Analysis of Structures - Baustatik-Info-Server

2.14. OOP WITH CLASSES Page 432.14.2 Implementation of a Time Stack ClassIn section 2.12 we have discussed a little program which implements a time checker using a stack container.We can implement this problem in a much more clearer version, if we do it in terms of the OOPapproach. The class TimeCheck, which is introduced, encapsulates the time stack list and the log filesname as attributes and the following methods.• Set reads the actual time with the datetime.now() and pushes it onto the time stack.• Get reads the actual time with the datetime.now(), pops the the last time object from the stack andcalculates the timespan. The timespan is optionally printed into the console window or into a logfile.• GetTime calculates the seconds in floats form the passed timedelta object.The main program, which is used to discuss the class follows the steps of the classical implementationof the problem discussed in section 2.12. We first create an empty tuple and an empty list. Than wecreate the TimeCheck instance 16 simple by assigning it’s name to a variable (s = TimeCheck()). Topush a time object onto the stack, we call the class’s member function Set. So, if we want to check theperformance of a code, we first call the Set method and after having executed the code, we call the Getmethod. The Get method will print the comment and will return the used seconds of execution time infloats. The simplest kind of an implementation is the implementation in the file of the main program.This you can see in the following example.A UML diagram of the class TimeCheck is given in figure 2.12.TimeCheckself. log: name of the log fileself. stack: stack listself. init (..): contructorself.Set(..): push a timeself.GetTime(..): calculate secondsself.Get(..): pop a timeThe class TimeCheck contentsall the data and functions touse a time stack and to get thetime-span information in a properfloat format. The class is able topresent a formated output of themeasured time-spans.Figure 2.12: UML-Diagram of the TimeCheck ClassOOP Implementation of the Time Checking Problem’’’Class to investigate the timespan, to measure the performanceby implementing a time stack container’’’# - module - member aliasfrom datetime import datetime as time # we need the datetime packageclass TimeCheck():# class name# constructor16 A physical created object in memory of a class is called instance of a class.2.12.2011