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Re: Access to single object from multiple other objects

by kschwab (Priest)
on Nov 02, 2013 at 21:21 UTC ( #1060980=note: print w/ replies, xml ) Need Help??


in reply to Access to single object from multiple other objects

One option would be a simplistic factory that held a single "shared thing", and was responsible for creating the other objects, so that they could have a reference to the shared thing without having to explicitly pass the "shared thing" around.

Something like this:

#!/usr/bin/perl -w use strict; package SharedThing; sub new { my $that = shift; my $class = ref($that) || $that; return bless {"counter" => 0}, ref($that) || $that; } sub hello { my $this=shift; $this->{counter}++; printf "hello, count is [%d]\n",$this->{counter}; } package MyFactory; sub new { my $that = shift; my $class = ref($that) || $that; my $this = {}; bless $this, $class; $this->{sharedthing}=SharedThing->new(); return $this; } sub A {A->new(@_);} sub B {B->new(@_);} package A; sub new { my $that = shift; my $class = ref($that) || $that; my $this = {}; bless $this, $class; $this->{factory}=shift; # call the "hello" method of the "shared thing" so that # we can see that it's indeed a single instance $this->{factory}->{sharedthing}->hello(); return $this; } package B; our @ISA=qw(A); package main; my $factory=MyFactory->new(); my $a1=$factory->A(); my $a2=$factory->A(); my $b1=$factory->B(); my $b2=$factory->B();

All of the instances of A and B have a reference to the factory passed to them when they are instantiated, and so, they can get to $this->{factory}->{sharedthing}...the single shared object.


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