Provided by: libconfig-model-perl_2.082-1_all 
NAME
Config::Model::Node - Class for configuration tree node
VERSION
version 2.082
SYNOPSIS
use Config::Model;
# define configuration tree object
my $model = Config::Model->new;
$model->create_config_class(
name => 'OneConfigClass',
class_description => "OneConfigClass detailed description",
element => [
[qw/X Y Z/] => {
type => 'leaf',
value_type => 'enum',
choice => [qw/Av Bv Cv/]
}
],
status => [ X => 'deprecated' ],
description => [ X => 'X-ray description (can be long)' ],
summary => [ X => 'X-ray' ],
accept => [
'ip.*' => {
type => 'leaf',
value_type => 'uniline',
summary => 'ip address',
}
]
);
my $instance = $model->instance (root_class_name => 'OneConfigClass');
my $root = $instance->config_root ;
# X is not shown below because of its deprecated status
print $root->describe,"\n" ;
# name value type comment
# Y [undef] enum choice: Av Bv Cv
# Z [undef] enum choice: Av Bv Cv
# add some data
$root->load( step => 'Y=Av' );
# add some accepted element, ipA and ipB are created on the fly
$root->load( step => q!ipA=192.168.1.0 ipB=192.168.1.1"! );
# show also ip* element created in the last "load" call
print $root->describe,"\n" ;
# name value type comment
# Y Av enum choice: Av Bv Cv
# Z [undef] enum choice: Av Bv Cv
# ipA 192.168.1.0 uniline
# ipB 192.168.1.1 uniline
DESCRIPTION
This class provides the nodes of a configuration tree. When created, a node object will
get a set of rules that will define its properties within the configuration tree.
Each node contain a set of elements. An element can contain:
• A leaf element implemented with Config::Model::Value. A leaf can be plain
(unconstrained value) or be strongly typed (values are checked against a set of
rules).
• Another node.
• A collection of items: a list element, implemented with Config::Model::ListId. Each
item can be another node or a leaf.
• A collection of identified items: a hash element, implemented with
Config::Model::HashId. Each item can be another node or a leaf.
Configuration class declaration
A class declaration is made of the following parameters:
name
Mandatory "string" parameter. This config class name can be used by a node element in
another configuration class.
class_description
Optional "string" parameter. This description will be used when generating user
interfaces.
class
Optional "string" to specify a Perl class to override the default implementation
(Config::Model::Node). This Perl Class must inherit Config::Model::Node. Use with
care.
element
Mandatory "list ref" of elements of the configuration class :
element => [ foo => { type = 'leaf', ... },
bar => { type = 'leaf', ... }
]
Element names can be grouped to save typing:
element => [ [qw/foo bar/] => { type = 'leaf', ... } ]
See below for details on element declaration.
level
Optional "list ref" of the elements whose level are different from default value
("normal"). Possible values are "important", "normal" or "hidden".
The level is used to set how configuration data is presented to the user in browsing
mode. "Important" elements will be shown to the user no matter what. "hidden" elements
will be explained with the warp notion.
level => [ [qw/X Y/] => 'important' ]
status
Optional "list ref" of the elements whose status are different from default value
("standard"). Possible values are "obsolete", "deprecated" or "standard".
Using a deprecated element will issue a warning. Using an obsolete element will raise
an exception (See Config::Model::Exception.
status => [ [qw/X Y/] => 'obsolete' ]
description
Optional "list ref" of element description. These descriptions will be used when
generating user interfaces.
description
Optional "list ref" of element summary. These descriptions will be used when
generating user interfaces or as comment when writing configuration files.
read_config
write_config
config_dir
Parameters used to load on demand configuration data. See Config::Model::BackendMgr
for details.
accept
Optional list of criteria (i.e. a regular expression to match ) to accept unknown
elements. Each criteria will have a list of specification that will enable
"Config::Model" to create a model snippet for the unknown element.
Example:
accept => [
'list.*' => {
type => 'list',
cargo => {
type => 'leaf',
value_type => 'string',
},
},
'str.*' => {
type => 'leaf',
value_type => 'uniline'
},
]
All "element" parameters can be used in specifying accepted elements.
If Text::Levenshtein::Damerau is installed, a warning will be issued if an accepted
element is too close to an existing element.
The parameter "accept_after" to specify where to insert the accepted element. This
will not change much the behavior of the tree, but will help generate more usable user
interfaces.
Example:
element => [
'Bug' => { type => 'leaf', value_type => 'uniline' } ,
]
accept => [
'Bug-.*' => {
value_type => 'uniline',
type => 'leaf'
accept_after => 'Bug' ,
}
]
The model snippet above will ensure that "Bug-Debian" will be shown right after "bug".
Element declaration
Element type
Each element is declared with a list ref that contains all necessary information:
element => [
foo => { ... }
]
This most important information from this hash ref is the mandatory type parameter. The
type type can be:
"node" The element is a simple node of a tree instantiated from a configuration class
(declared with "create_config_class( ... )" in Config::Model). See "Node
element".
