1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
#!/usr/bin/perl
use strict;
use warnings;
use Test::More;
use Test::Exception;
{
package Record;
use Moose;
has 'first_name' => (is => 'ro', isa => 'Str');
has 'last_name' => (is => 'ro', isa => 'Str');
package RecordSet;
use Moose;
has 'data' => (
is => 'ro',
isa => 'ArrayRef[Record]',
default => sub { [] },
);
has 'index' => (
is => 'rw',
isa => 'Int',
default => sub { 0 },
);
sub next {
my $self = shift;
my $i = $self->index;
$self->index($i + 1);
return $self->data->[$i];
}
package RecordSetIterator;
use Moose;
has 'record_set' => (
is => 'rw',
isa => 'RecordSet',
);
# list the fields you want to
# fetch from the current record
my @fields = Record->meta->get_attribute_list;
has 'current_record' => (
is => 'rw',
isa => 'Record',
lazy => 1,
default => sub {
my $self = shift;
$self->record_set->next() # grab the first one
},
trigger => sub {
my $self = shift;
# whenever this attribute is
# updated, it will clear all
# the fields for you.
$self->$_() for map { '_clear_' . $_ } @fields;
}
);
# define the attributes
# for all the fields.
for my $field (@fields) {
has $field => (
is => 'ro',
isa => 'Any',
lazy => 1,
default => sub {
my $self = shift;
# fetch the value from
# the current record
$self->current_record->$field();
},
# make sure they have a clearer ..
clearer => ('_clear_' . $field)
);
}
sub get_next_record {
my $self = shift;
$self->current_record($self->record_set->next());
}
}
my $rs = RecordSet->new(
data => [
Record->new(first_name => 'Bill', last_name => 'Smith'),
Record->new(first_name => 'Bob', last_name => 'Jones'),
Record->new(first_name => 'Jim', last_name => 'Johnson'),
]
);
isa_ok($rs, 'RecordSet');
my $rsi = RecordSetIterator->new(record_set => $rs);
isa_ok($rsi, 'RecordSetIterator');
is($rsi->first_name, 'Bill', '... got the right first name');
is($rsi->last_name, 'Smith', '... got the right last name');
$rsi->get_next_record;
is($rsi->first_name, 'Bob', '... got the right first name');
is($rsi->last_name, 'Jones', '... got the right last name');
$rsi->get_next_record;
is($rsi->first_name, 'Jim', '... got the right first name');
is($rsi->last_name, 'Johnson', '... got the right last name');
done_testing;
|
