Mail::Message::Head::Subset(3)

NAME
Mail::Message::Head::Subset - subset of header information of a message

INHERITANCE
 Mail::Message::Head::Subset realizes a Mail::Message::Head::Complete

 Mail::Message::Head::Subset
   is a Mail::Message::Head
   is a Mail::Reporter

SYNOPSIS
  my $subset = Mail::Message::Head::Subset->new(...)
  $subset->isa('Mail::Message::Head')  # true
  $subset->guessBodySize               # integer or undef
  $subset->isDelayed                   # true

DESCRIPTION
Some types of folders contain an index file which lists a few lines of information per messages. Especially when it is costly to read header lines, the index speeds-up access considerably. For instance, the subjects of all messages are often wanted, but waiting for a thousand messages of the folder to be read may imply a thousand network reads (IMAP) or file openings (MH)

When you access header fields which are not in the header subset, the whole header has to be parsed (which may consume considerable time, depending on the type of folder).

Extends "DESCRIPTION" in Mail::Message::Head.

OVERLOADED
Extends "OVERLOADED" in Mail::Message::Head.

overload: "" stringifaction
    Inherited, see "OVERLOADED" in Mail::Message::Head

overload: bool true/false
    Inherited, see "OVERLOADED" in Mail::Message::Head

METHODS
Extends "METHODS" in Mail::Message::Head.

  Constructors
Extends "Constructors" in Mail::Message::Head.

$class->build( [PAIR|$field]-LIST )
    Inherited, see "Constructors" in Mail::Message::Head

$class->new(%options)
    Inherited, see "Constructors" in Mail::Message::Head

  Attributes
Extends "Attributes" in Mail::Message::Head.

  The header
Extends "The header" in Mail::Message::Head.

$obj->isDelayed()
    Inherited, see "The header" in Mail::Message::Head

$obj->isEmpty()
    Inherited, see "The header" in Mail::Message::Head

$obj->isModified()
    Inherited, see "The header" in Mail::Message::Head

$obj->knownNames()
    Inherited, see "The header" in Mail::Message::Head

$obj->message( [$message] )
    Inherited, see "The header" in Mail::Message::Head

$obj->modified( [BOOLEAN] )
    Inherited, see "The header" in Mail::Message::Head

$obj->orderedFields()
    Inherited, see "The header" in Mail::Message::Head

  Access to the header
Extends "Access to the header" in Mail::Message::Head.

$obj->count($name)
    Count the number of fields with this $name. If the $name cannot be found, the full header get loaded. In case we find any $name field, it is decided we know all of them, and loading is not needed.

$obj->get( $name, [$index] )
    Get the data which is related to the field with the $name. The case of the characters in $name does not matter. When a $name is used which is not known yet, realization will take place. Improves base, see "Access to the header" in Mail::Message::Head

$obj->study( $name, [$index] )
    Inherited, see "Access to the header" in Mail::Message::Head

  About the body
Extends "About the body" in Mail::Message::Head.

$obj->guessBodySize()
    The body size is defined in the "Content-Length" field. However, this field may not be known. In that case, a guess is made based on the known "Lines" field. When also that field is not known yet, "undef" is returned. Improves base, see "About the body" in Mail::Message::Head

$obj->isMultipart()
    Inherited, see "About the body" in Mail::Message::Head

  Internals
Extends "Internals" in Mail::Message::Head.

$obj->addNoRealize($field)
    Inherited, see "Internals" in Mail::Message::Head

$obj->addOrderedFields($fields)
    Inherited, see "Internals" in Mail::Message::Head

$obj->fileLocation()
    Inherited, see "Internals" in Mail::Message::Head

$obj->load()
    Inherited, see "Internals" in Mail::Message::Head

$obj->moveLocation($distance)
    Inherited, see "Internals" in Mail::Message::Head

$obj->read($parser)
    Inherited, see "Internals" in Mail::Message::Head

$obj->setNoRealize($field)
    Inherited, see "Internals" in Mail::Message::Head

  Error handling
Extends "Error handling" in Mail::Message::Head.

$obj->AUTOLOAD()
    Inherited, see "Error handling" in Mail::Reporter

$obj->notImplemented()
    Inherited, see "Error handling" in Mail::Reporter

  Cleanup
Extends "Cleanup" in Mail::Message::Head.

$obj->DESTROY()
    Inherited, see "Cleanup" in Mail::Reporter

DETAILS
Extends "DETAILS" in Mail::Message::Head.

DIAGNOSTICS

Error: class $package does not implement method $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. Cast by notImplemented()

SEE ALSO
This module is part of Mail-Box version 4.01, built on December 13, 2025. Website: http://perl.overmeer.net/CPAN/

LICENSE
For contributors see file ChangeLog.

This software is copyright (c) 2001-2025 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.