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).

       See documentation in the base class.

OVERLOADED

       See documentation in the base class.

       overload: ""()
           See "OVERLOADED" in Mail::Message::Head

       overload: bool()
           See "OVERLOADED" in Mail::Message::Head

METHODS

       See documentation in the base class.

   Constructors
       See documentation in the base class.

       Mail::Message::Head::Subset->build([PAIR|FIELD]-LIST)
           See "Constructors" in Mail::Message::Head

       Mail::Message::Head::Subset->new(OPTIONS)
           See "Constructors" in Mail::Message::Head

   The header
       See documentation in the base class.

       $obj->isDelayed()
           See "The header" in Mail::Message::Head

       $obj->isEmpty()
           See "The header" in Mail::Message::Head

       $obj->isModified()
           See "The header" in Mail::Message::Head

       $obj->knownNames()
           See "The header" in Mail::Message::Head

       $obj->message([MESSAGE])
           See "The header" in Mail::Message::Head

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

       $obj->orderedFields()
           See "The header" in Mail::Message::Head

   Access to the header
       See documentation in the base class.

       $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.

       $obj->study(NAME [,INDEX])
           See "Access to the header" in Mail::Message::Head

   About the body
       See documentation in the base class.

       $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.

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

   Internals
       See documentation in the base class.

       $obj->addNoRealize(FIELD)
           See "Internals" in Mail::Message::Head

       $obj->addOrderedFields(FIELDS)
           See "Internals" in Mail::Message::Head

       $obj->fileLocation()
           See "Internals" in Mail::Message::Head

       $obj->load()
           See "Internals" in Mail::Message::Head

       $obj->moveLocation(DISTANCE)
           See "Internals" in Mail::Message::Head

       $obj->read(PARSER)
           See "Internals" in Mail::Message::Head

       $obj->setNoRealize(FIELD)
           See "Internals" in Mail::Message::Head

   Error handling
       See documentation in the base class.

       $obj->AUTOLOAD()
           See "Error handling" in Mail::Reporter

       $obj->addReport(OBJECT)
           See "Error handling" in Mail::Reporter

       $obj->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])
       Mail::Message::Head::Subset->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL,
       CALLBACK])
           See "Error handling" in Mail::Reporter

       $obj->errors()
           See "Error handling" in Mail::Reporter

       $obj->log([LEVEL [,STRINGS]])
       Mail::Message::Head::Subset->log([LEVEL [,STRINGS]])
           See "Error handling" in Mail::Reporter

       $obj->logPriority(LEVEL)
       Mail::Message::Head::Subset->logPriority(LEVEL)
           See "Error handling" in Mail::Reporter

       $obj->logSettings()
           See "Error handling" in Mail::Reporter

       $obj->notImplemented()
           See "Error handling" in Mail::Reporter

       $obj->report([LEVEL])
           See "Error handling" in Mail::Reporter

       $obj->reportAll([LEVEL])
           See "Error handling" in Mail::Reporter

       $obj->trace([LEVEL])
           See "Error handling" in Mail::Reporter

       $obj->warnings()
           See "Error handling" in Mail::Reporter

   Cleanup
       See documentation in the base class.

       $obj->DESTROY()
           See "Cleanup" in Mail::Reporter

DETAILS

       See documentation in the base class.

DIAGNOSTICS

       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.

SEE ALSO

       This module is part of Mail-Box distribution version 2.110, built on January 05, 2014.
       Website: http://perl.overmeer.net/mailbox/

LICENSE

       Copyrights 2001-2014 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 http://www.perl.com/perl/misc/Artistic.html