类 OpenStruct

参见 as_json。

# File ext/json/lib/json/add/ostruct.rb, line 10
def self.json_create(object)
  new(object['t'] || object[:t])
end

创建一个新的 OpenStruct 对象。默认情况下，生成的 OpenStruct 对象将没有属性。

可选的 hash（如果给出）将生成属性和值（可以是 Hash、OpenStruct 或 Struct）。例如

require "ostruct"
hash = { "country" => "Australia", :capital => "Canberra" }
data = OpenStruct.new(hash)

data   # => #<OpenStruct country="Australia", capital="Canberra">

# File lib/ostruct.rb, line 134
def initialize(hash=nil)
  if HAS_PERFORMANCE_WARNINGS && Warning[:performance]
     warn "OpenStruct use is discouraged for performance reasons", uplevel: 1, category: :performance
  end

  if hash
    update_to_values!(hash)
  else
    @table = {}
  end
end

比较此对象和 other 以确定是否相等。当 other 是 OpenStruct 并且两个对象的 Hash 表相等时，OpenStruct 等于 other。

require "ostruct"
first_pet  = OpenStruct.new("name" => "Rowdy")
second_pet = OpenStruct.new(:name  => "Rowdy")
third_pet  = OpenStruct.new("name" => "Rowdy", :age => nil)

first_pet == second_pet   # => true
first_pet == third_pet    # => false

# File lib/ostruct.rb, line 423
def ==(other)
  return false unless other.kind_of?(OpenStruct)
  @table == other.table!
end

返回属性的值，如果不存在此属性，则返回 nil。

require "ostruct"
person = OpenStruct.new("name" => "John Smith", "age" => 70)
person[:age]   # => 70, same as person.age

# File lib/ostruct.rb, line 303
def [](name)
  @table[name.to_sym]
end

设置属性的值。

require "ostruct"
person = OpenStruct.new("name" => "John Smith", "age" => 70)
person[:age] = 42   # equivalent to person.age = 42
person.age          # => 42

# File lib/ostruct.rb, line 318
def []=(name, value)
  name = name.to_sym
  new_ostruct_member!(name)
  @table[name] = value
end

方法 OpenStruct#as_json 和 OpenStruct.json_create 可用于序列化和反序列化 OpenStruct 对象；参见 Marshal。

方法 OpenStruct#as_json 序列化 self，返回一个表示 self 的包含两个元素的哈希。

require 'json/add/ostruct'
x = OpenStruct.new('name' => 'Rowdy', :age => nil).as_json
# => {"json_class"=>"OpenStruct", "t"=>{:name=>'Rowdy', :age=>nil}}

方法 JSON.create 反序列化此类哈希，返回一个 OpenStruct 对象。

OpenStruct.json_create(x)
# => #<OpenStruct name='Rowdy', age=nil>

# File ext/json/lib/json/add/ostruct.rb, line 30
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

从对象中删除指定名称的字段，并返回该字段包含的值（如果已定义）。您可以选择提供一个代码块。如果字段未定义，则返回代码块的结果，或者如果未提供代码块，则引发 NameError。

require "ostruct"

person = OpenStruct.new(name: "John", age: 70, pension: 300)

person.delete_field!("age")  # => 70
person                       # => #<OpenStruct name="John", pension=300>

将值设置为 nil 不会删除属性。

person.pension = nil
person                 # => #<OpenStruct name="John", pension=nil>

person.delete_field('number')  # => NameError

person.delete_field('number') { 8675_309 } # => 8675309

# File lib/ostruct.rb, line 371
def delete_field(name, &block)
  sym = name.to_sym
  begin
    singleton_class.remove_method(sym, "#{sym}=")
  rescue NameError
  end
  @table.delete(sym) do
    return yield if block
    raise! NameError.new("no field `#{sym}' in #{self}", sym)
  end
end

查找并返回嵌套对象中由 name 和 identifiers 指定的对象。嵌套对象可以是各种类的实例。参见 Dig 方法。

示例

require "ostruct"
address = OpenStruct.new("city" => "Anytown NC", "zip" => 12345)
person  = OpenStruct.new("name" => "John Smith", "address" => address)
person.dig(:address, "zip") # => 12345
person.dig(:business_address, "zip") # => nil

# File lib/ostruct.rb, line 340
def dig(name, *names)
  begin
    name = name.to_sym
  rescue NoMethodError
    raise! TypeError, "#{name} is not a symbol nor a string"
  end
  @table.dig(name, *names)
end

生成所有属性（作为符号）及其对应值，或者如果未提供代码块，则返回一个枚举器。

require "ostruct"
data = OpenStruct.new("country" => "Australia", :capital => "Canberra")
data.each_pair.to_a   # => [[:country, "Australia"], [:capital, "Canberra"]]

# File lib/ostruct.rb, line 211
def each_pair
  return to_enum(__method__) { @table.size } unless defined?(yield)
  @table.each_pair{|p| yield p}
  self
end

比较此对象和 other 的相等性。当 other 是一个 OpenStruct 并且两个对象的 Hash 表相等时，OpenStruct 与 other 相等。

# File lib/ostruct.rb, line 433
def eql?(other)
  return false unless other.kind_of?(OpenStruct)
  @table.eql?(other.table!)
end

返回一个包含键和值详细摘要的字符串。

# File lib/ostruct.rb, line 388
def inspect
  ids = (Thread.current[InspectKey] ||= [])
  if ids.include?(object_id)
    detail = ' ...'
  else
    ids << object_id
    begin
      detail = @table.map do |key, value|
        " #{key}=#{value.inspect}"
      end.join(',')
    ensure
      ids.pop
    end
  end
  ['#<', self.class!, detail, '>'].join
end

返回一个表示 self 的 JSON 字符串。

require 'json/add/ostruct'
puts OpenStruct.new('name' => 'Rowdy', :age => nil).to_json

输出

{"json_class":"OpenStruct","t":{'name':'Rowdy',"age":null}}

# File ext/json/lib/json/add/ostruct.rb, line 48
def to_json(*args)
  as_json.to_json(*args)
end