| /* XsltFilter.java -- |
| Copyright (C) 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., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 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.pipeline; |
| |
| import java.io.IOException; |
| |
| import javax.xml.transform.TransformerFactory; |
| import javax.xml.transform.TransformerConfigurationException; |
| import javax.xml.transform.sax.*; |
| import javax.xml.transform.stream.StreamSource; |
| |
| import org.xml.sax.SAXException; |
| import org.xml.sax.ext.LexicalHandler; |
| |
| |
| /** |
| * Packages an XSLT transform as a pipeline component. |
| * Note that all DTD events (callbacks to DeclHandler and DTDHandler |
| * interfaces) are discarded, although XSLT transforms may be set up to |
| * use the LexicalHandler to write DTDs with only an external subset. |
| * Not every XSLT engine will necessarily be usable with this filter, |
| * but current versions of |
| * <a href="http://saxon.sourceforge.net">SAXON</a> and |
| * <a href="http://xml.apache.org/xalan-j">Xalan</a> should work well. |
| * |
| * @see TransformerFactory |
| * |
| * @author David Brownell |
| */ |
| final public class XsltFilter extends EventFilter |
| { |
| /** |
| * Creates a filter that performs the specified transform. |
| * Uses the JAXP 1.1 interfaces to access the default XSLT |
| * engine configured for in the current execution context, |
| * and parses the stylesheet without custom EntityResolver |
| * or ErrorHandler support. |
| * |
| * @param stylesheet URI for the stylesheet specifying the |
| * XSLT transform |
| * @param next provides the ContentHandler and LexicalHandler |
| * to receive XSLT output. |
| * @exception SAXException if the stylesheet can't be parsed |
| * @exception IOException if there are difficulties |
| * bootstrapping the XSLT engine, such as it not supporting |
| * SAX well enough to use this way. |
| */ |
| public XsltFilter (String stylesheet, EventConsumer next) |
| throws SAXException, IOException |
| { |
| // First, get a transformer with the stylesheet preloaded |
| TransformerFactory tf = null; |
| TransformerHandler th; |
| |
| try { |
| SAXTransformerFactory stf; |
| |
| tf = TransformerFactory.newInstance (); |
| if (!tf.getFeature (SAXTransformerFactory.FEATURE) // sax inputs |
| || !tf.getFeature (SAXResult.FEATURE) // sax outputs |
| || !tf.getFeature (StreamSource.FEATURE) // stylesheet |
| ) |
| throw new IOException ("XSLT factory (" |
| + tf.getClass ().getName () |
| + ") does not support SAX"); |
| stf = (SAXTransformerFactory) tf; |
| th = stf.newTransformerHandler (new StreamSource (stylesheet)); |
| } catch (TransformerConfigurationException e) { |
| throw new IOException ("XSLT factory (" |
| + (tf == null |
| ? "none available" |
| : tf.getClass ().getName ()) |
| + ") configuration error, " |
| + e.getMessage () |
| ); |
| } |
| |
| // Hook its outputs up to the pipeline ... |
| SAXResult out = new SAXResult (); |
| |
| out.setHandler (next.getContentHandler ()); |
| try { |
| LexicalHandler lh; |
| lh = (LexicalHandler) next.getProperty (LEXICAL_HANDLER); |
| out.setLexicalHandler (lh); |
| } catch (Exception e) { |
| // ignore |
| } |
| th.setResult (out); |
| |
| // ... and make sure its inputs look like ours. |
| setContentHandler (th); |
| setProperty (LEXICAL_HANDLER, th); |
| } |
| } |