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Class: Arel::Visitors::Visitor

Do not use. This class is for internal use only.
Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
Dot, MySQL, PostgreSQL, SQLite, ToSql
Inherits: Object
Defined in: activerecord/lib/arel/visitors/visitor.rb

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new ⇒ Visitor

[ GitHub ] 

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 6



def initialize
  @dispatch = get_dispatch_cache
end


  







Class Method Details



  

    .dispatch_cache   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 17



def self.dispatch_cache
  @dispatch_cache ||= Hash.new do |hash, klass|
    hash[klass] = :"visit_#{(klass.name || "").gsub("::", "_")}"
  end.compare_by_identity
end


  







Instance Attribute Details



  

    #dispatch   (readonly, private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 15



attr_reader :dispatch


  







Instance Method Details



  

    #accept(object, collector = nil)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 10



def accept(object, collector = nil)
  visit object, collector
end


  








  

    #get_dispatch_cache   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 23



def get_dispatch_cache
  self.class.dispatch_cache
end


  








  

    #visit(object, collector = nil)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/arel/visitors/visitor.rb', line 27



def visit(object, collector = nil)
  dispatch_method = dispatch[object.class]
  if collector
    send dispatch_method, object, collector
  else
    send dispatch_method, object
  end
rescue NoMethodError => e
  raise e if respond_to?(dispatch_method, true)
  superklass = object.class.ancestors.find { |klass|
    respond_to?(dispatch[klass], true)
  }
  raise(TypeError, "Cannot visit #{object.class}") unless superklass
  dispatch[object.class] = dispatch[superklass]
  retry
end