Summary

Bio::OntologyIO::Handlers::BaseSAXHandler

Package variables

Inherit

Bio::Root::Root

Synopsis

No synopsis!

Description

This module is an abstract module, serving as the base of any SAX Handler
implementation. It tries to offer the framework that SAX handlers generally
need, such as tag_stack, char_store, etc.
In the implementation handler, you can take advantage of this based module by
the following suggestions.
1) In start_element,

 sub start_element {
     my $self=shift;
     my $tag=$_[0]->{Name};
     my %args=%{$_[0]->{Attributes}};
     # Your code here.

     # Before you conclude the method, write these 2 line.
     $self->_visited_count_inc($tag);
     $self->_push_tag($tag);
 }

2) In end_element,

 sub end_element {
     my $self=shift;
     my $tag=shift->{Name};
     # Your code here.

     # Before you conclude the method, write these 2 lines.
     $self->_visited_count_dec($tag);
     $self->_pop_tag;
 }

3) In characters, or any other methods where you may use the tag
stack or count

 sub characters {
     my $self=shift;
     my $text=shift->{Data};

     $self->_chars_hash->{$self->_top_tag} .= $text;

 }
 $count = $self->_visited_count('myTag');
 $tag = $self->_top_tag;

Methods

Methods description

  Title   : _tag_stack
  Usage   : @tags = $self->_tag_stack;
  Function: Get an array of tags that have been accessed but not enclosed.
  Return  : 
  Args    :

  Title   : _top_tag
  Usage   : $top = $self->_top_tag;
  Function: get the top tag in the tag stack.
  Return  : a tag name
  Args    : [none]

  Title   : _chars_hash
  Usage   : $hash= $self->_chars_hash;
  Function: return the character cache for the specific tag
  Return  : a hash reference, which is intent for character storage for tags
  Args    : [none]

  Title   : _vistied_count_inc
  Usage   : $self->vistied_count_inc($tag); # the counter for the tag increase
  Function: the counter for the tag increase
  Return  : the current count after this increment
  Args    : the tag name [scalar]

  Title   : _visited_count_dec
  Usage   : $self->_visited_count_dec($tag);
  Function: the counter for the tag decreases by one
  Return  : the current count for the specific tag after the decrement
  Args    : the tag name [scalar]

  Title   : _visited_count
  Usage   : $count = $self->_visited_count
  Function: return the counter for the tag
  Return  : the current counter for the specific tag
  Args    : the tag name [scalar]

Methods code

sub new {

    my ($class, @args) = @_;
    my $self=$class->SUPER::new(@args);
    $self->_initialize(@args);
    return $self;

}

sub _initialize {

    my $self = shift;
    $self->{_tag_stack} = [];
    $self->{_visited_count} = {};
    $self->{_chars_hash} = {};
    $self->{_current_hash} = {};

}

sub _tag_stack {

    return @{shift->{_tag_stack}};

}

sub _push_tag {

    my($self,$tag)=@_;
    push @{$self->{_tag_stack}}, $tag;

}

sub _pop_tag {

    my $self=shift;
    return pop @{$self->{_tag_stack}};

}

sub _top_tag {

    my $self = shift;
    my @stack=@{$self->{_tag_stack}};
    return $stack[-1];
# get the last element in an array while remaining it in. There are few  ways
# 1) $stack[-1]
# 2) $stack[$#stack]
# 3) $stack[@stack-1]

}

sub _chars_hash {

    return shift->{_chars_hash};

}

sub _current_hash {

    return  shift->{_current_hash};

}

sub _visited_count_inc {

    my ($self, $tag) = @_;
    my $visited_count=$self->{_visited_count};
    if(exists $visited_count->{$tag}){
        $visited_count->{$tag}++;
    }else{
        $visited_count->{$tag}=1;
    }
    return $visited_count->{$tag};

}

sub _visited_count_dec {

    my ($self, $tag) = @_;
    my $visited_count=$self->{_visited_count};
    if(exists $visited_count->{$tag}){
        $visited_count->{$tag}--;
    }else{
        $self->throw("'$tag' has not been visited yet. How to decrease it?!");
    }
    return $visited_count->{$tag};

}

sub _visited_count {

    my ($self, $tag) = @_;
    return $self->{_visited_count}->{$tag};

}

General documentation

Juguang Xiao, juguang@tll.org.sg

The rest of the documentation details each of the object methods.
Interal methods are usually preceded with a _