| /********************************************************************** |
| * Copyright (c) 2005, 2008 IBM Corporation and others. All rights reserved. This |
| * program and the accompanying materials are made available under the terms of |
| * the Eclipse Public License v1.0 which accompanies this distribution, and is |
| * available at http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM - Initial API and implementation |
| * Jesper Steen M�ller - adapted from org.eclipse.core.internal.content |
| **********************************************************************/ |
| |
| package org.eclipse.wst.xsl.core.resolver; |
| |
| import java.io.IOException; |
| import java.io.StringReader; |
| import javax.xml.parsers.*; |
| |
| import org.eclipse.wst.xsl.core.XSLCore; |
| import org.eclipse.wst.xsl.core.internal.XSLCorePlugin; |
| import org.xml.sax.*; |
| import org.xml.sax.ext.LexicalHandler; |
| import org.xml.sax.helpers.DefaultHandler; |
| |
| /** |
| * A simple XML parser to find the XSL version of a given XML file, expectedly a XSLT stylesheet. |
| */ |
| public final class XSLVersionHandler extends DefaultHandler implements LexicalHandler, ErrorHandler { |
| /** |
| * An exception indicating that the parsing should stop. This is usually |
| * triggered when the top-level element has been found. |
| * |
| * @since 3.0 |
| */ |
| private class StopParsingException extends SAXException { |
| /** |
| * All serializable objects should have a stable serialVersionUID |
| */ |
| private static final long serialVersionUID = 1L; |
| |
| /** |
| * Constructs an instance of <code>StopParsingException</code> with a |
| * <code>null</code> detail message. |
| */ |
| public StopParsingException() { |
| super((String) null); |
| } |
| } |
| |
| private static final String XSLT_STYLESHEET = "stylesheet"; //$NON-NLS-1$ |
| |
| private static final String XSLT_TEMPLATE = "template"; //$NON-NLS-1$ |
| |
| private static final String XSLT_VERSION = "version"; //$NON-NLS-1$ |
| |
| /** |
| * This is the value of the version attribute in the XSLT file. |
| * This member variable is <code>null</code> unless the file has been |
| * parsed successful to the point of finding the top-level element, |
| * and locating the 'version' attribute there. |
| */ |
| private String versionAttribute = null; |
| |
| /** |
| * TODO: Add Javadoc |
| */ |
| public XSLVersionHandler() { |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#comment(char[], int, int) |
| */ |
| public final void comment(final char[] ch, final int start, final int length) { |
| // Not interested. |
| } |
| |
| /** |
| * Creates a new SAX parser for use within this instance. |
| * |
| * @return The newly created parser. |
| * |
| * @throws ParserConfigurationException |
| * If a parser of the given configuration cannot be created. |
| * @throws SAXException |
| * If something in general goes wrong when creating the parser. |
| * @throws SAXNotRecognizedException |
| * If the <code>XMLReader</code> does not recognize the |
| * lexical handler configuration option. |
| * @throws SAXNotSupportedException |
| * If the <code>XMLReader</code> does not support the lexical |
| * handler configuration option. |
| */ |
| private final SAXParser createParser(SAXParserFactory parserFactory) throws ParserConfigurationException, SAXException, SAXNotRecognizedException, SAXNotSupportedException { |
| // Initialize the parser. |
| final SAXParser parser = parserFactory.newSAXParser(); |
| final XMLReader reader = parser.getXMLReader(); |
| reader.setProperty("http://xml.org/sax/properties/lexical-handler", this); //$NON-NLS-1$ |
| reader.setErrorHandler(this); // This helps to ignore errors |
| // disable DTD validation |
| try { |
| // be sure validation is "off" or the feature to ignore DTD's will not apply |
| reader.setFeature("http://xml.org/sax/features/validation", false); //$NON-NLS-1$ |
| reader.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false); //$NON-NLS-1$ |
| } catch (SAXNotRecognizedException e) { |
| // not a big deal if the parser does not recognize the features |
| } catch (SAXNotSupportedException e) { |
| // not a big deal if the parser does not support the features |
| } |
| return parser; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#endCDATA() |
| */ |
| public final void endCDATA() { |
| // Not interested. |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#endDTD() |
| */ |
| public final void endDTD() { |
| // Not interested. |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#endEntity(java.lang.String) |
| */ |
| public final void endEntity(final String name) { |
| // Not interested. |
| } |
| |
| /** |
| * TODO: Add Javadoc |
| * @return |
| */ |
| public String getVersionAttribute() { |
| return versionAttribute; |
| } |
| |
| /** |
| * TODO: Add Javadoc |
| * @param contents |
| * @return |
| * @throws IOException |
| * @throws ParserConfigurationException |
| * @throws SAXException |
| */ |
| public boolean parseContents(InputSource contents) throws IOException, ParserConfigurationException, SAXException { |
| // Parse the file into we have what we need (or an error occurs). |
| try { |
| SAXParserFactory factory = XSLCorePlugin.getDefault().getFactory(); |
| if (factory == null) |
| return false; |
| final SAXParser parser = createParser(factory); |
| // to support external entities specified as relative URIs (see bug 63298) |
| parser.parse(contents, this); |
| } catch (StopParsingException e) { |
| // Abort the parsing normally. Fall through... |
| } |
| return true; |
| } |
| |
| /* |
| * Resolve external entity definitions to an empty string. This is to speed |
| * up processing of files with external DTDs. Not resolving the contents |
| * of the DTD is ok, as only the System ID of the DTD declaration is used. |
| * @see org.xml.sax.helpers.DefaultHandler#resolveEntity(java.lang.String, java.lang.String) |
| */ |
| public InputSource resolveEntity(String publicId, String systemId) throws SAXException { |
| return new InputSource(new StringReader("")); //$NON-NLS-1$ |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#startCDATA() |
| */ |
| public final void startCDATA() { |
| // Not interested. |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#startDTD(java.lang.String, |
| * java.lang.String, java.lang.String) |
| */ |
| public final void startDTD(final String name, final String publicId, final String systemId) throws SAXException { |
| // Not interested. |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ContentHandler#startElement(java.lang.String, |
| * java.lang.String, java.lang.String, org.xml.sax.Attributes) |
| */ |
| public final void startElement(final String uri, final String elementName, final String qualifiedName, final Attributes attributes) throws SAXException { |
| if (uri.equals(XSLCore.XSL_NAMESPACE_URI) && (XSLT_TEMPLATE.equals(elementName) || XSLT_STYLESHEET.equals(elementName))) { |
| versionAttribute = attributes.getValue(XSLT_VERSION); |
| } else { |
| versionAttribute = ""; //$NON-NLS-1$ |
| } |
| throw new StopParsingException(); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.xml.sax.ext.LexicalHandler#startEntity(java.lang.String) |
| */ |
| public final void startEntity(final String name) { |
| // Not interested. |
| } |
| |
| @Override |
| public void warning(SAXParseException e) throws SAXException { |
| // Not interested. |
| } |
| |
| @Override |
| public void error(SAXParseException e) throws SAXException { |
| // Not interested. |
| } |
| |
| @Override |
| public void fatalError(SAXParseException e) throws SAXException { |
| // Not interested. |
| } |
| } |