Class: Ruote::ParticipantList

Inherits:
Object
  • Object
show all
Defined in:
lib/ruote/svc/participant_list.rb

Overview

Tracking participants to [business] processes.

The methods here are mostly called via the engine (registering / unregistering participants) and via the dispatch_pool (when handing workitems to participants).

Instance Method Summary collapse

Constructor Details

#initialize(context) ⇒ ParticipantList

Returns a new instance of ParticipantList.



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# File 'lib/ruote/svc/participant_list.rb', line 43

def initialize(context)

  @context = context
end

Instance Method Details

#clear ⇒ Object

Clears this participant list.

Used by Engine#register(&block)



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# File 'lib/ruote/svc/participant_list.rb', line 294

def clear

  self.list=([])
end

#initialize_participant(klass, options) ⇒ Object 



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# File 'lib/ruote/svc/participant_list.rb', line 220

def initialize_participant(klass, options)

  participant = if klass.instance_method(:initialize).arity == 0
    klass.new
  else
    klass.new(options)
  end

  participant.context = @context if participant.respond_to?(:context=)

  participant
end

#instantiate(pinfo, opts = {}) ⇒ Object

Returns an instance of a participant



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# File 'lib/ruote/svc/participant_list.rb', line 197

def instantiate(pinfo, opts={})

  pa_class_name, options = pinfo

  if rp = options['require_path']
    require(rp)
  end
  if lp = options['load_path']
    load(lp)
  end

  pa_class = Ruote.constantize(pa_class_name)
  pa_m = pa_class.instance_methods

  irt = opts[:if_respond_to?]

  if irt && ! (pa_m.include?(irt.to_s) || pa_m.include?(irt.to_sym))
    return nil
  end

  initialize_participant(pa_class, options)
end

#list ⇒ Object

Used by Engine#participant_list

Returns a representation of this participant list as an array of ParticipantEntry instances.



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# File 'lib/ruote/svc/participant_list.rb', line 259

def list

  get_list['list'].collect { |e| ParticipantEntry.new(e) }
end

#list=(pl) ⇒ Object

Used by Engine#participant_list=

Takes as input an array of ParticipantEntry instances and updates this participant list with it.

See ParticipantList#list



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# File 'lib/ruote/svc/participant_list.rb', line 271

def list=(pl)

  list = get_list

  list['list'] = pl.collect { |e|
    ParticipantEntry.read(e)
  }.collect { |e|
    e[0] = e[0].source if e[0].is_a?(Regexp)
    e
  }

  if r = @context.storage.put(list)
    #
    # put failed, have to redo it
    #
    self.list=(pl)
  end
end

#lookup(participant_name, workitem, opts = {}) ⇒ Object

Returns a participant instance, or nil if there is no participant for the given participant name.

Mostly a combination of #lookup_info and #instantiate.



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# File 'lib/ruote/svc/participant_list.rb', line 159

def lookup(participant_name, workitem, opts={})

  pinfo = participant_name.is_a?(String) ?
    lookup_info(participant_name, workitem) : participant_name

  pinfo ?
    instantiate(pinfo, opts) : nil
end

#lookup_info(pname, workitem) ⇒ Object

Given a participant name, returns

Returns nil if there is no participant registered that covers the given participant name.



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# File 'lib/ruote/svc/participant_list.rb', line 173

def lookup_info(pname, workitem)

  get_list['list'].each do |regex, pinfo|

    next unless pname.match(regex)

    return pinfo if workitem.nil?

    pa = instantiate(pinfo, :if_respond_to? => :accept?)

    return pinfo if pa.nil?

    return pinfo if pa.accept?(
      Ruote::Workitem.new(workitem.merge('participant_name' => pname))
    )
  end

  # nothing found...

  nil
end

#names ⇒ Object

Return a list of names (regex) for the registered participants



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# File 'lib/ruote/svc/participant_list.rb', line 235

def names

  get_list['list'].collect { |re, pa| re }
end

#register(name, participant, options, block) ⇒ Object

Registers a participant. Called by Engine#register_participant.

Raises:

  • (ArgumentError) 


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# File 'lib/ruote/svc/participant_list.rb', line 50

def register(name, participant, options, block)

  raise(
    ArgumentError.new(
      "can only accept strings (classnames) or classes as participant arg")
  ) unless [ String, Class, NilClass ].include?(participant.class)

  klass = (participant || Ruote::BlockParticipant).to_s

  options = options.inject({}) { |h, (k, v)|

    h[k.to_s] = case v
      when Symbol then v.to_s
      when Proc then v.to_raw_source
      else v
    end

    h
  }

  if block
    options['on_workitem'] = block.to_raw_source
    @context.treechecker.block_check(options['on_workitem'])
  end

  key = (name.is_a?(Regexp) ? name : Regexp.new("^#{name}$")).source
  entry = [ key, [ klass, options ] ]

  list = get_list

  position = options['position'] || options['pos'] || 'last'

  if position == 'before'

    position = list['list'].index { |e| e.first == key } || -1

  elsif position == 'after'

    position = (list['list'].rindex { |e| e.first == key } || -2) + 1

  elsif position == 'over'

    position = list['list'].index { |e| e.first == key } || -1
    list['list'].delete_at(position) unless position == -1

  elsif options.delete('override') != false

    list['list'].delete_if { |e| e.first == key }
      # enforces only one instance of a participant per key/regex
  end

  case position
    when 'last' then list['list'] << entry
    when 'first' then list['list'].unshift(entry)
    when Fixnum then list['list'].insert(position, entry)
    else raise "cannot insert participant at position '#{position}'"
  end

  if r = @context.storage.put(list)
    #
    # if put returns something it means the put failed, have to redo the
    # work...
    #
    return register(name, participant, options, block)
  end

  if entry.last.first == 'Ruote::StorageParticipant'
    Ruote::StorageParticipant.new(@context)
  else
    nil
  end
end

#shutdown ⇒ Object

Calls #shutdown on any participant that sports this method.



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# File 'lib/ruote/svc/participant_list.rb', line 242

def shutdown

  get_list['list'].each do |re, (kl, op)|

    kl = (Ruote.constantize(kl) rescue nil)

    if (kl.instance_method(:shutdown) rescue false)
      initialize_participant(kl, op).shutdown
    end
  end
end

#unregister(name_or_participant) ⇒ Object

Removes a participant, given via its name or directly from this participant list.

Called usually by Engine#unregister_participant.



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# File 'lib/ruote/svc/participant_list.rb', line 128

def unregister(name_or_participant)

  code = nil
  entry = nil
  list = get_list

  name_or_participant = name_or_participant.to_s

  entry = list['list'].find { |re, pa| name_or_participant.match(re) }

  return nil unless entry

  code = entry.last if entry.last.is_a?(String)

  list['list'].delete(entry)

  if r = @context.storage.put(list)
    #
    # put failed, have to redo it
    #
    return unregister(name_or_participant)
  end

  entry.first
end