1 # Copyright 2013 The Chromium Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 class Metric(object): 6 """Base class for all the metrics that are used by telemetry measurements. 7 8 The Metric class represents a way of measuring something. Metrics are 9 helper classes used by PageMeasurements. Each PageMeasurement may use 10 multiple metrics; each metric should be focussed on collecting data 11 about one thing. 12 """ 13 14 def Start(self, page, tab): 15 """Start collecting data for this metric.""" 16 raise NotImplementedError() 17 18 def Stop(self, page, tab): 19 """Stop collecting data for this metric (if applicable).""" 20 raise NotImplementedError() 21 22 def AddResults(self, tab, results): 23 """Add the data collected into the results object for a measurement. 24 25 Metrics may implement AddResults to provide a common way to add results 26 to the PageMeasurementResults in PageMeasurement.AddMeasurement -- 27 results should be added with results.Add(trace_name, unit, value). 28 """ 29 raise NotImplementedError() 30 31