"warped_node"
The element is a node whose properties (mostly "config_class_name") can be changed
(warped) according to the values of one or more leaf elements in the configuration
tree. See Config::Model::WarpedNode for details.
"leaf" The element is a scalar value. See "Leaf element"
"hash" The element is a collection of nodes or values (default). Each element of this
collection is identified by a string (Just like a regular hash, except that you
can set up constraint of the keys). See "Hash element"
"list" The element is a collection of nodes or values (default). Each element of this
collection is identified by an integer (Just like a regular perl array, except
that you can set up constraint of the keys). See "List element"
"check_list"
The element is a collection of values which are unique in the check_list. See
CheckList.
"class" Override the default class for leaf, list and hash elements. The override class be
inherit Config::Model::Value for leaf element, Config::Model::HashId for hash
element and Config::Model::ListId for list element.
Node element
When declaring a "node" element, you must also provide a "config_class_name" parameter.
For instance:
$model ->create_config_class
(
name => "ClassWithOneNode",
element => [
the_node => {
type => 'node',
config_class_name => 'AnotherClass',
},
]
) ;
Leaf element
When declaring a "leaf" element, you must also provide a "value_type" parameter. See
Config::Model::Value for more details.
Hash element
When declaring a "hash" element, you must also provide a "index_type" parameter.
You can also provide a "cargo_type" parameter set to "node" or "leaf" (default).
See Config::Model::HashId and Config::Model::AnyId for more details.
List element
You can also provide a "cargo_type" parameter set to "node" or "leaf" (default).
See Config::Model::ListId and Config::Model::AnyId for more details.
Constructor
The "new" constructor accepts the following parameters:
config_file
Specify configuration file to be used by backend. This parameter may override a file
declared in the model. Note that this parameter is not propagated in children nodes.
Introspection methods
name
Returns the location of the node, or its config class name (for root node).
get_type
Returns "node".
config_model
Returns the entire configuration model (Config::Model object).
model
Returns the configuration model of this node (data structure).
config_class_name
Returns the configuration class name of this node.
instance
Returns the instance object containing this node. Inherited from Config::Model::AnyThing
has_element ( name => element_name, [ type => searched_type ] )
Returns 1 if the class model has the element declared or if the element name is matched by
the optional "accept" parameter. If "type" is specified, the element name must also match
the type.
find_element ( element_name , [ case => any ])
Returns $name if the class model has the element declared or if the element name is
matched by the optional "accept" parameter.
If case is set to any, has_element will return the element name who match the passed name
in a case-insensitive manner.
Returns empty if no matching element is found.
model_searcher ()
Returns an object dedicated to search an element in the configuration model (respecting
privilege level).
This method returns a Config::Model::SearchElement object. See
Config::Model::SearchElement for details on how to handle a search.
This method is inherited from Config::Model::AnyThing.
element_model ( element_name )
Returns model of the element.
element_type ( element_name )
Returns the type (e.g. leaf, hash, list, checklist or node) of the element.
element_name()
Returns the element name that contain this object. Inherited from Config::Model::AnyThing
index_value()
See "index_value()" in Config::Model::AnyThing
parent()
See "parent()" in Config::Model::AnyThing
root()
See "root()" in Config::Model::AnyThing
location()
See "location()" in Config::Model::AnyThing
backend_support_annotation
Returns 1 if at least one of the backends attached to self or a parent node support to
read and write annotations (aka comments) in the configuration file.
Element property management
get_element_name ( ... )
Return all elements names available.
Optional parameters are:
• type: Returns only element of requested type (e.g. "list", "hash", "leaf",...). By
default return elements of any type.
• cargo_type: Returns only element which contain requested type. E.g. if
"get_element_name" is called with "cargo_type => leaf", "get_element_name" will return
simple leaf elements, but also hash or list element that contain leaf object. By
default return elements of any type.
• check: "yes", "no" or "skip"
Returns an array in array context, and a string (e.g. "join(' ',@array)") in scalar
context.
children
Like get_element_name without parameters. Returns the list of elements. This method is
polymorphic for all non-leaf objects of the configuration tree.
next_element ( ... )
This method provides a way to iterate through the elements of a node. Mandatory parameter
is "name". Optional parameter: "status".
Returns the next element name for status (default "normal"). Returns undef if no next
element is available.
previous_element ( name => element_name )
This method provides a way to iterate through the elements of a node.
Returns the previous element name. Returns undef if no previous element is available.
get_element_property ( element => ..., property => ... )
Retrieve a property of an element.
I.e. for a model :
status => [ X => 'deprecated' ]
element => [ X => { ... } ]
This call will return "deprecated":
$node->get_element_property ( element => 'X', property => 'status' )
set_element_property ( element => ..., property => ... )
Set a property of an element.
reset_element_property ( element => ... )
Reset a property of an element according to the original model.
