NAME

Config::Model::Iterator - Iterates forward or backward a configuration tree

VERSION

version 2.017

SYNOPSIS

 use Config::Model;
 use Log::Log4perl qw(:easy);
 Log::Log4perl->easy_init($WARN);

 # define configuration tree object
 my $model = Config::Model->new;
 $model->create_config_class(
    name    => "Foo",
    element => [
        [qw/bar baz/] => {
            type       => 'leaf',
            value_type => 'string',
            level => 'important' ,
        },
    ]
 );
 $model->create_config_class(
    name    => "MyClass",
    element => [
        foo_nodes => {
            type       => 'hash',     # hash id
            index_type => 'string',
            level => 'important' ,
            cargo      => {
                type              => 'node',
                config_class_name => 'Foo'
            },
        },
    ],
 );

 my $inst = $model->instance( root_class_name => 'MyClass' );
 # create some Foo objects
 $inst->config_root->load("foo_nodes:foo1 - foo_nodes:foo2  ") ;

 my $my_leaf_cb = sub {
    my ($iter, $data_r,$node,$element,$index, $leaf_object) = @_ ;
    print "leaf_cb called for ",$leaf_object->location,"\n" ;
 } ;
 my $my_hash_cb = sub {
    my ($iter, $data_r,$node,$element,@keys) = @_ ;
    print "hash_element_cb called for element $element with keys @keys\n" ;
 } ;

 my $iterator = $inst -> iterator ( 
    leaf_cb         => $my_leaf_cb,
    hash_element_cb => $my_hash_cb , 
 );

 $iterator->start ;
 ### prints
 # hash_element_cb called for element foo_nodes with keys foo1 foo2
 # leaf_cb called for foo_nodes:foo1 bar
 # leaf_cb called for foo_nodes:foo1 baz
 # leaf_cb called for foo_nodes:foo2 bar
 # leaf_cb called for foo_nodes:foo2 baz

DESCRIPTION

This module provides a class that is able to iterate forward or backward a configuration tree. The iterator will stop and call back user defined subroutines on one of the following condition:

A configuration item contains an error (mostly undefined mandatory values)
A configuration item contains warnings and the constructor's argument call_back_on_warning was set.
A configuration item has a important level and the constructor's argument call_back_on_important was set.. See level parameter for details.

By default, the iterator will only stop on element with an intermediate experience.

The iterator supports going forward and backward (to support back and next buttons on a wizard widget).

CONSTRUCTOR

The constructor should be used only by Config::Model::Instance with the iterator method.

Creating an iterator

A iterator requires at least two kind of call-back: a call-back for leaf elements and a call-back for hash elements (which will be also used for list elements).

These call-back must be passed when creating the iterator (the parameters are named leaf_cb and hash_element_cb)

Here are the the parameters accepted by iterator:

call_back_on_important

Whether to call back when an important element is found (default 0).

call_back_on_warning

Whether to call back when an item with warnings is found (default 0).

experience

Specifies the experience of the element scanned by the wizard (default 'intermediate').

status

Specifies the status of the element scanned by the wizard (default 'standard').

leaf_cb

Subroutine called backed for leaf elements. See "Callback prototypes" in Config::Model::ObjTreeScanner for signature and details. (mandatory)

hash_element_cb

Subroutine called backed for hash elements. See "Callback prototypes" in Config::Model::ObjTreeScanner for signature and details. (mandatory)

Custom callbacks

By default, leaf_cb will be called for all types of leaf elements (i.e enum. integer, strings, ...). But you can provide dedicated call-back for each type of leaf:

 enum_value_cb, integer_value_cb, number_value_cb, boolean_value_cb,
 uniline_value_cb, string_value_cb

Likewise, you can also provide a call-back dedicated to list elements with list_element_cb

Methods

AUTHOR

Dominique Dumont, (ddumont at cpan dot org)

CPAN RT