Re: what is the bettter/performant way to compare org.w3c.dom.DocumentFragment
On 1/17/2012 6:38 PM, Arne Vajh?j wrote:
On 1/17/2012 10:03 AM, Mausam wrote:
I have a java class, whose contains a DocumentFragment.
In the equals method of my class, I am converting the DocumentFragment
to a String and comparing an equals on the String.
I know this is not the best way, because "attributes" e.g can change
order in Element of DocumentFragment, or e.g documents differ only in
the sequence of unordered elements.
So in such cases this equality will fail.
I think XML Canonicalization will solve the problem.
It comes as a cost though.
Example:
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.xml.security.Init;
import org.apache.xml.security.c14n.CanonicalizationException;
import org.apache.xml.security.c14n.Canonicalizer;
import org.apache.xml.security.c14n.InvalidCanonicalizerException;
import org.xml.sax.SAXException;
public class XmlComp {
static {
Init.init();
}
private static String canonicalize(String s) throws
InvalidCanonicalizerException, UnsupportedEncodingException,
CanonicalizationException, ParserConfigurationException, IOException,
SAXException {
Canonicalizer c14n =
Canonicalizer.getInstance(Canonicalizer.ALGO_ID_C14N_OMIT_COMMENTS);
String res = new
String(c14n.canonicalize(s.getBytes(Canonicalizer.ENCODING)),
Canonicalizer.ENCODING);
return res;
}
public static void main(String[] args) throws Exception {
String s1 = "<a><b c='1' d='2'/></a>";
String s2 = "<a><b d='2' c='1'/></a>";
System.out.println(s1);
System.out.println(s2);
System.out.println(canonicalize(s1));
System.out.println(canonicalize(s2));
}
}
outputs:
<a><b c='1' d='2'/></a>
<a><b d='2' c='1'/></a>
<a><b c="1" d="2"></b></a>
<a><b c="1" d="2"></b></a>
Arne