The Tuplespace manages access to the tuples it contains, ensuring mutual exclusion requirements are met.

The sec option for the write, take, move, read and notify methods may either be a number of seconds or a Renewer object.

Methods
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Included Modules
Class Public methods
new(period=60)

Creates a new TupleSpace. period is used to control how often to look for dead tuples after modifications to the TupleSpace.

If no dead tuples are found period seconds after the last modification, the TupleSpace will stop looking for dead tuples.

# File ../ruby/lib/rinda/tuplespace.rb, line 438
def initialize(period=60)
  super()
  @bag = TupleBag.new
  @read_waiter = TupleBag.new
  @take_waiter = TupleBag.new
  @notify_waiter = TupleBag.new
  @period = period
  @keeper = nil
end
Instance Public methods
move(port, tuple, sec=nil)

Moves tuple to port.

# File ../ruby/lib/rinda/tuplespace.rb, line 485
def move(port, tuple, sec=nil)
  template = WaitTemplateEntry.new(self, tuple, sec)
  yield(template) if block_given?
  synchronize do
    entry = @bag.find(template)
    if entry
      port.push(entry.value) if port
      @bag.delete(entry)
      notify_event('take', entry.value)
      return entry.value
    end
    raise RequestExpiredError if template.expired?

    begin
      @take_waiter.push(template)
      start_keeper if template.expires
      while true
        raise RequestCanceledError if template.canceled?
        raise RequestExpiredError if template.expired?
        entry = @bag.find(template)
        if entry
          port.push(entry.value) if port
          @bag.delete(entry)
          notify_event('take', entry.value)
          return entry.value
        end
        template.wait
      end
    ensure
      @take_waiter.delete(template)
    end
  end
end
notify(event, tuple, sec=nil)

Registers for notifications of event. Returns a NotifyTemplateEntry. See NotifyTemplateEntry for examples of how to listen for notifications.

event can be:

'write'

A tuple was added

'take'

A tuple was taken or moved

'delete'

A tuple was lost after being overwritten or expiring

The TupleSpace will also notify you of the 'close' event when the NotifyTemplateEntry has expired.

# File ../ruby/lib/rinda/tuplespace.rb, line 568
def notify(event, tuple, sec=nil)
  template = NotifyTemplateEntry.new(self, event, tuple, sec)
  synchronize do
    @notify_waiter.push(template)
  end
  template
end
read(tuple, sec=nil)

Reads tuple, but does not remove it.

# File ../ruby/lib/rinda/tuplespace.rb, line 522
def read(tuple, sec=nil)
  template = WaitTemplateEntry.new(self, tuple, sec)
  yield(template) if block_given?
  synchronize do
    entry = @bag.find(template)
    return entry.value if entry
    raise RequestExpiredError if template.expired?

    begin
      @read_waiter.push(template)
      start_keeper if template.expires
      template.wait
      raise RequestCanceledError if template.canceled?
      raise RequestExpiredError if template.expired?
      return template.found
    ensure
      @read_waiter.delete(template)
    end
  end
end
read_all(tuple)

Returns all tuples matching tuple. Does not remove the found tuples.

# File ../ruby/lib/rinda/tuplespace.rb, line 546
def read_all(tuple)
  template = WaitTemplateEntry.new(self, tuple, nil)
  synchronize do
    entry = @bag.find_all(template)
    entry.collect do |e|
      e.value
    end
  end
end
take(tuple, sec=nil, &block)

Removes tuple

# File ../ruby/lib/rinda/tuplespace.rb, line 478
def take(tuple, sec=nil, &block)
  move(nil, tuple, sec, &block)
end
write(tuple, sec=nil)

Adds tuple

# File ../ruby/lib/rinda/tuplespace.rb, line 451
def write(tuple, sec=nil)
  entry = create_entry(tuple, sec)
  synchronize do
    if entry.expired?
      @read_waiter.find_all_template(entry).each do |template|
        template.read(tuple)
      end
      notify_event('write', entry.value)
      notify_event('delete', entry.value)
    else
      @bag.push(entry)
      start_keeper if entry.expires
      @read_waiter.find_all_template(entry).each do |template|
        template.read(tuple)
      end
      @take_waiter.find_all_template(entry).each do |template|
        template.signal
      end
      notify_event('write', entry.value)
    end
  end
  entry
end
Instance Private methods
create_entry(tuple, sec)
# File ../ruby/lib/rinda/tuplespace.rb, line 578
def create_entry(tuple, sec)
  TupleEntry.new(tuple, sec)
end
keep_clean()

Removes dead tuples.

# File ../ruby/lib/rinda/tuplespace.rb, line 585
def keep_clean
  synchronize do
    @read_waiter.delete_unless_alive.each do |e|
      e.signal
    end
    @take_waiter.delete_unless_alive.each do |e|
      e.signal
    end
    @notify_waiter.delete_unless_alive.each do |e|
      e.notify(['close'])
    end
    @bag.delete_unless_alive.each do |e|
      notify_event('delete', e.value)
    end
  end
end
need_keeper?()

Checks the tuplespace to see if it needs cleaning.

# File ../ruby/lib/rinda/tuplespace.rb, line 632
def need_keeper?
  return true if @bag.has_expires?
  return true if @read_waiter.has_expires?
  return true if @take_waiter.has_expires?
  return true if @notify_waiter.has_expires?
end
notify_event(event, tuple)

Notifies all registered listeners for event of a status change of tuple.

# File ../ruby/lib/rinda/tuplespace.rb, line 606
def notify_event(event, tuple)
  ev = [event, tuple]
  @notify_waiter.find_all_template(ev).each do |template|
    template.notify(ev)
  end
end
start_keeper()

Creates a thread that scans the tuplespace for expired tuples.

# File ../ruby/lib/rinda/tuplespace.rb, line 616
def start_keeper
  return if @keeper && @keeper.alive?
  @keeper = Thread.new do
    while true
      sleep(@period)
      synchronize do
        break unless need_keeper?
        keep_clean
      end
    end
  end
end