Class: StateMachine::NodeCollection
- Inherits:
-
Object
- Object
- StateMachine::NodeCollection
- Includes:
- Enumerable, Assertions
- Defined in:
- lib/state_machine/node_collection.rb
Overview
Represents a collection of nodes in a state machine, be it events or states.
Direct Known Subclasses
Instance Attribute Summary collapse
-
#machine ⇒ Object
The machine associated with the nodes.
Instance Method Summary collapse
-
#<<(node) ⇒ Object
Adds a new node to the collection.
-
#[](key, index_name = @default_index) ⇒ Object
Gets the node indexed by the given key.
-
#at(index) ⇒ Object
Gets the node at the given index.
-
#concat(nodes) ⇒ Object
Appends a group of nodes to the collection.
-
#each ⇒ Object
Calls the block once for each element in self, passing that element as a parameter.
-
#fetch(key, index_name = @default_index) ⇒ Object
Gets the node indexed by the given key.
-
#initialize(machine, options = {}) ⇒ NodeCollection
constructor
Creates a new collection of nodes for the given state machine.
-
#initialize_copy(orig) ⇒ Object
Creates a copy of this collection such that modifications don’t affect the original collection.
-
#keys(index_name = @default_index) ⇒ Object
Gets the set of unique keys for the given index.
-
#length ⇒ Object
Gets the number of nodes in this collection.
-
#update(node) ⇒ Object
Updates the indexed keys for the given node.
Methods included from Assertions
#assert_exclusive_keys, #assert_valid_keys
Constructor Details
#initialize(machine, options = {}) ⇒ NodeCollection
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
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# File 'lib/state_machine/node_collection.rb', line 19 def initialize(machine, = {}) assert_valid_keys(, :index) = {:index => :name}.merge() @machine = machine @nodes = [] @indices = Array([:index]).inject({}) {|indices, attribute| indices[attribute] = {}; indices} @default_index = Array([:index]).first end |
Instance Attribute Details
#machine ⇒ Object
The machine associated with the nodes
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# File 'lib/state_machine/node_collection.rb', line 10 def machine @machine end |
Instance Method Details
#<<(node) ⇒ Object
Adds a new node to the collection. By doing so, this will also add it to the configured indices.
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# File 'lib/state_machine/node_collection.rb', line 59 def <<(node) @nodes << node @indices.each {|attribute, index| index[value(node, attribute)] = node} self end |
#[](key, index_name = @default_index) ⇒ Object
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.
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# File 'lib/state_machine/node_collection.rb', line 124 def [](key, index_name = @default_index) index(index_name)[key] end |
#at(index) ⇒ Object
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
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# File 'lib/state_machine/node_collection.rb', line 110 def at(index) @nodes[index] end |
#concat(nodes) ⇒ Object
Appends a group of nodes to the collection
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# File 'lib/state_machine/node_collection.rb', line 66 def concat(nodes) nodes.each {|node| self << node} end |
#each ⇒ Object
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 --
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# File 'lib/state_machine/node_collection.rb', line 97 def each @nodes.each {|node| yield node} self end |
#fetch(key, index_name = @default_index) ⇒ Object
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
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# 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 |
#initialize_copy(orig) ⇒ Object
Creates a copy of this collection such that modifications don’t affect the original collection
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# File 'lib/state_machine/node_collection.rb', line 31 def initialize_copy(orig) #:nodoc: super nodes = @nodes @nodes = [] @indices = @indices.inject({}) {|indices, (name, index)| indices[name] = {}; indices} concat(nodes.map {|n| n.dup}) end |
#keys(index_name = @default_index) ⇒ Object
Gets the set of unique keys for the given index
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# File 'lib/state_machine/node_collection.rb', line 53 def keys(index_name = @default_index) index(index_name).keys end |
#length ⇒ Object
Gets the number of nodes in this collection
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# File 'lib/state_machine/node_collection.rb', line 48 def length @nodes.length end |
#update(node) ⇒ Object
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.
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# 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 |