Python版
https://github.com/faif/python-patterns/blob/master/structural/facade.py
#!/usr/bin/env python # -*- coding: utf-8 -*- """ *What is this pattern about? The Facade pattern is a way to provide a simpler unified interface to a more complex system. It provides an easier way to access functions of the underlying system by providing a single entry point. This kind of abstraction is seen in many real life situations. For example, we can turn on a computer by just pressing a button, but in fact there are many procedures and operations done when that happens (e.g., loading programs from disk to memory). In this case, the button serves as an unified interface to all the underlying procedures to turn on a computer. *What does this example do? The code defines three classes (TC1, TC2, TC3) that represent complex parts to be tested. Instead of testing each class separately, the TestRunner class acts as the facade to run all tests with only one call to the method runAll. By doing that, the client part only needs to instantiate the class TestRunner and call the runAll method. As seen in the example, the interface provided by the Facade pattern is independent from the underlying implementation. Since the client just calls the runAll method, we can modify the classes TC1, TC2 or TC3 without impact on the way the client uses the system. *Where is the pattern used practically? This pattern can be seen in the Python standard library when we use the isdir function. Although a user simply uses this function to know whether a path refers to a directory, the system makes a few operations and calls other modules (e.g., os.stat) to give the result. *References: https://sourcemaking.com/design_patterns/facade https://fkromer.github.io/python-pattern-references/design/#facade http://python-3-patterns-idioms-test.readthedocs.io/en/latest/ChangeInterface.html#facade *TL;DR80 Provides a simpler unified interface to a complex system. """ from __future__ import print_function import time SLEEP = 0.1 # Complex Parts class TC1: def run(self): print(u"###### In Test 1 ######") time.sleep(SLEEP) print(u"Setting up") time.sleep(SLEEP) print(u"Running test") time.sleep(SLEEP) print(u"Tearing down") time.sleep(SLEEP) print(u"Test Finished\n") class TC2: def run(self): print(u"###### In Test 2 ######") time.sleep(SLEEP) print(u"Setting up") time.sleep(SLEEP) print(u"Running test") time.sleep(SLEEP) print(u"Tearing down") time.sleep(SLEEP) print(u"Test Finished\n") class TC3: def run(self): print(u"###### In Test 3 ######") time.sleep(SLEEP) print(u"Setting up") time.sleep(SLEEP) print(u"Running test") time.sleep(SLEEP) print(u"Tearing down") time.sleep(SLEEP) print(u"Test Finished\n") # Facade class TestRunner: def __init__(self): self.tc1 = TC1() self.tc2 = TC2() self.tc3 = TC3() self.tests = [self.tc1, self.tc2, self.tc3] def runAll(self): [i.run() for i in self.tests] # Client if __name__ == ‘__main__‘: testrunner = TestRunner() testrunner.runAll() ### OUTPUT ### # ###### In Test 1 ###### # Setting up # Running test # Tearing down # Test Finished # # ###### In Test 2 ###### # Setting up # Running test # Tearing down # Test Finished # # ###### In Test 3 ###### # Setting up # Running test # Tearing down # Test Finished #
Python转载版
原文地址:https://www.cnblogs.com/demonzk/p/9035434.html
时间: 2024-10-05 05:32:20