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Compact.pm
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Compact.pm
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package Hash::Compact;
use 5.008001;
use strict;
use warnings;
use Carp qw(croak);
use Scalar::Util qw(blessed);
our $VERSION = '0.04';
sub new {
my $class = shift;
my $options = @_ > 1 && (ref $_[-1] || '') eq 'HASH' ? pop : {};
my $self = bless { __HASH_COMPACT_OPTIONS__ => $options }, $class;
my $args = shift || {};
croak '$args must be a hash-ref'
if (ref $args || '') ne 'HASH';
while (my ($key, $value) = each %$args) {
$self->param($key, $value);
}
$self;
}
sub options { $_[0]->{__HASH_COMPACT_OPTIONS__} }
sub param {
my $self = shift;
my $value;
if (@_ > 1) {
croak 'incorrect key/value pair'
if @_ % 2;
my %args = @_;
while (my ($key, $value) = each %args) {
my $option = $self->options->{$key} || {};
$key = $option->{alias_for} || $key;
if (defined $value && !ref $value && $value eq ($option->{default} || '')) {
delete $self->{$key};
}
else {
$self->{$key} = $value;
}
}
}
else {
my $key = shift;
my $option = $self->options->{$key} || {};
$value = $self->{$option->{alias_for} || $key} || $option->{default};
}
$value;
}
sub to_hash {
my $self = shift;
+{
map {
my $value = $self->{$_};
if (blessed $value && $value->can('to_hash')) {
$_ => $value->to_hash;
}
else {
$_ => $value;
}
}
grep { $_ ne '__HASH_COMPACT_OPTIONS__' } keys %$self
}
}
1;
__END__
=encoding utf8
=head1 NAME
Hash::Compact - A hash-based object implementation with key alias and
default value support
=head1 SYNOPSIS
package My::Memcached;
use strict;
use warnings;
use parent qw(Cache::Memcached::Fast);
use JSON;
use Hash::Compact;
my $OPTIONS = {
foo => {
alias_for => 'f',
},
bar => {
alias_for => 'b',
default => 'bar',
},
};
sub get {
my ($self, $key) = @_;
my $value = $self->SUPER::get($key);
Hash::Compact->new(decode_json $value, $OPTIONS);
}
sub set {
my ($self, $key, $value, $expire) = @_;
my $hash = Hash::Compact->new($value, $OPTIONS);
$self->SUPER::set($key, encode_json $hash->to_hash, $expire);
}
package main;
use strict;
use warnings;
use Test::More;
my $key = 'key';
my $value = { foo => 'foo' };
my $memd = My::Memcached->new({servers => [qw(localhost:11211)]});
$memd->set($key, $value);
my $cached_value = $memd->get($key);
is $cached_value->param('foo'), 'foo';
is $cached_value->param('bar'), 'bar';
is_deeply $cached_value->to_hash, +{ f => 'foo' };
$cached_value->param(bar => 'baz');
$memd->set($key, $cached_value->to_hash);
$cached_value = $memd->get($key);
is $cached_value->param('foo'), 'foo';
is $cached_value->param('bar'), 'baz';
is_deeply $cached_value->to_hash, +{ f => 'foo', b => 'baz' };
done_testing;
=head1 DESCRIPTION
When we store some structured value into a column of a relational
database or some key/value storage, redundancy of long key names can
be a problem for storage space.
This module is yet another hash-based object implementation which aims
to be aware of both space efficiency and easiness to use for us.
=head1 METHODS
=head2 new (I<\%hash> I<[, \%options]>)
my $hash = Hash::Compact->new({
foo => 'foo',
}, {
foo => {
alias_for => 'f',
},
bar => {
alias_for => 'b',
default => 'bar',
},
},
);
Creates and returns a new Hash::Compact object. If C<\%options> not
passed, Hash::Compact object C<$hash> will be just a plain hash-based
object.
C<\%options> is a hash-ref which key/value pairs are associated with
ones of C<\%hash>. It may contain the fields below:
=over 4
=item * alias_for
Alias to an actual key. If it's passed, C<\%hash> will be compacted
into another hash which has aliased key. The original key of C<\%hash>
will be just an alias to an actual key.
=item * default
If this exists and the value associated with the key of C<\%hash> is
undefined, Hash::Compact object C<$hash> returns just the value. It's
for space efficiency; C<$hash> doesn't need to have key/value pair
when the value isn't defined or it's same as default value.
=back
=head2 param (I<$key> I<[, $value]>)
$hash->param('foo'); #=> 'foo'
$hash->param('bar'); #=> 'bar' (returns the default value)
$hash->param(bar => 'baz');
$hash->param('bar'); #=> 'baz'
Setter/getter method.
=head2 to_hash ()
my $compact_hash_ref = $hash->to_hash;
#=> { f => 'foo', b => 'baz' } (returns a compacted hash)
Returns a compacted hash according to C<\%options> passed into the
constructor above;
=head1 AUTHOR
Kentaro Kuribayashi E<lt>kentarok@gmail.comE<gt>
=head1 SEE ALSO
=head1 LICENSE
Copyright (C) Kentaro Kuribayashi
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut