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

VERSION
    version 1.04

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 module 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;

    *   Lvaluable

    *   Inheritable

    *   Overridable

    *   Redefinable

    *   Thread-Safe

   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:

    *   threads

    *   threads::shared

    *   forks

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/>.