1Config::Model::WarpedNoUdsee(r3)Contributed Perl DocumenCtoantfiiogn::Model::WarpedNode(3)
2
6 Config::Model::WarpedNode - Node that change config class properties
7
9 version 2.152
10
12 use Config::Model;
13 my $model = Config::Model->new;
15 foreach (qw/X Y/) {
16 $model->create_config_class(
17 name => "Class$_",
18 element => [ foo => {qw/type leaf value_type string/} ]
19 );
20 }
21 $model->create_config_class(
22 name => "MyClass",
23 element => [
25 master_switch => {
26 type => 'leaf',
27 value_type => 'enum',
28 choice => [qw/cX cY/]
29 },
30 'a_warped_node' => {
32 type => 'warped_node',
33 warp => }
34 follow => { ms => '! master_switch' },
35 rules => [
36 '$ms eq "cX"' => { config_class_name => 'ClassX' },
37 '$ms eq "cY"' => { config_class_name => 'ClassY' },
38 ]
39 }
40 },
41 ],
42 );
43 my $inst = $model->instance(root_class_name => 'MyClass' );
45 my $root = $inst->config_root ;
46 print "Visible elements: ",join(' ',$root->get_element_name),"\n" ;
48 # Visible elements: master_switch
49 $root->load( steps => 'master_switch=cX' );
51 print "Visible elements: ",join(' ',$root->get_element_name),"\n" ;
52 # Visible elements: master_switch a_warped_node
53 my $node = $root->grab('a_warped_node') ;
55 print "a_warped_node class: ",$node->config_class_name,"\n" ;
56 # a_warped_node class: ClassX
57 $root->load( steps => 'master_switch=cY' );
59 print "a_warped_node class: ",$node->config_class_name,"\n" ;
60 # a_warped_node class: ClassY
61
63 This class provides a way to change dynamically the configuration class
64 (or some other properties) of a node. The changes are done according to
65 the model declaration.
66 This declaration specifies one (or several) leaf in the configuration
68 tree that triggers the actual property change of the warped node. This
69 leaf is also referred as warp master.
70 When the warp master(s) value(s) changes, "WarpedNode" creates an
72 instance of the new class required by the warp master.
73 If the morph parameter is set, the values held by the old object are
75 (if possible) copied to the new instance of the object using copy_from
76 method.
77 Warped node can alter the following properties:
79 config_class_name
81 level
82
84 "WarpedNode" should not be created directly.
85
87 Parameter overview
88 A warped node must be declared with the following parameters:
89 type
91 Always set to "warped_node".
92 follow
94 Grab string leading to the "Config::Model::Value" warp master. See
95 "Warp follow argument" in Config::Model::Warper for details.
96 morph
98 boolean. If 1, "WarpedNode" tries to recursively copy the value
99 from the old object to the new object using copy_from method. When
100 a copy is not possible, undef values are assigned to object
101 elements.
102 rules
104 Hash or array ref that specify the property change rules according
105 to the warp master(s) value(s). See "Warp rules argument" in
106 Config::Model::Warper for details on how to specify the warp master
107 values (or combination of values).
108 Effect declaration
110 For a warped node, the effects are declared with these parameters:
111 config_class_name
113 When requested by the warp master,the "WarpedNode" creates a
114 new object of the type specified by this parameter:
115 XZ => { config_class_name => 'SlaveZ' }
117 Instead of a string, you can an array ref which contains the
119 class name and constructor arguments :
120 XY => { config_class_name => ['SlaveY', foo => 'bar' ], },
122 class Specify a Perl class to implement the above config class. This
124 Perl Class must inherit Config::Model::Node.
125
127 The following methods are forwarded to contained node:
128 fetch_element config_class_name get_element_name has_element
130 is_element_available element_type load fetch_element_value get_type
131 get_cargo_type describe
132
134 name
135 Return the name of the node (even if warped out).
136 is_accessible
138 Returns true if the node hidden behind this warped node is accessible,
139 i.e. the warp master have values so a node was warped in.
140 get_actual_node
142 Returns the node object hidden behind the warped node. Croaks if the
143 node is not accessible.
144 load_data
146 Parameters: "( hash_ref )"
147 Load configuration data with a hash ref. The hash ref key must match
149 the available elements of the node carried by the warped node.
150
152 $model ->create_config_class
153 (
154 element =>
155 [
156 tree_macro => { type => 'leaf',
157 value_type => 'enum',
158 choice => [qw/XX XY XZ ZZ/]
159 },
160 bar => {
161 type => 'warped_node',
162 follow => '! tree_macro',
163 morph => 1,
164 rules => [
165 XX => { config_class_name
166 => [ 'ClassX', 'foo' ,'bar' ]}
167 XY => { config_class_name => 'ClassY'},
168 XZ => { config_class_name => 'ClassZ'}
169 ]
170 }
171 ]
172 );
173 In the example above we see that:
175 • The 'bar' slot can refer to a "ClassX", "ClassZ" or "ClassY"
177 object.
178 • The warper object is the "tree_macro" attribute of the root of the
180 object tree.
181 • When "tree_macro" is set to "ZZ", "bar" is not available. Trying to
183 access "bar" raises an exception.
184 • When "tree_macro" is changed from "ZZ" to "XX", "bar" refers to a
186 brand new "ClassX" object constructed with "ClassX->new(foo =>
187 'bar')"
188 • Then, if "tree_macro" is changed from "XX" to "XY", "bar" refers to
190 a brand new "ClassY" object. But in this case, the object is
191 initialized with most if not all the attributes of "ClassX". This
192 copy is done whenever "tree_macro" is changed.
193
195 Dominique Dumont, (ddumont at cpan dot org)
196
198 Config::Model::Instance, Config::Model, Config::Model::HashId,
199 Config::Model::ListId, Config::Model::AnyThing, Config::Model::Warper,
200 Config::Model::WarpedNode, Config::Model::Value
201
203 Dominique Dumont
204
206 This software is Copyright (c) 2005-2022 by Dominique Dumont.
207 This is free software, licensed under:
209 The GNU Lesser General Public License, Version 2.1, February 1999
211perl v5.36.0 2022-08-10 Config::Model::WarpedNode(3)