Java tutorial
/* * See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package com.xpn.xwiki.internal.xml; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.util.EmptyStackException; import org.apache.commons.codec.binary.Base64OutputStream; import org.apache.commons.io.IOUtils; import org.dom4j.Document; import org.dom4j.Element; import org.dom4j.io.OutputFormat; import org.xml.sax.Attributes; import org.xml.sax.SAXException; /** * This a minimal implementation to transform an XMLWriter into a <code>{@link org.dom4j.dom.DOMDocument}</code> * builder. * <p> * This implementation allow the use of a same function accepting an XMLWriter, to either produce output into an * <code>{@link java.io.OutputStream}</code> or to create a <code>{@link org.dom4j.dom.DOMDocument}</code>. Here a * sample of the way to do so: * </p> * <code><pre> * public void toXML(XMLWriter wr) throws IOException * { * Element docel = new DOMElement("html"); * wr.writeOpen(docel); * Element hbel = new DOMElement("head"); * wr.writeOpen(hbel); * Element el = new DOMElement("title"); * el.addText("My Title"); * wr.write(el); * wr.writeClose(hbel); * hbel = new DOMElement("body"); * wr.writeOpen(hbel); * el = new DOMElement("p"); * el.addText("My Body"); * wr.write(el); * } * * public void toXML(OutputStream out) throws IOException * { * XMLWriter wr = new XMLWriter(out, new OutputFormat(" ", true, "UTF-8")); * * Document doc = new DOMDocument(); * wr.writeDocumentStart(doc); * toXML(wr); * wr.writeDocumentEnd(doc); * } * * public Document toXMLDocument() * { * Document doc = new DOMDocument(); * DOMXMLWriter wr = new DOMXMLWriter(doc, new OutputFormat(" ", true, "UTF-8")); * * try { * toXML(wr); * return doc; * } catch (IOException e) { * throw new RuntimeException(e); * } * } * </pre></code> * <p> * <b>WARNING</b> - This implementation in INCOMPLETE and a minimal support. It should be improve as needed over time * </p> * * @version $Id: fbce6500ea6fabb69708ae7722a15c090488b836 $ */ public class DOMXMLWriter extends XMLWriter { /** * The <code>{@link Document}</code> currently built by this writer. */ private Document doc; /** * The <code>{@link OutputFormat}</code> providing the encoding requested. */ private OutputFormat format; /** * Create a new <code>{@link DOMXMLWriter}</code> that will build into the provided document using the default * encoding. * * @param doc <code>{@link Document}</code> that will be build by this writer */ public DOMXMLWriter(Document doc) { this.format = DEFAULT_FORMAT; this.doc = doc; } /** * Create a new <code>{@link DOMXMLWriter}</code> that will build into the provided document using the encoding * provided in the <code>{@link OutputFormat}</code>. * * @param doc <code>{@link Document}</code> that will be build by this writer * @param format <code>{@link OutputFormat}</code> used to retrieve the proper encoding */ public DOMXMLWriter(Document doc, OutputFormat format) { this.format = format; this.doc = doc; } /** * {@inheritDoc} * <p> * Add the element into the <code>{@link Document}</code> as a children of the element at the top of the stack of * opened elements, putting the whole stream content as text in the content of the <code>{@link Element}</code>. The * stream is converted to a String encoded in the current encoding. * * @see com.xpn.xwiki.internal.xml.XMLWriter#write(org.dom4j.Element, java.io.InputStream) */ @Override public void write(Element element, InputStream is) throws IOException { element.addText(IOUtils.toString(is, this.format.getEncoding())); write(element); } /** * {@inheritDoc} * <p> * Add the element into the <code>{@link Document}</code> as a children of the element at the top of the stack of of * the <code>{@link Element}</code>. * * @see com.xpn.xwiki.internal.xml.XMLWriter#write(org.dom4j.Element, java.io.Reader) */ @Override public void write(Element element, Reader rd) throws IOException { element.addText(IOUtils.toString(rd)); write(element); } /** * {@inheritDoc} * <p> * Add the element into the <code>{@link