/ 
Grep-Query-1.011
River stage one • 2 direct dependents • 2 total dependents
/ Grep::Query::FieldAccessor

NAME

Grep::Query::FieldAccessor - Helper object to hold methods to access fields in the supplied hashes/objects

SYNOPSIS

use Grep::Query::FieldAccessor;

# fill up an object with accessors
#
my $fieldAccessor1 = Grep::Query::FieldAccessor->new();
$fieldAccessor1->add('name', sub { $_[0]->getName() });
$fieldAccessor1->add('age', sub { $_[0]->calculateAge() });
...

# equal, but provide it all in one go
#
my $fieldAccessor2 = Grep::Query::FieldAccessor->new
    (
        {
            name => sub { $_[0]->getName() },
            age => sub { $_[0]->calculateAge() },
            ...
        }
    );

DESCRIPTION

When using a Grep::Query holding a query denoting fields, an object of this type must be passed along.

It must contain methods, indexed on field names, that given an item in the queried list, can extract the value to compare with.

Beware: Ensure the methods supplied don't cause side-effects when they are called (such as causing the object or other things to change).

METHODS

new( [ $hash ] )

Creates a new field accessor object.

If the optional $hash is provided, fields will be populated from it, otherwise the "add" method must be used.

newDefault( @fieldlist )

Creates a new field accessor object with default accessors for all the fields in the given list. It will handle fields expressing navigation paths automatically.

add( $fieldname, $sub )

Adds an accessor for the given field.

Croaks if the params don't seem to be what they should be or if a field is added more than once.

access( $fieldname, $obj )

(normally used by the internal query execution)

Looks up the code sub for the given field and executes it with obj as a parameter and returns the result.

assertField

(normally used by the internal query execution)

Retrieves the code sub for the given field.

Croaks if no such field is defined.

AUTHOR

Kenneth Olwing, <knth at cpan.org>

BUGS

Please report any bugs or feature requests to bug-grep-query at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Grep-Query. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Grep::Query

You can also look for information at:

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT

Copyright 2016 Kenneth Olwing.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.