=head1 NAME

Mail::Message::Head::ResentGroup - header fields tracking message delivery

=head1 INHERITANCE

 Mail::Message::Head::ResentGroup
   is a Mail::Message::Head::FieldGroup
   is a Mail::Reporter

=head1 SYNOPSIS

 my $rg = Mail::Message::Head::ResentGroup->new(head => $head,
              From => 'me@home.nl', To => 'You@tux.aq');
 $head->addResentGroup($rg);

 my $rg = $head->addResentGroup(From => 'me');

 my @from = $rg->From;

 my @rgs = $head->resentGroups;
 $rg[2]->delete if @rgs > 2;

=head1 DESCRIPTION

A I<resent group> is a set of header fields which describe one intermediate
step in the message transport.  Resent groups B<have NOTHING to do> with
user activety; there is no relation to the C<user's> sense of creating
reply, forward, or bounce messages at all!

=head1 METHODS

=head2 Constructors

=over 4

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

See L<Mail::Message::Head::FieldGroup/"Constructors">

=item $obj-E<gt>B<from>([HEAD|MESSAGE, OPTIONS])

WARNING: this method has two very different purposes.  For backward
compatibility reasons, without arguments L<resentFrom()|Mail::Message::Head::ResentGroup/"Access to the header"> is called to
return the C<From> field of this resent group.

With any arguments, a list of C<Mail::Message::Head::ResentGroup> objects
is returned, taken from the specified MESSAGE or message HEAD.

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

=item Mail::Message::Head::ResentGroup-E<gt>B<implementedTypes>()

See L<Mail::Message::Head::FieldGroup/"Constructors">

=item Mail::Message::Head::ResentGroup-E<gt>B<new>([FIELDS], OPTIONS)

Create an object which maintains one set of resent headers.  The
FIELDS are L<Mail::Message::Field|Mail::Message::Field> objects from the same header.

OPTIONS which start with capitals will be used to construct additional
fields.  These option names are prepended with C<Resent-*>, keeping the
capitization of what is specified.

 -Option      --Defined in     --Default
  Bcc                            undef
  Cc                             undef
  Date                           <now>
  Delivered-To                   undef
  From                           <required>
  Message-ID                     <uniquely created>
  Received                       <created>
  Return-Path                    undef
  Sender                         undef
  To                             undef
  head                           <created automatically>
  log           Mail::Reporter   'WARNINGS'
  message_head                   undef
  software      Mail::Message::Head::FieldGroup  undef
  trace         Mail::Reporter   'WARNINGS'
  type          Mail::Message::Head::FieldGroup  undef
  version       Mail::Message::Head::FieldGroup  undef

=over 2

=item Bcc => STRING|OBJECT|OBJECTS

=item Cc => STRING|OBJECT|OBJECTS

=item Date => STRING

When this resent-group is dispatched by the resender of the message. Like
the C<Date> field, it is not the date and time that the message was
actually transported.

=item Delivered-To => STRING|FIELD

=item From => STRING|OBJECT|OBJECTS

=item Message-ID => STRING|FIELD

The C<Resent-Message-ID> which identifies this resent group.  The FIELD
must contain a message id.

=item Received => STRING

The C<Received> field is the starting line for a resent group of header
lines. If it is not defined, one is created using L<createReceived()|Mail::Message::Head::ResentGroup/"Internals">.

=item Return-Path => STRING|FIELD

=item Sender => STRING|OBJECT

Only permitted when more than one from address is specified.  In this case,
it selects one of these addresses as the main originator of the message.

=item To => STRING|OBJECT|OBJECTS

=item head => OBJECT

The header where the data is stored in. By default a
L<Mail::Message::Head::Partial|Mail::Message::Head::Partial> is created for you.

=item log => LEVEL

=item message_head => HEAD

The real header of the message where this resent group is part of.  The
C<head> used in this class is only a container for a subset of fields.

=item software => STRING

=item trace => LEVEL

=item type => STRING

=item version => STRING

=back

=back

=head2 The header

=over 4

=item $obj-E<gt>B<add>((FIELD =E<gt> VALUE) | OBJECT)

All fields appear only once, so C<add()> behaves as L<set()|Mail::Message::Head::ResentGroup/"The header">.

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

Not applicable to resent-groups: the same name can appear in more than
one group.  Therefore, a FIELDNAME is sufficiently distinctive.

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

See L<Mail::Message::Head::FieldGroup/"The header">

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

See L<Mail::Message::Head::FieldGroup/"The header">

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

See L<Mail::Message::Head::FieldGroup/"The header">

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

See L<Mail::Message::Head::FieldGroup/"The header">

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

See L<Mail::Message::Head::FieldGroup/"The header">

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

Returns (optionally after setting) the real header where this resent group
belongs to.  This may be undef at creation, and then later filled in
when L<Mail::Message::Head::Complete::addResentGroup()|Mail::Message::Head::Complete/"Access to the header"> is called.

