Java tutorial
/* * Copyright 1999-2005 The Apache Software Foundation. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.opensymphony.xwork.util; import java.util.Map; import com.opensymphony.util.ClassLoaderUtil; import com.opensymphony.xwork.util.location.Location; import com.opensymphony.xwork.util.location.LocationAttributes; import com.opensymphony.xwork.XworkException; import com.opensymphony.xwork.ObjectFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.xml.sax.Attributes; import org.xml.sax.ContentHandler; import org.xml.sax.Locator; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import org.xml.sax.helpers.DefaultHandler; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.xml.parsers.SAXParserFactory; import javax.xml.parsers.SAXParser; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMResult; import javax.xml.transform.sax.SAXTransformerFactory; import javax.xml.transform.sax.TransformerHandler; /** * Helper class to create and retrieve information from location-enabled * DOM-trees. * * @author Don Brown * @author tmjee * @since 1.2 * @version $Date: 2007-11-26 18:02:22 +0900 (, 26 11 2007) $ $Id: DomHelper.java 1687 2007-11-26 09:02:22Z tm_jee $ */ public class DomHelper { private static final Log LOG = LogFactory.getLog(DomHelper.class); public static final String XMLNS_URI = "http://www.w3.org/2000/xmlns/"; public static Location getLocationObject(Element element) { return LocationAttributes.getLocation(element); } /** * Creates a W3C Document that remembers the location of each element in * the source file. The location of element nodes can then be retrieved * using the {@link #getLocationObject(Element)} method. * * @param inputSource the inputSource to read the document from */ public static Document parse(InputSource inputSource) { return parse(inputSource, null); } /** * Creates a W3C Document that remembers the location of each element in * the source file. The location of element nodes can then be retrieved * using the {@link #getLocationObject(Element)} method. * * @param inputSource the inputSource to read the document from * @param dtdMappings a map of DTD names and public ids */ public static Document parse(InputSource inputSource, Map dtdMappings) { SAXParserFactory factory = null; String parserProp = System.getProperty("xwork.saxParserFactory"); if (parserProp != null) { try { Class clazz = ObjectFactory.getObjectFactory().getClassInstance(parserProp); factory = (SAXParserFactory) clazz.newInstance(); } catch (ClassNotFoundException e) { LOG.error("Unable to load saxParserFactory set by system property 'xwork.saxParserFactory': " + parserProp, e); } catch (Exception e) { LOG.error("Unable to load saxParserFactory set by system property 'xwork.saxParserFactory': " + parserProp, e); } } if (factory == null) { factory = SAXParserFactory.newInstance(); } factory.setValidating((dtdMappings != null)); factory.setNamespaceAware(true); SAXParser parser = null; try { parser = factory.newSAXParser(); } catch (Exception ex) { throw new XworkException("Unable to create SAX parser", ex); } DOMBuilder builder = new DOMBuilder(); // Enhance the sax stream with location information ContentHandler locationHandler = new LocationAttributes.Pipe(builder); try { parser.parse(inputSource, new StartHandler(locationHandler, dtdMappings)); } catch (Exception ex) { throw new XworkException(ex); } return builder.getDocument(); } /** * The <code>DOMBuilder</code> is a utility class that will generate a W3C * DOM Document from SAX events. * * @author <a href="mailto:cziegeler@apache.org">Carsten Ziegeler</a> */ static public class DOMBuilder implements ContentHandler { /** The default transformer factory shared by all instances */ protected static SAXTransformerFactory FACTORY; /** The transformer factory */ protected SAXTransformerFactory factory; /** The result */ protected DOMResult result; /** The parentNode */ protected Node parentNode; protected ContentHandler nextHandler; static { String parserProp = System.getProperty("xwork.saxTransformerFactory"); if (parserProp != null) { try { Class clazz = ObjectFactory.getObjectFactory().getClassInstance(parserProp); FACTORY = (SAXTransformerFactory) clazz.newInstance(); } catch (ClassNotFoundException e) { LOG.error( "Unable to load SAXTransformerFactory set by system property 'xwork.saxTransformerFactory': " + parserProp, e); } catch (Exception e) { LOG.error( "Unable to load SAXTransformerFactory set by system property 'xwork.saxTransformerFactory': " + parserProp, e); } } if (FACTORY == null) { FACTORY = (SAXTransformerFactory) TransformerFactory.newInstance(); } } /** * Construct a new instance of this DOMBuilder. */ public DOMBuilder() { this((Node) null); } /** * Construct a new instance of this DOMBuilder. */ public DOMBuilder(SAXTransformerFactory factory) { this(factory, null); } /** * Constructs a new instance that appends nodes to the given parent