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## --------------------------------------------------------------------------- |
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## $Id: Object.pm,v 1.5 2003/02/09 16:24:46 joko Exp $ |
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## --------------------------------------------------------------------------- |
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## $Log: Object.pm,v $ |
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## Revision 1.5 2003/02/09 16:24:46 joko |
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## + pseudo constructor mechanism by calling method 'constructor' on object instantiation |
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## |
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## Revision 1.4 2003/01/22 17:56:49 root |
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## + fix: just use the logger if it's available |
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## |
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## Revision 1.3 2003/01/20 16:54:22 joko |
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## + sub fromPackage: refactored from libp's 'getNewPerlObjFromPkgName' or s.th.l.th. |
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## |
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## Revision 1.2 2002/12/27 16:05:42 joko |
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## + played with Devel::CallerItem and Devel::StackTrace |
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## |
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## Revision 1.1 2002/12/13 21:46:29 joko |
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## + initial check-in |
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## |
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## --------------------------------------------------------------------------- |
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package DesignPattern::Object; |
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|
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use strict; |
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use warnings; |
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|
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|
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use Data::Dumper; |
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#use Devel::CallerItem; |
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#use Devel::StackTrace; |
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|
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|
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# get logger instance |
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my $logger = eval { Log::Dispatch::Config->instance; }; |
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|
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sub new { |
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|
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# the classname in most cases |
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my $classname = shift; |
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|
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# use already blessed reference, if passed in - else use the very classname |
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my $class = ref ($classname) || $classname; |
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|
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$logger->debug( "$classname->new( ... )" . "\t[via " . __PACKAGE__ . "]" ) if $logger; |
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|
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# the base for our object - a plain perl hash, which .... |
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my $self = {}; |
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# note: |
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# this makes an instance of an arbitrary perl variable, |
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# the most often used for this purpose is - guess it - the hash, |
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# since it resembles object-properties in a convenient way: |
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# $object->{property} = 'Hello World!'; |
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# if you _do_ care about privacy you might take a look |
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# at CPAN's Tie::SecureHash or Class::Contract ... have fun! |
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|
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# TODO: what about logging in here? inherit from |
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# DesignPattern::Object::Logger for this purpose.... |
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# ... or would this give us (harmful) circular module dependencies??? |
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#$logger->debug( __PACKAGE__ . "->new( @args )" ); # this is not "common"! |
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|
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|
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# remember the stacktrace: abstract this out (DesignPattern::Object::Trace) or parametrize! |
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#my $trace = Devel::StackTrace->new(); |
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#print Dumper($trace); |
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#print Dumper($trace->frame(1)->args()); |
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|
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#print "args: ", $self->{'__caller'}->hasargs(), "\n"; |
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|
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#print Dumper($self); |
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#exit; |
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|
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|
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# argument-handling ... |
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|
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# ... get them ... |
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my @args = (); |
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@_ && (@args = @_); |
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|
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# ... check if we can coerce them into an array (this needs an even number of arguments) |
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my $argcount = $#args + 1; |
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my $fract = $argcount / 2; |
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|
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my $seperate = pop @args if $fract != int($fract); |
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|
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# mixin arguments |
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$self = { @args }; |
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|
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# scan for arguments prefixed by a double underscore '__' |
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foreach (keys %$self) { |
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if (/^__(.+?)$/) { |
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$self->{__bridge}->{$1} = $self->{$_}; |
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delete $self->{$_}; |
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} |
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} |
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|
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# mixin seperate - FIXME: should this not be done after blessing? |
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$self->{__bridge}->{'arg'} = $seperate if $seperate; |
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|
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# ... bless hash into object using classname |
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bless $self, $class; |
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|
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# remember the caller |
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$self->{__bridge}->{caller_module} = caller; |
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#print Dumper(caller(2)); |
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#exit; |
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|
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$self->{__bridge}->{class_name} = $classname; |
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|
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# patches for backward compatibility |
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$self->{'__arg'} = $self->{__bridge}->{'arg'} if $self->{__bridge}->{'arg'}; |
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$self->{'__caller'} = $self->{__bridge}->{caller_module} if $self->{__bridge}->{caller_module}; |
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$self->{'__classname'} = $self->{__bridge}->{class_name} if $self->{__bridge}->{class_name}; |
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|
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$self->_init() if $self->can('_init'); |
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$self->constructor() if $self->can('constructor'); |
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|
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# trace |
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#print Dumper($self); |
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#exit; |
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|
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return $self; |
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} |
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|
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sub _abstract_function { |
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my $self = shift; |
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my $self_classname = ref $self; |
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my $function_name = shift; |
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# was: |
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$logger->warning( __PACKAGE__ . ": function '$function_name' is an abstract method, please implement it in '$self_classname'."); |
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# is: |
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#die( __PACKAGE__ . ": Function '$function_name' is an abstract method, please implement it in '$self_classname'."); |
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#exit; |
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} |
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|
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sub fromPackage { |
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my $self = shift; |
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#my $self_classname = ref $self; |
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my $pkgname = shift; |
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my @args = @_; |
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# my $args = shift; |
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|
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# my $caller = $self->{'__caller'}; |
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|
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#print Dumper($args); |
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|
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$logger->debug( __PACKAGE__ . "->fromPackage( pkgname $pkgname args @args )" ); |
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|
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# perl-load |
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my $evstring = "use $pkgname;"; |
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eval($evstring); |
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|
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# report errors |
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if ($@) { |
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# build error-messages |
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my $errmsg_native = __PACKAGE__ . ':' . __LINE__ . " Error in eval \"$evstring\": " . $@; |
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#my $classname = $self->{__classname}; |
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my $errmsg_critical = ''; |
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if ($errmsg_native =~ m/Can't locate (.+?) in \@INC/) { |
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$errmsg_critical = "Could not instantiate object from package '$pkgname' - location of '$1' failed."; |
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} else { |
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$errmsg_critical = $errmsg_native; |
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} |
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# write error to logging-output (console|file|database) |
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$logger->debug( $errmsg_native ); |
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$logger->critical( $errmsg_critical ); |
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return; |
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} |
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|
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# object-creation |
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my $object = $pkgname->new(@args); |
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|
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# run boot-methods on object |
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$object->_init() if $object->can('_init'); |
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$object->constructor() if $object->can('constructor'); |
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|
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return $object; |
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} |
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