Class: Roby::Promise::Null

Inherits:
Object show all
Defined in:
lib/roby/promise.rb

Overview

A null object for Roby::Promise

Instance Method Summary collapse

Constructor Details

#initialize(value = nil) ⇒ Null

Returns a new instance of Null.



299
300
301
302
 
# File 'lib/roby/promise.rb', line 299

def initialize(value = nil)
    @creation_time = Time.now
    @value = value
end

Instance Method Details

#add_observer(&block) ⇒ Object 



326
327
328
 
# File 'lib/roby/promise.rb', line 326

def add_observer(&block)
    block.call(@creation_time, value, nil)
end

#before ⇒ Object

Raises:

  • (NullPromise) 


307
 
# File 'lib/roby/promise.rb', line 307

def before(*); raise NullPromise, "attempting to add a step on a null promise" end

#complete? ⇒ Boolean

Returns:

  • (Boolean) 


316
 
# File 'lib/roby/promise.rb', line 316

def complete?; true end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


305
 
# File 'lib/roby/promise.rb', line 305

def empty?; true end

#execute ⇒ Object 



313
 
# File 'lib/roby/promise.rb', line 313

def execute; self end

#fail ⇒ Object

Raises:

  • (NullPromise) 


312
 
# File 'lib/roby/promise.rb', line 312

def fail(*); raise NullPromise, "a null promise cannot fail" end

#fulfilled? ⇒ Boolean

Returns:

  • (Boolean) 


317
 
# File 'lib/roby/promise.rb', line 317

def fulfilled?; true end

#null? ⇒ Boolean

Returns:

  • (Boolean) 


304
 
# File 'lib/roby/promise.rb', line 304

def null?; true end

#on_error ⇒ Object

Raises:

  • (NullPromise) 


309
 
# File 'lib/roby/promise.rb', line 309

def on_error(*); raise NullPromise, "attempting to add a step on a null promise" end

#on_success ⇒ Object

Raises:

  • (NullPromise) 


308
 
# File 'lib/roby/promise.rb', line 308

def on_success(*); raise NullPromise, "attempting to add a step on a null promise" end

#pending? ⇒ Boolean

Returns:

  • (Boolean) 


315
 
# File 'lib/roby/promise.rb', line 315

def pending?; false end

#reason ⇒ Object 



323
 
# File 'lib/roby/promise.rb', line 323

def reason; end

#rejected? ⇒ Boolean

Returns:

  • (Boolean) 


318
 
# File 'lib/roby/promise.rb', line 318

def rejected?; false end

#state ⇒ Object 



324
 
# File 'lib/roby/promise.rb', line 324

def state; :fulfilled end

#then ⇒ Object

Raises:

  • (NullPromise) 


310
 
# File 'lib/roby/promise.rb', line 310

def then(*); raise NullPromise, "attempting to add a step on a null promise" end

#unscheduled? ⇒ Boolean

Returns:

  • (Boolean) 


314
 
# File 'lib/roby/promise.rb', line 314

def unscheduled?; false end

#value ⇒ Object 



321
 
# File 'lib/roby/promise.rb', line 321

def value(*); @value end

#value! ⇒ Object 



322
 
# File 'lib/roby/promise.rb', line 322

def value!(*); @value end

#wait ⇒ Object 



319
 
# File 'lib/roby/promise.rb', line 319

def wait; end