/* Copyright 2002-2004 Elliotte Rusty Harold
This library is free software; you can redistribute it and/or modify
it under the terms of version 2.1 of the GNU Lesser General Public
License as published by the Free Software Foundation.
This library 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 library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330,
Boston, MA 02111-1307 USA
You can contact Elliotte Rusty Harold by sending e-mail to
[email protected]. Please include the word "XOM" in the
subject line. The XOM home page is located at http://www.xom.nu/
*/
package nu.xom.samples;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import nu.xom.Attribute;
import nu.xom.Builder;
import nu.xom.Element;
import nu.xom.NodeFactory;
import nu.xom.Nodes;
import nu.xom.ParsingException;
/**
* <p>
* Demonstrates extracting the content of particular named elements
* from one XML document, and storing them into new files.
* The names of these files are based on an attribute of the
* original element.
* </p>
*
* @author Elliotte Rusty Harold
* @version 1.0
*
*/
public class StreamingExampleExtractor extends NodeFactory {
private int chapter = 0;
private boolean inExample = false;
private Nodes empty = new Nodes();
// We don't need the comments.
public Nodes makeComment(String data) {
return empty;
}
// We need text nodes only inside examples
public Nodes makeText(String data) {
if (inExample) return super.makeText(data);
return empty;
}
public Element makeRootElement(String name, String namespace) {
if ("example".equals(name)) {
inExample = true;
}
if ("chapter".equals(name)) {
chapter++;
}
return super.startMakingElement(name, namespace);
}
public Element startMakingElement(String name, String namespace) {
if ("example".equals(name)) {
inExample = true;
}
if ("chapter".equals(name)) {
chapter++;
}
if (inExample) return super.startMakingElement(name, namespace);
else return null;
}
public Nodes finishMakingElement(Element element) {
if (element.getQualifiedName().equals("example")) {
try {
extractExample(element, chapter);
}
catch (IOException ex) {
System.err.println(
"Problem writing " + element.getAttributeValue("id")
+ " in chapter " + chapter
);
}
inExample = false;
}
return new Nodes(element);
}
public Nodes makeAttribute(String name, String URI,
String value, Attribute.Type type) {
if (inExample && name.equals("id")) {
return super.makeAttribute(name, URI, value, type);
}
return empty;
}
public Nodes makeDocType(String rootElementName,
String publicID, String systemID) {
return empty;
}
public Nodes makeProcessingInstruction(
String target, String data) {
return empty;
}
private static void extractExample(Element example, int chapter)
throws IOException {
String fileName = example.getAttribute("id").getValue();
System.out.println(fileName);
Element programlisting
= example.getFirstChildElement("programlisting");
// A few examples use screens instead of programlistings
if (programlisting == null) {
programlisting = example.getFirstChildElement("screen");
}
// If it's still null, skip it
if (programlisting == null) return;
String code = programlisting.getValue();
// write code into a file
File dir = new File("examples2/" + chapter);
dir.mkdirs();
File file = new File(dir, fileName);
System.out.println(file);
FileOutputStream fout = new FileOutputStream(file);
try {
Writer out = new OutputStreamWriter(fout, "UTF-8");
// Buffering almost always helps performance a lot
out = new BufferedWriter(out);
out.write(code);
// Be sure to flush and close your streams
out.flush();
}
finally {
fout.close();
}
}
public static void main(String[] args) {
if (args.length <= 0) {
System.out.println(
"Usage: java nu.xom.samples.StreamingExampleExtractor URL");
return;
}
String url = args[0];
try {
Builder builder = new Builder(new StreamingExampleExtractor());
// Read the document
builder.build(args[0]);
}
catch (ParsingException ex) {
System.out.println(ex);
}
catch (IOException ex) {
System.out.println(
"Due to an IOException, the parser could not read " + url
);
System.out.println(ex);
}
} // end main
}
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