Class: Thread::Future
- Inherits:
-
Object
- Object
- Thread::Future
- Defined in:
- lib/thread/future.rb
Overview
A future is an object that incapsulates a block which is called in a different thread, upon retrieval the caller gets blocked until the block has finished running, and its result is returned and cached.
Constant Summary collapse
- Cancel =
Class.new(Exception)
Class Method Summary collapse
Instance Method Summary collapse
-
#cancel ⇒ Object
Cancel the future, #value will yield a Cancel exception.
-
#cancelled? ⇒ Boolean
Check if the future has been cancelled.
-
#delivered? ⇒ Boolean
(also: #realized?)
Check if the future has been called.
-
#exception ⇒ Object
Return the raised exception.
-
#exception? ⇒ Boolean
Check if an exception has been raised.
-
#initialize(pool = nil, &block) ⇒ Future
constructor
Create a future with the passed block and optionally using the passed pool.
-
#value(timeout = nil) ⇒ Object
(also: #~)
Get the value of the future, if it’s not finished running this call will block.
-
#value!(timeout = nil) ⇒ Object
(also: #!)
Do the same as #value, but return nil in case of exception.
Constructor Details
#initialize(pool = nil, &block) ⇒ Future
Create a future with the passed block and optionally using the passed pool.
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# File 'lib/thread/future.rb', line 21 def initialize(pool = nil, &block) raise ArgumentError, 'no block given' unless block @mutex = Mutex.new task = proc { begin deliver block.call rescue Exception => e @exception = e deliver nil end } @thread = pool ? pool.process(&task) : Thread.new(&task) ObjectSpace.define_finalizer self, self.class.finalizer(WeakRef.new(@thread)) end |
Class Method Details
Instance Method Details
#cancel ⇒ Object
Cancel the future, #value will yield a Cancel exception
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# File 'lib/thread/future.rb', line 74 def cancel return self if delivered? @mutex.synchronize { @thread.raise Cancel.new('future cancelled') } self end |
#cancelled? ⇒ Boolean
Check if the future has been cancelled
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# File 'lib/thread/future.rb', line 85 def cancelled? @mutex.synchronize { @exception.is_a? Cancel } end |
#delivered? ⇒ Boolean Also known as: realized?
Check if the future has been called.
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# File 'lib/thread/future.rb', line 65 def delivered? @mutex.synchronize { instance_variable_defined? :@value } end |
#exception ⇒ Object
Return the raised exception.
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# File 'lib/thread/future.rb', line 58 def exception @mutex.synchronize { @exception } end |
#exception? ⇒ Boolean
Check if an exception has been raised.
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# File 'lib/thread/future.rb', line 51 def exception? @mutex.synchronize { instance_variable_defined? :@exception } end |
#value(timeout = nil) ⇒ Object Also known as: ~
Get the value of the future, if it’s not finished running this call will block.
In case the block raises an exception, it will be raised, the exception is cached and will be raised every time you access the value.
An optional timeout can be passed which will return nil if nothing has been delivered.
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# File 'lib/thread/future.rb', line 98 def value(timeout = nil) raise @exception if exception? return @value if delivered? @mutex.synchronize { cond.wait(@mutex, *timeout) } if exception? raise @exception elsif delivered? return @value end end |
#value!(timeout = nil) ⇒ Object Also known as: !
Do the same as #value, but return nil in case of exception.
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# File 'lib/thread/future.rb', line 117 def value!(timeout = nil) begin value(timeout) rescue Exception nil end end |