File Coverage

blib/lib/Algorithm/Dependency/Source.pm

Criterion	Covered	Total	%
statement	44	51	86.3
branch	11	20	55.0
condition	7	15	46.7
subroutine	10	11	90.9
pod	5	5	100.0
total	77	102	75.5

line	stmt	bran	cond	sub	pod	time	code
1							package Algorithm::Dependency::Source;
2
3							=pod
4
5							=head1 NAME
6
7							Algorithm::Dependency::Source - Implements a source of heirachy items
8
9							=head1 DESCRIPTION
10
11							The Algorithm::Dependency::Source class provides an abstract parent class for
12							implementing sources for the heirachy data the algorithm will use. For an
13							example of an implementation of this, see
14							L<Algorithm::Dependency::Source::File>, which is bundled with the main
15							L<Algorithm::Dependency> package.
16
17							=head1 METHODS
18
19							=cut
20
21	8			8		109	use strict;
	8					100
	8					121
22	8			8		185	use Algorithm::Dependency ();
	8					75
	8					76
23	8			8		362	use Params::Util qw{_SET};
	8					211
	8					266
24
25	8			8		176	use vars qw{$VERSION};
	8					73
	8					112
26							BEGIN {
27	8			8		148	$VERSION = '1.102';
28							}
29
30
31
32
33
34							#####################################################################
35							# Constructor
36
37							=pod
38
39							=head2 new @arguments
40
41							Although you cannot directly use the C<new> constructor for
42							C<Algorithm::Dependency::Source>, it will work the same in all subclasses.
43
44							The constructor takes zero or more subclass specific arguments to define the
45							location of the source of the items, and returns a new object. Alrough it
46							may check that the arguments you passed are valid, the source will usually
47							NOT actually load the items from the source, instead defering the loading
48							until you need to use the items.
49
50							Returns a new object on success, or C<undef> on error.
51
52							=cut
53
54							sub new {
55	10			10	1	130	my $class = shift;
56
57							# This can't be created directly, it must be through
58							# a SUPER::new call
59	10	50				114	if ( $class eq __PACKAGE__ ) {
60	0					0	die "Cannot directly instantiate Algorithm::Dependency::Source."
61							. " You must use a subclass";
62							}
63
64							# Create the basic object
65	10					150	my $self = bless {
66							# Has the source been loaded
67							loaded => 0,
68
69							# Indexes
70							items_hash => undef,
71							items_array => undef,
72							}, $class;
73
74	10					141	$self;
75							}
76
77							=pod
78
79							=head2 load
80
81							The C<load> method is the public method used to actually load the items from
82							their storage location into the the source object. The method will
83							automatically called, as needed, in most circumstances. You would generally
84							only want to use C<load> manually if you think there may be some uncertainty
85							that the source will load correctly, and want to check it will work.
86
87							Returns true if the items are loaded successfully, or C<undef> on error.
88
89							=cut
90
91							sub load {
92	10			10	1	97	my $self = shift;
93
94							# If this is a reload, clean up in preperation
95	10	50				147	if ( $self->{loaded} ) {
96	0					0	$self->{loaded} = 0;
97	0					0	$self->{items_hash} = undef;
98	0					0	$self->{items_array} = undef;
99							}
100
101							# Pass through to the real loader
102	10					188	my $items = $self->_load_item_list;
103	10	50				181	return $items unless $items;
104	10	50				170	unless ( _SET($items, 'Algorithm::Dependency::Item') ) {
105	0					0	die( ref($self) . "::_load_item_list did not return an Algorithm::Dependency::Item set" );
106							}
107
108							# Add the items
109	10					1133	foreach my $item ( @$items ) {
110							# Have we added this one already?
111	100					2095	my $id = $item->id;
112	100	50				1123	if ( $self->{items_hash}->{ $id } ) {
113							# Duplicate entry
114	0					0	return undef;
115							}
116
117							# Add it
118	100					2907	push @{ $self->{items_array} }, $item;
	100					1088
119	100					1293	$self->{items_hash}->{$id} = $item;
120							}
121
122	10					195	$self->{loaded} = 1;
123							}
124
125							=pod
126
127							=head2 item $name
128
129							The C<item> method fetches and returns the item object specified by the
130							name argument.
131
132							Returns an L<Algorithm::Dependency::Item> object on success, or C<undef> if
