OpenStruct
class OpenStruct
An OpenStruct is a data structure, similar to a Hash, that allows the definition of arbitrary attributes with their accompanying values. This is accomplished by using Ruby's metaprogramming to define methods on the class itself.
Examples:
require 'ostruct' person = OpenStruct.new person.name = "John Smith" person.age = 70 person.pension = 300 puts person.name # -> "John Smith" puts person.age # -> 70 puts person.address # -> nil
An OpenStruct employs a Hash internally to store the methods and values and can even be initialized with one:
australia = OpenStruct.new(:country => "Australia", :population => 20_000_000) p australia # -> <OpenStruct country="Australia" population=20000000>
Hash keys with spaces or characters that would normally not be able to use for method calls (e.g. ()[]*) will not be immediately available on the OpenStruct object as a method for retrieval or assignment, but can be still be reached through the Object#send method.
measurements = OpenStruct.new("length (in inches)" => 24) measurements.send("length (in inches)") # -> 24 data_point = OpenStruct.new(:queued? => true) data_point.queued? # -> true data_point.send("queued?=",false) data_point.queued? # -> false
Removing the presence of a method requires the execution the delete_field method as setting the property value to nil
will not remove the method.
first_pet = OpenStruct.new(:name => 'Rowdy', :owner => 'John Smith') first_pet.owner = nil second_pet = OpenStruct.new(:name => 'Rowdy') first_pet == second_pet # -> false first_pet.delete_field(:owner) first_pet == second_pet # -> true
Implementation:
An OpenStruct utilizes Ruby's method lookup structure to find and define the necessary methods for properties. This is accomplished through the method method_missing and define_method.
This should be a consideration if there is a concern about the performance of the objects that are created, as there is much more overhead in the setting of these properties compared to using a Hash or a Struct.
Public Class Methods
Public Instance Methods
Returns a hash, that will be turned into a JSON object and represent this object.
# File ext/json/lib/json/add/ostruct.rb, line 17 def as_json(*) klass = self.class.name klass.to_s.empty? and raise JSON::JSONError, "Only named structs are supported!" { JSON.create_id => klass, 't' => table, } end
Stores class name (OpenStruct) with this struct's values v
as a JSON string.
# File ext/json/lib/json/add/ostruct.rb, line 28 def to_json(*args) as_json.to_json(*args) end
Ruby Core © 1993–2017 Yukihiro Matsumoto
Licensed under the Ruby License.
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Licensed under their own licenses.