1.9 KiB
1.9 KiB
| title | localeTitle |
|---|---|
| Builder | Construtor |
O construtor é um padrão de design que pode abstrair e desacoplar a criação de um objeto muito complexo.
Construtor em Python
Aqui está um exemplo de implementação do Builder Pattern no Python3.
# Builder
class CourseBuilder(object):
def __init__(self, teacher):
self.teacher = teacher
def build_course(self):
self.teacher.provide_homework()
self.teacher.provide_exam()
return self.teacher.course
# Teacher
class Teacher(object):
def __init__(self, name=None):
self.name = name
self.course = Course()
def provide_homework(self):
raise NotImplementedError
def provide_exam(self):
raise NotImplementedError
class MathTeacher(Teacher):
def provide_homework(self):
self.course.homework = 'This is Math homework provided by {}.'.format(self.name)
def provide_exam(self):
self.course.exam = 'This is Math exam tested by {}.'.format(self.name)
class HistoryTeacher(Teacher):
def provide_homework(self):
self.course.homework = 'This is History homework provided by {}.'.format(self.name)
def provide_exam(self):
self.course.exam = 'This is History exam tested by {}.'.format(self.name)
# Target objects to be produced
class Course(object):
def __init__(self):
self.homework = None
self.exam = None
def __str__(self):
return 'Homework: {}\nExam: {}\n'.format(self.homework, self.exam)
math_course = CourseBuilder(MathTeacher('Harry')).build_course()
print(math_course)
>>> Homework: This is Math homework provided by Harry.
>>> Exam: This is Math exam tested by Harry.
history_course = CourseBuilder(HistoryTeacher('Potter')).build_course()
print(history_course)
>>> Homework: This is History homework provided by Potter.
>>> Exam: This is History exam tested by Potter.