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NAME
Data::Page - help when paging through sets of results
SYNOPSIS
use Data::Page;
my $page = Data::Page->new();
$page->total_entries($total_entries);
$page->entries_per_page($entries_per_page);
$page->current_page($current_page);
print " First page: ", $page->first_page, "\n";
print " Last page: ", $page->last_page, "\n";
print "First entry on page: ", $page->first, "\n";
print " Last entry on page: ", $page->last, "\n";
DESCRIPTION
When searching through large amounts of data, it is often the case that
a result set is returned that is larger than we want to display on one
page. This results in wanting to page through various pages of data. The
maths behind this is unfortunately fiddly, hence this module.
The main concept is that you pass in the number of total entries, the
number of entries per page, and the current page number. You can then
call methods to find out how many pages of information there are, and
what number the first and last entries on the current page really are.
For example, say we wished to page through the integers from 1 to 100
with 20 entries per page. The first page would consist of 1-20, the
second page from 21-40, the third page from 41-60, the fourth page from
61-80 and the fifth page from 81-100. This module would help you work
this out.
METHODS
new
This is the constructor, which takes no arguments.
my $page = Data::Page->new();
There is also an old, deprecated constructor, which currently takes two
mandatory arguments, the total number of entries and the number of
entries per page. It also optionally takes the current page number:
my $page = Data::Page->new($total_entries, $entries_per_page, $current_page);
total_entries
This method get or sets the total number of entries:
print "Entries:", $page->total_entries, "\n";
entries_per_page
This method gets or sets the total number of entries per page (which
defaults to 10):
print "Per page:", $page->entries_per_page, "\n";
current_page
This method gets or sets the current page number (which defaults to 1):
print "Page: ", $page->current_page, "\n";
entries_on_this_page
This methods returns the number of entries on the current page:
print "There are ", $page->entries_on_this_page, " entries displayed\n";
first_page
This method returns the first page. This is put in for reasons of
symmetry with last_page, as it always returns 1:
print "Pages range from: ", $page->first_page, "\n";
last_page
This method returns the total number of pages of information:
print "Pages range to: ", $page->last_page, "\n";
first
This method returns the number of the first entry on the current page:
print "Showing entries from: ", $page->first, "\n";
last
This method returns the number of the last entry on the current page:
print "Showing entries to: ", $page->last, "\n";
previous_page
This method returns the previous page number, if one exists. Otherwise
it returns undefined:
if ($page->previous_page) {
print "Previous page number: ", $page->previous_page, "\n";
}
next_page
This method returns the next page number, if one exists. Otherwise it
returns undefined:
if ($page->next_page) {
print "Next page number: ", $page->next_page, "\n";
}
splice
This method takes in a listref, and returns only the values which are on
the current page:
@visible_holidays = $page->splice(\@holidays);
skipped
This method is useful paging through data in a database using SQL LIMIT
clauses. It is simply $page->first - 1:
$sth = $dbh->prepare(
q{SELECT * FROM table ORDER BY rec_date LIMIT ?, ?}
);
$sth->execute($date, $page->skipped, $page->entries_per_page);
NOTES
It has been said before that this code is "too simple" for CPAN, but I
must disagree. I have seen people write this kind of code over and over
again and they always get it wrong. Perhaps now they will spend more
time getting the rest of their code right...
SEE ALSO
Related modules which may be of interest: Data::Pageset,
Data::Page::Tied, Data::SpreadPagination.
AUTHOR
Based on code originally by Leo Lapworth, with many changes added by by
Leon Brocard <acme@astray.com>.
COPYRIGHT
Copyright (C) 2000-8, Leon Brocard
LICENSE
This module is free software; you can redistribute it or modify it under
the same terms as Perl itself.
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