Class: Arborist::Node::Root

Inherits:
Arborist::Node show all
Extended by:
MethodUtilities
Defined in:
lib/arborist/node/root.rb

Overview

The class of the root node of an Arborist tree. This class is a Singleton.

Constant Summary

Constants inherited from Arborist::Node

LOADED_INSTANCE_KEY, OPERATIONAL_ATTRIBUTES, UNREACHABLE_STATES, VALID_IDENTIFIER

Instance Attribute Summary

Attributes inherited from Arborist::Node

#ack, #children, #dependencies, #errors, #identifier, #last_contacted, #pending_change_events, #previous_ack, #properties, #quieted_reasons, #source, #status_changed, #status_history, #status_last_changed, #subscriptions, #update_delta, #warnings

Class Method Summary collapse

Instance Method Summary collapse

Methods included from MethodUtilities

attr_predicate, attr_predicate_accessor, dsl_accessor, singleton_attr_accessor, singleton_attr_reader, singleton_attr_writer, singleton_method_alias, singleton_predicate_accessor, singleton_predicate_reader

Methods inherited from Arborist::Node

#<<, #==, #acked_description, #acknowledge, #add_child, add_loaded_instance, add_subnode_factory_method, #add_subscription, #all_of, #any_of, #broadcast_events, #clear_transition_temp_vars, #config, curried_create, #dependencies_down?, #dependencies_up?, #depends_on, #description, #each, each_in, #fetch_values, #find_matching_subscriptions, #flap_threshold, #flapping, from_hash, #handle_event, #handle_node_disabled_event, #handle_node_down_event, #handle_node_quieted_event, #handle_node_up_event, #has_children?, #has_dependencies?, #has_quieted_reason?, inherited, #inspect, load, #make_delta_event, #make_update_event, #marshal_dump, #marshal_load, #match_criteria?, #matches?, #merge_and_record_delta, #merge_new_properties, #modify, #node_description, #node_subscribers, #operational?, #operational_values, parent_types, #publish_events, #reachable?, #register_secondary_dependencies, #remove_child, #remove_subscription, #reparent, #state_has_changed?, #status, #status_description, #status_history_size, subnode_type?, #tags, #to_h, #type, #unacknowledge, #unreachable?, #update_errors, #update_properties, #update_warnings

Methods included from HashUtilities

compact_hash, hash_matches, merge_recursively, stringify_keys, symbolify_keys

Constructor Details

#initialize ⇒ Root

Set up the root node.



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# File 'lib/arborist/node/root.rb', line 37

def initialize( * )
	super( '_' ) do
		description "The root node."
		self.source = URI( __FILE__ )
	end

	@status = 'up'
	@status.freeze
end

Class Method Details

.instance ⇒ Object

Override the default constructor to use the singleton ::instance instead.



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# File 'lib/arborist/node/root.rb', line 24

def self::instance( * )
	@instance ||= new
	return @instance
end

.new ⇒ Object

Create the instance of the Root node (if necessary) and return it.



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# File 'lib/arborist/node/root.rb', line 17

def self::new( * )
	@instance ||= super
	return @instance
end

.reset ⇒ Object

Reset the singleton instance; mainly used for testing.



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# File 'lib/arborist/node/root.rb', line 31

def self::reset
	@instance = nil
end

Instance Method Details

#family ⇒ Object

Return the node family, so observers can know ancestry after serialization for custom node types that inherit from this class.



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# File 'lib/arborist/node/root.rb', line 50

def family
	return :root
end

#on_node_enabled(transition) ⇒ Object

Callback for when a node goes from disabled to unknown. Override, so we immediately transition from unknown to up.



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# File 'lib/arborist/node/root.rb', line 69

def on_node_enabled( transition )
	super
	events = self.update( {} ) # up!
	self.publish_events( events )
end

#parent ⇒ Object

Override the reader mode of Node#parent for the root node, which never has a parent.



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# File 'lib/arborist/node/root.rb', line 78

def parent( * )
	return nil
end

#restore(other_node) ⇒ Object

Ignore restores of serialized root nodes.



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# File 'lib/arborist/node/root.rb', line 56

def restore( other_node )
	self.log.info "Ignoring restored root node."
end

#update(properties, monitor_key = '_') ⇒ Object

Don’t allow properties to be set on the root node.



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# File 'lib/arborist/node/root.rb', line 62

def update( properties, monitor_key='_' )
	return super( {} )
end