Class: DataGraph::Linkage

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/data_graph/linkage.rb

Direct Known Subclasses

CpkLinkage

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utils

cpk?, foreign_key, patherize_attrs, primary_keys, reference_key

Constructor Details

#initialize(assoc, options = {}) ⇒ Linkage

Returns a new instance of Linkage.



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# File 'lib/data_graph/linkage.rb', line 16

def initialize(assoc, options={})
  @macro = assoc.macro
  @name = assoc.name
  @through = nil
  
  case macro
  when :belongs_to
    @parent_columns = foreign_key(assoc)
    @child_columns  = reference_key(assoc)
  when :has_many, :has_one
    if through_assoc = assoc.through_reflection
      @through = assoc.source_reflection.name
      
      assoc = through_assoc
      options = {:only => [], :include => {@through => options}}
    end
    
    @parent_columns = reference_key(assoc)
    @child_columns  = foreign_key(assoc)
  else
    raise "currently unsupported association macro: #{macro}"
  end
  
  klass = assoc.klass
  @child_node = Node.new(assoc.klass, options)
  @table_name = klass.table_name
  @connection = klass.connection
end

Instance Attribute Details

#child_columns ⇒ Object (readonly)

Returns the value of attribute child_columns.



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# File 'lib/data_graph/linkage.rb', line 13

def child_columns
  @child_columns
end

#child_node ⇒ Object (readonly)

Returns the value of attribute child_node.



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# File 'lib/data_graph/linkage.rb', line 14

def child_node
  @child_node
end

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/data_graph/linkage.rb', line 11

def connection
  @connection
end

#macro ⇒ Object (readonly)

Returns the value of attribute macro.



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# File 'lib/data_graph/linkage.rb', line 7

def macro
  @macro
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/data_graph/linkage.rb', line 8

def name
  @name
end

#parent_columns ⇒ Object (readonly)

Returns the value of attribute parent_columns.



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# File 'lib/data_graph/linkage.rb', line 12

def parent_columns
  @parent_columns
end

#table_name ⇒ Object (readonly)

Returns the value of attribute table_name.



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# File 'lib/data_graph/linkage.rb', line 10

def table_name
  @table_name
end

#through ⇒ Object (readonly)

Returns the value of attribute through.



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# File 'lib/data_graph/linkage.rb', line 9

def through
  @through
end

Instance Method Details

#child_id(record) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 53

def child_id(record)
  record.send child_columns.at(0)
end

#conditions(id_map) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 57

def conditions(id_map)
  ["#{table_name}.#{connection.quote_column_name(child_columns.at(0))} IN (?)", id_map.keys.flatten]
end

#inherit(method_name, paths) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 94

def inherit(method_name, paths)
  dup.inherit!(method_name, paths)
end

#inherit!(method_name, paths) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 98

def inherit!(method_name, paths)
  paths = paths.collect {|path| "#{through}.#{path}"} if through
  @child_node = @child_node.send(method_name, paths)
  self
end

#link(parents) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 61

def link(parents)
  id_map = Hash.new {|hash, key| hash[key] = [] }
  
  parents = arrayify(parents)
  parents.each do |parent|
    id_map[parent_id(parent)] << parent
  end
  
  children = child_node.find(:all, 
    :select => child_columns, 
    :conditions => conditions(id_map))
  visited = []
  
  arrayify(children).each do |child|
    id_map[child_id(child)].each do |parent|
      visited << parent
      set_child(parent, child)
    end
  end
  
  if macro == :has_many && through
    visited.each do |parent|
      parent.send(name).uniq!
    end
  end
  
  (parents - visited).each do |parent|
    set_child(parent, nil)
  end
  
  children
end

#node ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 45

def node
  through ? child_node[through] : child_node
end

#parent_id(record) ⇒ Object 



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# File 'lib/data_graph/linkage.rb', line 49

def parent_id(record)
  record.send parent_columns.at(0)
end