Implementation of concurrent query in CoffeeScript

Cakefile

# We have several database replicas and want to minimize latency by querying them 
# all and returning the first response to arrive.
#
# http://concur.rspace.googlecode.com/hg/talk/concur.html#slide-54

class Connection
	constructor: (@name) ->

	query: (query, continuation) ->
		@op = setTimeout(=>
			continuation(@name)
			null
		, Math.floor(Math.random()*10000))

	abort: ->
		clearTimeout(@op)

do_query = (conns, query, continuation) ->
	for conn in conns
		conn.query(query, (result) ->
			continuation(result)

			for conn in conns
				conn.abort()

			null
		)

task 'run', 'Run the thing.', (options) ->
	conns = (new Connection(i) for i in [1..10])

	do_query(conns, 'foobar', (result) ->
		console.log("First connection to return was #{result}.")
	)

Invocation:

$ cake run