libs/DesignPattern/Bridge.pm

## --------------------------------------------------------------------------------
##  $Id: Bridge.pm,v 1.3 2002/12/16 19:57:12 joko Exp $
## --------------------------------------------------------------------------------
##  $Log: Bridge.pm,v $
##  Revision 1.3  2002/12/16 19:57:12  joko
##  + sub unload
##
##  Revision 1.2  2002/12/15 02:06:15  joko
##  + feature to be able to specify module in non-perl-style when loading plugins: e.g. $process->load('Setup/Storage')
##
##  Revision 1.1  2002/12/13 21:46:29  joko
##  + initial check-in
##
## --------------------------------------------------------------------------------


package DesignPattern::Bridge;

use strict;
use warnings;

use base qw( DesignPattern::Object );

use Data::Dumper;

## ========   object inheritance   ========

# TODO:
#   - this is no inheritance and it doesn't have to be
#   - implement this module as a bridge to its sub-modules
#   - use the BridgePattern (http://c2.com/cgi/wiki?BridgePattern) 
#       Using patterns was already successfully done with Data::Storage::Handler
#       by implementing the AdapterPattern (http://c2.com/cgi/wiki?AdapterPattern)
#       with Perl's AUTOLOAD-mechanism
#   - try to use Perl's "tie" command to implement this functionality here instead of using AUTOLOAD!
#   - sub getChildNodes
#   - sub run

# get logger instance
my $logger = Log::Dispatch::Config->instance;
  
my $meta;

## ========   object constructor   ========
  sub new {
    my $invocant = shift;
    my $class = ref($invocant) || $invocant;
    my @args = ();
    @_ && (@args = @_);
    $logger->debug( __PACKAGE__ . "->new(@args)" );
    my $self = { @_ };
    #print "class: $class", "\n";
    bless $self, $class;
    ##if (my $bizWorks = shift) {
      ##$self->boot($bizWorks);
    ##}
    
    return $self;
  }


## ========   method overrider   ========
  sub AUTOLOAD2 {
    
    my $self = shift;
    our $AUTOLOAD;
    
    ##print "AUTOLOAD\n";

    my $method = $AUTOLOAD;
    $method =~ s/^.*:://;
  
    $logger->debug( __PACKAGE__ . "->" . $method . "(@_)" . " (AUTOLOAD called, not dispatched)" );

    ## ->DESTROY would - if not declared - trigger an AUTOLOAD also
    return if $method =~ m/::DESTROY$/;
  
##    if ($self->_filter_AUTOLOAD($method)) {
##      $self->_accessStorage();
##      $self->{STORAGEHANDLE}->$method(@_);
##    }
    
  }

  sub _getPluginPackage {
    my $self = shift;
    my $modulename_load = shift;

    # substitute slashes through double double-colons to load modules perl-style
    $modulename_load =~ s/\//::/g;
    
    # build full package name
    my $self_classname = ref $self;
    my $package = $self_classname . '::' . $modulename_load;
    return $package;
  }
  
  sub load {

    my $self = shift;
    my $modulename_load = shift;

    my $self_modulename = ref $self;
    my $package = $self->_getPluginPackage($modulename_load);
    
    if ($meta->{loaded}->{$package}) {
      return 1;
    }
    
    #$logger->info( __PACKAGE__ . "->load: $package" );
    #$logger->info( __PACKAGE__ . "->load: $self_modulename" );
    $logger->debug( $self_modulename . "->load: $package\t[via " . __PACKAGE__ . "]" );

    # this is the module testing phase - use mixin doesn't seem to propagate errors by default
    eval("use $package;");
    if ($@) {
      $meta->{loaded}->{$package} = 0;
      # include caller information
      my @caller = caller;
      my $caller_msg = $caller[1] . ':' . $caller[2];
      $logger->error( __PACKAGE__ . "->load: $@ ($caller_msg)" );
    }

#print "ref-1: ", ref $self, "\n";
#print "ref-2: ", ref $self::SUPER, "\n";
    