Information management
fetch_element ( name => .. , [ check => ..] )
Fetch and returns an element from a node.
check can be set to yes, no or skip. When check is "no" or "skip", can return "undef" when
the element is unknown, or 0 if the element is not available (hidden).
fetch_element_value ( name => ... [ check => ...] )
Fetch and returns the value of a leaf element from a node.
store_element_value ( name, value )
Store a value in a leaf element from a node.
Can be invoked with named parameters (name, value, check)
is_element_available( name => ..., )
Returns 1 if the element "name" is available and if the element is not "hidden". Returns 0
otherwise.
As a syntactic sugar, this method can be called with only one parameter:
is_element_available( 'element_name' ) ;
accept_element( name )
Checks and returns the appropriate model of an acceptable element (be it explicitly
declared, or part of an "accept" declaration). Returns undef if the element cannot be
accepted.
accept_regexp( name )
Returns the list of regular expressions used to check for acceptable parameters. Useful
for diagnostics.
element_exists( element_name )
Returns 1 if the element is known in the model.
is_element_defined( element_name )
Returns 1 if the element is defined.
grab(...)
See "grab(...)" in Config::Model::AnyThing.
grab_value(...)
See "grab_value(...)" in Config::Model::AnyThing.
grab_root()
See "grab_root()" in Config::Model::AnyThing.
get( path => ..., mode => ... , check => ... , get_obj => 1|0, autoadd => 1|0)
Get a value from a directory like path. If "get_obj" is 1, "get" will return leaf object
instead of returning their value.
set( path , value)
Set a value from a directory like path.
data modification
migrate
Force a read of the configuration and perform all changes regarding deprecated elements or
values. Return 1 if data needs to be saved.
apply_fixes
Scan the tree from this node and apply fixes that are attached to warning specifications.
See "warn_if_match" or "warn_unless_match" in "" in Config::Model::Value.
load ( step => string [ ... ])
Load configuration data from the string into the node and its siblings.
This string follows the syntax defined in Config::Model::Loader. See "load ( ... )" in
Config::Model::Loader for details on parameters.
This method can also be called with a single parameter:
$node->load("some data:to be=loaded");
load_data ( data => hash_ref, [ check => $check, ... ])
Load configuration data with a hash ref. The hash ref key must match the available
elements of the node (or accepted element). The hash ref structure must match the
structure of the configuration model.
Use "check => skip" to make data loading more tolerant: bad data will be discarded.
"load_data" can be called with a single hash ref parameter.
needs_save
return 1 if one of the elements of the node's sub-tree has been modified.
Serialization
dump_tree ( ... )
Dumps the configuration data of the node and its siblings into a string. See "dump_tree"
in Config::Model::Dumper for parameter details.
This string follows the syntax defined in Config::Model::Loader. The string produced by
"dump_tree" can be passed to "load".
dump_annotations_as_pod ( ... )
Dumps the configuration annotations of the node and its siblings into a string. See
"dump_annotations_as_pod" in Config::Model::Dumper for parameter details.
describe ( [ element => ... ] )
Provides a description of the node elements or of one element.
report ()
Provides a text report on the content of the configuration below this node.
audit ()
Provides a text audit on the content of the configuration below this node. This audit will
show only value different from their default value.
copy_from ( from => another_node_object, [ check => ... ] )
Copy configuration data from another node into this node and its siblings. The copy can be
made in a tolerant mode where invalid data is discarded with "check => skip". This method
can be called with a single argument: "copy_from($another_node)"
Help management
get_help ( [ [ description | summary ] => element_name ] )
If called without element, returns the description of the class (Stored in
"class_description" attribute of a node declaration).
If called with an element name, returns the description of the element (Stored in
"description" attribute of a node declaration).
If called with 2 argument, either return the "summary" or the "description" of the
element.
Returns an empty string if no description was found.
tree_searcher( type => ... )
Returns an object able to search the configuration tree. Parameters are :
type
Where to perform the search. It can be "element", "value", "key", "summary",
"description", "help" or "all".
Typically, you will have to call "search" on this object.
Returns a Config::Model::TreeSearcher object.
Lazy load of node data
As configuration model are getting bigger, the load time of a tree gets longer. The
Config::Model::BackendMgr class provides a way to load the configuration information only
when needed.
AUTHOR
Dominique Dumont, (ddumont at cpan dot org)
SEE ALSO
Config::Model, Config::Model::Instance, Config::Model::HashId, Config::Model::ListId,
Config::Model::CheckList, Config::Model::WarpedNode, Config::Model::Value
AUTHOR
Dominique Dumont
COPYRIGHT AND LICENSE
This software is Copyright (c) 2005-2016 by Dominique Dumont.
This is free software, licensed under:
The GNU Lesser General Public License, Version 2.1, February 1999