TAP::Parser::IteratorFactory

Section: Perl Programmers Reference Guide (3perl)
Updated: 2019-04-20
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NAME

TAP::Parser::IteratorFactory - Figures out which SourceHandler objects to use for a given Source

VERSION

Version 3.42

SYNOPSIS

  use TAP::Parser::IteratorFactory;
  my $factory = TAP::Parser::IteratorFactory->new({ %config });
  my $iterator  = $factory->make_iterator( $filename );

DESCRIPTION

This is a factory class that takes a TAP::Parser::Source and runs it through all the registered TAP::Parser::SourceHandlers to see which one should handle the source.

If you're a plugin author, you'll be interested in how to ``register_handler''s, how ``detect_source'' works.

METHODS

Class Methods

"new"

Creates a new factory class:

  my $sf = TAP::Parser::IteratorFactory->new( $config );

$config is optional. If given, sets ``config'' and calls ``load_handlers''.

"register_handler"

Registers a new TAP::Parser::SourceHandler with this factory.

  __PACKAGE__->register_handler( $handler_class );

"handlers"

List of handlers that have been registered.

Instance Methods

"config"

 my $cfg = $sf->config;
 $sf->config({ Perl => { %config } });

Chaining getter/setter for the configuration of the available source handlers. This is a hashref keyed on handler class whose values contain config to be passed onto the handlers during detection & creation. Class names may be fully qualified or abbreviated, eg:

  # these are equivalent
  $sf->config({ 'TAP::Parser::SourceHandler::Perl' => { %config } });
  $sf->config({ 'Perl' => { %config } });

"load_handlers"

 $sf->load_handlers;

Loads the handler classes defined in ``config''. For example, given a config:

  $sf->config({
    MySourceHandler => { some => 'config' },
  });

"load_handlers" will attempt to load the "MySourceHandler" class by looking in @INC for it in this order:

  TAP::Parser::SourceHandler::MySourceHandler
  MySourceHandler

"croak"s on error.

"make_iterator"

  my $iterator = $src_factory->make_iterator( $source );

Given a TAP::Parser::Source, finds the most suitable TAP::Parser::SourceHandler to use to create a TAP::Parser::Iterator (see ``detect_source''). Dies on error.

"detect_source"

Given a TAP::Parser::Source, detects what kind of source it is and returns one TAP::Parser::SourceHandler (the most confident one). Dies on error.

The detection algorithm works something like this:

  for (@registered_handlers) {
    # ask them how confident they are about handling this source
    $confidence{$handler} = $handler->can_handle( $source )
  }
  # choose the most confident handler

Ties are handled by choosing the first handler.

SUBCLASSING

Please see ``SUBCLASSING'' in TAP::Parser for a subclassing overview.

Example

If we've done things right, you'll probably want to write a new source, rather than sub-classing this (see TAP::Parser::SourceHandler for that).

But in case you find the need to...

  package MyIteratorFactory;

  use strict;

  use base 'TAP::Parser::IteratorFactory';

  # override source detection algorithm
  sub detect_source {
    my ($self, $raw_source_ref, $meta) = @_;
    # do detective work, using $meta and whatever else...
  }

  1;

AUTHORS

Steve Purkis

ATTRIBUTION

Originally ripped off from Test::Harness.

Moved out of TAP::Parser & converted to a factory class to support extensible TAP source detective work by Steve Purkis.