    # V1:
    #bless $self, $package;

    # V2:
    # switch into foreign package and mixin plugin-module
    $self->mixinPackage($package);

    return 1;
    
  }

  # TODO: maybe refactor to DesignPattern::Object? what about the '$logger'?
  sub mixinPackage {
    my $self = shift;
    my $package = shift;
    # switch into foreign package and mixin plugin-module
    my $self_classname = ref $self;
    eval("package $self_classname; use mixin '$package';");
    #eval("use mixin_all '$package';");
    if ($@) {
      $meta->{loaded}->{$package} = 0;
      $logger->error( __PACKAGE__ . "->load: $@" );
    } else {
      $meta->{loaded}->{$package} = 1;
    }
  }

  sub unload {

    my $self = shift;
    my $modulename_unload = shift;

    my $package = $self->_getPluginPackage($modulename_unload);
    
    if ($meta->{loaded}->{$package}) {
      $meta->{loaded}->{$package} = 0;
      my $where = __PACKAGE__ . ':' . __LINE__;
      $logger->debug( __PACKAGE__ . "->unload: FIXME: DESTROY object is not implemented at '$where'." );
    }

  }


  sub boot {
    my $self = shift;
    $self->_abstract_function('boot');
  }
  
  sub include {
    my $self = shift;
    my $includefile = shift;
    my $package = shift;
    # TODO: do better error-detection here / prevent dies under all circumstances!
    require $includefile;
    $self->mixinPackage($package) if $package;
  }

