perl closure object闭包和对象

asfsd

　　[root@dou shili]# cat Student.pm
　　package Student;
　　sub new { # Constructor
　　my $class = shift;
　　my $data = {};
　　our $students;
　　my $ref = sub { # Closure
　　my($access_type,$key,$value) = @_;
　　if($access_type eq "set") {
　　$data->{$key} = $value;
　　if($key eq "Name") {
　　++$students;
　　print "New student created.we have ", $students, " students.\n";
　　}
　　}
　　elsif($access_type eq "get") {
　　return $data->{$key};
　　}
　　elsif($access_type eq "keys") {
　　return (keys %{$data});
　　}
　　else {
　　die "Access type should be set or get";
　　}
　　};
　　bless($ref,$class);
　　#return $ref;
　　}# end constructor
　　sub set {
　　my $self = shift;
　　my($key,$value) = @_;
　　$self->("set",$key,$value);
　　}
　　sub get {
　　my($self,$key) = @_;
　　return $self->("get",$key);
　　}
　　sub display {
　　my $self = shift;
　　my @keys = $self->("keys");
　　@keys = reverse(@keys);
　　foreach my $key (@keys) {
　　my $value = $self->("get",$key);
　　printf "%-25s%-5s:%-20s\n",$self,$key,$value;
　　}
　　print "\n";
　　}
　　1;
　　[root@dou shili]# cat useStudent.pl
　　#!/usr/bin/perl -w
　　use strict;
　　use Student;
　　my $prt1 = Student->new();
　　my $prt2 = Student->new();
　　my $prt3 = Student->new();
　　$prt1->set("Name","Tomcat");
　　$prt1->set("Major","Math");
　　$prt2->set("Name","Oracle");
　　$prt2->set("Major","American");
　　$prt3->set("Name","Hello");
　　$prt3->set("Major","World");
　　$prt1->display();
　　$prt2->display();
　　$prt3->display();
　　print "\nThe major for ",$prt1->get("Name"), "is ", $prt1->get("Major"), ".\n\n";
　　[root@dou shili]# perl useStudent.pl
　　New student created.we have 1 students.
　　New student created.we have 2 students.
　　New student created.we have 3 students.
　　Student=CODE(0x160e53d0) Name :Tomcat
　　Student=CODE(0x160e53d0) Major:Math
　　Student=CODE(0x1610af20) Name :Oracle
　　Student=CODE(0x1610af20) Major:American
　　Student=CODE(0x1610b030) Name :Hello
　　Student=CODE(0x1610b030) Major:World
　　The major for Tomcatis Math.