Class: Hold::Sequel::PropertyMapper::CustomQuerySingleValue

Inherits:
Hold::Sequel::PropertyMapper show all
Defined in:
lib/hold/sequel/property_mapper/custom_query_single_value.rb

Overview

A read-only mapper for properties which are a single instance of a model class loaded from another repo.

It allows you to fetch the item via an arbitrary custom query against the target repository.

You supply a block which takes the dataset and mapper arguments supplied by the repository’s query_for_version method, but also an additional ID argument for the ID of the object for which the property is being fetched.

example:

map_custom_query_single_value('foo') do |id, dataset, mapping|
  dataset.join(:bar, ...).
    ...
    .filter(:boz_id => id)
end

Instance Attribute Summary collapse

Attributes inherited from Hold::Sequel::PropertyMapper

#property, #property_name, #repository

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Hold::Sequel::PropertyMapper

#build_insert_row, #build_update_row, #columns_aliases_and_tables_for_select, #load_values, #make_filter, #make_multi_filter, #post_delete, #post_insert, #post_update, #pre_delete, #pre_insert, #pre_update

Constructor Details

#initialize(repo, property_name, options = {}, &block) ⇒ CustomQuerySingleValue

Returns a new instance of CustomQuerySingleValue.



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# File 'lib/hold/sequel/property_mapper/custom_query_single_value.rb', line 24

def initialize(repo, property_name, options={}, &block)
  super(repo, property_name, &nil) # re &nil: our &block is otherwise implicitly passed on to super it seems, bit odd
  @model_class = options[:model_class] or raise ArgumentError
  @query_block = block
end

Instance Attribute Details

#model_class ⇒ Object (readonly)

Returns the value of attribute model_class.



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# File 'lib/hold/sequel/property_mapper/custom_query_single_value.rb', line 21

def model_class
  @model_class
end

#target_repo ⇒ Object

Returns the value of attribute target_repo.



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# File 'lib/hold/sequel/property_mapper/custom_query_single_value.rb', line 22

def target_repo
  @target_repo
end

Class Method Details

.setter_dependencies_for(options = {}) ⇒ Object 



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# File 'lib/hold/sequel/property_mapper/custom_query_single_value.rb', line 16

def self.setter_dependencies_for(options={})
  features = [*options[:model_class]].map {|klass| [:get_class, klass]}
  {:target_repo => [IdentitySetRepository, *features]}
end

Instance Method Details

#load_value(row = nil, id = nil, version = nil) ⇒ Object 



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# File 'lib/hold/sequel/property_mapper/custom_query_single_value.rb', line 30

def load_value(row=nil, id=nil, version=nil)
  target_repo.query(version) do |dataset, mapping|
    @query_block.call(id, dataset, mapping)
  end.single_result
end