty("org.xml.sax.driver"); - if (className == null) { - Parser parser; - try { - parser = ParserFactory.makeParser(); - } catch (Exception e) { - parser = null; - } - if (parser == null) { - throw new - SAXException("System property org.xml.sax.driver not specified"); - } else { - return new ParserAdapter(parser); - } - } else { - return createXMLReader(className); - } - } - - - /** - * Attempt to create an XML reader from a class name. - * - *Given a class name, this method attempts to load - * and instantiate the class as an XML reader.
- * - * @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 - { - try { - return (XMLReader)(Class.forName(className).newInstance()); - } 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); - } - - } - -} - -// end of XMLReaderFactory.java