Action.pm

package Workflow::Action;

# Note: we may implement a separate event mechanism so that actions
# can trigger other code (to read observations from database?)

use warnings;
use strict;
use base qw( Workflow::Base );
use Log::Log4perl qw( get_logger );
use Workflow::Action::InputField;
use Workflow::Validator::HasRequiredField;
use Workflow::Factory qw( FACTORY );
use Carp qw(croak);

$Workflow::Action::VERSION = '1.50';

my @PROPS    = qw( name class description );
my @INTERNAL = qw( _factory );
__PACKAGE__->mk_accessors( @PROPS, @INTERNAL );

####################
# INPUT FIELDS

sub add_fields {
    my ( $self, @fields ) = @_;
    push @{ $self->{_fields} }, @fields;
}

sub required_fields {
    my ($self) = @_;
    return grep { $_->requirement() eq 'required' } @{ $self->{_fields} };
}

sub optional_fields {
    my ($self) = @_;
    return grep { $_->requirement() eq 'optional' } @{ $self->{_fields} };
}

sub fields {
    my ($self) = @_;
    return @{ $self->{_fields} };
}

####################
# VALIDATION

sub add_validators {
    my ( $self, @validator_info ) = @_;
    my @validators = ();
    foreach my $conf (@validator_info) {
        my $validator = $self->_factory()->get_validator( $conf->{name} );
        my @args      = $self->normalize_array( $conf->{arg} );
        push @validators,
            {
            validator => $validator,
            args      => \@args
            };
    }
    push @{ $self->{_validators} }, @validators;
}

sub get_validators {
    my ($self) = @_;
    return () if ( not defined $self->{_validators} );
    return @{ $self->{_validators} };
}

sub validate {
    my ( $self, $wf ) = @_;
    my @validators = $self->get_validators;
    return unless ( scalar @validators );

    my $context = $wf->context;
    foreach my $validator_info (@validators) {
        my $validator    = $validator_info->{validator};
        my $args         = $validator_info->{args};

        # TODO: Revisit this statement it does not look right
        # runtime_args becomes the WF object??
        my @runtime_args = ($wf);
        foreach my $arg ( @{$args} ) {
            if ( $arg =~ /^\$(.*)$/ ) {
                push @runtime_args, $context->param($1);
            } else {
                push @runtime_args, $arg;
            }
        }
        $validator->validate(@runtime_args);
    }
}

# Subclasses override...

sub execute {
    my ( $self, $wf ) = @_;
    croak "Class ", ref($self), " must implement 'execute()'\n";
}

########################################
# PRIVATE

sub init {
    my ( $self, $wf, $params ) = @_;

    my $log = get_logger();

    # So we don't destroy the original...
    my %copy_params = %{$params};

    $self->_factory( $wf->_factory() );
    $self->class( $copy_params{class} );
    $self->name( $copy_params{name} );
    $self->description( $copy_params{description} );

    ## init normal fields
    my @fields = $self->normalize_array( $copy_params{field} );
    foreach my $field_info (@fields) {
        if ( my $field_class = $field_info->{class} ) {
            $log->debug("Using custom field class $field_class");
            $self->add_fields( $field_class->new($field_info) );
        } else {
            $log->debug("Using standard field class");
            $self->add_fields(
                Workflow::Action::InputField->new($field_info) );
        }
    }

    ## establish validator for fields with is_required="yes"
    @fields = $self->required_fields();
    my $validator = Workflow::Validator::HasRequiredField->new(
        {   name  => 'HasRequiredField for is_required fields',
            class => 'Workflow::Validator::HasRequiredField'
        }
    );
    my @args = ();
    foreach my $field (@fields) {
        next if ( not $field );    ## empty @fields array
        push @args, $field->name();
    }
    push @{ $self->{_validators} },
        {
        validator => $validator,
        args      => \@args
        };

