/* Copyright 2002, 2003 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.benchmarks;
import java.io.IOException;
import java.text.DecimalFormat;
import nu.xom.Attribute;
import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.ParsingException;
/**
* <p>
* Simple memory benchmark focusing on a big document
* full of small elements or a user supplied document.
* </p>
*
*
* @author Elliotte Rusty Harold
* @version 1.0
*
*/
class MemoryTest {
public static Document makeFullUnicode() {
Element root = new Element("root");
Document doc = new Document(root);
for (int i = 0x20; i <= 0xD7FF; i++) {
Element data = new Element("d");
data.appendChild(((char) i) + "");
data.addAttribute(new Attribute("c", String.valueOf(i)));
root.appendChild(data);
}
// skip surrogates between 0xD800 and 0xDFFF
for (int i = 0xE000; i <= 0xFFFD; i++) {
Element data = new Element("d");
data.appendChild(((char) i) + "");
data.addAttribute(new Attribute("c", String.valueOf(i)));
root.appendChild(data);
}
System.gc();
// Plane-1 characters are tricky because Java
// strings encode them as surrogate pairs. First, fill
// a byte array with the characters from 1D100 to 1D1FF
// (the musical symbols)
for (int i = 0; i < 256; i++) {
// algorithm from RFC 2781
int u = 0x1D100 + i;
int uprime = u - 0x10000;
int W1 = 0xD800;
int W2 = 0xDC00;
W2 = W2 | (uprime & 0x7FF );
W1 = W1 | (uprime & 0xFF800);
Element data = new Element("d");
data.appendChild( ((char) W1) + "" + ((char) W2) );
data.addAttribute(new Attribute("c", String.valueOf(u)));
root.appendChild(data);
}
return doc;
}
public static void main(String[] args)
throws IOException, ParsingException {
DecimalFormat format = new DecimalFormat();
format.setMaximumFractionDigits(2);
Runtime r = Runtime.getRuntime();
System.gc(); System.gc(); System.gc();
long before = r.totalMemory() - r.freeMemory();
Document doc;
if (args.length > 0) {
Builder builder = new Builder();
doc = builder.build(args[0]);
builder = null;
}
else {
doc = makeFullUnicode();
}
long after = r.totalMemory() - r.freeMemory();
double usage = (after - before)/(1024.0*1024.0);
System.out.println("Memory used: "
+ format.format(usage) + "M");
System.gc(); System.gc(); System.gc();
long postGC = r.totalMemory() - r.freeMemory();
usage = (postGC - before)/(1024.0*1024.0);
System.out.println("Memory used after garbage collection: "
+ format.format(usage) + "M");
// Make sure the document isn't prematurely garbage collected
System.out.println("Meaningless number: "
+ doc.toXML().length());
}
}
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