Similar to SAX2's Locator interface.
An application can implement this interface and
then register it with the setLocator() method to
find out in which line and column and file a given
node appears.
Java binding:
package org.w3c.dom;
public interface DOMLocator {
public int getLineNumber();
public int getColumnNumber();
public int getByteOffset();
public int getUtfOffset();
public Node getRelatedNode();
public String getUri();
}