133							the named item does not exist in the source.
134
135							=cut
136
137							sub item {
138	1037			1037	1	14514	my $self = shift;
139	1037	50	33			20620	my $id = (defined $_[0] and ! ref $_[0] and $_[0] ne '') ? shift : return undef;
			33
140	1037	50	33			19760	$self->{loaded} or $self->load or return undef;
141
142							# Return the item (or undef)
143	1037					19570	$self->{items_hash}->{$id};
144							}
145
146							=pod
147
148							=head2 items
149
150							The C<items> method returns, as a list of objects, all of the items
151							contained in the source. The item objects will be returned in the same order
152							as that in the storage location.
153
154							Returns a list of L<Algorithm::Dependency::Item> objects on success, or
155							C<undef> on error.
156
157							=cut
158
159							sub items {
160	14			14	1	137	my $self = shift;
161	14	50	66			187	$self->{loaded} or $self->load or return undef;
162	14					120	@{ $self->{items_array} };
	14					273
163							}
164
165							=pod
166
167							=head2 missing_dependencies
168
169							By default, we are leniant with missing dependencies if the item is neved
170							used. For systems where having a missing dependency can be very bad, the
171							C<missing_dependencies> method checks all Items to make sure their
172							dependencies exist.
173
174							If there are any missing dependencies, returns a reference to an array of
175							their ids. If there are no missing dependencies, returns 0. Returns
176							C<undef> on error.
177
178							=cut
179
180							sub missing_dependencies {
181	5			5	1	51	my $self = shift;
182	5	50	66			112	$self->{loaded} or $self->load or return undef;
183
184							# Merged the depends of all the items, and see if
185							# any are missing.
186	4					49	my %missing = map { $_ => 1 }
	34					326
187	40					484	grep { ! $self->item($_) }
188	5					74	map { $_->depends }
189							$self->items;
190	5	100				272	%missing ? [ sort keys %missing ] : 0;
191							}
192
193
194
195
196
197							#####################################################################
198							# Catch unimplemented methods in subclasses
199
200							sub _load_item_list {
201	0			0			die "Class $_[0] failed to define the method _load_item_list";
202							}
203
204							1;
205
206							=pod
207
208							=head1 EXTENDING
209
210							C<Algorithm::Dependency::Source> itself is a fairly thin module, and it
211							is intended that you will probably need to extend it to be able to
212							extract item data from whatever location you have stored them.
213
214							This is usually a fairly simple two step process.
215
216							=over 4
217
218							=item Overload the C<new> method.
219
220							Assuming your subclass takes some form or argument on creation, you will
221							need to overload the C<new> method to accept the arguments, validate them,
222							and store them in the source object.
223
224							=item Define the method C<_load_item_list>.
225
226							Leaving our parent's C<load> method to take care of conflict, errors, and
227							whatever, the C<_load_item_list> method is used to simply create a list of
228							L<Algorithm::Dependency::Item> objects from wherever you store the item,
229							and return them as a list.
230
231							=back
232
233							Having completed these two things, your subclass should be completed. For
234							an example of the code, have a look at the source for the simple subclass
235							L<Algorithm::Dependency::Source::File>.
236
237							=head1 SUPPORT
238
239							For general comments, contact the author.
240
241							To file a bug against this module, in a way you can keep track of, see the
242							CPAN bug tracking system.
243
244							L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Algorithm-Dependency>
245
246							=head1 AUTHOR
247
248							Adam Kennedy E<lt>cpan@ali.asE<gt>, L<http://ali.as/>
249
250							=head1 SEE ALSO
251
252							L<Algorithm::Dependency>, L<Algorithm::Dependency::Source::File>
253
254							=head1 COPYRIGHT
255
256							Copyright (c) 2003 - 2005 Adam Kennedy. All rights reserved.
257
258							This program is free software; you can redistribute
259							it and/or modify it under the same terms as Perl itself.
260
261							The full text of the license can be found in the
262							LICENSE file included with this module.
263
264							=cut
265