class ViewModel::TraversalContext

Abstract base for Serialize and DeserializeContexts.

Attributes

shared_context[R]

Public Class Methods

new(shared_context: nil, **shared_context_params) click to toggle source
Calls superclass method
# File lib/view_model/traversal_context.rb, line 31
def initialize(shared_context: nil, **shared_context_params)
  super()
  @shared_context     = shared_context || self.class.shared_context_class.new(**shared_context_params)
  @parent_context     = nil
  @parent_viewmodel   = nil
  @parent_association = nil
  @root               = true
end
new_child(...) click to toggle source
# File lib/view_model/traversal_context.rb, line 27
def self.new_child(...)
  self.allocate.tap { |c| c.initialize_as_child(...) }
end
shared_context_class() click to toggle source
# File lib/view_model/traversal_context.rb, line 19
def self.shared_context_class
  SharedContext
end

Public Instance Methods

for_child(parent_viewmodel, association_name:, **rest) click to toggle source
# File lib/view_model/traversal_context.rb, line 51
def for_child(parent_viewmodel, association_name:, **rest)
  self.class.new_child(
    shared_context:     shared_context,
    parent_context:     self,
    parent_viewmodel:   parent_viewmodel,
    parent_association: association_name,
    **rest)
end
for_references() click to toggle source

Obtain a semi-independent context for descending through a shared reference: keep the same shared context, but drop any tree location specific local context (since a shared reference could equally have been reached via any parent)

# File lib/view_model/traversal_context.rb, line 64
def for_references
  self.class.new(shared_context: shared_context)
end
initialize_as_child(shared_context:, parent_context:, parent_viewmodel:, parent_association:) click to toggle source

Overloaded constructor for initialization of descendent node contexts. Shared context is the same, ancestry is established, and subclasses can override to maintain other node-specific state.

# File lib/view_model/traversal_context.rb, line 43
def initialize_as_child(shared_context:, parent_context:, parent_viewmodel:, parent_association:)
  @shared_context     = shared_context
  @parent_context     = parent_context
  @parent_viewmodel   = parent_viewmodel
  @parent_association = parent_association
  @root               = false
end
nearest_root() click to toggle source
# File lib/view_model/traversal_context.rb, line 112
def nearest_root
  if root?
    self
  else
    parent_context&.nearest_root
  end
end
nearest_root_viewmodel() click to toggle source
# File lib/view_model/traversal_context.rb, line 120
def nearest_root_viewmodel
  if root?
    raise RuntimeError.new('Attempted to find nearest root from a root context. This is probably not what you wanted.')
  elsif parent_context.root?
    parent_viewmodel
  else
    parent_context.nearest_root_viewmodel
  end
end
parent_association(idx = 0) click to toggle source
# File lib/view_model/traversal_context.rb, line 84
def parent_association(idx = 0)
  if idx == 0
    @parent_association
  else
    parent_context(idx - 1)&.parent_association
  end
end
parent_context(idx = 0) click to toggle source
# File lib/view_model/traversal_context.rb, line 68
def parent_context(idx = 0)
  if idx == 0
    @parent_context
  else
    @parent_context&.parent_context(idx - 1)
  end
end
parent_ref(idx = 0) click to toggle source
# File lib/view_model/traversal_context.rb, line 92
def parent_ref(idx = 0)
  parent_viewmodel(idx)&.to_reference
end
parent_viewmodel(idx = 0) click to toggle source
# File lib/view_model/traversal_context.rb, line 76
def parent_viewmodel(idx = 0)
  if idx == 0
    @parent_viewmodel
  else
    parent_context(idx - 1)&.parent_viewmodel
  end
end
root?() click to toggle source
# File lib/view_model/traversal_context.rb, line 108
def root?
  @root
end
run_callback(hook, view, **args) click to toggle source
# File lib/view_model/traversal_context.rb, line 96
def run_callback(hook, view, **args)
  # Run in-viewmodel callback hooks before context hooks, as they are
  # permitted to alter the model.
  if view.respond_to?(hook.dsl_viewmodel_callback_method)
    view.public_send(hook.dsl_viewmodel_callback_method, hook.context_name => self, **args)
  end

  callbacks.each do |callback|
    callback.run_callback(hook, view, self, **args)
  end
end