Represents a collection of nodes in a state machine, be it events or states.
Creates a new collection of nodes for the given state machine. By default, the collection is empty.
Configuration options:
:index - One or more attributes to automatically generate hashed indices for in order to perform quick lookups. Default is to index by the :name attribute
# File lib/state_machine/node_collection.rb, line 19 def initialize(machine, options = {}) assert_valid_keys(options, :index) options = {:index => :name}.merge(options) @machine = machine @nodes = [] @indices = Array(options[:index]).inject({}) {|indices, attribute| indices[attribute] = {}; indices} @default_index = Array(options[:index]).first end
Adds a new node to the collection. By doing so, this will also add it to the configured indices.
# File lib/state_machine/node_collection.rb, line 59 def <<(node) @nodes << node @indices.each {|attribute, index| index[value(node, attribute)] = node} self end
Gets the node indexed by the given key. By default, this will look up the key in the first index configured for the collection. A custom index can be specified like so:
collection['parked', :value]
The above will look up the "parked" key in a hash indexed by each node's value attribute.
If the key cannot be found, then nil will be returned.
# File lib/state_machine/node_collection.rb, line 124 def [](key, index_name = @default_index) index(index_name)[key] end
Gets the node at the given index.
states = StateMachine::NodeCollection.new states << StateMachine::State.new(machine, :parked) states << StateMachine::State.new(machine, :idling) states.at(0).name # => :parked states.at(1).name # => :idling
# File lib/state_machine/node_collection.rb, line 110 def at(index) @nodes[index] end
Appends a group of nodes to the collection
# File lib/state_machine/node_collection.rb, line 66 def concat(nodes) nodes.each {|node| self << node} end
Calls the block once for each element in self, passing that element as a parameter.
states = StateMachine::NodeCollection.new states << StateMachine::State.new(machine, :parked) states << StateMachine::State.new(machine, :idling) states.each {|state| puts state.name, ' -- '}
...produces:
parked -- idling --
# File lib/state_machine/node_collection.rb, line 97 def each @nodes.each {|node| yield node} self end
Gets the node indexed by the given key. By default, this will look up the key in the first index configured for the collection. A custom index can be specified like so:
collection['parked', :value]
The above will look up the "parked" key in a hash indexed by each node's value attribute.
If the key cannot be found, then an IndexError exception will be raised:
collection['invalid', :value] # => IndexError: "invalid" is an invalid value
# File lib/state_machine/node_collection.rb, line 140 def fetch(key, index_name = @default_index) self[key, index_name] || raise(IndexError, "#{key.inspect} is an invalid #{index_name}") end
Gets the set of unique keys for the given index
# File lib/state_machine/node_collection.rb, line 53 def keys(index_name = @default_index) index(index_name).keys end
Gets the number of nodes in this collection
# File lib/state_machine/node_collection.rb, line 48 def length @nodes.length end
Changes the current machine associated with the collection. In turn, this will change the state machine associated with each node in the collection.
# File lib/state_machine/node_collection.rb, line 42 def machine=(new_machine) @machine = new_machine each {|node| node.machine = new_machine} end
Updates the indexed keys for the given node. If the node's attribute has changed since it was added to the collection, the old indexed keys will be replaced with the updated ones.
# File lib/state_machine/node_collection.rb, line 73 def update(node) @indices.each do |attribute, index| old_key = RUBY_VERSION < '1.9' ? index.index(node) : index.key(node) new_key = value(node, attribute) # Only replace the key if it's changed if old_key != new_key index.delete(old_key) index[new_key] = node end end end
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