Class: Rinda::TupleSpace
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Instance Chain:
self,
MonitorMixin,
DRbUndumped
|
|
Inherits: | Object |
Defined in: | lib/rinda/tuplespace.rb |
Overview
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.
Class Method Summary
-
.new(period = 60) ⇒ TupleSpace
constructor
Creates a new
TupleSpace
.
Instance Attribute Summary
-
#need_keeper? ⇒ Boolean
readonly
private
Checks the tuplespace to see if it needs cleaning.
Instance Method Summary
-
#move(port, tuple, sec = nil) {|template| ... }
Moves
tuple
toport
. -
#notify(event, tuple, sec = nil)
Registers for notifications of
event
. -
#read(tuple, sec = nil) {|template| ... }
Reads
tuple
, but does not remove it. -
#read_all(tuple)
Returns all tuples matching
tuple
. -
#take(tuple, sec = nil, &block)
Removes
tuple
-
#write(tuple, sec = nil)
Adds
tuple
- #create_entry(tuple, sec) private
-
#keep_clean
private
Removes dead tuples.
-
#notify_event(event, tuple)
private
Notifies all registered listeners for
event
of a status change oftuple
. -
#start_keeper
private
Creates a thread that scans the tuplespace for expired tuples.
Constructor Details
.new(period = 60) ⇒ TupleSpace
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.
Instance Attribute Details
#need_keeper? ⇒ Boolean
(readonly, private)
Checks the tuplespace to see if it needs cleaning.
# File '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
Instance Method Details
#create_entry(tuple, sec) (private)
[ GitHub ]# File 'lib/rinda/tuplespace.rb', line 578
def create_entry(tuple, sec) TupleEntry.new(tuple, sec) end
#keep_clean (private)
Removes dead tuples.
# File '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
#move(port, tuple, sec = nil) {|template| ... }
Moves tuple
to port
.
# File '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 port ? nil : 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 port ? nil : 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 '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
#notify_event(event, tuple) (private)
Notifies all registered listeners for event
of a status change of tuple
.
# File '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
#read(tuple, sec = nil) {|template| ... }
Reads tuple
, but does not remove it.
# File '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 '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
#start_keeper (private)
Creates a thread that scans the tuplespace for expired tuples.
# File '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
#take(tuple, sec = nil, &block)
Removes tuple
# File '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 '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