node. */ public DOMBuilder(Node parentNode) { this(null, parentNode); } /** * Construct a new instance of this DOMBuilder. */ public DOMBuilder(SAXTransformerFactory factory, Node parentNode) { this.factory = factory == null ? FACTORY : factory; this.parentNode = parentNode; setup(); } /** * Setup this instance transformer and result objects. */ private void setup() { try { TransformerHandler handler = this.factory.newTransformerHandler(); nextHandler = handler; if (this.parentNode != null) { this.result = new DOMResult(this.parentNode); } else { this.result = new DOMResult(); } handler.setResult(this.result); } catch (javax.xml.transform.TransformerException local) { throw new XworkException("Fatal-Error: Unable to get transformer handler", local); } } /** * Return the newly built Document. */ public Document getDocument() { if (this.result == null || this.result.getNode() == null) { return null; } else if (this.result.getNode().getNodeType() == Node.DOCUMENT_NODE) { return (Document) this.result.getNode(); } else { return this.result.getNode().getOwnerDocument(); } } public void setDocumentLocator(Locator locator) { nextHandler.setDocumentLocator(locator); } public void startDocument() throws SAXException { nextHandler.startDocument(); } public void endDocument() throws SAXException { nextHandler.endDocument(); } public void startElement(String uri, String loc, String raw, Attributes attrs) throws SAXException { nextHandler.startElement(uri, loc, raw, attrs); } public void endElement(String arg0, String arg1, String arg2) throws SAXException { nextHandler.endElement(arg0, arg1, arg2); } public void startPrefixMapping(String arg0, String arg1) throws SAXException { nextHandler.startPrefixMapping(arg0, arg1); } public void endPrefixMapping(String arg0) throws SAXException { nextHandler.endPrefixMapping(arg0); } public void characters(char[] arg0, int arg1, int arg2) throws SAXException { nextHandler.characters(arg0, arg1, arg2); } public void ignorableWhitespace(char[] arg0, int arg1, int arg2) throws SAXException { nextHandler.ignorableWhitespace(arg0, arg1, arg2); } public void processingInstruction(String arg0, String arg1) throws SAXException { nextHandler.processingInstruction(arg0, arg1); } public void skippedEntity(String arg0) throws SAXException { nextHandler.skippedEntity(arg0); } } public static class StartHandler extends DefaultHandler { private ContentHandler nextHandler; private Map dtdMappings; /** * Create a filter that is chained to another handler. * @param next the next handler in the chain. */ public StartHandler(ContentHandler next, Map dtdMappings) { nextHandler = next; this.dtdMappings = dtdMappings; } public void setDocumentLocator(Locator locator) { nextHandler.setDocumentLocator(locator); } public void startDocument() throws SAXException { nextHandler.startDocument(); } public void endDocument() throws SAXException { nextHandler.endDocument(); } public void startElement(String uri, String loc, String raw, Attributes attrs) throws SAXException { nextHandler.startElement(uri, loc, raw, attrs); } public void endElement(String arg0, String arg1, String arg2) throws SAXException { nextHandler.endElement(arg0, arg1, arg2); } public void startPrefixMapping(String arg0, String arg1) throws SAXException { nextHandler.startPrefixMapping(arg0, arg1); } public void endPrefixMapping(String arg0) throws SAXException { nextHandler.endPrefixMapping(arg0); } public void characters(char[] arg0, int arg1, int arg2) throws SAXException { nextHandler.characters(arg0, arg1, arg2); } public void ignorableWhitespace(char[] arg0, int arg1, int arg2) throws SAXException { nextHandler.ignorableWhitespace(arg0, arg1, arg2); } public void processingInstruction(String arg0, String arg1) throws SAXException { nextHandler.processingInstruction(arg0, arg1); } public void skippedEntity(String arg0) throws SAXException { nextHandler.skippedEntity(arg0); } public InputSource resolveEntity(String publicId, String systemId) { boolean containsDtdMappings = dtdMappings.containsKey(publicId); if (dtdMappings != null && containsDtdMappings) { String val = dtdMappings.get(publicId).toString(); if (LOG.isDebugEnabled()) { LOG.debug("using local copy of dtd with Public ID [" + publicId + "] located in [" + val + "]"); } return new InputSource(ClassLoaderUtil.getResourceAsStream(val, DomHelper.class)); } return null; } public void warning(SAXParseException exception) { } public void error(SAXParseException exception) throws SAXException { LOG.error(exception.getMessage() + " at (" + exception.getPublicId() + ":" + exception.getLineNumber() + ":" + exception.getColumnNumber() + ")"); throw exception; } public void fatalError(SAXParseException exception) throws SAXException { LOG.fatal(exception.getMessage() + " at (" + exception.getPublicId() + ":" + exception.getLineNumber() + ":" + exception.getColumnNumber() + ")"); throw exception; } } }