Is there a way to redefine/disable self.new?

Question

I'm trying to figure out a way to safely free resources acquired by a class. I tried using finalize, but it's unreliable. Sometimes I close my program before GC has a chance to free resources.

So I decided to use class instance in a block like this:

class Foo

  def destroy # free resources
      #...
  end

  #...

  def self.create(*args)
      instance = self.new(*args)
      begin
        yield instance
      ensure
        instance.destroy
      end
end

Foo.create do |foo|
  # use foo
end

That works fine, but I still can create an instance using new that I'd have to destroy explicitly. I tried to write my own new but it seems like it's just overloaded by default new.

Is there a way to redefine\disable new?

Answer 1

That is initialize method, that should be made private:

class Foo
  @foo : String

  private def initialize(@foo)
  end

  def destroy
    puts "Destroying #{self}"
  end

  def self.create(arg)
    instance = new(arg)
    yield instance
  ensure
    instance.destroy if instance
  end
end

Foo.create("bar") do |foo| # will work
  p foo
end

Foo.new("bar")             # will raise

Playground