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

Returns the fields in the order as should appear in header according
to rfc2822.  For the C<Resent-*> fields of the group, the order is
not that important, but the C<Return-Path>, C<Delivered-To>, and C<Received>
must come first.  Only fields mentioned in the RFC are returned.

=item $obj-E<gt>B<set>((FIELD =E<gt> VALUE) | OBJECT)

Set a FIELD to a (new) VALUE.  The FIELD names which do not start with
'Resent-*' but need it will have that added.  It is also an option to
specify a fully prepared message field OBJECT.  In any case, a field
OBJECT is returned.

example: 

 my $this = Mail::Message::Head::ResentGroup->new;
 $this->set(To => 'fish@tux.aq');
 $msg->addResentGroup($this);
 $msg->send;

 $msg->bounce(To => 'fish@tux.aq')->send;   # the same

 my $this = Mail::Message::Head::ResentGroup
     ->new(To => 'fish@tux.aq');

=back

=head2 Access to the header

=over 4

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

In scalar context, the C<Resent-Bcc> field is returned.  In list context,
the addresses as specified within the bcc field are returned as
L<Mail::Address|Mail::Address> objects.  Bcc fields are not transmitted (hidden for
external parties).

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

In scalar context, the C<Resent-Cc> field is returned.  In list context,
the addresses as specified within the cc field are returned as
L<Mail::Address|Mail::Address> objects.

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

Returns the C<Resent-Date> field, or C<undef> if it was not defined.

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

The timestamp as stored within the C<Resent-Date> field converted to
local system time.

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

The field which describes the C<Delivered-To> of this resent group.

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

Returns a list of all addresses specified in the C<Resent-To>, C<-Cc>, and
C<-Bcc> fields of this resent group.

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

=item Mail::Message::Head::ResentGroup-E<gt>B<isResentGroupFieldName>(NAME)

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

Returns the message-ID used for this group of resent lines.

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

The field which describes the C<Received> data of this resent group.

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

The timestamp as stored within the C<Received> field converted to
local system time.

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

In scalar context, the C<Resent-From> field is returned.  In list
context, the addresses as specified within the from field are
returned as L<Mail::Address|Mail::Address> objects.

For reasons of backward compatibility and consistency, the L<from()|Mail::Message::Head::ResentGroup/"METHODS">
method will return the same as this method.

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

The field which describes the C<Return-Path> of this resent group.

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

In scalar context, the C<Resent-Sender> field is returned.  In list
context, the addresses as specified within the from field are
returned as L<Mail::Address|Mail::Address> objects.

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

See L<Mail::Message::Head::FieldGroup/"Access to the header">

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

In scalar context, the C<Resent-To> field is returned.  In list context,
the addresses as specified within the to field are returned as
L<Mail::Address|Mail::Address> objects.

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

See L<Mail::Message::Head::FieldGroup/"Access to the header">

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

See L<Mail::Message::Head::FieldGroup/"Access to the header">

=back

=head2 Internals

=over 4

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

See L<Mail::Message::Head::FieldGroup/"Internals">

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

Create a received field for this resent group.  This is automatically
called if none was specified during creation of this resent group object.

The content of this field is described in RFC2821 section 4.4.  It could use
some improvement.

=item $obj-E<gt>B<detected>(TYPE, SOFTWARE, VERSION)

See L<Mail::Message::Head::FieldGroup/"Internals">

=back

=head2 Error handling

=over 4

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

=item Mail::Message::Head::ResentGroup-E<gt>B<defaultTrace>([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Message::Head::FieldGroup/"Error handling">

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

See L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<log>([LEVEL [,STRINGS]])

=item Mail::Message::Head::ResentGroup-E<gt>B<log>([LEVEL [,STRINGS]])

See L<Mail::Reporter/"Error handling">

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

=item Mail::Message::Head::ResentGroup-E<gt>B<logPriority>(LEVEL)

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Message::Head::FieldGroup/"Error handling">

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

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

See L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

=over 4

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

See L<Mail::Reporter/"Cleanup">

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

See L<Mail::Reporter/"Cleanup">

=back

=head1 DIAGNOSTICS

=over 4

=item Error: Message header required for creation of ResentGroup.

It is required to know to which header the resent-group
is created.  Use the C<head> option.  Maybe you should use
L<Mail::Message::Head::Complete::addResentGroup()|Mail::Message::Head::Complete/"Access to the header"> with DATA, which will
organize the correct initiations for you.

=item Error: Package $package does not implement $method.

Fatal error: the specific package (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.

=back

=head1 SEE ALSO

This module is part of Mail-Box distribution version 2.106,
built on August 15, 2012. Website: F<http://perl.overmeer.net/mailbox/>

=head1 LICENSE

Copyrights 2001-2012 by [Mark Overmeer]. 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://www.perl.com/perl/misc/Artistic.html>

