/[cvs]/nfo/perl/libs/DesignPattern/Object.pm
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revision 1.1 by joko, Fri Dec 13 21:46:29 2002 UTC revision 1.9 by joko, Thu Mar 27 15:44:32 2003 UTC
# Line 1  Line 1 
1  ## --------------------------------------------------------------------------------  ## ---------------------------------------------------------------------------
2  ##  $Id$  ##  $Id$
3  ## --------------------------------------------------------------------------------  ## ---------------------------------------------------------------------------
4  ##  $Log$  ##  $Log$
5    ##  Revision 1.9  2003/03/27 15:44:32  joko
6    ##  fixes/enhancements to 'sub log_basic'
7    ##
8    ##  Revision 1.8  2003/02/19 00:36:59  joko
9    ##  + bugfix: this {logger} is the instance itself, so has to be fed with ( level => xyz and namespace => xyz )
10    ##  + minor modifications in behaviour
11    ##
12    ##  Revision 1.7  2003/02/18 18:34:35  joko
13    ##  + fix: just logs if possible (sub log_basic)
14    ##
15    ##  Revision 1.6  2003/02/11 11:04:27  joko
16    ##  + metadata (args, caller, etc.) are now stored inside {__bridge}
17    ##
18    ##  Revision 1.5  2003/02/09 16:24:46  joko
19    ##  + pseudo constructor mechanism by calling method 'constructor' on object instantiation
20    ##
21    ##  Revision 1.4  2003/01/22 17:56:49  root
22    ##  + fix: just use the logger if it's available
23    ##
24    ##  Revision 1.3  2003/01/20 16:54:22  joko
25    ##  + sub fromPackage: refactored from libp's 'getNewPerlObjFromPkgName' or s.th.l.th.
26    ##
27    ##  Revision 1.2  2002/12/27 16:05:42  joko
28    ##  + played with Devel::CallerItem and Devel::StackTrace
29    ##
30  ##  Revision 1.1  2002/12/13 21:46:29  joko  ##  Revision 1.1  2002/12/13 21:46:29  joko
31  ##  + initial check-in  ##  + initial check-in
32  ##  ##
33  ## --------------------------------------------------------------------------------  ## ---------------------------------------------------------------------------
34    
35    
36  package DesignPattern::Object;  package DesignPattern::Object;
# Line 13  package DesignPattern::Object; Line 38  package DesignPattern::Object;
38  use strict;  use strict;
39  use warnings;  use warnings;
40    
41    
42    use Data::Dumper;
43    #use Devel::CallerItem;
44    #use Devel::StackTrace;
45    
46    
47    my $_dp_globals;
48    
49    $_dp_globals = {
50      TRACE => 0,
51    };
52    
53    
54    sub new {
55      
56      # the classname in most cases
57      my $classname = shift;
58      
59      # use already blessed reference, if passed in - else use the very classname
60      my $class = ref ($classname) || $classname;
61      
62      #$self->log_basic( "$classname->new( ... )" . "\t[via " . __PACKAGE__ . "]" , 'debug');
63      
64      # the base for our object - a plain perl hash, which ....
65      my $self = {};
66      # note:
67      # this makes an instance of an arbitrary perl variable,
68      # the most often used for this purpose is - guess it - the hash,
69      # since it resembles object-properties in a convenient way:
70      #   $object->{property} = 'Hello World!';
71      # if you _do_ care about privacy you might take a look
72      # at CPAN's Tie::SecureHash or Class::Contract ...   have fun!
73      
74      # TODO: what about logging in here? inherit from
75      # DesignPattern::Object::Logger for this purpose....
76      # ... or would this give us (harmful) circular module dependencies???
77      #$self->log_basic( __PACKAGE__ . "->new( @args )", 'debug' );      # this is not "common"!
78    
79        
80      # remember the stacktrace: abstract this out (DesignPattern::Object::Trace) or parametrize!
81      #my $trace = Devel::StackTrace->new();
82      #print Dumper($trace);
83      #print Dumper($trace->frame(1)->args());
84    
85    #print "args: ", $self->{'__caller'}->hasargs(), "\n";
86    
87      #print Dumper($self);
88      #exit;
89    
90    
91      # argument-handling ...
92    
93        # ... get them ...
94        my @args = ();
95        @_ && (@args = @_);
96        
97        # ... check if we can coerce them into an array (this needs an even number of arguments)
98      my $argcount = $#args + 1;
99      my $fract = $argcount / 2;
100      
101      my $seperate = pop @args if $fract != int($fract);
102    
103      # mixin arguments
104      $self = { @args };
105      
106      # scan for arguments prefixed by a double underscore '__'
107      foreach (keys %$self) {
108        if (/^__(.+?)$/) {
109          $self->{__bridge}->{$1} = $self->{$_};
110          delete $self->{$_};
111        }
112      }
113      
114      # mixin seperate - FIXME: should this not be done after blessing?
