=encoding utf8

=head1 NAME

User::Identity::Item - general base class for User::Identity

=head1 INHERITANCE

 User::Identity::Item is extended by
   Mail::Identity
   User::Identity
   User::Identity::Archive
   User::Identity::Collection
   User::Identity::Location
   User::Identity::System

=head1 SYNOPSIS

=head1 DESCRIPTION

The C<User::Identity::Item> base class is extended into useful modules: it
has no use by its own.

=head1 METHODS

=head2 Constructors

=over 4

=item User::Identity::Item-E<gt>B<new>( [$name], %options )

 -Option     --Default
  description  undef
  name         <required>
  parent       undef

=over 2

=item description => STRING

Free format description on the collected item.

=item name => STRING

A simple name for this item.  Try to give a useful name in the context of
the item time.  Each time when you lookup items, you need to specify
this name, so it should be unique and not to hard to handle in your program.
For instance, when a person is addressed, you usually will give him/her
this a nickname.

=item parent => OBJECT

The encapsulating object: the object which collects this one.

=back

=back

=head2 Attributes

=over 4

=item $obj-E<gt>B<description>()

Free format description on this item.  Please do not add
any significance to the content of this field: if you are in need
for an extra attribute, please contact the author of the module to
implement it, or extend the object to suit your needs.

=item $obj-E<gt>B<name>( [$newname] )

The name of this item.  Names are unique within a collection... a second
object with the same name within any collection will destroy the already
existing object with that name.

Changing the name of an item is quite dangerous.  You probably want to
call L<User::Identity::Collection::renameRole()|User::Identity::Collection/"Maintaining roles"> instead.

=back

=head2 Collections

=over 4

=item $obj-E<gt>B<add>($collection, $role)

The $role is added to the $collection.  The $collection is the name of a
collection, which will be created automatically with L<addCollection()|User::Identity::Item/"Collections"> if
needed.  The $collection can also be specified as existing collection object.

The $role is anything what is acceptable to
L<User::Identity::Collection::addRole()|User::Identity::Collection/"Maintaining roles"> of the
collection at hand, and is returned.  $role typically is a list of
parameters for one role, or a reference to an array containing these
values.

example: 

 my $ui   = User::Identity->new(...);
 my $home = $ui->add(location => [home => street => '27 Roadstreet', ...] );
 my $work = $ui->add(location => work, tel => '+31-2231-342-13', ... );

 my $travel = User::Identity::Location->new(travel => ...);
 $ui->add(location => $travel);

 my $system = User::Identity::Collection::System->new(...);
 $ui->add($system => 'localhost');

=item $obj-E<gt>B<addCollection>( $object | <[$type], %options> )

Add a new collection of roles to an item.  This can be achieved in two ways:
either create an L<User::Identity::Collection|User::Identity::Collection> $object yourself and then
pass that to this method, or supply all the %options needed to create such
an object and it will be created for you.  The object which is added is
returned, and can be used for many methods directly.

For %options, see the specific type of collection.  Additional options are
listed below.

 -Option--Default
  type    <required>

=over 2

=item type => STRING|CLASS

The nickname of a collection class or the CLASS name itself of the
object to be created.  Required if an object has to be created.
Predefined type nicknames are C<email>, C<system>, and C<location>.

=back

example: 

 my $me   = User::Identity->new(...);
 my $locs = User::Identity::Collection::Locations->new();
 $me->addCollection($locs);

 my $email = $me->addCollection(type => 'email');
 my $email = $me->addCollection('email');

=item $obj-E<gt>B<collection>($name)

In scalar context the collection object with the $name is returned.
In list context, all the roles within the collection are returned.

example: 

 my @roles = $me->collection('email');        # list of collected items
 my @roles = $me->collection('email')->roles; # same of collected items
 my $coll  = $me->collection('email');        # a User::Identity::Collection

=item $obj-E<gt>B<parent>( [$parent] )

Returns the parent of an Item (the enclosing item).  This may return C<undef>
if the object is stand-alone.

=item $obj-E<gt>B<removeCollection>($object|$name)

=item $obj-E<gt>B<type>()

=item User::Identity::Item-E<gt>B<type>()

Returns a nice symbolic name for the type.

=item $obj-E<gt>B<user>()

Go from this object to its parent, to its parent, and so on, until a
L<User::Identity|User::Identity> is found or the top of the object tree has been
reached.

example: 

 print $email->user->fullName;

=back

=head2 Searching

=over 4

=item $obj-E<gt>B<find>($collection, $role)

Returns the object with the specified $role within the named collection.
The collection can be specified as name or object.

example: 

 my $role  = $me->find(location => 'work');       # one location
 my $role  = $me->collection('location')->find('work'); # same

 my $email = $me->addCollection('email');
 $me->find($email => 'work');
 $email->find('work');   # same

=back

=head1 DIAGNOSTICS

=over 4

=item Error: $object is not a collection.

The first argument is an object, but not of a class which extends
L<User::Identity::Collection|User::Identity::Collection>.

=item Error: Cannot load collection module for $type ($class).

Either the specified $type does not exist, or that module named $class returns
compilation errors.  If the type as specified in the warning is not
the name of a package, you specified a nickname which was not defined.
Maybe you forgot the 'require' the package which defines the nickname.

=item Error: Creation of a collection via $class failed.

The $class did compile, but it was not possible to create an object
of that class using the options you specified.

=item Error: Don't know what type of collection you want to add.

If you add a collection, it must either by a collection object or a
list of options which can be used to create a collection object.  In
the latter case, the type of collection must be specified.

=item Error: Each item requires a name

You have to specify a name for each item.  These names need to be
unique within one collection, but feel free to give the same name
to an e-mail address and a location.

=item Warning: No collection $name

The collection with $name does not exist and can not be created.

=item Warning: Unknown option $name for a $class

One used option is not defined.  Check the manual page of the class to
see which options are accepted.

=item Warning: Unknown options @names for a $class

More than one option is not defined.

=back

=head1 SEE ALSO

This module is part of User-Identity distribution version 1.00,
built on October 14, 2020. Website: F<http://perl.overmeer.net/CPAN/>

=head1 LICENSE

Copyrights 2003-2020 by [Mark Overmeer <markov@cpan.org>]. For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See F<http://dev.perl.org/licenses/>

