Class: UU::OS::REST::DTO

Inherits:

Object

Object
UU::OS::REST::DTO

show all

Defined in:

uu_os_framework-0.29.16/lib/uu/os/rest/dto.rb

Overview

Each DTO should define constructor accepting JSON, Hash or instance of same DTO. For purpose of serialization, methods to_hash and to_json should be defined. This ancestor provides all this functionality so they need to be overriden only in special cases.

Descendants of this class must define getters and setters (which are delegating to attributes from this class). These setters and getters are responsible for any necessary data transformations.

Direct Known Subclasses

Instance Method Summary (collapse)

- (DTO) initialize(init_data = nil) constructor

Creates new instance of DTO.
- (Hash) to_hash

Serializes DTO to Hash.
- (String) to_json(options = nil)

Serialize DTO to JSON.

Constructor Details

- (`DTO`) initialize(init_data = nil)

Creates new instance of DTO. In case there is some problem with default parsing of init_data, method handle_custom_init_data is invoked in order to provide descendants option to handle special types of init_data.

Parameters:

init_data (Object) (defaults to: nil) —
Data used for instantiation. Accepted values:
- JSON string with serialized DTO
- Hash containing DTO attributes
- Instance of same DTO

# File 'uu_os_framework-0.29.16/lib/uu/os/rest/dto.rb', line 25

def initialize(init_data = nil)
  @attributes = {}
  original_data = init_data
  if init_data.nil?
    return
  elsif init_data.kind_of?self.class
    # In case of self instance only reuse existing DTO attributes
    @attributes = init_data.send(:attributes)
    return
  elsif init_data.kind_of?String
    # Input of type String should be JSON with serialized DTO
    begin
      init_data = JSON.parse(init_data, :symbolize_names => true)
    rescue Exception => e
      begin
        handle_custom_init_data(original_data, e)
        return
      rescue Exception => e1
        if init_data.empty?
          # In case init_data is empty String (invalid JSON) and init_data are not
          # handled by particular DTO type, consider empty init_data as nil init_data
          # and create empty instance of this DTO.
          return
        else
          raise e1
        end
      end
    end
  end
  if !init_data.kind_of?Hash
    error = ArgumentError.new("Parameter must be a valid JSON String, a Hash or an instance of #{self.class}, but was #{init_data.class}.")
    handle_custom_init_data(original_data, error)
    return
  end
  # Handle attributes given as Hash (either given directly or deserialized from JSON)
  init_data.entries.each do |attribute|
    # Delegate each attribute to setter in particular DTO
    setter = get_setter(attribute[0])
    begin
      self.send(setter, attribute[1])
    rescue Exception => e
      handle_custom_init_data(original_data, e)
      return
    end
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (`Object`) method_missing(method, *args, &block)

Handle invocation of missing setter while constructing new DTO.

# File 'uu_os_framework-0.29.16/lib/uu/os/rest/dto.rb', line 106

def method_missing(method, *args, &block)
  if (method.to_s[/=$/]) && (args.size == 1)
    UU::OS::Logger.new(self).warning("#{self.class} does not contain setter \"#{method}\". Either DTO is being created with wrong parameters or there is some change in API.")
  else
    super.method_missing(method, args, &block)
  end
end

Instance Method Details

- (`Hash`) to_hash

Serializes DTO to Hash. Serialization is done recursively, that means to_hash is invoked on all attributes of type DTO. Manipulating data in returned structure does not change data in original DTOs. This method should be overridden in descendants in case some additional attributes transformation is necessary.

Returns:

(Hash) —

Hash representing DTO

# File 'uu_os_framework-0.29.16/lib/uu/os/rest/dto.rb', line 79

def to_hash
  result = {}
  @attributes.entries.each do |attribute|
    if attribute[1].kind_of?UU::OS::REST::DTO
      result[attribute[0]] = attribute[1].to_hash
    else
      result[attribute[0]] = attribute[1]
    end
  end
  result
end

- (`String`) to_json(options = nil)

Serialize DTO to JSON. DTO is first serialized to Hash using method to_hash, result is than serialized to JSON. This method should be overridden in descendants in case some additional attributes transformation is necessary.