    ## init normal validators
    my @validator_info = $self->normalize_array( $copy_params{validator} );
    $self->add_validators(@validator_info);

    delete @copy_params{qw( class name description field validator )};

    # everything else is just a passthru param

    while ( my ( $key, $value ) = each %copy_params ) {
        $self->param( $key, $value );
    }
}

1;

__END__

=pod

=head1 NAME

Workflow::Action - Base class for Workflow actions

=head1 VERSION

This documentation describes version 1.09 of this package

=head1 SYNOPSIS

 # Configure the Action...
 <action name="CreateUser"
         class="MyApp::Action::CreateUser">
   <field name="username" is_required="yes"/>
   <field name="email" is_required="yes"/>
   <validator name="IsUniqueUser">
       <arg>$username</arg>
   </validator>
   <validator name="IsValidEmail">
       <arg>$email</arg>
   </validator>
 </action>

 # Define the action

 package MyApp::Action::CreateUser;

 use base qw( Workflow::Action );
 use Workflow::Exception qw( workflow_error );

 sub execute {
     my ( $self, $wf ) = @_;
     my $context = $wf->context;

     # Since 'username' and 'email' have already been validated we
     # don't need to check them for uniqueness, well-formedness, etc.

     my $user = eval {
         User->create({ username => $context->param( 'username' ),
                        email    => $context->param( 'email' ) })
     };

     # Wrap all errors returned...

     if ( $@ ) {
         workflow_error
             "Cannot create new user with name '", $context->param( 'username' ), "': $EVAL_ERROR";
     }

     # Set the created user in the context for the application and/or
     # other actions (observers) to use

     $context->param( user => $user );

     # return the username since it might be used elsewhere...
     return $user->username;
 }

=head1 DESCRIPTION

This is the base class for all Workflow Actions. You do not have to
use it as such but it is strongly recommended.

=head1 CONFIGURATION

You configure your actions and map them to a specific module in your actions
configuration file using the syntax
above and that shown in L<Workflow>. In some cases, you'll have actions
that apply to all workflows. In more elaborate configurations, you may have
one workflow server loading multiple workflows and multiple actions for each.
In these
cases, you'll have multiple workflow types and you may want actions
with the same names to have different behaviors for each type.

For example, you may have a workflow type Ticket and another type Order_Parts.
They both may have a Submit action, but you'll want the Submit to be different
for each.

You can specify a type in your actions configuration to associate that action
with that workflow type. If you don't provide a type, the action is available
to all types. For example:

  <actions>
    <type>Ticket</type>
    <description>Actions for the Ticket workflow only.</description>
    <action name="TIX_NEW"
           class="TestApp::Action::TicketCreate">
  ...Addtional configuration...

The type must match an existing workflow type or the action will never
be called.

=head1 ADDITIONAL ATTRIBUTES

You can validate additional attributes in of your action by doing two things:

=over

=item *

Set C<$Workflow::Factory::VALIDATE_ACTION_CONFIG> to 1.

=item *

Provide function validate_config() in your action class.

=back

Then, this function will be called with all the acton attributes when
it is parsed.  For exmaple, if your action XML looks like this:

  <action name="BEGIN" class="My::Class" when="NOW">

You can validate it like this:

  sub My::Class::validate_config {
    my $config = shift;
    unless ('NOW' eq $config->{when}) {
      configuration_error "`$$config{when}' is not a valid value " .
                          "for `when'";
    }
  }

=head1 OBJECT METHODS

=head2 Public Methods

=head3 new()

Subclasses may override this method, but it's not very common. It is
called when you invoke a method in your Workflow object that returns
an Action object, for example, methods such as $wf->_get_action will
call this method.

B<Your action classes usually subclass directly from Workflow::Action
and they I<don't> need to override this method at all>. However, under
some circumstances, you may find the need to extend your action
classes.

