Class: SimpleAttributeMapper::Mapper

Inherits:
Object
  • Object
show all
Defined in:
lib/simple_attribute_mapper/mapper.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(mappings = {}) ⇒ Mapper

Returns a new instance of Mapper.



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# File 'lib/simple_attribute_mapper/mapper.rb', line 3

def initialize(mappings = {})
  @mappings = mappings
end

Instance Attribute Details

#mappings ⇒ Object (readonly)

Returns the value of attribute mappings.



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# File 'lib/simple_attribute_mapper/mapper.rb', line 7

def mappings
  @mappings
end

Instance Method Details

#map(source, target_class) ⇒ Object 



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# File 'lib/simple_attribute_mapper/mapper.rb', line 9

def map(source, target_class)
  map_attributes(source, target_class.new)
end

#map_attributes(source, target_instance) ⇒ Object

Raises:



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# File 'lib/simple_attribute_mapper/mapper.rb', line 13

def map_attributes(source, target_instance)
  raise UnMappableError.new("source has no attributes") unless source.respond_to?(:attributes)

  map_matching_attributes(source, target_instance)
  map_specified_attributes(source, target_instance)

  target_instance
end

#map_matching_attributes(source, target) ⇒ Object 



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# File 'lib/simple_attribute_mapper/mapper.rb', line 22

def map_matching_attributes(source, target)
  source.attributes.each do |attribute|
    attribute_writer = "#{attribute[0]}=".to_sym
    attribute_value = attribute[1]

    if target.respond_to?(attribute_writer)
      target.send(attribute_writer, attribute_value)
    end
  end
end

#map_specified_attributes(source, target) ⇒ Object 



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# File 'lib/simple_attribute_mapper/mapper.rb', line 33

def map_specified_attributes(source, target)
  mappings.each do |source_attribute, target_attribute|
    attribute_writer = "#{target_attribute}=".to_sym
    attribute_value = resolve_attribute_value(source_attribute, source)
    # puts "#{attribute_writer} - #{attribute_value}"
    target.send(attribute_writer, attribute_value)
  end
end

#resolve_attribute_value(mapping_key, source) ⇒ Object 



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# File 'lib/simple_attribute_mapper/mapper.rb', line 42

def resolve_attribute_value(mapping_key, source)
  if mapping_key.is_a?(Symbol)
    source.send(mapping_key)
  elsif mapping_key.is_a?(Array)
    resolve_nested_value(mapping_key, source)
  elsif mapping_key.is_a?(Proc)
    mapping_key.call(source)
  else
    raise "Fatal, mapping for '#{mapping_key}' is unknown"
  end
end

#resolve_nested_value(mapping_key, source) ⇒ Object 



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# File 'lib/simple_attribute_mapper/mapper.rb', line 54

def resolve_nested_value(mapping_key, source)
  root_key = mapping_key.shift
  current = source.send(root_key)

  mapping_key.each do |nested|
    value = current.send(nested)
    if nested == mapping_key.last
      return value
    end
    current = value
  end
end