VOTABLE::DESCRIPTION - VOTABLE DESCRIPTION XML element class
use VOTABLE::DESCRIPTION;
This class implements the DESCRIPTION
element from the VOTABLE
DTD. This element is used to store a textual description of its parent
element.
The DESCRIPTION
element is a Tier 0 element, and is described by
the following excerpt from the VOTABLE
1.0 DTD:
<!ELEMENT DESCRIPTION (#PCDATA)>
=head2 Methods
new($str_or_ref, %options)
Create a new VOTABLE::DESCRIPTION
object, and return a reference to
it. If the first argument ($str_or_ref
) is a string, it is used as
the initial PCDATA
content of the DESCRIPTION
element. If the
first argument is a reference to a XML::DOM::Element
object, that
object is used to initialize the new DESCRIPTION
element
(implicitly assuming that the XML::DOM::Element
object contains a
valid DESCRIPTION
element). The %options
hash is used to set the
attributes of the new element. If the first argument is missing or
undefined, or an empty string, create and return an empty
VOTABLE::DESCRIPTION
object. Return undef
if an error occurs.
get
Return a string containing the PCDATA
content of the DESCRIPTION
element. Return undef
if the element has no PCDATA
content, or
an error occurs.
set($str)
Set the PCDATA
content of the DESCRIPTION
element to the
specified string. Return the string on success, or undef
if an
error occurs.
_
') are for
internal use only, and should not be used outside of the VOTABLE
class hierarchy.
get_XXX
and set_XXX
accessors for attributes
and elements are derived directly from the names of the attributes or
elements. Attribute and element names containing embedded hyphens
('-
') use accessors where the hyphen is mapped to an underscore
('_
') in the name of the accessor method. This is a necessity,
since the hyphen is not a valid name character in Perl.
VOTABLE::DESCRIPTION
object always has an underlying
XML::DOM::Element
object. As long as the internal structure is
manipulated only by the publicly-available methods, this should be an
adequate assumption. If a method detects an aberrant case, a warning
message is printed (using the Carp::carp
subroutine), and the
method fails.
XML::DOM
methods always
succeed. If a method detects an aberrant case, a warning message is
printed (using the Carp::carp
subroutine), and the method fails.
set_XXX
accessors do not perform validation of the
new attribute values. The exceptions are the accessors for attributes
with enumerated values; the new value is checked against the list of
acceptable values, as defined in the DTD.
VOTABLE
, VOTABLE::Document
, VOTABLE::FIELD
,
VOTABLE::PARAM
, VOTABLE::RESOURCE
, VOTABLE::TABLE
Eric Winter, NASA GSFC (elwinter@milkyway.gsfc.nasa.gov)
$Id: DESCRIPTION.pm,v 1.1.1.9 2002/05/21 14:09:37 elwinter Exp $