Class: ROM::Processor::Transproc

Inherits:
ROM::Processor show all
Includes:
Transproc::Composer
Defined in:
lib/rom/processor/transproc.rb

Overview

Data mapping transformer builder using Transproc

This builds a transproc function that is used to map a whole relation

See Also:

Defined Under Namespace

Modules: Functions

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from ROM::Processor

inherited

Constructor Details

#initialize(header) ⇒ Transproc

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Transproc.



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# File 'lib/rom/processor/transproc.rb', line 66

def initialize(header)
  @header = header
  @model = header.model
  @mapping = header.mapping
  initialize_row_proc
end

Instance Attribute Details

#header ⇒ Header (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns header from a mapper.

Returns:

  • (Header) —

    header from a mapper



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# File 'lib/rom/processor/transproc.rb', line 37

def header
  @header
end

#mapping ⇒ Hash (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns header’s attribute mapping.

Returns:

  • (Hash) —

    header’s attribute mapping



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# File 'lib/rom/processor/transproc.rb', line 47

def mapping
  @mapping
end

#model ⇒ Class (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns model class from a mapper.

Returns:

  • (Class) —

    model class from a mapper



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# File 'lib/rom/processor/transproc.rb', line 42

def model
  @model
end

#row_proc ⇒ Proc (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns row-processing proc.

Returns:

  • (Proc) —

    row-processing proc



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# File 'lib/rom/processor/transproc.rb', line 52

def row_proc
  @row_proc
end

Class Method Details

.build(header) ⇒ Transproc::Function

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Build a transproc function from the header

Parameters:

Returns:

  • (Transproc::Function) 


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# File 'lib/rom/processor/transproc.rb', line 61

def self.build(header)
  new(header).to_transproc
end

Instance Method Details

#to_transproc ⇒ Transproc::Function

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Coerce mapper header to a transproc data mapping function

Returns:

  • (Transproc::Function) 


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# File 'lib/rom/processor/transproc.rb', line 78

def to_transproc
  compose(t(:identity)) do |ops|
    combined = header.combined
    ops << t(:combine, combined.map(&method(:combined_args))) if combined.any?
    ops << header.preprocessed.map { |attr| visit(attr, true) }
    ops << t(:map_array, row_proc) if row_proc
    ops << header.postprocessed.map { |attr| visit(attr, true) }
  end
end