code: @Override
  	protected boolean isContentType(String schemaId, String schemaVersion, String systemId, String publicId) {
  		return (this.publicId != null && this.publicId.equalsIgnoreCase(publicId))
  				|| (this.systemId != null && this.systemId.equalsIgnoreCase(systemId));
  	}
docs: Replies if the specified stream contains data
  that corresponds to this magic number.
  
  @param schemaId is the ID of the XSL schema associated to this magic number.
  @param schemaVersion is the ID of the XSL schema associated to this magic number.
  @param systemId is the DTD system ID associated to this magic number.
  @param publicId is the DTD system ID associated to this magic number.
  @return <code>true</code> if this magic number is corresponding to the given
  XML document, otherwise <code>false</code>.