KinoSearch::Util::Class - class building utility
This is a private class and the interface may change radically and without warning. Do not use it on its own.
package KinoSearch::SomePackage::SomeClass; use base qw( KinoSearch::Util::Class ); our %instance_vars = __PACKAGE__->init_instance_vars( # constructor params / members foo => undef, bar => {}, # members baz => {}, );
KinoSearch::Util::Class is a class-building utility a la Class::Accessor, Class::Meta, etc. It provides three main services:
A mechanism for inheriting instance variable declarations.
A constructor with basic argument checking.
Convenience methods which help in defining abstract classes.
The %instance_vars hash, which is always a package global, serves as a template for the creation of a hash-based object. It is built up from all the %instance_vars hashes in the module's parent classes, using init_instance_vars().
Key-value pairs in an %instance_vars hash are labeled as "constructor params" and/or "members". Items which are labeled as constructor params can be used as arguments to new().
our %instance_vars = __PACKAGE__->init_instance_vars( # constructor params / members foo => undef, bar => {}, # members baz => '', ); # ok: specifies foo, uses default for bar, derives baz my $object = __PACKAGE__->new( foo => $foo ); # not ok: baz isn't a constructor param my $object = __PACKAGE__->new( baz => $baz ); # ok if a parent class defines boffo as a constructor param my $object = __PACKAGE__->new( foo => $foo, boffo => $boffo, );
%instance_vars can contain hashrefs, array-refs, and full-fledged Perl objects. However, it cannot contain C-struct based objects, since Clone's clone() method doesn't know how to duplicate those safely.
# ok, Lock is a Perl object our %instance_vars = __PACKAGE__->init_instance_vars( # members term => KinoSearch::Store::Lock->new, ); # BAD! causes memory errors, since TermInfo is a C-struct object our %instance_vars = __PACKAGE__->init_instance_vars( # members tinfo => KinoSearch::Index::TermInfo->new, );
A generic constructor with basic argument checking. new() expects hash-style labeled parameters; the label names must be present in the %instance_vars hash, or it will croak().
After verifying the labeled parameters, new() creates a deep clone of %instance_vars, and merges in the labeled arguments. It then calls $self->init_instance() before returning the blessed reference.
$self->init_instance();
Perform customized initialization routine. By default, this is a no-op.
our %instance_vars = __PACKAGE__->init_instance_vars( a_safe_variable_name_that_wont_clash => 1, freep_warble => undef, );
Package method only. Return a flat list containing the arguments, plus all the key-value pairs in the parent class's %instance_vars hash.
sub an_abstract_method { shift->abstract_death } sub an_unimplemented_method { shift->unimplemented_death } sub maybe_someday { shift->todo_death }
These are just different ways to die(), and are of little interest until your particular application comes face to face with one of them.
abstract_death indicates that a method must be defined in a subclass.
unimplemented_death indicates a feature/function that will probably not be implemented. Typically, this would appear for a sub that a developer intimately familiar with Lucene would expect to find.
todo_death indicates a feature that might get implemented someday.
Copyright 2005-2006 Marvin Humphrey
See KinoSearch version 0.07.
To install KinoSearch, copy and paste the appropriate command in to your terminal.
cpanm
cpanm KinoSearch
CPAN shell
perl -MCPAN -e shell install KinoSearch
For more information on module installation, please visit the detailed CPAN module installation guide.