Class: ActiveFacts::Metamodel::EntityType

Inherits:
DomainObjectType show all
Defined in:
lib/activefacts/metamodel/metamodel.rb,
lib/activefacts/metamodel/extensions.rb

Instance Attribute Summary

Attributes inherited from ObjectType

#injected_surrogate_role

Instance Method Summary collapse

Methods inherited from ObjectType

#all_role_transitive, #is_static

Instance Method Details

#add_supertype(supertype, is_identifying_supertype, assimilation) ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 812

def add_supertype(supertype, is_identifying_supertype, assimilation)
  inheritance_fact = constellation.TypeInheritance(self, supertype, :concept => :new)

  inheritance_fact.assimilation = assimilation

  # Create a reading:
  sub_role = constellation.Role(inheritance_fact, 0, :object_type => self, :concept => :new)
  super_role = constellation.Role(inheritance_fact, 1, :object_type => supertype, :concept => :new)

  rs = constellation.RoleSequence(:new)
  constellation.RoleRef(rs, 0, :role => sub_role)
  constellation.RoleRef(rs, 1, :role => super_role)
  constellation.Reading(inheritance_fact, 0, :role_sequence => rs, :text => "{0} is a kind of {1}", :is_negative => false)

  rs2 = constellation.RoleSequence(:new)
  constellation.RoleRef(rs2, 0, :role => super_role)
  constellation.RoleRef(rs2, 1, :role => sub_role)
  # Decide in which order to include is a/is an. Provide both, but in order.
  n = 'aeioh'.include?(sub_role.object_type.name.downcase[0]) ? 'n' : ''
  constellation.Reading(inheritance_fact, 2, :role_sequence => rs2, :text => "{0} is a#{n} {1}", :is_negative => false)

  if is_identifying_supertype
    inheritance_fact.provides_identification = true
  end

  # Create uniqueness constraints over the subtyping fact type.
  p1rs = constellation.RoleSequence(:new)
  constellation.RoleRef(p1rs, 0).role = sub_role
  pc1 = constellation.PresenceConstraint(:new, :vocabulary => vocabulary)
  pc1.name = "#{name}MustHaveSupertype#{supertype.name}"
  pc1.role_sequence = p1rs
  pc1.is_mandatory = true   # A subtype instance must have a supertype instance
  pc1.min_frequency = 1
  pc1.max_frequency = 1
  pc1.is_preferred_identifier = false
  trace :constraint, "Made new subtype PC GUID=#{pc1.concept.guid} min=1 max=1 over #{p1rs.describe}"

  p2rs = constellation.RoleSequence(:new)
  constellation.RoleRef(p2rs, 0).role = super_role
  pc2 = constellation.PresenceConstraint(:new, :vocabulary => vocabulary)
  pc2.name = "#{supertype.name}MayBeA#{name}"
  pc2.role_sequence = p2rs
  pc2.is_mandatory = false
  pc2.min_frequency = 0
  pc2.max_frequency = 1
  # The supertype role often identifies the subtype:
  pc2.is_preferred_identifier = inheritance_fact.provides_identification
  trace :supertype, "identification of #{name} via supertype #{supertype.name} was #{inheritance_fact.provides_identification ? '' : 'not '}added"
  trace :constraint, "Made new supertype PC GUID=#{pc2.concept.guid} min=1 max=1 over #{p2rs.describe}"
  inheritance_fact
end

#all_subtype ⇒ Object

An array of all direct subtypes



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# File 'lib/activefacts/metamodel/extensions.rb', line 783

def all_subtype
  all_type_inheritance_as_supertype.map(&:subtype)
end

#all_supertype ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 778

def all_supertype
  supertypes
end

#all_supertype_inheritance ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 765

def all_supertype_inheritance
  all_type_inheritance_as_subtype.sort_by{|ti|
      [ti.provides_identification ? 0 : 1, ti.supertype.name]
    }
end

#assimilation ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 571

def assimilation
  ti = all_type_inheritance_as_subtype.map(&:assimilation).compact[0]
end

#common_supertype(other) ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 805

def common_supertype(other)
  return nil unless other.is_a?(ActiveFacts::Metamodel::EntityType)
  candidates = supertypes_transitive & other.supertypes_transitive
  return candidates[0] if candidates.size <= 1
  candidates[0] # REVISIT: This might not be the closest supertype
end

#create_link_fact_types ⇒ Object

This entity type has just objectified a fact type. Create the necessary ImplicitFactTypes with objectification and mirror roles



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# File 'lib/activefacts/metamodel/extensions.rb', line 866

def create_link_fact_types
  fact_type.all_role.map do |role|
    next if role.mirror_role_as_base_role     # Already exists
    link_fact_type = @constellation.LinkFactType(:new, :implying_role => role)
    objectification_role = @constellation.Role(link_fact_type, 0, :object_type => self, :concept => :new)
    mirror_role = @constellation.MirrorRole(
      link_fact_type, 1,
      :concept => :new,
      :object_type => role.object_type,
      :base_role => role,
      :role_name => role.role_name
    )

    link_fact_type.concept.implication_rule =
    objectification_role.concept.implication_rule =
    mirror_role.concept.implication_rule = 'objectification'
    link_fact_type
  end
end

