Ruby Enumerator to Java Iterator

gistfile1.rb

class EnumeratorIterator

  def initialize(delegate)
    @buffer = []
    # We expect an Enumerable or Enumerator
    @delegate = delegate.is_a?(Enumerable) ? delegate.to_enum : delegate
    _next
  end

  def has_next
    !@next.nil?
  end

  def next
    prev = @next
    _next
    prev
  end

  def remove
    raise NotImplementedError.new
  end

  private

  def _next
    @next = @buffer.shift
    return unless @next.nil?

    @next = @delegate.next rescue nil
    return if @next.nil?

    if @next.is_a? Enumerable
      @buffer += @next.to_a
    else
      @buffer << @next
    end
    _next
  end
end


a = EnumeratorIterator.new([1,2,3,4,5, [6,7], 8, [9, 10]].to_enum)
while a.has_next
  puts a.next
end