Add some org packages.

From-SVN: r43922

libjava/org/xml/sax/helpers/XMLReaderFactory.java

@@ -0,0 +1,136 @@
+// XMLReaderFactory.java - factory for creating a new reader.
+// Written by David Megginson, sax@megginson.com
+// NO WARRANTY!  This class is in the Public Domain.
+
+// $Id: XMLReaderFactory.java,v 1.1 2000/10/02 02:43:20 sboag Exp $
+
+package org.xml.sax.helpers;
+import org.xml.sax.Parser;
+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>
+ * </blockquote>
+ *
+ * <p>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 <code>org.xml.sax.driver</code> system 
+ * property:</p>
+ *
+ * <pre>
+ * try {
+ *   XMLReader myReader = XMLReaderFactory.createXMLReader();
+ * } catch (SAXException e) {
+ *   System.err.println(e.getMessage());
+ * }
+ * </pre>
+ *
+ * <p>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.</p>
+ *
+ * <p><strong>Note to implementors:</strong> 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.</p>
+ *
+ * @since SAX 2.0
+ * @author David Megginson, 
+ *         <a href="mailto:sax@megginson.com">sax@megginson.com</a>
+ * @version 2.0
+ * @see org.xml.sax.XMLReader
+ */
+final public class XMLReaderFactory
+{
+
+    /**
+     * Private constructor.
+     *
+     * <p>This constructor prevents the class from being instantiated.</p>
+     */
+    private XMLReaderFactory ()
+    {
+    }
+
+
+    /**
+     * Attempt to create an XML reader from a system property.
+     *
+     * <p>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.</p>
+     *
+     * <p>Note that many Java interpreters allow system properties
+     * to be specified on the command line.</p>
+     *
+     * @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.
+     *
+     * <p>Given a class name, this method attempts to load
+     * and instantiate the class as an XML reader.</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
+    {
+	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