Class: StatemachineParser

Inherits:
Statemachine::StatemachineBuilder
  • Object
show all
Includes:
REXML, StreamListener
Defined in:
lib/MINT-scxml/scxml-parser.rb

Instance Method Summary collapse

Constructor Details

#initialize(context = nil, logger = nil, queue = nil) ⇒ StatemachineParser

Returns a new instance of StatemachineParser.



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# File 'lib/MINT-scxml/scxml-parser.rb', line 20

def initialize(context = nil, logger = nil, queue = nil)
  super()

  @statemachine.messenger = logger
  @statemachine.message_queue = queue
  @statemachine.context= context

  # The current variables are used to temporarily store the value of the _"type"
  # in order to acquire the necessary data before adding the to its proper stack
  @current_transition = nil
  @current_state = nil
  @current_element = nil

  # Stacks
  # These stacks (created as Arrays but used as stacks: push & pop) are used
  # to store and treat the structure of the scxml file read.
  # Some require auxiliary stacks due to the necessity of different treatments
  # in different situations (e.g.: substate_aux is necessary due to the fact that
  # a parallel state's superstate can have substates that would only be treated when
  # the superstate is closed, which only happens after the parallel state is treated.
  # Which in turn can have its own set of substates).
  # Obs: These variables are used as stacks due to two basic situations: the ability of
  #      nested elements in statemachines and the need to create a single structure to be
  #      passed to element's constructors.
  @actions = Array.new            # stores the actions to later be added to the transition they belong.
  @actions_aux = Array.new
  @state = Array.new              # stores the order of nested states to be treated and used further on.
  @substate = Array.new           # similar to state, it stores the substates in order to later be added
                                  # and have the proper transition treatment related to its parent state
  @substate_aux = Array.new
  @transitions = Array.new        # stores the transitions in order to be later added to its proper state.
        # so on and so forth.
  @parallel_state = Array.new
  @history_states = Array.new
  @history_target = Array.new

  # These variables are used to store the value of the element that gives its
  # name in order to be used as parameters or "situation check" in future parts
  # of the parser.
  @parallel = nil
  @history_state = nil

  # These variables are used to help in the creation of actions that have if clauses.
  @if_actions = Array.new
  @if_actions_aux = Array.new
  @if = Array.new
  @tag = Array.new
  @cond = Array.new

  # These boolean variables are used to determine in which case we are on
  # so to treat each case properly.
  #   If a history state was read, if inside a parallel state and if it has
  #   an outermost scxml_state (the latter implicates on different treatments due
  #   to the fact that it is added to the states stack and therefore it might not be
  #   empty as expected in certain situations)
  @history = false
  @is_parallel = false
  @scxml_state = false
end

Instance Method Details

#build_from_scxml(filename) ⇒ Object

This function parses scxml from a file



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# File 'lib/MINT-scxml/scxml-parser.rb', line 81

def build_from_scxml(filename)
  source = File.new filename
  Document.parse_stream(source, self)
  #@statemachine.reset
  @statemachine
end

#build_from_scxml_string(stringbuffer) ⇒ Object

This function parses scxml directly from the string parameter “stringbuffer”



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# File 'lib/MINT-scxml/scxml-parser.rb', line 89

def build_from_scxml_string(stringbuffer)
  Document.parse_stream(stringbuffer, self)
  #@statemachine.reset
  @statemachine
end

#creating_ifs ⇒ Object

This function deals with the different scenarios for the creation of actions with if



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# File 'lib/MINT-scxml/scxml-parser.rb', line 97

def creating_ifs
  if @if.size == 1
    @if_actions.push(@if_actions_aux.last) if @if_actions_aux.size != 0
    if @actions_aux.size != 0
      @actions_aux.each do |j|
        @if_actions.push(j)
      end
      @actions_aux = []
    end
    @actions.push([@tag.last, @cond.last, @if_actions])
  else
    if @if_actions.size != 0
      @if_actions_aux.push(@if_actions)
    end
    @actions_aux.push([@tag.last, @cond.last, @if_actions_aux.last])
  end
  @if_actions = []
  @cond.pop
  @tag.pop
  @if_actions_aux.pop if @if_actions_aux.size != 0
end

#tag_end(name) ⇒ Object

This function defines the actions to be taken for each different tag when the tag is closed



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# File 'lib/MINT-scxml/scxml-parser.rb', line 272

def tag_end(name)
  case name
    when 'parallel'
      @statemachine.add_state(@parallel.subject)
      @is_parallel = false
      @substate = @substate_aux
      @substate_aux = []
    when 'state'
      if @state.last.is_a? Statemachine::SuperstateBuilder
        s = statemachine.get_state(@state.last.subject.id)

        if (s.id == @history_state)
          if @history_target.last
            s.default_history = @history_target.last.to_sym
            @history_target.pop
          end
        end

