/ 
OP-0.305
/ OP::Class

NAME

OP::Class - Root-level "Class" class

SYNOPSIS

Class Allocation

#
# File: OP/Example.pm
#

use OP;

create "OP::Example" => {
  #
  # This is an empty class prototype
  #
};

Class Consumer

#
# File: testscript.pl
#

use strict;
use warnings;

use OP::Example;

my $exa = OP::Example->new();

$exa->setName("My First OP Object");

$exa->save("This is a checkin comment");

say "Saved object:";

$exa->print();

DESCRIPTION

OP::Class is the root-level parent class in OP, and also provides the class prototyping function create().

METHODS

Public Class Methods

  • get(OP::Class $class: Str $key)

    Get the named class variable

    my $class = "OP::Example";

my $scalar = $class->get($key);

my @array = $class->get($key);

my %hash = $class->get($key);

  • set(OP::Class $class: Str $key, *@value)

    Set the named class variable to the received value

    my $class = "OP::Example";

$class->set($key, $scalar);

$class->set($key, @array);

$class->set($key, %hash);

  • pretty(OP::Class $class: Str $key)

    Transform camelCase to Not Camel Case

    my $class = "OP::Example";

my $uglyStr = "betterGetThatLookedAt";

my $prettyStr = $class->pretty($uglyStr);

  • members(OP::Class $class:)

    Class introspection method.

    Return an array ref of all messages supported by this class.

    Does not include messages from superclasses.

    my $members = OP::Example->members();

  • membersHash(OP::Class $class:)

    Class introspection method.

    Return a hash ref of all messages supported by this class.

    Does not include messages from superclasses.

    my $membersHash = OP::Example->membersHash();

Private Class Methods

  • init(OP::Class $class:)

    Abstract callback method invoked immediately after a new class is allocated via create().

    Override in subclass with additional logic, if necessary.

  • __checkVarName(OP::Class $class: Str $varName)

    Checks the "safeness" of a class variable name before eval'ing it.

PROTOTYPE COMPONENTS

Class (Package) Name

The name of the class being created is the first argument sent to create().

use OP;

#
# The class name will be "OP::Example":
#
create "OP::Example" => {

};

Class Prototype

A class prototype is a hash describing all fundamental characteristics of an object class. It's the second argument sent to create().

create "OP::Example" => {
  #
  # This is an empty prototype (perfectly valid)
  #
};

Instance Variables

Instance variables are declared with the assert class method:

create "YourApp::Example" => {
  favoriteNumber => OP::Int->assert()

};

The allowed values for a given instance variable may be specified as arguments to the assert method.

Instance variables may be augmented with subtyping rules using the subtype function, which is also sent as an argument to assert. See OP::Subtype for a list of allowed subtype arguments.

create "YourApp::Example" => {
  favoriteColor  => OP::Str->assert(
    qw| red green blue |,
    subtype(
      optional => true
    )
  ),
};

Instance Methods

Instance methods are declared as keys in the class prototype. The name of the method is the key, and its value in the prototype is a Perl 5 sub{}.

create "OP::Example" => {
  #
  # Add a public instance method, $self->handleFoo()
  #
  handleFoo => sub {
    my $self = shift;

    printf 'The value of foo is %s', $self->foo();
    print "\n";

    return true;
  }
}

my $exa = OP::Example->new();

$exa->setFoo("Bar");

$exa->handleFoo();

#
# Expected output:
#
# The value of foo is Bar
#

The OP convention for private or protected instance methods is to prefix them with a single underscore.

create "OP::Example" => {
  #
  # private instance method
  #
  _handleFoo => sub {
    my $self = shift;

    say "The value of foo is $self->{foo}";
  }
};

Class Variables

Class variables are declared as keys in the class prototype. They should be prepended with double underscores (__). The value in the prototype is the literal value to be used for the class variable.

use OP;

create "OP::Example" => {
  #
  # Override a few class variables
  #
  __useYaml => false,
  __dbiType => OP::DBIType::MySQL
};

OP class variables are just Perl package variables, scoped in list context.

Class Methods

Class methods are declared in the same manner as instance methods. The only difference is that the class will be the receiver.

create "OP::Example" => {
  #
  # Add a public class method
  #
  loadXml => sub {
    my $class = shift;
    my $xml = shift;

    # ...
  }
};

The OP convention for private or protected class methods is to prefix them with double underscores.

create "OP::Example" => {
  #
  # Override a private class method
  #
  __basePath => sub {
    my $class = shift;

    return join('/', '/tmp', $class);
  }
};

Inheritance

By default, classes created with create() inherit from OP::Node. To override this, include a __BASE__ attribute, specifying the parent class name.

create "OP::Example" => {
  #
  # Override parent class
  #
  __BASE__ => "Acme::CustomClass"
};

OPTIONAL EXPORTS

Constants

Functions

  • create(Str $class: Hash $prototype)

    Allocate a new OP-derived class.

    Objects instantiated from classes allocated with create() have built-in runtime assertions-- simple but powerful rules in the class prototype which define runtime and schema attributes. See the OP::Type module for more about assertions.

    OP classes are regular old Perl packages. create() is just a wrapper to the package keyword, with some shortcuts thrown in.

    use OP;

create "OP::Example" => {
  __someClassVar => true,

  someInstanceVar => OP::Str->assert(),

  anotherInstanceVar => OP::Str->assert(),

  publicInstanceMethod => sub {
    my $self = shift;

    # ...
  },

  _privateInstanceMethod => sub {
    my $self = shift;

    # ...
  },

  publicClassMethod => sub {
    my $class = shift;

    # ...
  },

  __privateClassMethod => sub {
    my $class = shift;

    # ...
  },
};

DIAGNOSTICS

XXX TODO Figure out what to put in this section.

CONFIGURATION AND ENVIRONMENT

OP looks for the .oprc configuration file under the location specified by $OP_HOME. See OP::Constants for details.

OP under mod_perl/mod_perl2

OP classes should be precompiled under mod_perl by referencing them in the Apache instance's startup.pl script. OP_HOME must be set in a BEGIN block.

#
# File: startup.pl
#
BEGIN {
  $ENV{OP_HOME} = '/home/user/op'; # Directory with the .oprc
}

#
# Load any OP-derived packages at startup:
#
use MyApp::Component;
use MyApp::OtherComponent;

1;

OP under HTML::Mason

It is highly recommended to use a startup script to preload OP and the packages used in your web application.

#
# File: httpd.conf
#
PerlModule HTML::Mason::ApacheHandler
PerlRequire /opt/op/bin/startup.pl

<LocationMatch "/.*\.html$">
  SetHandler perl-script

  PerlHandler HTML::Mason::ApacheHandler
</LocationMatch>

DEPENDENCIES

See the META.yml which accompanied this distribution for a current list of prerequisites.

INCOMPATIBILITIES

Probably.

BUGS AND LIMITATIONS

Likely.

Test suite is currently incomplete.

SEE ALSO

OP::Type, OP::Subtype

This file is part of OP.