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#!/usr/bin/env perl -w
# SET UP A WINDOW HIERARCHY
package Window;
my $id = 1;
sub new { bless { id=>$id++ }, ref($_[0])||$_[0] }
sub handle
{
if ($_[2]->isa(OffMode))
{
print "No window operations available in OffMode\n";
}
else
{
print "Window $_[0]->{id} can't handle a ",
ref($_[1]), " command in ",
ref($_[2]), " mode\n";
}
}
package ModalWindow; @ISA = qw( Window );
sub handle
{
if ($_[1]->isa(Accept))
{
if ($_[2]->isa(OffMode))
{
print "Modal window $_[0]->{id} can't accept in OffMode!\n";
}
else
{
print "Modal window $_[0]->{id} accepts!\n";
}
}
elsif ($_[1]->isa(ReshapeCommand))
{
print "Modal windows can't handle reshape commands\n";
}
else
{
$_[0]->SUPER::handle(@_[1,2]);
}
}
package MovableWindow; @ISA = qw( Window );
sub handle
{
if ($_[1]->isa(Move) && $_[2]->isa(OnMode))
{
print "Moving window $_[0]->{id}!\n";
}
else
{
$_[0]->SUPER::handle(@_[1,2]);
}
}
package ResizableWindow; @ISA = qw( MovableWindow );
sub handle
{
if ($_[1]->isa(MoveAndResize) && $_[2]->isa(OnMode))
{
print "Moving and resizing window $_[0]->{id}!\n";
}
elsif ($_[1]->isa(Resize) && $_[2]->isa(OnMode))
{
print "Resizing window $_[0]->{id}!\n";
}
else
{
$_[0]->SUPER::handle(@_[1,2]);
}
}
# SET UP A COMMAND HIERARCHY
package Command;
sub new { bless {}, ref($_[0])||$_[0] }
package ReshapeCommand; @ISA = qw( Command );
package Accept; @ISA = qw( Command );
package Move; @ISA = qw( ReshapeCommand );
package Resize; @ISA = qw( ReshapeCommand );
package MoveAndResize; @ISA = qw( Move Resize );
# SET UP A MODE HIERARCHY
package Mode;
sub new { bless {}, ref($_[0])||$_[0] }
package OnMode; @ISA = qw( Mode );
package ModalMode; @ISA = qw( Mode );
package OffMode; @ISA = qw( Mode );
package main;
# CREATE SOME WINDOWS...
@window = (
new ModalWindow,
new MovableWindow,
new ResizableWindow,
);
# ...AND SOME COMMANDS...
@command = (
new Move,
new Resize,
new MoveAndResize,
new Accept,
);
# ...AND SOME MODES...
@mode = (
new OffMode,
new ModalMode,
new OnMode,
new OnMode,
new OnMode,
);
# AND INTERACT THEM ALL...
srand(0);
for (1..10000)
{
$w = $window[rand @window];
$c = $command[rand @command];
$m = $mode[rand @mode];
print "handle(",ref($w),",",ref($c),",",ref($m),")...\n\t";
eval { $w->handle($c,$m) } or print $@;
}
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