ch15.003_prob_ex15.1

Perl Best Practices the source code

##############################################################################
## Example 15.1 (NOT RECOMMENDED) from Chapter 15 of "Perl Best Practices"  ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


#  Example 15-1. Typical hash-based Perl classes


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;


package File::Hierarchy;
 
 
# Objects of this class have the following attributes...
#     'root'   - The root directory of the file hierarchy
#     'files'  - An array storing an object for each file in the root directory
 
# Constructor takes path of file system root directory...
sub new {
    my ($class, $root) = @_;
 
    # Bless a hash to instantiate the new object...
    my $new_object = bless {}, $class;
 
    # Initialize the object's "root" attribute...
    $new_object->{root} = $root;
 
    return $new_object;
}
 
# Retrieve files from root directory...
sub get_files {
    my ($self) = @_;
 
    # Load up the "files" attribute, if necessary...
    if (!exists $self->{files}) {
        $self->{files} 
            = File::System->list_files($self->{root});
    }
 
    # Flatten the "files" attribute's array to produce a file list...
    return @{$self->{files}};
}
 
 
package File::Hierarchy::File;
 
 
# Objects of this class have the following attributes...
#     'name' - the name of the file
 
# Constructor takes name of file...
sub new {
    my ($class, $filename) = @_;
 
    # Bless a hash to instantiate the new object...
    my $new_object = bless {}, $class;
 
    # Initialize the object's "name" attribute...
    $new_object->{name} = $filename;
 
    return $new_object;
}
 
# Retrieve name of file...
sub get_name {
    my ($self) = @_;
 
    return $self->{name};
}