1Class::Adapter::Clear(3U)ser Contributed Perl DocumentatiColnass::Adapter::Clear(3)
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NAME

6       Class::Adapter::Clear - A handy base Adapter class that makes no
7       changes
8

VERSION

10       version 1.09
11

SYNOPSIS

13       Hello World with CGI.pm the normal way
14
15         # Load and create the CGI
16         use CGI;
17         $q = new CGI;
18
19         # Create the page
20         print $q->header,                    # HTTP Header
21               $q->start_html('hello world'), # Start the page
22               $q->h1('hello world'),         # Hello World!
23               $q->end_html;                  # End the page
24
25       Hello World with CGI.pm the Adapter'ed way
26
27         # Load and create the CGI
28         use CGI;
29         $q = new CGI;
30
31         # Convert to an Adapter
32         use Class::Adapter::Clear;
33         $q = new Class::Adapter::Clear( $q );
34
35         # Create the page
36         print $q->header,                    # HTTP Header
37               $q->start_html('hello world'), # Start the page
38               $q->h1('hello world'),         # Hello World!
39               $q->end_html;                  # End the page
40
41       Creating a CGI Adapter class using Class::Adapter::Clear
42
43         package My::CGI;
44
45         use base 'Class::Adapter::Clear';
46
47         # Optional - Create the thing we are decorating auto-magically
48         sub new {
49             my $class = shift;
50
51             # Create the object we are decorating
52             my $query = CGI->new(@_);
53
54             # Wrap it in the Adapter
55             $class->SUPER::new($query);
56         }
57
58         # Decorate the h1 method to change what is created
59         sub h1 {
60               my $self = shift;
61               my $str  = shift;
62
63           # Do something before the real method call
64           if ( defined $str and $str eq 'hello world' ) {
65               $str = 'Hello World!';
66           }
67
68           $self->_OBJECT_->($str, @_);
69         }
70

DESCRIPTION

72       "Class::Adapter::Clear" provides the base class for creating one common
73       type of Class::Adapter classes. For more power, move up to
74       Class::Adapter::Builder.
75
76       On it's own "Class::Adapter::Clear" passes all methods through to the
77       same method in the parent object with the same parameters, responds to
78       "->isa" like the parent object, and responds to "->can" like the parent
79       object.
80
81       It looks like a "Duck", and it quacks like a "Duck".
82
83       On this base, you simple implement whatever method you want to do
84       something special to.
85
86         # Different method, same parameters
87         sub method1 {
88             my $self = shift;
89             $self->_OBJECT_->method2(@_); # Call a different method
90         }
91
92         # Same method, different parameters
93         sub method1 {
94             my $self = shift;
95             $self->_OBJECT_->method1( lc($_[0]) ); # Lowercase the param
96         }
97
98         # Same method, same parameters, tweak the result
99         sub method1 {
100             my $self = shift;
101             my $rv = $self->_OBJECT_->method1(@_);
102             $rv =~ s/\n/<br>\n/g; # Add line-break HTML tags at each newline
103             return $rv;
104         }
105
106       As you can see, the advantage of this full-scale Adapter approach,
107       compared to inheritance, or function wrapping (see Class::Hook), is
108       that you have complete and utter freedom to do anything you might need
109       to do, without stressing the Perl inheritance model or doing anything
110       unusual or tricky with "CODE" references.
111
112       You may never need this much power. But when you need it, you really
113       need it.
114
115       As an aside, Class::Adapter::Clear is implemented with the following
116       Class::Adapter::Builder formula.
117
118         use Class::Adapter::Builder
119             ISA      => '_OBJECT_',
120             AUTOLOAD => 1;
121

METHODS

123   new $object
124       As does the base Class::Adapter class, the default "new" constructor
125       takes a single object as argument and creates a new object which holds
126       the passed object.
127
128       Returns a new "Class::Adapter::Clear" object, or "undef" if you do not
129       pass in an object.
130

SEE ALSO

132       Class::Adapter, Class::Adapter::Builder
133

SUPPORT

135       Bugs may be submitted through the RT bug tracker
136       <https://rt.cpan.org/Public/Dist/Display.html?Name=Class-Adapter> (or
137       bug-Class-Adapter@rt.cpan.org <mailto:bug-Class-Adapter@rt.cpan.org>).
138

AUTHOR

140       Adam Kennedy <adamk@cpan.org>
141

143       This software is copyright (c) 2005 by Adam Kennedy.
144
145       This is free software; you can redistribute it and/or modify it under
146       the same terms as the Perl 5 programming language system itself.
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150perl v5.32.0                      2020-07-28          Class::Adapter::Clear(3)
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