Strategic

Domain-Driven-Design

for

Improving

Flutter

Architecture

Majid Hajian

mhadaily

Updated - April 2020

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Share Experiences

Well?

Best Practices

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Patterns

Methodology

+

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Resource Capacity

Project Complexity

App development Complexity Growth

without DDD

Resource Capacity

Project Complexity

App development Complexity Growth

with DDD

When DDD can help?

Flutter APP

Amount of data

Performance

Business Logic complexity

Technical complexity

YAGNI

You are not gonna need it

Shortening development time

KISS

Keep it short and simple

Maintainable code

DDD

Focus on essential parts

Simplifying the problem

What we will learn today

Introduction to DDD

Proposed Flutter architectures

Strategic Domain Driven Design

DEMO

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ME.dart

import 'package:flutter/material.dart';

MaterialApp(
   ThemeData(
        name: "Majid Hajian",
        location: "Oslo, Norway",
        description: '''
        	Passionate Software engineer, 
	        Community Leader, Author and international Speaker
         ''',
        main: "Flutter/Dart, PWA, IoT",
        homepage: "https://www.majidhajian.com",
        socials: {
          twitter: "https://www.twitter.com/mhadaily",
          github: "https://www.github.com/mhadaily"
        },
        books: {
          "Progressive Web App with Angular": {
             version: "1.0.0", 
             publishedBy: "Apress", 
             foundOn: "www.pwawithangular.com",
          }
        },
        author: {
          packtpub: "PWA development, 7 hours video course",
          Udemy: "PWA development, 7 hours video course"
        }
        founder: "Softiware As (www.Softiware.com)"
        devDependencies: {
          tea: "green", mac: "10.14+",
        },
        engines: {
          MobileEraConference: "Orginizer",
          ngVikingsConference: "Orginizer", 
          MobileMeetupOslo:"Co-Orginizer",
          FlutterDartOslo: "Co-Orginizer",
          GDGOslo: "Co-Orginizer",          
        }
     ),
 )

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Find me on the internet by

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Domain

Driven

Design

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When we develop a Software

Primarily focus is

Technology

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When we develop a Software

Primarily focus is

Technology

Business

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Write code

Build An App

Understand Client Needs

Solve Problems

D

is for

DOMAIN

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Strategic design tools

Tactical

design tools

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Strategic design tools

Tactical

design tools

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Why is Strategic Domain-Driven Design Important?

Strategic

DDD

Decomposing

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Strategic

DDD

Decomposing

Core Domain

Sub Domains

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A Manufacturer App

Sales

Manage Employees

Accounting

Marketing

Product Catalog

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customer

name

interest

Sales

customer

name

phone

Employees

customer

address

availability

Marketing

customer

name

payment method

Accounting

mhadaily

customer

name

interest

Advanced issue found

▲

Sales

customer

name

phone

Support

customer

address

availability

Order

customer

name

payment method

Accounting

Bounded Context

Namespace

Folder

Project

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customer

name

interest

Sales

customer

name

phone

Employees

Ubiquitous Language

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customer

name

interest

Sales

customer

name

phone

Employees

customer

address

availability

Marketing

customer

name

payment method

Accounting

Context Map

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customer

name

interest

Sales

customer

name

phone

Employees

customer

address

availability

Marketing

customer

name

payment method

Accounting

Shared

Kernel

e.g.

USER

Authentication

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customer

name

interest

Sales

customer

name

phone

Support

customer

address

availability

Order

customer

name

payment method

Accounting

Open Host Service

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customer

name

interest

Sales

customer

name

phone

Support

customer

address

availability

Order

customer

name

payment method

Accounting

Open Host Service

API

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Navigation

Map

by Eric Evans

Flutter

Architecture

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Enterprise

Manufacturing App

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Sales

Common

Catalog

E-commerce App

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Sales

Common

Catalog

E-commerce App

Presentation

Screen

Logic Holder

Widgets

Smart UI - Feature

Screen

Logic Holder

Smart UI - Feature

BLoC

ChangeNotifier

BLoC

ChangeNotifier

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Sales

Common

Catalog

E-commerce App

Presentation

Application

Use Case Specific Facades

Simplify

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Sales

Common

Catalog

E-commerce App

Domain

Presentation

Application

Text

Entities

Interfaces

Logic

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Object Values

Sales

Common

Catalog

E-commerce App

Domain

Infrastructure

Presentation

Application

Text

Remote Data Source

Models

Local Data Source

Geo Location, ...

