class IChannel:
    def __init__(self): raise NotImplementedError()
    def add(self,timestamp,data,controller): pass
    def get(self,query): pass

class PrinterChannel(IChannel):
    def __init__(self,name):
        self.name = name
    def add(self,timestamp,data,controller):
        print "{0}: timestamp={1} value={2}".format(self.name, timestamp, data)

class SimpleMemoryChannel(IChannel):
    def __init__(self):
        self.data = ""
    def add(self,timestamp,data,controller):
        self.data = data
    def get(self,query):
        return str(self.data)

class IntervalStoreChannel(IChannel):
    SECONDS=1000
    MINUTES=60*1000
    HOURS=60*60*1000
    DAYS=24*60*60*1000
    def __init__(self): pass