NAME

FlatFile::DataStore::Preamble - Perl module that implements a flat file data store preamble class.

SYNOPSYS

use FlatFile::DataStore::Preamble;

my $preamble = FlatFile::DataStore::Preamble->new( {
    datastore => $ds,         # FlatFile::DataStore object
    indicator => $indicator,  # single-character crud flag
    transind  => $transind,   # single-character crud flag
    date      => $date,       # pre-formatted date
    transnum  => $transint,   # transaction number (integer)
    keynum    => $keynum,     # record sequence number (integer)
    reclen    => $reclen,     # record length (integer)
    thisfnum  => $fnum,       # file number (in base format)
    thisseek  => $datapos,    # seek position (integer)
    prevfnum  => $prevfnum,   # ditto these ...
    prevseek  => $prevseek,
    nextfnum  => $nextfnum,
    nextseek  => $nextseek,
    user      => $user_data,  # pre-formatted user-defined data
    } );

my $string = $preamble->string();

my $clone = FlatFile::DataStore::Preamble->new( {
    datastore => $ds,
    string    => $string
    } );

DESCRIPTION

FlatFile::DataStore::Preamble - Perl module that implements a flat file data store preamble class. This class defines objects used by FlatFile::DataStore::Record and FlatFile::DataStore. You will probably not ever call new() yourself, but you might call some of the accessors either directly or via a FF::DS::Record object;

A "preamble" is a string of fixed-length fields that precedes every record in a FlatFile::DataStore data file. In addition, this string constitutes the entry in the data store key file for each current record.

VERSION

FlatFile::DataStore::Preamble version 1.00

CLASS METHODS

FlatFile::DataStore::Preamble->new( $parms )

Constructs a new FlatFile::DataStore::Preamble object.

The parm $parms is a hash reference containing key/value pairs to populate the preamble string. If there is a $parms->{'string'} value, it will be parsed into fields and the resulting key/value pairs will replace the $parms hash reference.

OBJECT METHODS: ACCESSORS

The following methods set and return their respective attribute values if $value is given. Otherwise, they just return the value.

$preamble->string(    $value ); # full preamble string
$preamble->indicator( $value ); # single-character crud indicator
$preamble->transind(  $value ); # single-character crud indicator
$preamble->date(      $value ); # date as YYYY-MM-DD (hh:mm:ss)
$preamble->transnum(  $value ); # transaction number (integer)
$preamble->keynum(    $value ); # record sequence number (integer)
$preamble->reclen(    $value ); # record length (integer)
$preamble->thisfnum(  $value ); # file number (in base format)
$preamble->thisseek(  $value ); # seek position (integer)
$preamble->prevfnum(  $value ); # ditto these ...
$preamble->prevseek(  $value ); # 
$preamble->nextfnum(  $value ); # 
$preamble->nextseek(  $value ); # 
$preamble->user(      $value ); # pre-formatted user-defined data
$preamble->crud(      $value ); # hash ref of all crud indicators

Note: the class code uses these accessors to set values in the object as it is assembling the preamble string in new(). Unless you have a really good reason, you should not set these values yourself (outside of a call to new()). For example: setting the date with date() will not change the date in the string attribute.

In other words, even though these are read/write accessors, you should only use them for reading.

Convenience methods

is_created(), is_updated(), is_deleted();

These methods return true if the indicator matches the value implied by the method name, e.g.,

print "Deleted!" if $preamble->is_deleted();

AUTHOR

Brad Baxter, <bbaxter@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2010 by Brad Baxter

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.