115      $self->{__bridge}->{'arg'} = $seperate if $seperate;
116    
117      # ... bless hash into object using classname
118      bless $self, $class;
119    
120      # remember the caller
121        $self->{__bridge}->{caller_module}  = caller;
122        #print Dumper(caller(2));
123        #exit;
124    
125      $self->{__bridge}->{class_name} = $classname;
126    
127      # patches for backward compatibility
128        $self->{'__arg'} = $self->{__bridge}->{'arg'} if $self->{__bridge}->{'arg'};
129        $self->{'__caller'} = $self->{__bridge}->{caller_module} if $self->{__bridge}->{caller_module};
130        $self->{'__classname'} = $self->{__bridge}->{class_name} if $self->{__bridge}->{class_name};
131    
132      $self->_init() if $self->can('_init');
133      $self->constructor() if $self->can('constructor');
134    
135      # trace
136        #print Dumper($self);
137        #exit;
138    
139      return $self;
140    }  
141    
142  sub _abstract_function {  sub _abstract_function {
143    my $self = shift;    my $self = shift;
144    my $self_classname = ref $self;    my $self_classname = ref $self;
145    my $function_name = shift;    my $function_name = shift;
146    # was:    # was:
147    # $logger->error( __PACKAGE__ . ": function \"$fName\" is an abstract method, please implement it in \"$class\"");    $self->log_basic( __PACKAGE__ . ": function '$function_name' is an abstract method, please implement it in '$self_classname'.", 'warning');
148    # is:    # is:
149    die( __PACKAGE__ . ": Function '$function_name' is an abstract method, please implement it in '$self_classname'.");    #die( __PACKAGE__ . ": Function '$function_name' is an abstract method, please implement it in '$self_classname'.");
150    #exit;    #exit;
151  }  }
152    
153    sub fromPackage {
154      my $self = shift;
155      #my $self_classname = ref $self;
156      my $pkgname = shift;
157      my @args = @_;
158    #  my $args = shift;
159    
160    #      my $caller = $self->{'__caller'};
161    
162    #print Dumper($args);
163    
164      $self->log_basic( __PACKAGE__ . "->fromPackage( pkgname $pkgname args @args )", 'debug');
165      
166      # perl-load
167        my $evstring = "use $pkgname;";
168        eval($evstring);
169      
170      # report errors
171        if ($@) {
172          # build error-messages
173          my $issuer = __PACKAGE__ . ':' . __LINE__;
174          my $errmsg_native = "Error in eval: " .  $@;
175          #my $classname = $self->{__classname};
176          my $errmsg_critical = '';
177          if ($errmsg_native =~ m/Can't locate (.+?) in \@INC/) {
178            $errmsg_critical = "Could not instantiate object from package '$pkgname' ('$1' not found).";
179          } else {
180            $errmsg_critical = $errmsg_native;
181          }
182          # write error to logging-output (console|file|database)
183          $self->log_basic( $errmsg_native . " (issuer='$issuer', code='$evstring')", 'debug' );
184          $self->log_basic( $errmsg_critical, 'warning' );
185          return;
186        }
187      
188      # object-creation
189        my $object = $pkgname->new(@args);
190    
191      # trace
192        #print Dumper($object);
193    
194      # run boot-methods on object
195        $object->_init() if $object->can('_init');
196        $object->constructor() if $object->can('constructor');
197    
198      return $object;
199    }
200    
201    sub log_basic {
202      my $self = shift;
203      my $message = shift;
204      my $level = shift;
205      
206      #return;
207      $level ||= 'info';
208    
209      my $notSoGood = ($level =~ /warning|error|critical/);
210      
211      # STDERR?
212      if ($level && $notSoGood) {
213        print STDERR $level, ": ", $message, "\n";
214      }
215    
216      # STDOUT?
217      if ($_dp_globals->{TRACE} || $notSoGood) {
218        print $level, ": ", $message, "\n";
219      }
220    
221      # get logger instance
222      if (!$_dp_globals->{logger}) {
223        $_dp_globals->{logger} = eval { Log::Dispatch::Config->instance; };
224      }
225      
226      if ($_dp_globals->{logger}) {
227        $_dp_globals->{logger}->log( level => $level, message => $message);
228      #} else {
229        #print $level, ": ", $message, "\n";
230      }
231      
232    }
233    
234  1;  1;
235    __END__
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