package Edge;
use strict;

sub new {
    my ($class, %params) = @_;
    bless {
 	'_strength' => $params{'strength'} || 1,
	'_length'   => $params{'length'}   || 1,
	'_vertex_1' => $params{'vertex_1'} || 0,
	'_vertex_2' => $params{'vertex_2'} || 0,
	'_label'    => $params{'label'}    || '',
    }, $class;
} # new

sub print_edge {
    print 'label='   , $_[0]->{'_label'}   , "\n";
    print 'strength=', $_[0]->{'_strength'}, "\n";
    print 'length='  , $_[0]->{'_length'}  , "\n";
    print 'vertex_1=', $_[0]->{'_vertex_1'}->query_label(), "\n";
    print 'vertex_2=', $_[0]->{'_vertex_2'}->query_label(), "\n";

} # print_edge

# ------------------------------------------------------------------
# Set functions.

sub set_strength {
    $_[0]->{_strength} = $_[1] if defined($_[1]);
} # set_strength

sub set_length {
    $_[0]->{_length} = $_[1] if defined($_[1]);
} # set_length

sub set_label {
    $_[0]->{_label} = $_[1] if defined($_[1]);
} # set_label

sub set_vertex_1 {
    $_[0]->{_vertex_1} = $_[1] if defined($_[1]);
} # set_vertex_1

sub set_vertex_2 {
    $_[0]->{_vertex_2} = $_[1] if defined($_[1]);
} # set_vertex_2

sub set_verteces {
    $_[0]->{_vertex_1} = $_[1] if defined($_[1]);
    $_[0]->{_vertex_2} = $_[2] if defined($_[2]);
} # set_verteces

# ------------------------------------------------------------------
# Query functions.

sub query_strength {
    $_[0]->{_strength};
} # query_strength

sub query_length {
    $_[0]->{_length};
} # query_length

sub query_label {
    $_[0]->{_label};
} # query_label

sub query_vertex_1 {
    $_[0]->{_vertex_1};
} # query_vertex_1

sub query_vertex_2 {
    $_[0]->{_vertex_2};
} # query_vertex_2

sub query_verteces {
    ( $_[0]->{_vertex_1}, $_[0]->{_vertex_2} );
} # query_verteces

1;