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Object-Base-1.05
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NAME

Object::Base - Multi-threaded base class to establish a class deriving relationship with parent classes

VERSION

version 1.05

ABSTRACT

Multi-threaded base class to establish a class deriving relationship with parent classes

    package Foo;
    use Object::Base;
    
    package Bar;
    use Object::Base qw('Foo', 'Baz');
    attributes 'attr1', 'attr2', ':shared';

DESCRIPTION

Object::Base provides blessed and thread-shared(with :shared feature) object with in new method. new method can be used as a constructor and overridable in derived classes. new() should be called in derived class constructors to create and bless self-object.

Derived classes own package automatically uses threads, threads::shared, strict, warnings with using Object::Base. If Perl is not built to support threads; it uses forks, forks::shared instead of threads, threads::shared. Object::Base should be loaded as first module.

Import parameters of Object::Base, define parent classes of derived class. If none of parent classes derived from Object::Base or any parent isn't defined, Object::Base is automatically added in parent classes.

Attributes

Attributes define read-write accessors binded value of same named key in objects own hash if attribute names is valid subroutine identifiers. Otherwise, attribute defines feature to get new features into class.

Attributes;

Modifiers

Attributes can have their own modifiers in hash reference at definition.

default

getter method of default value of attribute, otherwise value is default value

    attributes
            'attr1' => {
                    'default' => sub {
                            my ($self, $attr) = @_;
                            return "default value of $attr";
                    },
            },
            'attr2' => {
                    'default' => "default value of attr2",
            };

getter

getter method of attribute

    my $attr1_val;
    attributes
            'attr1' => {
                    'getter' => sub {
                            my ($self, $attr, $current_value) = @_;
                            return $attr1_val;
                    },
            };

setter

setter method of attribute

    my $attr1_val;
    attributes
            'attr1' => {
                    'setter' => sub {
                            my ($self, $attr, $current_value, $new_value) = @_;
                            $attr1_val = $new_value;
                    },
            };

Features

:shared

Class will be craated as thread-shared.

:lazy

Attribute default value will be initialized at first fetching or storing.

Examples

    package Foo;
    use Object::Base;
    my $attr3_def = 6;
    my $attr3_val;
    attributes ':shared', 'attr1', 'attr2', ':lazy',
            'attr3' => {
                    'default' => sub {
                            my ($self, $attr) = @_;
                            $attr3_val = $attr3_def;
                            return $attr3_def;
                    },
                    'getter' => sub {
                            my ($self, $attr, $current_value) = @_;
                            return $attr3_val+1;
                    },
                    'setter' => sub {
                            my ($self, $attr, $current_value, $new_value) = @_;
                            $attr3_val = $new_value-1;
                    },
            };
    
    package Bar;
    use Object::Base 'Foo';
    attributes 'attr3', ':shared' => undef, 'attr2' => undef;
    
    package main;
    use threads;
    use threads::shared;
    
    # object of Foo
    my $foo = Foo->new();
    
    # usage of attribute
    $foo->attr1(1);
    print $foo->attr1, "\n"; # prints '1'
    
    # attributes are lvalued
    $foo->attr1++;
    print $foo->attr1, "\n"; # prints '2'
    
    # special attribute ':shared'
    print "\$foo is ", is_shared($foo)? "shared": "not shared", "\n";
    
    # attributes can have modifiers: default, getter, setter
    print "attr3 value ", $foo->attr3, " and stored as $attr3_val", "\n"; # prints 'attr3 value 7 and stored as 6'
    
    # object of derived class Bar
    my $bar = Bar->new();
    
    # attributes can be added derived classes
    $bar->attr3(3);
    
    # attributes are inheritable
    $bar->attr1(3);
    
    # attributes are overridable #1
    eval { $bar->attr2 = 4 }; print "Eval: $@"; # prints error 'Eval: Attribute attr2 is not defined in Bar at ...'
    
    # attributes are overridable #2
    print "\$bar is ", is_shared($bar)? "shared": "not shared", "\n"; # prints '$bar is not shared'
    
    # assigning ref values to shared class attributes
    eval { $foo->attr2 = { key1 => 'val1' } }; print "Eval: $@"; # prints error 'Eval: Invalid value for shared scalar at ...'
    $foo->attr2({ key2 => 'val2' }); # uses shared_clone assigning ref value
    print $foo->attr2->{key2}, "\n"; # prints 'val2'
    
    # attributes in thread
    my $thr1 = threads->create(sub { $foo->attr1 = 5; $bar->attr1 = 5; });
    my $thr2 = threads->create(sub { sleep 1; print "\$foo is shared and attr1: ", $foo->attr1, ", \$bar is not shared and attr1: ", $bar->attr1, "\n"; });
    $thr1->join();
    $thr2->join();

INSTALLATION

To install this module type the following

    perl Makefile.PL
    make
    make test
    make install

from CPAN

    cpan -i Object::Base

DEPENDENCIES

This module requires these other modules and libraries:

REPOSITORY

GitHub https://github.com/orkunkaraduman/p5-Object-Base

CPAN https://metacpan.org/release/Object-Base

AUTHOR

Orkun Karaduman <orkunkaraduman@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2017 Orkun Karaduman <orkunkaraduman@gmail.com>

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.