import java.time.format.DateTimeFormatter as DateTimeFormatter
import java.time.Instant as Instant
import java.time.LocalDateTime as LocalDateTime
import java.time.ZoneOffset as ZoneOffset

#with Channel("ABORF-A0-HVPS:I", monitored=False) as ch:
#    print ch.read()

class Channel:
    def __init__(self,channel_name, monitored, polling):
        self.channel_name=channel_name
        self.monitored= monitored
        self.polling = polling

    def  __enter__(self):
        self.channel=GenericChannel(self.channel_name,self.channel_name)
        self.channel.setMonitored(self.monitored)
        self.channel.setPolling(self.polling)
        self.channel.initialize()
        return self.channel

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.channel.close()


timeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")

def get_time_str(timestamp):
        instant = Instant.ofEpochMilli(timestamp)
        currentTime = LocalDateTime.ofInstant(instant, ZoneOffset.systemDefault())        
        return currentTime.format(timeFormatter);


def write_archive(f, timestamp, value):
    print f + " " + get_time_str(timestamp) + " " + str(value)
    

class ChannelListener (DeviceListener):
    def onCacheChanged(self, ch, value, former, timestamp, valueChange):
        write_archive(ch.name, timestamp, value)

val=None
with Channel("ABORF-A0-HVPS:I", True, 0) as ch:
    #val = ch.update()
    #val=ch.takeTimestamped()
    #write_archive(ch.name, val.timestamp, val.value)
    channel_listener = ChannelListener()
    ch.addListener(channel_listener)
    ch.update()
    val=ch.take()
    time.sleep(10.0)