Workflow::Validator::IUsermContributedWorkflow::Validator::InEnumeratedType(3)NAMEWorkflow::Validator::InEnumeratedType - Ensure a value is one of a
declared set of values
VERSION
This documentation describes version 1.04 of this package
SYNOPSIS
# Inline the enumeration...
<action name="PlayGame">
<validator name="InEnumeratedType">
<value>Rock</value>
<value>Scissors</value>
<value>Paper</value>
<arg value="$play"/>
</validator>
</action>
# Or declare it in the validator to be more readable...
<validator name="RSP"
class="Validator::InEnumeratedType">
<value>Rock</value>
<value>Scissors</value>
<value>Paper</value>
</validator>
# ...and use it in your action
<action name="PlayGame">
<validator name="RSP">
<arg value="$play"/>
</validator>
</action>
DESCRIPTION
This validator ensures that a value matches one of a set of values. You
declare the values in the set (or enumerated type) in either the main
validator declaration or in the declaration inside the action, then
pass a single argument of the value in the context you would like to
check.
Declaring the members of the enumerated type in the validator
configuration makes for more readable (and brief) action
configurations, as well as making the types more reusable, but it is
really up to you.
SUBCLASSING
Strategy
Unlike some other validator classes this one is setup to be
subclassable. It is usable as-is, of course, but many times you will
find that you have need of more interesting types in your enumeration
than simple strings. So this class provides the hooks for you to simply
create your own.
For instance, in a trouble ticket system you may have the idea that
tickets can only be assigned to particular users. Maybe they are in a
'worker' role, maybe they are some administrators, whatever. By
creating a class to have these users as an enumerated type, combined
with declaring the required Action fields, you make for a pretty
powerful piece of reflection.
Onto the code. First we declare a field type of 'worker':
<field type="worker"
class="MyApp::Field::Worker"/>
Next a validator of this enumerated type:
<validator name="IsWorker"
class="MyApp::Validator::WorkerEnumeration"/>
We then associate this field type with a field in the action and the
validator to ensure the user selects a worker from the right pool:
<action name="AssignTicket">
<field name="assignee"
type="worker"
is_required="yes"/>
...
<validator name="IsWorker">
<arg value="$assignee"/>
</validator>
Note that the name of the field and the name used in the validator are
the same. This allows external applications to query the action for its
fields, get 'assignee' as the name and get a list of User objects (or
something similar) as the types from which to choose a value, and
checks that same field to ensure a correct choice was submitted.
The implementation for the validator might look like:
package MyApp::Validator::WorkerEnumeration;
sub validate {
my ( $self, $wf, $worker_id ) = @_;
my $ticket = $context->param( 'ticket' );
unless ( $ticket ) {
my $ticket_id = $context->param( 'ticket_id' );
$ticket = Ticket->fetch( $ticket_id );
}
my $workers = $ticket->fetch_available_workers();
my @worker_id = map { $_->id } @{ $workers };
$self->add_enumerated_values( @worker_id );
$self->SUPER::validate( $wf, $worker_id );
}
METHODS
_init( \%params )
This method initializes the class and the enumerated class.
It uses "add_enumerated_values" to add the set of values for
enumeration.
The primary parameter is value, which should be used to specify the
either a single value or a reference to array of values to be added.
validator
The validator method is the public API. It encapulates
"is_enumerated:value" and works with Workflow.
add_enumerated_values( @values )
This method ads an array of values to be regarded as enumerations for
the validator.
get_enumerated_values()
This method returns the defined enumerated values for the class as an
array.
is_enumerated_value( $value )
This is most often the single method you will want to modify.
The method offers assertion of a given value, as to whether it is an
enumerated type as defined in the class.
EXCEPTIONS
· Validator 'InEnumeratedType' must be initialized with the values
you wish to validate against using the parameter 'value'.
This Workflow::Exception is thrown from "_init" if the 'value'
parameter is not set.
· Value '$value' must be one of: <@values>
This Workflow::Exception is thrown from "_validator" if the value
to be asserted is not mathing any of the enumerated values defined
as part of the set.
COPYRIGHT
Copyright (c) 2003-2007 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.
AUTHORS
Current maintainer Jonas B. Nielsen <jonasbn@cpan.org>
Original author Chris Winters <chris@cwinters.com>
perl v5.14.12011Workflow::Validator::InEnumeratedType(3)
