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我试图在Concurrent::ScheduledTask#execute方法中调用一个块，但块本身永远不会被执行。

我也尝试过使用Concurrent::ScheduledTask#new方法，但结果是一样的。我觉得这里可能有一个我遗漏的基本问题。任何帮助将非常感激！

require 'concurrent'
##
# A basic Event
class Event
  attr_accessor :ticks
  # @param ticks [Numeric] The amount of ticks we wait before executing this event
  def initialize(ticks = 1.0)
    @ticks = ticks
    puts "Event created with #{@ticks} ticks"
  end
  # Calls the block of this event for execution.
  def execute(&block)
    if !block_given?
      raise AbstractEventExecution.new(self)
    else
      Concurrent::ScheduledTask.execute(@ticks *= 0.75) { block.call }
      puts "Executed in #{@ticks} ticks"
    end
  end
end

class AbstractEventExecution < StandardError
  attr_accessor :event
  def initialize(event)
    @event = event
    super("The Event #{event} was not provided an execution block and is abstract.")
  end
end

event1 = Event.new(105)
event2 = Event.new(1000)
event3 = Event.new(50)
event1.execute { puts "hai from event 1" }
event2.execute { puts "hai from event 2" }
event3.execute { puts "hai from event 3" }

输出如下：

Event created with 105 ticks
Event created with 1000 ticks
Event created with 50 ticks
executing an event...
Executed in 78.75 ticks
executing an event...
Executed in 750.0 ticks
executing an event...
Executed in 37.5 ticks

我不确定为什么puts "hai from event x"根本没有显示。此外，执行此操作时没有延迟。应该分别有 78.75、750.0 和 37.5 秒的延迟，根本没有！

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1 回答 1

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两者都Concurrent::ScheduledTask#new返回Concurrent::ScheduledTask#execute一个 [ScheduledTask] 对象，然后主线程退出。

这就是为什么"hai from event x"从未显示。

require 'concurrent'
##
# A basic Event
class Event
  attr_accessor :ticks
  # @param ticks [Numeric] The amount of ticks we wait before executing this event
  def initialize(ticks = 1.0)
    @ticks = ticks
    puts "Event created with #{@ticks} ticks"
  end

  # Calls the block of this event for execution.
  def execute(&block)
    if !block_given?
      raise AbstractEventExecution.new(self)
    else
      task = Concurrent::ScheduledTask.execute(@ticks *= 0.75) { block.call }
      puts "Executed in #{@ticks} ticks"
      task
    end
  end
end

class AbstractEventExecution < StandardError
  attr_accessor :event

  def initialize(event)
    @event = event
    super("The Event #{event} was not provided an execution block and is abstract.")
  end
end

event1 = Event.new(1)
event2 = Event.new(2)
event3 = Event.new(3)
t1 = event1.execute { puts "hai from event 1" }
t2 = event2.execute { puts "hai from event 2" }
t3 = event3.execute { puts "hai from event 3" }

# waiting for all threads to finish
[t1, t2, t3].map(&:wait)
于 2019-10-16T07:49:01.680 回答