        # Every state belonging to this superstate should respond to the superstate's transitions
        @substate.each do |j|
          if s
            s1 = statemachine.get_state(j.subject.id)
            s.transitions.each do |k|
              s1.add(k) if s1
            end
          end
        end
      end

      # In case of parallel statemachines the outmost states will become parallel statemachines
      # only considering parallel on a root level
      if @parallel_state.size == 1 and @parallel.is_a? Statemachine::ParallelStateBuilder
        statemachine_aux = Statemachine::Statemachine.new(@parallel.subject)
        statemachine_aux.add_state(@parallel_state.last.subject)
        @statemachine.remove_state(@parallel_state.last.subject)
        @substate.each do |j|
          j.subject.modify_statemachine(statemachine_aux)
          statemachine_aux.add_state(j.subject)
          @statemachine.remove_state(j.subject)
        end
        #statemachine_aux.reset
        @parallel.subject.add_statemachine(statemachine_aux)
      end

      @substate.push(@state.last)

      if (@state.size == 1 and not @scxml_state) or (@state.size == 2 and @scxml_state) or (@parallel_state.size == 1)
        @substate = []
        # TODO make this better. Too inefficient
        while @history_states.size != 0
          # change every transitions where @history_states.last was the target state to history_states.last+"_H"
          # for every history state
          @statemachine.states.each_value do |s|
            s.transitions.each do |t|
              if t.destination_id == @history_states.last
                t.destination_id = (t.destination_id.to_s + "_H").to_s
              end
            end
          end
          @history_states.pop
        end
      end
      @state.pop
      @parallel_state.pop if @is_parallel
    when 'transition'
      if @transitions.last.event == nil
        if @history
          @history_target.push(@transitions.last.target)
          @history = false
        else
          if @is_parallel and @parallel_state.empty?
            @parallel.event(nil, @transitions.last.target.to_sym, @actions, @transitions.last.cond)
          else
            @state.last.event(nil, @transitions.last.target.to_sym, @actions, @transitions.last.cond)
          end
        end
      else
        if @transitions.last.target != nil
          if @is_parallel and @parallel_state.empty?
            @parallel.event(@transitions.last.event.to_sym, @transitions.last.target.to_sym, @actions, @transitions.last.cond)
          else
            @state.last.event(@transitions.last.event.to_sym, @transitions.last.target.to_sym, @actions, @transitions.last.cond)
          end
        else
          # if it doesn't have a target state, it is its own target state
          if @is_parallel and @parallel_state.empty?
            @parallel.event(@transitions.last.event.to_sym, @state.last.subject.id.to_sym, @actions, @transitions.last.cond)
          else
            @state.last.event(@transitions.last.event.to_sym, @state.last.subject.id.to_sym, @actions, @transitions.last.cond)
          end
        end
      end
      @actions=[]
      @transitions.pop
    when 'onentry'
      if @is_parallel and @parallel_state.empty?
        @parallel.on_entry(@actions)
      else
        @state.last.on_entry(@actions)
      end
      @actions=[]
    when 'onexit'
      if @is_parallel and @parallel_state.empty?
        @parallel.on_exit(@actions)
      else
        @state.last.on_exit(@actions)
      end
      @actions=[]
    when 'history'
      @history = false
    when 'if'
      creating_ifs
      @if.pop
    when 'script'
      @script = false
      if @if.last
        @if_actions.push(["script", @script_code])
      else
        @actions.push(["script", @script_code])
      end
    else

  end
end

#tag_start(name, attributes) ⇒ Object

This function defines the actions to be taken for each different tag when the tag is opened



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# File 'lib/MINT-scxml/scxml-parser.rb', line 120

def tag_start(name, attributes)
  case name
    when 'scxml'
      # If the initial tag <scxml> has a n  ame attribute, define it as the most outer super state
      if attributes['name']
        @scxml_state = true
        @current_state = State.new
        @current_state.id = attributes['id']
        @current_state.initial = attributes['initial']
        state = Statemachine::SuperstateBuilder.new(attributes['name'].to_sym, @subject, @statemachine)
        # If the current state has an initial state defined, add it to the state created.
        if @current_state.initial != nil
          state.startstate(@current_state.initial.to_sym)
        end
        # Adds it to a list of "open" states
        @state.push(state)
      end
    when 'parallel'
      @is_parallel = true
      # If the parent superstate of the parallel state has substates, save them for later
      if not @substate.empty?
        @substate_aux = @substate
        @substate = []
      end
      # If there is a state that encapsulates the parallel state, change it to a superstate
      if not @state.empty? and @state.last.is_a? Statemachine::StateBuilder
        state = Statemachine::SuperstateBuilder.new(@state.last.subject.id, @state.last.subject.superstate, @state.last.subject.statemachine)
        @state.pop            # pops the old one
        @state.push(state)    # pushes the new one
      end
      if @state.empty?
        @parallel = Statemachine::ParallelStateBuilder.new(attributes['id'].to_sym, @subject, @statemachine)
      else
        @parallel = Statemachine::ParallelStateBuilder.new(attributes['id'].to_sym, @state.last.subject, @statemachine)
      end