#identification_is_inherited ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 566

def identification_is_inherited
  preferred_identifier and
    preferred_identifier.role_sequence.all_role_ref.detect{|rr| rr.role.fact_type.is_a?(ActiveFacts::Metamodel::TypeInheritance) }
end

#identifying_supertype ⇒ Object

A subtype does not have a identifying_supertype if it defines its own identifier



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# File 'lib/activefacts/metamodel/extensions.rb', line 801

def identifying_supertype
  ti = identifying_type_inheritance and ti.supertype
end

#identifying_type_inheritance ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 794

def identifying_type_inheritance
  all_type_inheritance_as_subtype.detect do |ti|
    ti.provides_identification
  end
end

#is_partitioned ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 580

def is_partitioned
  assimilation == 'partitioned'
end

#is_separate ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 575

def is_separate
  # Independent Object Types, Entity Types marked separate and TypeInheritance marked not absorbed
  super || !['absorbed', nil].include?(assimilation)
end

#preferred_identifier ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 584

def preferred_identifier
  return @preferred_identifier if @preferred_identifier
  if fact_type
    # Objectified unaries are identified by the ID of the object that plays the role:
    if fact_type.all_role.size == 1
      entity_type = fact_type.all_role.single.object_type
      return @preferred_identifier = entity_type.preferred_identifier
    end

    # When compiling a fact instance, the delayed creation of a preferred identifier might be necessary
    if c = fact_type.check_and_add_spanning_uniqueness_constraint
      fact_type.check_and_add_spanning_uniqueness_constraint = nil
      c.call
    end

    # For a nested fact type, the PI is a unique constraint over N or N-1 roles
    fact_roles = Array(fact_type.all_role)
    trace :pi, "Looking for PI on nested fact type #{name}" do
      pi = catch :pi do
          fact_roles[0,2].each{|r|                  # Try the first two roles of the fact type, that's enough
              r.all_role_ref.map{|rr|               # All role sequences that reference this role
                  role_sequence = rr.role_sequence

                  # The role sequence is only interesting if it cover only this fact's roles
                  # or roles of the objectification
                  next if role_sequence.all_role_ref.size < fact_roles.size-1 # Not enough roles
                  next if role_sequence.all_role_ref.size > fact_roles.size   # Too many roles
                  next if role_sequence.all_role_ref.detect do |rsr|
                      if (of = rsr.role.fact_type) != fact_type
                        case of.all_role.size
                        when 1    # A unary FT must be played by the objectification of this fact type
                          next rsr.role.object_type != fact_type.entity_type
                        when 2    # A binary FT must have the objectification of this FT as the other player
                          other_role = (of.all_role-[rsr.role])[0]
                          next other_role.object_type != fact_type.entity_type
                        else
                          next true # A role in a ternary (or higher) cannot be usd in our identifier
                        end
                      end
                      rsr.role.fact_type != fact_type
                    end

                  # This role sequence is a candidate
                  pc = role_sequence.all_presence_constraint.detect{|c|
                      c.max_frequency == 1 && c.is_preferred_identifier
                    }
                  throw :pi, pc if pc
                }
            }
          throw :pi, nil
        end
      trace :pi, "Got PI #{pi.name||pi.object_id} for nested #{name}" if pi
      trace :pi, "Looking for PI on entity that nests this fact" unless pi
      raise "Oops, pi for nested fact is #{pi.class}" unless !pi || pi.is_a?(ActiveFacts::Metamodel::PresenceConstraint)
      return @preferred_identifier = pi if pi
    end
  end

  trace :pi, "Looking for PI for ordinary entity #{name} with #{all_role.size} roles:" do
    trace :pi, "Roles are in fact types #{all_role.map{|r| r.fact_type.describe(r)}*", "}"
    pi = catch :pi do
        all_supertypes = supertypes_transitive
        trace :pi, "PI roles must be played by one of #{all_supertypes.map(&:name)*", "}" if all_supertypes.size > 1
        all_role.each{|role|
            next unless role.is_unique || fact_type
            next if role.fact_type.is_a?(TypeInheritance) && !role.fact_type.provides_identification
            ftroles = Array(role.fact_type.all_role)

            # Skip roles in ternary and higher fact types, they're objectified
            # REVISIT: This next line prevents a unary being used as a preferred_identifier:
            next if ftroles.size != 2

            trace :pi, "Considering role in #{role.fact_type.describe(role)}"

            # Find the related role which must be included in any PI:
            # Note this works with unary fact types:
            pi_role = ftroles[ftroles[0] != role ? 0 : -1]

            next if ftroles.size == 2 && pi_role.object_type == self
            trace :pi, "  Considering #{pi_role.object_type.name} as a PI role"

