Class: AzaharaSchema::DerivedAttribute

Inherits:
Attribute
  • Object
show all
Defined in:
lib/azahara_schema/derived_attribute.rb

Overview

The class is attribute for derivateve attribute, it is used for working with combination of attributes as one attribute.

Instance Attribute Summary collapse

Attributes inherited from Attribute

#format, #model, #name, #table_alias

Instance Method Summary collapse

Methods inherited from Attribute

#add_sort, #aggregable?, #arel_sort_field, #arel_table, #association_hash, #attribute_name, #available_operators, #available_values, #build_json_options!, #column?, #filter?, #filter_name, #path, #primary_key_name, #searchable?

Constructor Details

#initialize(model, name, derivation_method, *attribute_names, **options) ⇒ DerivedAttribute

Returns a new instance of DerivedAttribute.



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# File 'lib/azahara_schema/derived_attribute.rb', line 13

def initialize(model, name, derivation_method, *attribute_names, **options)
  self.attribute_names = attribute_names
  self.derivation_method = derivation_method.to_sym
  @options = options
  super(model, name, type)
end

Instance Attribute Details

#attribute_names ⇒ Object

Returns the value of attribute attribute_names.



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# File 'lib/azahara_schema/derived_attribute.rb', line 11

def attribute_names
  @attribute_names
end

#derivation_method ⇒ Object

Returns the value of attribute derivation_method.



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# File 'lib/azahara_schema/derived_attribute.rb', line 10

def derivation_method
  @derivation_method
end

Instance Method Details

#add_join(scope) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 89

def add_join(scope)
  attributes.each{|a| scope = a.add_join(scope) }
  scope
end

#add_preload(scope) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 94

def add_preload(scope)
  attributes.each{|a| scope = a.add_preload(scope) }
  scope
end

#add_statement(scope, operator, values) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 78

def add_statement(scope, operator, values)
  super(add_join(scope), operator, values)
end

#arel_field(t_alias = nil) ⇒ Object

do not alias tables - let attributes derived from handle that



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# File 'lib/azahara_schema/derived_attribute.rb', line 52

def arel_field(t_alias=nil)
  case derivation_method
  when :concat
    arel_fields = attributes.collect{|a| a.arel_field}
    (1..arel_fields.length-1).to_a.reverse.each{|i| arel_fields.insert(i, Arel::Nodes::SqlLiteral.new("'#{concat_divider}'")) }
    Arel::Nodes::NamedFunction.new 'CONCAT', arel_fields
  else
    raise "DerivedAttribute(#{name}) - derivation_method '#{derivation_method}' is not supported"
  end
end

#arel_join(parent = nil, join_type = ::Arel::Nodes::OuterJoin, a_tbl = self.arel_table(self.table_alias)) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 82

def arel_join(parent=nil, join_type=::Arel::Nodes::OuterJoin, a_tbl=self.arel_table(self.table_alias))
  parent ||= self.arel_table(nil)
  joined = parent
  attributes.each{|a| joined = a.arel_join(joined, join_type) }
  joined
end

#arel_statement(operator, values) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 67

def arel_statement(operator, values)
  case operator
  when '~'
    arl = attributes[0].arel_statement(operator, values)
    attributes[1..-1].each{|att| arl = arl.or( att.arel_statement(operator, values) ) }
    arl
  else
    super
  end
end

#attributes ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 28

def attributes
  @attributes ||= options[:attributes] || options[:schema].available_attributes_hash.slice(*attribute_names).values
end

#concat_divider ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 32

def concat_divider
  options[:divider] || ' '
end

#options ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 36

def options
  @options || {}
end

#type ⇒ Object

——————-| OVERRIDES |———————



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# File 'lib/azahara_schema/derived_attribute.rb', line 42

def type
  case derivation_method
  when :concat
    'string'
  else
    raise "DerivedAttribute(#{name}) - derivation_method '#{derivation_method}' is not supported"
  end
end

#value(record) ⇒ Object 



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# File 'lib/azahara_schema/derived_attribute.rb', line 63

def value(record)
  record.try(name) || attributes.collect{|a| a.value(record) }.join(concat_divider)
end