NAME¶
Config::Model::WarpedNode - Node that change config class properties
VERSION¶
version 2.061
SYNOPSIS¶
use Config::Model;
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init($WARN);
my $model = Config::Model->new;
foreach (qw/X Y/) {
$model->create_config_class(
name => "Class$_",
element => [ foo => {qw/type leaf value_type string/} ]
);
}
$model->create_config_class(
name => "MyClass",
element => [
master_switch => {
type => 'leaf',
value_type => 'enum',
choice => [qw/cX cY/]
},
'a_warped_node' => {
type => 'warped_node',
follow => { ms => '! master_switch' },
rules => [
'$ms eq "cX"' => { config_class_name => 'ClassX' },
'$ms eq "cY"' => { config_class_name => 'ClassY' },
]
},
],
);
my $inst = $model->instance(root_class_name => 'MyClass' );
my $root = $inst->config_root ;
print "Visible elements: ",join(' ',$root->get_element_name),"\n" ;
# Visible elements: master_switch
$root->load( step => 'master_switch=cX' );
print "Visible elements: ",join(' ',$root->get_element_name),"\n" ;
# Visible elements: master_switch a_warped_node
my $node = $root->grab('a_warped_node') ;
print "a_warped_node class: ",$node->config_class_name,"\n" ;
# a_warped_node class: ClassX
$root->load( step => 'master_switch=cY' );
print "a_warped_node class: ",$node->config_class_name,"\n" ;
# a_warped_node class: ClassY
DESCRIPTION¶
This class provides a way to change dynamically the configuration class (or some
other properties) of a node. The changes are done according to the model
declaration.
This declaration will specify one (or several) leaf in the configuration tree
that will trigger the actual property change of the warped node. This leaf is
also referred as
warp master.
When the warp master(s) value(s) changes, "WarpedNode" will create an
instance of the new class required by the warp master.
If the morph parameter is set, the values held by the old object are (if
possible) copied to the new instance of the object using copy_from method.
Warped node can alter the following properties:
config_class_name
level
Constructor¶
"WarpedNode" should not be created directly.
Warped node model declaration¶
Parameter overview¶
A warped node must be declared with the following parameters:
- type
- Always set to "warped_node".
- follow
- Grab string leading to the "Config::Model::Value" warp master.
See "Warp follow argument" in Config::Model::Warper for
details.
- morph
- boolean. If 1, "WarpedNode" will try to recursively copy the
value from the old object to the new object using copy_from method. When a
copy is not possible, undef values will be assigned to object
elements.
- rules
- Hash or array ref that specify the property change rules according to the
warp master(s) value(s). See "Warp rules argument" in
Config::Model::Warper for details on how to specify the warp master values
(or combination of values).
Effect declaration¶
For a warped node, the effects are declared with these parameters:
- config_class_name
- When requested by the warp master,the "WarpedNode" will create a
new object of the type specified by this parameter:
XZ => { config_class_name => 'SlaveZ' }
If you pass an array ref, the array will contain the class name and
constructor arguments :
XY => { config_class_name => ['SlaveY', foo => 'bar' ], },
Forwarded methods¶
The following methods are forwarded to contained node:
fetch_element config_class_name get_element_name has_element
is_element_available element_type load fetch_element_value get_type
get_cargo_type describe
Methods¶
name¶
Return the name of the node (even if warped out).
is_accessible¶
Returns true if the node hidden behind this warped node is accessible, i.e. the
warp master have values so a node was warped in.
get_actual_node¶
Returns the node object hidden behind the warped node. Croaks if the node is not
accessible.
load_data ( hash_ref )¶
Load configuration data with a hash ref. The hash ref key must match the
available elements of the node carried by the warped node.
EXAMPLE¶
$model ->create_config_class
(
element =>
[
tree_macro => { type => 'leaf',
value_type => 'enum',
choice => [qw/XX XY XZ ZZ/]
},
bar => {
type => 'warped_node',
follow => '! tree_macro',
morph => 1,
rules => [
XX => { config_class_name
=> [ 'ClassX', 'foo' ,'bar' ]}
XY => { config_class_name => 'ClassY'},
XZ => { config_class_name => 'ClassZ'}
]
}
]
);
In the example above we see that:
- •
- The 'bar' slot can refer to a "ClassX", "ClassZ" or
"ClassY" object.
- •
- The warper object is the "tree_macro" attribute of the root of
the object tree.
- •
- When "tree_macro" is set to "ZZ", "bar" will
not be available. Trying to access bar will raise an exception.
- •
- When "tree_macro" is changed from "ZZ" to
"XX", "bar" will refer to a brand new
"ClassX" object constructed with "ClassX->new(foo =>
'bar')"
- •
- Then, if "tree_macro" is changed from "XX" to
"XY", "bar" will refer to a brand new
"ClassY" object. But in this case, the object will be
initialized with most if not all the attributes of "ClassX".
This copy will be done whenever "tree_macro" is changed.
AUTHOR¶
Dominique Dumont, (ddumont at cpan dot org)
SEE ALSO¶
Config::Model::Instance, Config::Model, Config::Model::HashId,
Config::Model::ListId, Config::Model::AnyThing, Config::Model::Warper,
Config::Model::WarpedNode, Config::Model::Value
AUTHOR¶
Dominique Dumont
COPYRIGHT AND LICENSE¶
This software is Copyright (c) 2014 by Dominique Dumont.
This is free software, licensed under:
The GNU Lesser General Public License, Version 2.1, February 1999