Class: PgGraph::Reflection

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_graph/reflector.rb

Constant Summary collapse

METHODS = 
%w(match this that multi pluralize default_reflection).map(&:to_sym)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(match, this, that, multi = nil, pluralize = nil, default_reflection = false) ⇒ Reflection

this and that are template strings, nil, or false



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# File 'lib/pg_graph/reflector.rb', line 56

def initialize(match, this, that, multi = nil, pluralize = nil, default_reflection = false)
  constrain match, Regexp, String
  constrain this, String, NilClass
  constrain that, String, FalseClass, NilClass
  constrain multi, true, false, nil
  constrain pluralize, TrueClass, FalseClass, NilClass
  constrain default_reflection, TrueClass, FalseClass, NilClass
  @match = match.is_a?(Regexp) ? match.source : match
  if @match =~ /^\/(.*)\/$/
    re = $1
    @re = Regexp.new("^(?:\\w+\\.)*#{re}$")
    @components = re.scan(/(?<!\\)\\(?:\\\\)*\./).count + 1
  else
    @re = Regexp.new("^(?:\\w+\\.)*#{@match}$")
    @components = @match.count(".") + 1
  end
  (1..4).include?(@components) or raise "Illegal number of name components: #{@match}"
  @this = this
  @that = that
  @multi = multi
  @pluralize = pluralize
  @default_reflection = default_reflection || false
end

Instance Attribute Details

#components ⇒ Object (readonly)

Number of name components (database, schema, table, column). It can be between one and four. By ordering reflections from highest to lowest number of components, specific matches will be tested before more general matches



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# File 'lib/pg_graph/reflector.rb', line 45

def components
  @components
end

#default_reflection ⇒ Object (readonly)

True if this is a default reflection



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# File 'lib/pg_graph/reflector.rb', line 48

def default_reflection
  @default_reflection
end

#match ⇒ Object (readonly)

Textual representation of match RE (String)



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# File 'lib/pg_graph/reflector.rb', line 14

def match
  @match
end

#multi ⇒ Object (readonly)

If true or nil, the reflection applies to multiple references in a table to the same referenced table. nil is used to mark the rule to not be included in the count of references. This is used to exclude explicit patterns like /^parent_id$/ that can co-exist with a another reference to the table



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# File 'lib/pg_graph/reflector.rb', line 31

def multi
  @multi
end

#pluralize ⇒ Object (readonly)

Pluralize the result of #that if true. Default nil. Note that if pluralize is nil, the Reflector will pluralize unless the column is unique



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# File 'lib/pg_graph/reflector.rb', line 36

def pluralize
  @pluralize
end

#re ⇒ Object (readonly)

RE corresponding to #match. #re always match a full UID



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# File 'lib/pg_graph/reflector.rb', line 39

def re
  @re
end

#that ⇒ Object (readonly)

Template for ‘that’ field name or false if the field should not be included in the model. Can be nil



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# File 'lib/pg_graph/reflector.rb', line 21

def that
  @that
end

#this ⇒ Object (readonly)

Template for ‘this’ field name. Can be nil



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# File 'lib/pg_graph/reflector.rb', line 17

def this
  @this
end

Class Method Details

.load_yaml(hash) ⇒ Object

hash has the keys :match, :this, :that, and :pluralize. The keys can also be strings



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# File 'lib/pg_graph/reflector.rb', line 95

def self.load_yaml(hash)
  Reflection.new *METHODS.map { |key|
    value = hash[key].nil? ? hash[key.to_s] : hash[key]
    value == "nil" ? nil : value
  }
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/pg_graph/reflector.rb', line 87

def ==(other)
  METHODS.all? { |method| self.send(method) == other.send(method) }
end

#dump ⇒ Object 



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# File 'lib/pg_graph/reflector.rb', line 50

def dump
  puts "Reflection"
  indent { putv :match, :re, :this, :that, :multi?, :pluralize, :components }
end

#inspect ⇒ Object 



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# File 'lib/pg_graph/reflector.rb', line 91

def inspect() "#<Reflection #{match}>" end

#multi? ⇒ Boolean

True if this reflection applies to multiple references in a table

Returns:

  • (Boolean) 


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# File 'lib/pg_graph/reflector.rb', line 24

def multi? = multi || multi.nil?

#to_yaml ⇒ Object 



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# File 'lib/pg_graph/reflector.rb', line 80

def to_yaml
  {
    match: match, this: this, that: that, multi: multi, pluralize: pluralize,
    default_reflection: default_reflection
  }
end