            # If this is an identifying role, the PI is a PC whose role_sequence spans the role.
            # Walk through all role_sequences that span this role, and test each:
            pi_role.all_role_ref.each{|rr|
                role_sequence = rr.role_sequence  # A role sequence that includes a possible role

                trace :pi, "    Considering role sequence #{role_sequence.describe}"

                # All roles in this role_sequence must be in fact types which
                # (apart from that role) only have roles played by the original
                # entity type or a supertype.
                #trace :pi, "      All supertypes #{all_supertypes.map{|st| "#{st.object_id}=>#{st.name}"}*", "}"
                if role_sequence.all_role_ref.detect{|rsr|
                    fact_type = rsr.role.fact_type
                    trace :pi, "      Role Sequence touches #{fact_type.describe(pi_role)}"

                    fact_type_roles = fact_type.all_role
                    trace :pi, "      residual is #{fact_type_roles.map{|r| r.object_type.name}.inspect} minus #{rsr.role.object_type.name}"
                    residual_roles = fact_type_roles-[rsr.role]
                    residual_roles.detect{|rfr|
                        trace :pi, "        Checking residual role #{rfr.object_type.object_id}=>#{rfr.object_type.name}"
# This next line looks right, but breaks things. Find out what and why:
#                              !rfr.unique or
                          !all_supertypes.include?(rfr.object_type)
                      }
                  }
                  trace :pi, "      Discounting this role_sequence because it includes alien roles"
                  next
                end

                # Any presence constraint over this role sequence is a candidate
                rr.role_sequence.all_presence_constraint.detect{|pc|
                    # Found it!
                    if pc.is_preferred_identifier
                      trace :pi, "found PI #{pc.name||pc.object_id}, is_preferred_identifier=#{pc.is_preferred_identifier.inspect} over #{pc.role_sequence.describe}"
                      throw :pi, pc
                    end
                  }
              }
          }
        throw :pi, nil
      end
    raise "Oops, pi for entity is #{pi.class}" if pi && !pi.is_a?(ActiveFacts::Metamodel::PresenceConstraint)
    trace :pi, "Got PI #{pi.name||pi.object_id} for #{name}" if pi

    if !pi
      if (supertype = identifying_supertype)
        # This shouldn't happen now, as an identifying supertype is connected by a fact type
        # that has a uniqueness constraint marked as the preferred identifier.
        #trace :pi, "PI not found for #{name}, looking in supertype #{supertype.name}"
        #pi = supertype.preferred_identifier
        #return nil
      elsif fact_type
        possible_pi = nil
        fact_type.all_role.each{|role|
          role.all_role_ref.each{|role_ref|
            # Discount role sequences that contain roles not in this fact type:
            next if role_ref.role_sequence.all_role_ref.detect{|rr| rr.role.fact_type != fact_type }
            role_ref.role_sequence.all_presence_constraint.each{|pc|
              next unless pc.max_frequency == 1
              possible_pi = pc
              next unless pc.is_preferred_identifier
              pi = pc
              break
            }
            break if pi
          }
          break if pi
        }
        if !pi && possible_pi
          trace :pi, "Using existing PC as PI for #{name}"
          pi = possible_pi
        end
      else
        trace :pi, "No PI found for #{name}"
        debugger if respond_to?(:debugger)
      end
    end
    raise "No PI found for #{name}" unless pi
    @preferred_identifier = pi
  end
end

#preferred_identifier_roles ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 747

def preferred_identifier_roles
  preferred_identifier.role_sequence.all_role_ref_in_order.map(&:role)
end

#rank_in_preferred_identifier(role) ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 751

def rank_in_preferred_identifier(role)
  preferred_identifier_roles.index(role)
end

#subtypes ⇒ Object

An array of all direct subtypes:



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# File 'lib/activefacts/metamodel/extensions.rb', line 756

def subtypes
  # REVISIT: There's no sorting here. Should there be?
  all_type_inheritance_as_supertype.map{|ti| ti.subtype }
end

#subtypes_transitive ⇒ Object 



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# File 'lib/activefacts/metamodel/extensions.rb', line 761

def subtypes_transitive
  [self] + subtypes.map{|st| st.subtypes_transitive}.flatten.uniq
end

#supertypes ⇒ Object

An array of all direct supertypes



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# File 'lib/activefacts/metamodel/extensions.rb', line 772

def supertypes
  all_supertype_inheritance.map{|ti|
      ti.supertype
    }
end

#supertypes_transitive ⇒ Object

An array of self followed by all supertypes in order:



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# File 'lib/activefacts/metamodel/extensions.rb', line 788

def supertypes_transitive
  ([self] + all_type_inheritance_as_subtype.map{|ti|
      ti.supertype.supertypes_transitive
    }).flatten.uniq
end