Module: Phronomy::WorkflowContext

Defined in:
lib/phronomy/workflow_context.rb

Overview

Module for defining Workflow context data.

In StateChart terminology this is the extended state/context, as opposed to the current FSM phase.

An application context may define handle_fsm_event(event). FSMSession calls it on the EventLoop thread before evaluating a declared transition. The method may mutate the context and return false to continue transition evaluation, return a replacement WorkflowContext, or return :consume to discard a stale/unrelated event without firing a transition.

Defined Under Namespace

Modules: ClassMethods

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#thread_id ⇒ Object (readonly)

Returns the value of attribute thread_id.



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# File 'lib/phronomy/workflow_context.rb', line 43

def thread_id
  @thread_id
end

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/phronomy/workflow_context.rb', line 15

def self.included(base)
  base.extend(ClassMethods)
  base.instance_variable_set(:@fields, {})
end

Instance Method Details

#halted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/phronomy/workflow_context.rb', line 49

def halted?
  phase != :__end__
end

#initialize(**attrs) ⇒ Object 



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# File 'lib/phronomy/workflow_context.rb', line 59

def initialize(**attrs)
  unknown = attrs.keys - self.class.fields.keys
  unless unknown.empty?
    raise ArgumentError,
      "Unknown WorkflowContext field(s): #{unknown.inspect}"
  end

  self.class.fields.each do |name, config|
    default =
      if config[:default].is_a?(Proc)
        config[:default].call
      else
        config[:default]
      end
    instance_variable_set(
      :"@#{name}",
      attrs.fetch(name, default)
    )
  end
  @thread_id = nil
  @phase = :__end__
end

#merge(updates) ⇒ Object

Returns a new context with field update policies applied.



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# File 'lib/phronomy/workflow_context.rb', line 83

def merge(updates)
  unknown = updates.keys - self.class.fields.keys
  unless unknown.empty?
    raise ArgumentError,
      "Unknown WorkflowContext field(s): #{unknown.inspect}"
  end

  new_attrs = {}
  self.class.fields.each_key do |name|
    field_config = self.class.fields[name]
    new_attrs[name] =
      if updates.key?(name)
        case field_config[:type]
        when :append
          Array(public_send(name)) + Array(updates[name])
        when :merge
          (public_send(name) || {}).merge(updates[name])
        else
          updates[name]
        end
      else
        deep_dup_value(public_send(name))
      end
  end

  new_context = self.class.new(**new_attrs)
  new_context.set_graph_metadata(
    thread_id: @thread_id,
    phase: @phase
  )
  new_context
end

#phase ⇒ Object 



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# File 'lib/phronomy/workflow_context.rb', line 45

def phase
  @phase || :__end__
end

#set_graph_metadata(thread_id: nil, phase: nil) ⇒ Object 



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# File 'lib/phronomy/workflow_context.rb', line 53

def set_graph_metadata(thread_id: nil, phase: nil)
  @thread_id = thread_id unless thread_id.nil?
  @phase = phase unless phase.nil?
  self
end

#to_h ⇒ Object 



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# File 'lib/phronomy/workflow_context.rb', line 116

def to_h
  self.class.fields.keys.each_with_object({}) do |name, result|
    result[name] = public_send(name)
  end
end