From: Daniel Sheppard <daniels@...>
Date: 2005-11-02T10:06:27+09:00
Subject: Re: City and Connection

The proper answer is that you can implement this a million different
ways, depending on the performance needs of your program, the usage of
the classes by other objects, the phase of the moon and the degree of
bacon in your house.

The other answer is:

class Connection
  @@all_connections = []
  attr_reader :endpoints
  def initialize(endpoints)
    @endpoints = endpoints
    @@all_connections << self
  end
  def all_connections
    @@all_connections
  end
end

class City
  def connections
	Connection.all_connections.select do |conn|
		conn.endpoints.include?(self)
      end
  end
end

The other answer might be wrong though.


> -----Original Message-----
> From: draq [mailto:boyang.xia@gmail.com] 
> Sent: Tuesday, 1 November 2005 2:32 AM
> To: ruby-talk ML
> Subject: City and Connection
> 
> E. g. I am going to make a programm for a forwarding agency 
> containing two classes: City and Connection.
> 
> The class City contains information about clients, goods etc. 
> and the class Connection implies the path length, potential 
> toll charges and type of the road.
> 
> How can I implement the two classes the best? With both 
> classes referring to each other?
> 
> 
> 
> 
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