1;
1	joko	1.1	## --------------------------------------------------------------------------------
2	joko	1.4	## $Id: Bridge.pm,v 1.3 2002/12/16 19:57:12 joko Exp $
3	joko	1.1	## --------------------------------------------------------------------------------
4	joko	1.2	## $Log: Bridge.pm,v $
5	joko	1.4	## Revision 1.3 2002/12/16 19:57:12 joko
6			## + sub unload
7			##
8	joko	1.3	## Revision 1.2 2002/12/15 02:06:15 joko
9			## + feature to be able to specify module in non-perl-style when loading plugins: e.g. $process->load('Setup/Storage')
10			##
11	joko	1.2	## Revision 1.1 2002/12/13 21:46:29 joko
12			## + initial check-in
13			##
14	joko	1.1	## --------------------------------------------------------------------------------
15
16
17			package DesignPattern::Bridge;
18
19			use strict;
20			use warnings;
21
22			use base qw( DesignPattern::Object );
23
24	joko	1.2	use Data::Dumper;
25
26	joko	1.1	## ======== object inheritance ========
27
28			# TODO:
29			# - this is no inheritance and it doesn't have to be
30			# - implement this module as a bridge to its sub-modules
31			# - use the BridgePattern (http://c2.com/cgi/wiki?BridgePattern)
32			# Using patterns was already successfully done with Data::Storage::Handler
33			# by implementing the AdapterPattern (http://c2.com/cgi/wiki?AdapterPattern)
34			# with Perl's AUTOLOAD-mechanism
35			# - try to use Perl's "tie" command to implement this functionality here instead of using AUTOLOAD!
36			# - sub getChildNodes
37			# - sub run
38
39			# get logger instance
40			my $logger = Log::Dispatch::Config->instance;
41
42	joko	1.3	my $meta;
43	joko	1.1
44			## ======== object constructor ========
45			sub new {
46			my $invocant = shift;
47			my $class = ref($invocant) \|\| $invocant;
48			my @args = ();
49			@_ && (@args = @_);
50			$logger->debug( __PACKAGE__ . "->new(@args)" );
51			my $self = { @_ };
52			#print "class: $class", "\n";
53			bless $self, $class;
54			##if (my $bizWorks = shift) {
55			##$self->boot($bizWorks);
56			##}
57
58			return $self;
59			}
60
61
62			## ======== method overrider ========
63			sub AUTOLOAD2 {
64
65			my $self = shift;
66			our $AUTOLOAD;
67
68			##print "AUTOLOAD\n";
69
70			my $method = $AUTOLOAD;
71			$method =~ s/^.*:://;
72
73			$logger->debug( __PACKAGE__ . "->" . $method . "(@_)" . " (AUTOLOAD called, not dispatched)" );
74
75			## ->DESTROY would - if not declared - trigger an AUTOLOAD also
76			return if $method =~ m/::DESTROY$/;
77
78			## if ($self->_filter_AUTOLOAD($method)) {
79			## $self->_accessStorage();
80			## $self->{STORAGEHANDLE}->$method(@_);
81			## }
82
83			}
84	joko	1.3
85			sub _getPluginPackage {
86			my $self = shift;
87			my $modulename_load = shift;
88
89			# substitute slashes through double double-colons to load modules perl-style
90			$modulename_load =~ s/\//::/g;
91
92			# build full package name
93			my $self_classname = ref $self;
94			my $package = $self_classname . '::' . $modulename_load;
95			return $package;
96			}
97	joko	1.1
98			sub load {
99
100			my $self = shift;
101	joko	1.3	my $modulename_load = shift;
102	joko	1.1
103	joko	1.4	my $self_modulename = ref $self;
104	joko	1.3	my $package = $self->_getPluginPackage($modulename_load);
105	joko	1.1
106	joko	1.3	if ($meta->{loaded}->{$package}) {
107			return 1;
108			}
109	joko	1.2
110	joko	1.4	#$logger->info( __PACKAGE__ . "->load: $package" );
111			#$logger->info( __PACKAGE__ . "->load: $self_modulename" );
112			$logger->debug( $self_modulename . "->load: $package\t[via " . __PACKAGE__ . "]" );
113	joko	1.1
114			# this is the module testing phase - use mixin doesn't seem to propagate errors by default
115			eval("use $package;");
116			if ($@) {
117	joko	1.3	$meta->{loaded}->{$package} = 0;
118	joko	1.2	# include caller information
119			my @caller = caller;
120			my $caller_msg = $caller[1] . ':' . $caller[2];
121			$logger->error( __PACKAGE__ . "->load: $@ ($caller_msg)" );
122	joko	1.1	}
123
124			#print "ref-1: ", ref $self, "\n";
125			#print "ref-2: ", ref $self::SUPER, "\n";
126
127			# V1:
128			#bless $self, $package;
129
130			# V2:
131			# switch into foreign package and mixin plugin-module
132	joko	1.4	$self->mixinPackage($package);
133
134			return 1;
135
136			}
137
138			# TODO: maybe refactor to DesignPattern::Object? what about the '$logger'?
139			sub mixinPackage {
140			my $self = shift;
141			my $package = shift;
142			# switch into foreign package and mixin plugin-module
143	joko	1.3	my $self_classname = ref $self;
144	joko	1.1	eval("package $self_classname; use mixin '$package';");
145			#eval("use mixin_all '$package';");
146			if ($@) {
147	joko	1.3	$meta->{loaded}->{$package} = 0;
148	joko	1.1	$logger->error( __PACKAGE__ . "->load: $@" );
149	joko	1.3	} else {
150			$meta->{loaded}->{$package} = 1;
151	joko	1.1	}
152	joko	1.3	}
153
154			sub unload {
155
156			my $self = shift;
157			my $modulename_unload = shift;
158
159			my $package = $self->_getPluginPackage($modulename_unload);
160	joko	1.1
161	joko	1.3	if ($meta->{loaded}->{$package}) {
162			$meta->{loaded}->{$package} = 0;
163			my $where = __PACKAGE__ . ':' . __LINE__;
164			$logger->debug( __PACKAGE__ . "->unload: FIXME: DESTROY object is not implemented at '$where'." );
165			}
166
167	joko	1.1	}
168	joko	1.3
169	joko	1.1
170			sub boot {
171			my $self = shift;
172			$self->_abstract_function('boot');
173	joko	1.4	}
174
175			sub include {
176			my $self = shift;
177			my $includefile = shift;
178			my $package = shift;
179			# TODO: do better error-detection here / prevent dies under all circumstances!
180			require $includefile;
181			$self->mixinPackage($package) if $package;
182	joko	1.1	}
183
184			1;
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