new($str_or_ref, %options)
get_ID
set_ID($id)
get_action
set_action($action)
get_content_role
set_content_role($content_role)
get_content_type
set_content_type($content_type)
get_gref
set_gref($gref)
get_href
set_href($href)
get_title
set_title($title)
get_value
set_value($value)
get
set($str)
VOTABLE::LINK - VOTABLE LINK XML element class
use VOTABLE::LINK;
This class implements the LINK
element from the VOTABLE
DTD. This element is used to store traditional HTTP
hyperlinks to
supporting information (using the href
attribute), or a more
general-purpose link (using the gref
attribute).
The LINK
element is a Tier 0 element, and is described by the
following excerpt from the VOTABLE
1.0 DTD:
<!ELEMENT LINK (#PCDATA)> <!ATTLIST LINK ID ID #IMPLIED content-role (query | hints | doc) #IMPLIED content-type CDATA #IMPLIED title CDATA #IMPLIED value CDATA #IMPLIED href CDATA #IMPLIED gref CDATA #IMPLIED action CDATA #IMPLIED >
new($str_or_ref, %options)
Create a new VOTABLE::LINK
object, and return a reference to it. If
the first argument ($str_or_ref
) is a string, it is used as the
initial #PCDATA
content of the LINK
element. If the first
argument is a reference to a XML::DOM::Element
object, that object
is used to initialize the new LINK
element (implicitly assuming
that the XML::DOM::Element
object contains a valid LINK
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::LINK
object. Return undef
if an error occurs.
get_ID
Return the value of the ID
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_ID($id)
Set the value of the ID
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_action
Return the value of the action
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_action($action)
Set the value of the action
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_content_role
Return the value of the content-role attribute
. Return undef
if
the attribute has not been set, or an error occurs.
set_content_role($content_role)
Set the value of the content-role
attribute to the specified
value. Use undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_content_type
Return the value of the content-type
attribute. Return undef
if
the attribute has not been set, or an error occurs.
set_content_type($content_type)
Set the value of the content-type
attribute to the specified
value. Use undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_gref
Return the value of the gref
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_gref($gref)
Set the value of the gref
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_href
Return the value of the href
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_href($href)
Set the value of the href
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_title
Return the value of the title
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_title($title)
Set the value of the title
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get_value
Return the value of the value
attribute. Return undef
if the
attribute has not been set, or an error occurs.
set_value($value)
Set the value of the value
attribute to the specified value. Use
undef
as the argument to clear any existing value of the
attribute. Return the new value of the attribute on success, or
undef
if an error occurs.
get
Return a string containing the #PCDATA
content of the LINK
element. Return undef
if the element has no #PCDATA
content, or
an error occurs.
set($str)
Set the #PCDATA
content of the LINK
element to the specified
string. Use undef
as the argument to clear any existing value of
the text. 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, with the attribute or element name replacing
XXX
. 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
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 safe 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::FIELD
, VOTABLE::PARAM
,
VOTABLE::RESOURCE
, VOTABLE::TABLE
Eric Winter, NASA GSFC (elwinter@milkyway.gsfc.nasa.gov)
$Id: LINK.pm,v 1.1.1.9 2002/06/09 21:13:08 elwinter Exp $