Module Test::Unit::Util::Observable
In: lib/test/unit/util/observable.rb

This is a utility class that allows anything mixing it in to notify a set of listeners about interesting events.

Methods

add_listener   channels   notify_listeners   remove_listener  

Constants

NOTHING = "NOTHING/#{__id__}"   We use this for defaults since nil might mean something

Public Instance methods

add_listener(channel_name, listener_key=NOTHING) {|value| ...}

Adds the passed proc as a listener on the channel indicated by channel_name. listener_key is used to remove the listener later; if none is specified, the proc itself is used.

Whatever is used as the listener_key is returned, making it very easy to use the proc itself as the listener_key: 

 listener = add_listener("Channel") { ... }
 remove_listener("Channel", listener)

[Source]

    # File lib/test/unit/util/observable.rb, line 31
31:         def add_listener(channel_name, listener_key=NOTHING, &listener) # :yields: value
32:           unless(block_given?)
33:             raise ArgumentError.new("No callback was passed as a listener")
34:           end
35:       
36:           key = listener_key
37:           if (listener_key == NOTHING)
38:             listener_key = listener
39:             key = ProcWrapper.new(listener)
40:           end
41:       
42:           channels[channel_name] ||= {}
43:           channels[channel_name][key] = listener
44:           return listener_key
45:         end
notify_listeners(channel_name, *arguments)

Calls all the procs registered on the channel indicated by channel_name. If value is specified, it is passed in to the procs, otherwise they are called with no arguments.

[Source]

    # File lib/test/unit/util/observable.rb, line 74
74:         def notify_listeners(channel_name, *arguments)
75:           channel = channels[channel_name]
76:           return 0 unless (channel)
77:           listeners = channel.values
78:           listeners.each { |listener| listener.call(*arguments) }
79:           return listeners.size
80:         end
remove_listener(channel_name, listener_key)

Removes the listener indicated by listener_key from the channel indicated by channel_name. Returns the registered proc, or nil if none was found.

[Source]

    # File lib/test/unit/util/observable.rb, line 51
51:         def remove_listener(channel_name, listener_key)
52:           channel = channels[channel_name]
53:           return nil unless (channel)
54:           key = listener_key
55:           if (listener_key.instance_of?(Proc))
56:             key = ProcWrapper.new(listener_key)
57:           end
58:           if (channel.has_key?(key))
59:             return channel.delete(key)
60:           end
61:           return nil
62:         end

Private Instance methods

channels()

[Source]

    # File lib/test/unit/util/observable.rb, line 83
83:         def channels
84:           @channels ||= {}
85:           return @channels
86:         end

[Validate]