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Added type hints to dependency injection pattern #328

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Merged
merged 1 commit into from
Jun 20, 2020
Merged

Added type hints to dependency injection pattern #328

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30 changes: 18 additions & 12 deletions patterns/dependency_injection.py
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Original file line number Diff line number Diff line change
Expand Up @@ -24,27 +24,30 @@ def get_current_time_as_html_fragment(self):
"""

import datetime
from typing import Callable


class ConstructorInjection:

def __init__(self, time_provider):
def __init__(self, time_provider: Callable) -> None:
self.time_provider = time_provider

def get_current_time_as_html_fragment(self):
def get_current_time_as_html_fragment(self) -> str:
current_time = self.time_provider()
current_time_as_html_fragment = "<span class=\"tinyBoldText\">{}</span>".format(current_time)
current_time_as_html_fragment = '<span class="tinyBoldText">{}</span>'.format(
current_time
)
return current_time_as_html_fragment


class ParameterInjection:

def __init__(self):
def __init__(self) -> None:
pass

def get_current_time_as_html_fragment(self, time_provider):
def get_current_time_as_html_fragment(self, time_provider: Callable) -> str:
current_time = time_provider()
current_time_as_html_fragment = "<span class=\"tinyBoldText\">{}</span>".format(current_time)
current_time_as_html_fragment = '<span class="tinyBoldText">{}</span>'.format(
current_time
)
return current_time_as_html_fragment


Expand All @@ -54,16 +57,18 @@ class SetterInjection:
def __init__(self):
pass

def set_time_provider(self, time_provider):
def set_time_provider(self, time_provider: Callable):
self.time_provider = time_provider

def get_current_time_as_html_fragment(self):
current_time = self.time_provider()
current_time_as_html_fragment = "<span class=\"tinyBoldText\">{}</span>".format(current_time)
current_time_as_html_fragment = '<span class="tinyBoldText">{}</span>'.format(
current_time
)
return current_time_as_html_fragment


def production_code_time_provider():
def production_code_time_provider() -> str:
"""
Production code version of the time provider (just a wrapper for formatting
datetime for this example).
Expand All @@ -73,7 +78,7 @@ def production_code_time_provider():
return current_time_formatted


def midnight_time_provider():
def midnight_time_provider() -> str:
"""Hard-coded stub"""
return "24:01"

Expand Down Expand Up @@ -107,4 +112,5 @@ def main():

if __name__ == "__main__":
import doctest

doctest.testmod(optionflags=doctest.ELLIPSIS)