John Hoffer

Software Engineer at Harvard Medical School

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Setup works for any app!

92 Days!

1 Week

No Class!

Text

Counts as 20%!

Prototypes are little experiments

to test technologies

by implementing a tiny feature of the project

or exploring suitable architectures

and algorithms

Jupyter Notebook ("glue"-code)

Package structure

Package structure

from .controller import *
from .view import *
from .mathengine import MathEngine
class MathEngine:

  def __init__(self):
    '''
    A constructor.
    '''

    print('Really new Math Engine instance.')

  def add(self, number1, number2):
    '''
    Takes 2 integers, and adds them.
    '''

    return number1 + number2

No user interaction here! Just Logic!

from .ui import UI
class UI:

  def __init__(self):
    '''
    '''

    print('New UI')

  def start(self, controller):
    '''
    We ask the user for 2 numbers.
    '''

    print('Please enter number1')
    number1 = input()

    print('Please enter number2')
    number2 = input()

    result = controller.add(int(number1), int(number2))

    print('Result:', result)

UI stuff here that calls the logic!

Package structure

Controller is separate! (All calculations, logic, algorithms  etc.)

View is separate! (All user interactions)

Everything is bundled as one package!

We can import the package and use it!

This was the VC (View and Controller) part of the MVC pattern!

Why structure the code like this?

Architecture is more important than features!

Remember this!

Use Case Diagram

Activity Diagram

Properties

Methods

Class Diagram

Sequence Diagram

Keep it simple!

Divide and Conquer

Problem

Sub-Problem

Sub-Problem

Sub-Problem

Solved

Sub-Problem

Solved

Solution

Divide

Divide

Conquer

Conquer

It's a lifestyle!

Modularity

Split things up...

Subsystem

Module

vs.

independent value

can not function on its own

Information Hiding

treat stuff as black boxes!

Information Hiding

class MathEngine:

  def __init__(self):
    '''
    A constructor.
    '''

    print('Really new Math Engine instance.')

  def add(self, number1, number2):
    '''
    Takes 2 integers, and adds them.
    '''

    return number1 + number2
....

controller = MathEngine()
result = controller.add(int(number1), int(number2))

....

CS410 Lecture 12

By Daniel Haehn

CS410 Lecture 12

Slides for CS410 Software Engineering at UMass Boston. See https://cs410.net!

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