Document}</code> as a children of the element at the top of the stack of * opened elements, putting the whole stream content as Base64 text in the content of the * <code>{@link Element}</code>. * * @see com.xpn.xwiki.internal.xml.XMLWriter#writeBase64(org.dom4j.Element, java.io.InputStream) */ @Override public void writeBase64(Element element, InputStream is) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); Base64OutputStream out = new Base64OutputStream(baos, true, 0, null); IOUtils.copy(is, out); out.close(); element.addText(baos.toString(this.format.getEncoding())); write(element); } /** * {@inheritDoc} * <p> * Cleanup the stack of opened elements. * * @see com.xpn.xwiki.internal.xml.XMLWriter#writeDocumentEnd(org.dom4j.Document) */ @Override public void writeDocumentEnd(Document doc) throws IOException { if (!this.parent.isEmpty()) { writeClose(this.parent.firstElement()); } } /** * {@inheritDoc} * <p> * Does nothing, avoid default action. * * @see com.xpn.xwiki.internal.xml.XMLWriter#writeDocumentStart(org.dom4j.Document) */ @Override public void writeDocumentStart(Document doc) throws IOException { } /** * {@inheritDoc} * <p> * Add the element into the <code>{@link Document}</code> as a children of the element at the top of the stack of * opened elements. * * @see org.dom4j.io.XMLWriter#write(org.dom4j.Element) */ @Override public void write(Element element) throws IOException { if (this.parent.isEmpty()) { this.doc.setRootElement(element); } else { this.parent.peek().add(element); } } /** * {@inheritDoc} * <p> * Cleanup the stack of opened elements up to the given element. * * @see com.xpn.xwiki.internal.xml.XMLWriter#writeClose(org.dom4j.Element) */ @Override public void writeClose(Element element) throws IOException { try { while (this.parent.peek() != element) { this.parent.pop(); } this.parent.pop(); } catch (EmptyStackException e) { throw new IOException("FATAL: Closing a element that have never been opened"); } } /** * {@inheritDoc} * <p> * Add the element into the <code>{@link Document}</code> as a children of the element at the top of the stack of * opened elements. Add this element at the top of the stack of opened elements. * * @see com.xpn.xwiki.internal.xml.XMLWriter#writeOpen(org.dom4j.Element) */ @Override public void writeOpen(Element element) throws IOException { if (this.parent.isEmpty()) { this.doc.setRootElement(element); } else { this.parent.add(element); } this.parent.push(element); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#startCDATA() */ @Override public void startCDATA() throws SAXException { throw new SAXUnsupportedException(); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#startElement(java.lang.String, java.lang.String, java.lang.String, * org.xml.sax.Attributes) */ @Override public void startElement(String namespaceURI, String localName, String qName, Attributes attributes) throws SAXException { throw new SAXUnsupportedException(); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#startEntity(java.lang.String) */ @Override public void startEntity(String name) throws SAXException { throw new SAXUnsupportedException(); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#endCDATA() */ @Override public void endCDATA() throws SAXException { throw new SAXUnsupportedException(); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#endElement(java.lang.String, java.lang.String, java.lang.String) */ @Override public void endElement(String namespaceURI, String localName, String qName) throws SAXException { throw new SAXUnsupportedException(); } /** * {@inheritDoc} * * @see org.dom4j.io.XMLWriter#endEntity(java.lang.String) */ @Override public void endEntity(String name) throws SAXException { throw new SAXUnsupportedException(); } /** * Thrown for SAX api methods since we don't support them. */ public class SAXUnsupportedException extends RuntimeException { /** * Constructs a <code>SAXUnsupportedException</code>. */ public SAXUnsupportedException() { super("SAX api is not supported"); } } }