Class: Concurrent::Cancellation

Inherits:
Synchronization::Object show all
Defined in:
lib-edge/concurrent/edge/cancellation.rb

Overview

Note:

Edge Features are under active development and may change frequently.

  • Deprecations are not added before incompatible changes.
  • Edge version: major is always 0, minor bump means incompatible change, patch bump means compatible change.
  • Edge features may also lack tests and documentation.
  • Features developed in concurrent-ruby-edge are expected to move to concurrent-ruby when finalised.

Provides tools for cooperative cancellation. Inspired by https://msdn.microsoft.com/en-us/library/dd537607(v=vs.110).aspx

Examples:

# Create new cancellation. `cancellation` is used for cancelling, `token` is passed down to
# tasks for cooperative cancellation
cancellation, token = Concurrent::Cancellation.create
Thread.new(token) do |token|
  # Count 1+1 (simulating some other meaningful work) repeatedly
  # until the token is cancelled through cancellation.
  token.loop_until_canceled { 1+1 }
end
sleep 0.1
cancellation.cancel # Stop the thread by cancelling

Defined Under Namespace

Classes: Token

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.create(resolvable_future_or_event = Promises.resolvable_event, *resolve_args) ⇒ Array(Cancellation, Cancellation::Token)

Creates the cancellation object. Returns both the cancellation and the token for convenience.

Examples:

cancellation, token = Concurrent::Cancellation.create

Parameters:

  • resolve_args (Object) —

    resolve_args Arguments which are used when resolve method is called on resolvable_future_or_event

  • resolvable_future_or_event (Promises::Resolvable) (defaults to: Promises.resolvable_event) —

    resolvable used to track cancellation. Can be retrieved by token.to_future ot token.to_event.

Returns:



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# File 'lib-edge/concurrent/edge/cancellation.rb', line 29

def self.create(resolvable_future_or_event = Promises.resolvable_event, *resolve_args)
  cancellation = new(resolvable_future_or_event, *resolve_args)
  [cancellation, cancellation.token]
end

Instance Method Details

#cancel(raise_on_repeated_call = true) ⇒ true, false

Cancel this cancellation. All executions depending on the token will cooperatively stop.

Returns:

  • (true, false)

Raises:

  • when cancelling for the second tim



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# File 'lib-edge/concurrent/edge/cancellation.rb', line 45

def cancel(raise_on_repeated_call = true)
  !!@Cancel.resolve(*@ResolveArgs, raise_on_repeated_call)
end

#canceled? ⇒ true, false

Is the cancellation cancelled?

Returns:

  • (true, false) 


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# File 'lib-edge/concurrent/edge/cancellation.rb', line 51

def canceled?
  @Cancel.resolved?
end

#to_s ⇒ String Also known as: inspect

Short string representation.

Returns:

  • (String) 


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# File 'lib-edge/concurrent/edge/cancellation.rb', line 57

def to_s
  format '%s canceled:%s>', super[0..-2], canceled?
end

#token ⇒ Token

Returns the token associated with the cancellation.

Returns:



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# File 'lib-edge/concurrent/edge/cancellation.rb', line 38

def token
  @Token
end