NAME

RDF::Redland::Node - Redland RDF Node (RDF Resource, Property, Literal) Class

SYNOPSIS

use RDF::Redland;
my $node1=new RDF::Redland::Node("Hello, World!");
my $node2=new RDF::Redland::Node($uri);
my $node3=$node2->clone;

my $node4=RDF::Redland::Node->new_from_uri("http://example.com/");
my $node5=RDF::Redland::Node->new_literal("Hello, World!");
my $node6=RDF::Redland::Node->new_xml_literal("<tag>content</tag>");
my $node7=RDF::Redland::Node->new_from_blank_identifier("genid1");
...

print $node4->uri->as_string,"\n";  # Using RDF::Redland::URI::as_string
print $node5->literal_value_as_latin1,"\n";

DESCRIPTION

This class represents RDF URIs, literals and blank nodes in the RDF graph.

CONSTRUCTORS

new [STRING | URI | NODE]

Create a new URI node, literal node or copy an existing node.

If a literal STRING is given, make a plain literal node. If a URI class (perl URI or RDF::Redland::URI), make a resource node. Otherwise if an existing (RDF::Redland::Node) NODE is given, copy the existing node.

new_from_uri URI

Create a new URI node. URI can be either a RDF::Redland::URI object, a perl URI class or a literal string.

new_literal STRING [DATATYPE [XML_LANGUAGE]]

Create a new literal node for a literal value STRING. Optional datatype URI DATATYPE (RDF::Redland::URI, perl URI or string) and language (xml:lang attribute) XML_LANGUAGE may also be given.

new_xml_literal STRING

Create a new XML datatyped literal node for the XML in STRING.

new_from_blank_identifier IDENTIFIER

Create a new blank node with blank node identifier IDENTIFIER.

clone

Copy a RDF::Redland::Node.

METHODS

uri

Get the current URI of the node as an RDF::Redland::URI object.

blank_identifier

Get the current blank identifier of the node

type

Get the node type. It is recommended to use the is_resource, is_literal or is_blank methods in preference to this (both simpler and quicker).

The current list of types that are supported are:

$RDF::Redland::Node::Type_Resource
$RDF::Redland::Node::Type_Literal
$RDF::Redland::Node::Type_Blank

Example:

if ($node->type == $RDF::Redland::Node::Type_Resource) {
  print "Node is a resource with URI ", $node->uri->as_string, "\n";
} else {
  ...
}

is_resource

Return true if node is a resource (with a URI)

is_literal

Return true if node is a literal

is_blank

Return true if node is a blank nodeID

literal_value

Get the node literal value string as UTF-8 (when the node is of type $RDF::Redland::Node::Type_Literal)

literal_value_as_latin1

Get the node literal value string converted from UTF-8 to ISO Latin-1 (when the node is of type $RDF::Redland::Node::Type_Literal)

literal_value_language

Get the node literal XML language (when the node is of type $RDF::Redland::Node::Type_Literal) or undef if not present.

literal_value_is_wf_xml

Return non 0 if the literal string is well formed XML (when the node is of type $RDF::Redland::Node::Type_Literal).

literal_datatype

Return the RDF::Redland::URI of the literal datatype or undef if it is not a datatype.

as_string

Return the RDF::Redland::Node formatted as a string (UTF-8 encoded).

equals NODE

Return non zero if this node is equal to NODE

OLDER METHODS

new_from_literal STRING XML_LANGUAGE IS_WF

Create a new RDF::Redland::Node object for a literal value STRING with XML language (xml:lang attribute) XML_LANGUAGE and if content is well formed XML, when IS_WF is non 0. XML_LANGUAGE is optional can can be set to undef.

This method remains but using new_literal is prefered. For plain literals $node=new RDF::Redland::Node("blah") is simplest.

new_from_typed_literal STRING [DATATYPE [XML_LANGUAGE]]

Renamed to new_literal with same arguments.

new_from_uri_string URI_STRING

Create a new RDF::Redland::Node object for a resource with URI URI_STRING. It is equivalent to use the shorter $a=new RDF::Redland::Node->new_from_uri($uri_string)

new_from_node NODE

Create a new RDF::Redland::Node object from existing RDF::Redland::Node NODE (copy constructor). It is equivalent to use $new_node=$old_node->clone

SEE ALSO

RDF::Redland::Statement

AUTHOR

Dave Beckett - http://purl.org/net/dajobe/