Profile of Class/Singleton.pm

Filename	/usr/share/perl5/Class/Singleton.pm
Statements	Executed 19 statements in 279µs

Subroutines
Calls	P	F	Exclusive Time	Inclusive Time	Subroutine
2	1	1	15µs	18µs	Class::Singleton::::instanceClass::Singleton::instance
1	1	1	12µs	24µs	Class::Singleton::::BEGIN@19Class::Singleton::BEGIN@19
1	1	1	9µs	14µs	Class::Singleton::::BEGIN@20Class::Singleton::BEGIN@20
1	1	1	6µs	15µs	Class::Singleton::::BEGIN@73Class::Singleton::BEGIN@73
1	1	1	6µs	15µs	Class::Singleton::::BEGIN@56Class::Singleton::BEGIN@56
0	0	0	0s	0s	Class::Singleton::::_new_instanceClass::Singleton::_new_instance
0	0	0	0s	0s	Class::Singleton::::has_instanceClass::Singleton::has_instance

Call graph for these subroutines as a Graphviz dot language file.

Line	State ments	Time on line	Calls	Time in subs	Code
1					#============================================================================
2					#
3					# Class::Singleton.pm
4					#
5					# Implementation of a "singleton" module which ensures that a class has
6					# only one instance and provides global access to it. For a description
7					# of the Singleton class, see "Design Patterns", Gamma et al, Addison-
8					# Wesley, 1995, ISBN 0-201-63361-2
9					#
10					# Written by Andy Wardley <abw@wardley.org>
11					#
12					# Copyright (C) 1998-2008 Andy Wardley. All Rights Reserved.
13					# Copyright (C) 1998 Canon Research Centre Europe Ltd.
14					#
15					#============================================================================
16
17					package Class::Singleton;
18	1	9µs			require 5.004;
19	2	24µs	2	36µs	# spent 24µs (12+12) within Class::Singleton::BEGIN@19 which was called: # once (12µs+12µs) by parent::import at line 19 use strict; # spent 24µs making 1 call to Class::Singleton::BEGIN@19 # spent 12µs making 1 call to strict::import
20	2	65µs	2	19µs	# spent 14µs (9+5) within Class::Singleton::BEGIN@20 which was called: # once (9µs+5µs) by parent::import at line 20 use warnings; # spent 14µs making 1 call to Class::Singleton::BEGIN@20 # spent 5µs making 1 call to warnings::import
21
22	1	200ns			our $VERSION = 1.4;
23
24
25					#========================================================================
26					#
27					# instance()
28					#
29					# Module constructor. Creates an Class::Singleton (or derived) instance
30					# if one doesn't already exist. The instance reference is stored in the
31					# _instance variable of the $class package. This means that classes
32					# derived from Class::Singleton will have the variables defined in THEIR
33					# package, rather than the Class::Singleton package. The impact of this is
34					# that you can create any number of classes derived from Class::Singleton
35					# and create a single instance of each one. If the _instance variable
36					# was stored in the Class::Singleton package, you could only instantiate
37					# ONE object of ANY class derived from Class::Singleton. The first
38					# time the instance is created, the _new_instance() constructor is called
39					# which simply returns a reference to a blessed hash. This can be
40					# overloaded for custom constructors. Any addtional parameters passed to
41					# instance() are forwarded to _new_instance().
42					#
43					# Returns a reference to the existing, or a newly created Class::Singleton
44					# object. If the _new_instance() method returns an undefined value
45					# then the constructer is deemed to have failed.
46					#
47					#========================================================================
48
49					# spent 18µs (15+4) within Class::Singleton::instance which was called 2 times, avg 9µs/call: # 2 times (15µs+4µs) by DateTime::TimeZone::new at line 48 of DateTime/TimeZone.pm, avg 9µs/call sub instance {
50	2	1µs			my $class = shift;
51
52					# already got an object
53	2	800ns			return $class if ref $class;
54
55					# we store the instance in the _instance variable in the $class package.
56	2	77µs	2	24µs	# spent 15µs (6+9) within Class::Singleton::BEGIN@56 which was called: # once (6µs+9µs) by parent::import at line 56 no strict 'refs'; # spent 15µs making 1 call to Class::Singleton::BEGIN@56 # spent 9µs making 1 call to strict::unimport
57	2	5µs			my $instance = \${ "$class\::_instance" };
58	2	8µs	1	4µs	defined $$instance # spent 4µs making 1 call to DateTime::TimeZone::Floating::_new_instance
59					? $$instance
60					: ($$instance = $class->_new_instance(@_));
61					}
62
63
64					#=======================================================================
65					# has_instance()
66					#
67					# Public method to return the current instance if it exists.
68					#=======================================================================
69
70					sub has_instance {
71					my $class = shift;
72					$class = ref $class \|\| $class;
73	2	87µs	2	24µs	# spent 15µs (6+9) within Class::Singleton::BEGIN@73 which was called: # once (6µs+9µs) by parent::import at line 73 no strict 'refs'; # spent 15µs making 1 call to Class::Singleton::BEGIN@73 # spent 9µs making 1 call to strict::unimport
74					return ${"$class\::_instance"};
75					}
76
77
78					#========================================================================
79					# _new_instance(...)
80					#
81					# Simple constructor which returns a hash reference blessed into the
82					# current class. May be overloaded to create non-hash objects or
83					# handle any specific initialisation required.
84					#========================================================================
85
86					sub _new_instance {
87					my $class = shift;
88					my %args = @_ && ref $_[0] eq 'HASH' ? %{ $_[0] } : @_;
89					bless { %args }, $class;
90					}
91
- -
94	1	3µs			1;
95
96					__END__