/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*
* $Header:$
*/
package org.apache.beehive.netui.compiler.model;
import org.w3c.dom.Document;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.Comment;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;
import org.apache.beehive.netui.compiler.LocalFileEntityResolver;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.TransformerException;
import java.io.File;
import java.io.IOException;
import java.io.Writer;
public class XmlModelWriter
{
private static final int INDENT_LEN = 2;
private Document _doc;
private String _rootName;
private String _systemID;
private String _publicID;
public XmlModelWriter(File starterFile, String rootName, String publicID, String systemID, String headerComment)
throws XmlModelWriterException, IOException
{
assert rootName != null;
_rootName = rootName;
_systemID = systemID;
_publicID = publicID;
try
{
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
builder.setEntityResolver(LocalFileEntityResolver.getInstance());
if ( starterFile != null && starterFile.canRead() )
{
_doc = builder.parse(starterFile);
}
else
{
DOMImplementation impl = builder.getDOMImplementation();
DocumentType docType = impl.createDocumentType(_rootName, _publicID, _systemID);
_doc = impl.createDocument(null, _rootName, docType);
}
if (headerComment != null)
{
Element root = _doc.getDocumentElement();
Comment comment = _doc.createComment(headerComment);
root.insertBefore(comment, root.getFirstChild());
}
}
catch (ParserConfigurationException e)
{
throw new XmlModelWriterException(e);
}
catch (SAXException e)
{
throw new XmlModelWriterException(e);
}
}
/**
* Write the XML to a stream, without using standard APIs. This appears to be about ten times as fast (for our
* simple purposes) as using a Transformer ({@link #write}), and it avoids JDK and environment issues with obtaining
* a TransformerFactory.
*/
public void simpleFastWrite(Writer out)
throws IOException, XmlModelWriterException
{
out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
if (_publicID != null && _systemID != null) {
out.write("<!DOCTYPE ");
out.write(_rootName);
out.write(" PUBLIC \"");
out.write(_publicID);
out.write("\" \"");
out.write(_systemID);
out.write("\">\n");
}
writeElement(out, _doc.getDocumentElement(), 0);
}
/**
* Write the XML to a stream, using standard APIs. This appears to be about ten times slower than our custom writer
* ({@link #simpleFastWrite}).
*/
public void write(Writer out)
throws XmlModelWriterException, IOException
{
try
{
DOMSource domSource = new DOMSource(_doc);
StreamResult streamResult = new StreamResult(out);
TransformerFactory tf = TransformerFactory.newInstance();
tf.setAttribute("indent-number", new Integer(INDENT_LEN));
Transformer serializer = tf.newTransformer();
if (_publicID != null) {
serializer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, _publicID);
}
if (_systemID != null) {
serializer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, _systemID);
}
serializer.setOutputProperty(OutputKeys.INDENT, "yes");
serializer.transform(domSource, streamResult);
}
catch (TransformerException e)
{
throw new XmlModelWriterException(e);
}
}
public final Document getDocument()
{
return _doc;
}
public final Element getRootElement()
{
return _doc.getDocumentElement();
}
public final Element addElement(Element parent, String tagName) {
Element element = _doc.createElement(tagName);
parent.appendChild(element);
return element;
}
public final Element addElementWithText(Element parent, String tagName, String text) {
Element element = addElement(parent, tagName);
Text textNode = _doc.createTextNode(text);
element.appendChild(textNode);
return element;
}
public final void addComment(Element parent, String commentText) {
if (commentText != null) {
Comment comment = _doc.createComment(commentText);
parent.appendChild(comment);
}
}
private static void doIndent(Writer out, int indent)
throws IOException
{
for (int i = 0; i < indent; ++i) {
out.write(' ');
}
}
private static void writeElement(Writer out, Element element, int indent)
throws IOException
{
doIndent(out, indent);
out.write('<');
String tagName = element.getTagName();
out.write(tagName);
NamedNodeMap attrs = element.getAttributes();
for (int i = 0, len = attrs.getLength(); i < len; ++i) {
Node attr = attrs.item(i);
out.write(' ');
out.write(attr.getNodeName());
out.write("=\"");
filterValue(out, attr.getNodeValue(), true);
out.write('"');
}
String textContent = XmlElementSupport.getTextContent(element);
NodeList children = element.getChildNodes();
int childCount = children.getLength();
if (textContent != null) {
out.write('>');
filterValue(out, textContent, false);
out.write("</");
out.write(tagName);
out.write(">\n");
} else if (childCount > 0) {
out.write(">\n");
for (int i = 0; i < childCount; ++i) {
Node child = children.item(i);
if (child instanceof Comment) {
writeComment(out, (Comment) child, indent + INDENT_LEN);
} else if (child instanceof Text) {
assert XmlElementSupport.isWhiteSpace(child.getNodeValue()) : "expected only whitespace: " + child.getNodeValue();
} else {
assert child instanceof Element : child.getClass().getName();
writeElement(out, (Element) child, indent + INDENT_LEN);
}
}
doIndent(out, indent);
out.write("</");
out.write(tagName);
out.write(">\n");
}
else {
out.write("/>\n");
}
}
private static void writeComment(Writer out, Comment comment, int indent)
throws IOException
{
doIndent(out, indent);
out.write("<!--");
filterValue(out, comment.getNodeValue(), false);
out.write("-->\n");
}
private static void filterValue(Writer writer, String value, boolean filterQuote)
throws IOException {
for (int i = 0; i < value.length(); ++i) {
char c = value.charAt(i);
switch (c) {
case '<':
writer.write("<");
break;
case '>':
writer.write(">");
break;
case '&':
writer.write("&");
break;
default:
if (filterQuote && c == '"') {
writer.write(""");
} else {
writer.write(c);
}
}
}
}
}