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package GenericGraph;
use strict;
use warnings;
use Carp;
sub new {
my $packagename = shift;
my $self = {
_nodes => {}, # node_name => node_reference
_edge_counter => {}, # prev_node -> after_node = count
};
bless ($self, $packagename);
return($self);
}
sub get_or_create_node {
my $self = shift;
my $node_name = shift;
if ($self->node_exists($node_name)) {
return($self->get_node($node_name));
}
else {
# instantiate it, add it to the graph
return($self->create_node($node_name));
}
}
sub node_exists {
my $self = shift;
my $node_name = shift;
unless ($node_name =~ /\w/) {
confess "Error, node_name required";
}
if (exists $self->{_nodes}->{$node_name}) {
return(1);
}
else {
return(0);
}
}
sub get_node {
my $self = shift;
my $node_name = shift;
if (! $self->node_exists($node_name)) {
confess "Error, $node_name doesn't exist in graph";
}
my $node = $self->{_nodes}->{$node_name};
return($node);
}
sub get_all_nodes {
my $self = shift;
return(values %{$self->{_nodes}});
}
sub create_node {
my $self = shift;
my $node_name = shift;
if ($self->node_exists($node_name)) {
confess "Error, node $node_name already exists in the graph";
}
my $node = new GenericNode($node_name);
$self->{_nodes}->{$node_name} = $node;
return($node);
}
sub link_adjacent_nodes {
my $self = shift;
my ($before_node, $after_node, $edge_increment) = @_;
unless (ref $before_node && ref $after_node) {
confess "Error, need both before and after nodes for linking";
}
$before_node->add_next_node($after_node);
$after_node->add_prev_node($before_node);
if (defined($edge_increment)) {
if ($edge_increment =~ /^\d+/ && $edge_increment > 0) {
$self->{_edge_counter}->{$before_node}->{$after_node} += $edge_increment;
}
}
else {
$self->{_edge_counter}->{$before_node}->{$after_node}++;
}
return;
}
sub get_edge_count {
my $self = shift;
my ($prev_node, $next_node) = @_;
my $edge_count = $self->{_edge_counter}->{$prev_node}->{$next_node} || 0;
return($edge_count);
}
####
sub prune_nodes_from_graph {
my $self = shift;
my @nodes = @_;
my $graph_nodes_href = $self->{_nodes};
foreach my $node (@nodes) {
delete ($self->{_edge_counter}->{$node}); # remove edge counts starting at current node.
my $node_name = $node->get_value();
delete $graph_nodes_href->{$node_name};
my @next_nodes = $node->get_all_next_nodes();
my @prev_nodes = $node->get_all_prev_nodes();
foreach my $prev_node (@prev_nodes) {
$prev_node->delete_next_node($node);
$node->delete_prev_node($prev_node);
delete ($self->{_edge_counter}->{$prev_node}->{$node}); # remove edge counts for prev nodes linking to current node.
}
foreach my $next_node (@next_nodes) {
$next_node->delete_prev_node($node);
$node->delete_next_node($next_node);
}
}
return;
}
####
sub prune_edge {
my $self = shift;
my ($prev_node, $node) = @_;
# Sever connection between nodes.
$prev_node->delete_next_node($node);
$node->delete_prev_node($prev_node);
delete ($self->{_edge_counter}->{$prev_node}->{$node});
return;
}
####
sub print_path {
my @nodes = @_;
my $counter = 0;
foreach my $node (@nodes) {
$counter++;
printf("%4s", $counter);
print " " . $node->get_value() . "\n";
}
print "\n";
return;
}
####
sub toString {
my $self = shift;
my @nodes = $self->get_all_nodes();
my $text = "";
foreach my $node (@nodes) {
$text .= $node->toString() . "\n";
}
return($text);
}
####
sub get_root_nodes {
my $self = shift;
my @roots;
foreach my $node ($self->get_all_nodes()) {
unless ($node->get_all_prev_nodes()) {
push (@roots, $node);
}
}
return(@roots);
}
1; #EOM
|
