Class: PalletJack::KeyTransformer

Inherits:
Object
  • Object
show all
Defined in:
lib/palletjack/keytransformer.rb

Direct Known Subclasses

Reader, Writer

Defined Under Namespace

Classes: Reader, Writer

Instance Method Summary collapse

Constructor Details

#initialize(key_transforms = {}) ⇒ KeyTransformer

Returns a new instance of KeyTransformer.



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# File 'lib/palletjack/keytransformer.rb', line 206

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

Instance Method Details

#transform!(pallet) ⇒ Object

Destructively transform the values in pallet according to the loaded transform rules.

YAML structure:

- key:
  - transform1:
      [transform-specific configuration]
  - transform2:
      [transform-specific configuration]
  [...]

Transforms are evaluated in order from top to bottom, and the first one to successfully produce a value is used.

Transforms are methods in PalletJack::KeyTransformer::Writer, called by name. They should return the new value, or false if unsuccessful.

Transforms are given two parameters, param and context:

param

transform-specific configuration from transforms.yaml

context
pallet

The pallet object being processed

key

The key from transforms.yaml being processed

value

Current locally assigned value for key in pallet

abort

#throw this to abort transforms for current key



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# File 'lib/palletjack/keytransformer.rb', line 237

def transform!(pallet)
  @key_transforms.each do |keytrans_item|
    # Enable early termination of transforms for a key
    # by wrapping execution in a catch block.
    catch do |abort_tag|
      key, transforms = keytrans_item.flatten
      context = {
        pallet: pallet,
        key:    key,
        value:  pallet[key, shallow: true],
        abort:  abort_tag
      }

      transforms.each do |t|
        transform, param = t.flatten
        if self.respond_to?(transform.to_sym) then
          if new_value = self.send(transform.to_sym, param, context)
          then
            new_value = TraceableString.new(new_value)
            new_value.file = transform.file
            new_value.line = transform.line
            new_value.column = transform.column
            new_value.byte = transform.byte
            pallet[key] = new_value
            break
          end
        end
      end
    end
  end
  @hash
end