    when 'state'
      @current_state = State.new
      @current_state.id = attributes['id']
      @current_state.initial = attributes['initial']
      if @state.empty?
        # It is not a substate
        if @current_state.initial != nil
          # and it is a superstate
          state = Statemachine::SuperstateBuilder.new(attributes['id'].to_sym, @subject, @statemachine)
          state.startstate(@current_state.initial.to_sym)
        else
          # and it is a state
          state = Statemachine::StateBuilder.new(attributes['id'].to_sym, @subject, @statemachine)
        end
      else
        #It is a substate
        if @state.last.is_a? Statemachine::StateBuilder
          # Its parent is not a superstate yet
          if @is_parallel and @parallel_state.empty?
            state = Statemachine::SuperstateBuilder.new(@state.last.subject.id, @parallel.subject, @state.last.subject.statemachine)
          else
            state = Statemachine::SuperstateBuilder.new(@state.last.subject.id, @state.last.subject.superstate, @state.last.subject.statemachine)
          end
          @state.pop            # pops the old one
          @state.push(state)    # pushes the new one
          if @is_parallel
            @parallel_state.pop
            @parallel_state.push(state)
          end
        end
        if @current_state.initial != nil
          # and it is a superstate
          if @is_parallel and @parallel_state.empty?
            state = Statemachine::SuperstateBuilder.new(attributes['id'].to_sym, @parallel.subject, @statemachine)
          else
            state = Statemachine::SuperstateBuilder.new(attributes['id'].to_sym, @state.last.subject, @statemachine)
          end
          state.startstate(@current_state.initial.to_sym)
        else
          # and it is a state
          if @is_parallel and @parallel_state.empty?
            state = Statemachine::StateBuilder.new(attributes['id'].to_sym, @parallel.subject, @statemachine)
          else
            state = Statemachine::StateBuilder.new(attributes['id'].to_sym, @state.last.subject, @statemachine)
          end
        end
      end
      @state.push(state)
      @parallel_state.push(state) if @is_parallel
    when 'transition'
      @current_transition = Transition.new
      if attributes['target'] == @history_state.to_s and @history_state
        @current_transition.target = attributes['target']+"_H"
      else
        @current_transition.target = attributes['target']
      end
      if attributes['event']
        @current_transition.event = attributes['event']
      else
        @current_transition.event = nil
      end
      if attributes['cond']
        @current_transition.cond = attributes['cond']
      else
        @current_transition.cond = true
      end
      @transitions.push(@current_transition)
    when 'onentry'
    when 'onexit'
    when 'history'
      @history = true
      @history_states.push(@state.last.subject.id)
      @history_state = @state.last.subject.id
    when 'if'
      @if.push(true)
      if @if.size >= 1
        @if_actions_aux.push(@if_actions) if @if_actions.size != 0
        @if_actions = []
      end
      @cond.push(attributes['cond'])
      @tag.push("if")
    when 'elseif'
      creating_ifs
      @cond.push(attributes['cond'])
      @tag.push("elseif")
    when 'else'
      creating_ifs
      @cond.push(true)
      @tag.push("else")
    when 'log'
      if @if.last
        @if_actions.push(["log", attributes['expr']])
      else
        @actions.push(["log", attributes['expr']])
      end
    when 'send'
      if @if.last
        @if_actions.push(["send", attributes['target'], attributes['event']])
      else
        @actions.push(["send", attributes['target'], attributes['event']])
      end
    when 'invoke'
      if @if.last
        @if_actions.push(["invoke", attributes['src'].to_sym])
      else
        @actions.push(["invoke", attributes['src'].to_sym])
      end
    when 'script'
      @script = true
      @script_code = ""
    else
      @current_element = name
  end
end

#text(text) ⇒ Object 



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# File 'lib/MINT-scxml/scxml-parser.rb', line 397

def text(text)
  if @script
    @script_code += text
  end
end

#xmldecl(version, encoding, standalone) ⇒ Object 



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# File 'lib/MINT-scxml/scxml-parser.rb', line 403

def xmldecl(version, encoding, standalone)
end