XML in a Nutshell, 3rd Edition

Name

The Locator Interface

Synopsis

Unlike most other interfaces in the org.xml.sax package, the Locator interface does not have to be implemented. Instead, the parser has the option to provide an implementation. If it does so, it passes its implementation to the setDocumentLocator( ) method in the ContentHandler instance before it calls startDocument( ). You can save a reference to this object in a field in your ContentHandler class, like this:

private Locator locator;
     
public void setDocumentLocator(Locator locator) {
  this.locator = locator;
}

Once you’ve found the locator, you can then use it inside any other ContentHandler method, such as startElement( ) or characters( ), to determine in exactly which document and at which line and column the event took place. For instance, the locator allows you to determine that a particular start-tag began on the third column of the document’s seventeenth line at the URL http://www.slashdot.org/slashdot.xml:

package org.xml.sax;
     
public interface Locator {
     
  public String getPublicId(  );
  public String getSystemId(  );
  public int    getLineNumber(  );
  public int    getColumnNumber(  );
     
}