Suppose you want to define some extra properties to actions but you
also want for some of these properties to depend on a particular
state. For example, the action "icon" will almost allways be the same,
but the action "index" will depend on state, so you can display your
actions in a certain order according to that particular state. Here is
an example on how you easily do this by overriding new():

1) Set the less changing properties in your action definition:

  <actions>
    <type>foo</type>
    <action name="Browse"
      type="menu_button" icon="list_icon"
      class="actual::action::class">
    </action>

2) Set the state dependant properties in the state definition:

 <state name="INITIAL">
   <description>
     Manage Manufaturers
   </description>
   <action index="0" name="Browse" resulting_state="BROWSE">
     <condition name="roleis_oem_mgmt"/>
   </action>
   <action index="1" name="Create" resulting_state="CREATE">
     <condition name="roleis_oem_mgmt"/>
   </action>
   <action index="2" name="Back" resulting_state="CLOSED"/>
 </state>

3) Craft a custom action base class

  package your::action::base::class;

  use warnings;
  use strict;

  use base qw( Workflow::Action );
  use Workflow::Exception qw( workflow_error );

  # extra action class properties
  my @EXTRA_PROPS = qw( index icon type data );
  __PACKAGE__->mk_accessors(@EXTRA_PROPS);

  sub new {
    my ($class, $wf, $params) = @_;
    my $self = $class->SUPER::new($wf, $params);
    # set only our extra properties from action class def
    foreach my $prop (@EXTRA_PROPS) {
      next if ( $self->$prop );
      $self->$prop( $params->{$prop} );
    }
    # override specific extra action properties according to state
    my $wf_state = $wf->_get_workflow_state;
    my $action = $wf_state->{_actions}->{$self->name};
    $self->index($action->{index});
    return $self;
  }


  1;

B<Note>: this hack takes advantage of the fact that the XML parser
picks up the extra parameters and add them to the action hash of the
current $wf_state. Your milage may vary.

4) Use your custom action base class instead of the default

  package actual::action::class;

  use warnings;
  use strict;

  use base qw( your::base::action::class );
  use Workflow::Exception qw( workflow_error );

  sub execute {
    ...
  }

  1;


=head2 Private Methods

=head3 init( $workflow, \%params )

init is called in conjuction with the overall workflow initialization.

It sets up the necessary validators based on the on configured actions, input fields and required fields.

=head3 add_field( @fields )

Add one or more L<Workflow::Action::InputField>s to the action.

=head3 required_fields()

Return a list of L<Workflow::Action::InputField> objects that are required.

=head3 optional_fields()

Return a list of L<Workflow::Action::InputField> objects that are optional.

=head3 fields()

Return a list of all L<Workflow::Action::InputField> objects
associated with this action.

=head3 add_validators( @validator_config )

Given the 'validator' configuration declarations in the action
configuration, ask the L<Workflow::Factory> for the
L<Workflow::Validator> object associated with each name and store that
along with the arguments to be used, runtime and otherwise.

=head3 get_validators()

Get a list of all the validator hashrefs, each with two keys:
'validator' and 'args'. The 'validator' key contains the appropriate
L<Workflow::Validator> object, while 'args' contains an arrayref of
arguments to pass to the validator, some of which may need to be
evaluated at runtime.

=head3 validate( $workflow )

Run through all validators for this action. If any fail they will
throw a L<Workflow::Exception>, the validation subclass.

=head3 execute( $workflow )

Subclasses B<must> implement -- this will perform the actual
work. It's not required that you return anything, but if the action
may be used in a L<Workflow::State> object that has multiple resulting
states you should return a simple scalar for a return value.

=head3 add_fields

Method to add fields to the workflow. The method takes an array of
fields.


=head1 SEE ALSO

L<Workflow>

L<Workflow::Factory>

=head1 COPYRIGHT

Copyright (c) 2003-2004 Chris Winters. All rights reserved.

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=head1 AUTHORS

Chris Winters E<lt>chris@cwinters.comE<gt>

=cut