NAME

VOTABLE::DATA - VOTABLE DATA XML element class

SYNOPSIS

use VOTABLE::DATA;

DESCRIPTION

This class implements the DATA element from the VOTABLE DTD. This is a wrapper element around the BINARY, FITS, and TABLEDATA elements, and constitutes the data segment of a TABLE element.

The DATA element is a Tier 3 element, and is described by the following excerpt from the VOTABLE 1.0 DTD:

 <!ELEMENT DATA (TABLEDATA | BINARY | FITS)>

Methods

`new($xmldom_element, %options)`

Create and return a new VOTABLE::DATA object, based on the supplied XML::DOM::Element object, using %options to set the attributes of the new object. If no XML::DOM::Element object is specified, or is undefined, create and return an empty VOTABLE::DATA object. Return undef if an error occurs.

`get_binary`

Return the VOTABLE::BINARY object for the BINARY element which is the child of this DATA element. Return undef if no BINARY element is found, or an error occurs.

`set_binary($votable_binary)`

Set the BINARY element for this DATA element using the supplied VOTABLE::BINARY object. Any existing BINARY, FITS, or TABLEDATA element in this DATA element is replaced by the new BINARY element. Return the VOTABLE::BINARY object on success, or undef if an error occurs.

`get_fits`

Return the VOTABLE::FITS object for the FITS element which is the child of this DATA element. Return undef if no FITS element is found, or an error occurs.

`set_fits($votable_fits)`

Set the FITS element for this DATA element using the supplied VOTABLE::FITS object. Any existing BINARY, FITS, or TABLEDATA element in this DATA element is replaced by the new FITS element. Return the VOTABLE::FITS object on success, or undef if an error occurs.

`get_tabledata`

Return the VOTABLE::TABLEDATA object for the TABLEDATA element which is the child of this DATA element. Return undef if no TABLEDATA element is found, or an error occurs.

`set_tabledata($votable_tabledata)`

Set the TABLEDATA element for this DATA element using the supplied VOTABLE::TABLEDATA object. Any existing BINARY, FITS, or TABLEDATA element in this DATA element is replaced by the new TABLEDATA element. Return the VOTABLE::TABLEDATA object on success, or undef if an error occurs.

Notes on class internals

Method names that begin with a leading underscore ('_') are for internal use only, and should not be used outside of the VOTABLE class hierarchy.
The names of the 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.

WARNINGS

This code (perhaps unwisely) assumes that object internal structure is always maintained. For example, this code assumes that every VOTABLE::TABLEDATA 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.
Similarly, this code assumes that 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.
Most attribute 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.

AUTHOR

Eric Winter, NASA GSFC (elwinter@milkyway.gsfc.nasa.gov)

VERSION

$Id: DATA.pm,v 1.1.1.7 2002/05/21 14:08:54 elwinter Exp $