Raw Data

Models

Repositories

Sales

Catalog

E-commerce App

Domain

Infrastructure

Presentation

Application

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Sales

Catalog

E-commerce App

Domain

Infrastructure

Presentation

Application

API

mhadaily

Simpler

Sales

Common

Catalog

E-commerce App

Presentation

Screen

Logic Holder

BLoC

Widgets

Screen

Logic Holder

BLoC

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Utils

Sales

Common

Catalog

E-commerce App

Logic

Presentation

Text

Advanced issue found

▲

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Logic

Business logic

GetLatestNewsWithAuthorsUseCase

Sales

Common

Catalog

E-commerce App

Logic

Data

Presentation

Text

Remote Data Source

Local Data Source

Geo Location, ...

Raw Data

Models

Logic

Repositories

Sales

Catalog

E-commerce App

Logic

Data

Presentation

Logic

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Demo

source code

https://github.com/mhadaily/flutter-architecture-ddd

├── lib
│   ├── catalog
│   │   ├── api
│   │   │   └── index.dart
│   │   ├── application
│   │   │   └── catalog_facade_service.dart
│   │   ├── domain
│   │   │   ├── entities
│   │   │   │   └── product.dart
│   │   │   ├── interfaces
│   │   │   │   └── product_interface.dart
│   │   │   └── logic
│   │   │       ├── catalog_logic.dart
│   │   │       └── get_official_product_manufacturer.dart
│   │   ├── infrastructure
│   │   │   ├── data_sources
│   │   │   │   ├── product_local_data_provider.dart
│   │   │   │   └── product_remote_data_provider.dart
│   │   │   ├── models
│   │   │   │   └── product_model.dart
│   │   │   └── repositories
│   │   │       └── product_repository.dart
│   │   └── presentation
│   │       ├── catalog-detail
│   │       │   ├── bloc
│   │       │   │   ├── bloc.dart
│   │       │   │   ├── catalog_detail_bloc.dart
│   │       │   │   ├── catalog_detail_event.dart
│   │       │   │   └── catalog_detail_state.dart
│   │       │   └── catalog_detail_screen.dart

│   │       ├── catalog-list
│   │       │   ├── bloc
│   │       │   │   ├── bloc.dart
│   │       │   │   ├── catalog_list_bloc.dart
│   │       │   │   ├── catalog_list_event.dart
│   │       │   │   └── catalog_list_state.dart
│   │       │   └── catalog_list_screen.dart
│   │       └── widgets
│   │           └── catalog_name.dart
│   ├── common
│   │   ├── config
│   │   │   └── config.dart
│   │   ├── exceptions
│   │   │   ├── exceptions.dart
│   │   │   ├── local_exceptions.dart
│   │   │   └── server_exceptions.dart
│   │   ├── helpers
│   │   │   └── helpers.dart
│   │   ├── platform
│   │   │   └── connectivity.dart
│   │   ├── utils
│   │   │   └── utils.dart
│   │   └── widgets
│   │       └── widgets.dart
│   ├── injections.dart
│   └── main.dart

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Advanced

── catalog
│   ├── logic
│   │   ├── catalog_logic.dart
│   │   ├── get_official_product_manufacturer.dart
│   │   └── product_repository.dart
│   └── presentation
│       ├── catalog-detail
│       │   ├── bloc
│       │   │   ├── bloc.dart
│       │   │   ├── catalog_detail_bloc.dart
│       │   │   ├── catalog_detail_event.dart
│       │   │   └── catalog_detail_state.dart
│       │   └── catalog_detail_screen.dart
│       ├── catalog-list
│       │   ├── bloc
│       │   │   ├── bloc.dart
│       │   │   ├── catalog_list_bloc.dart
│       │   │   ├── catalog_list_event.dart
│       │   │   └── catalog_list_state.dart
│       │   └── catalog_list_screen.dart
│       └── widgets
│           └── catalog_name.dart

├── common
│   ├── config
│   │   └── config.dart
│   ├── exceptions
│   │   ├── exceptions.dart
│   │   ├── local_exceptions.dart
│   │   └── server_exceptions.dart
│   ├── helpers
│   │   └── helpers.dart
│   ├── platform
│   │   └── connectivity.dart
│   ├── utils
│   │   └── utils.dart
│   └── widgets
│       └── widgets.dart
├── data_sources
│   ├── product_local_data_provider.dart
│   ├── product_model.dart
│   └── product_remote_data_provider.dart
├── injections.dart
└── main.dart

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Simple

NOT HARD RULES

BUT GUIDANCE

LET DDD GUIDE US

Summary

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Introduction to DDD

Flutter architecture inspired by DDD

Strategic Domain Driven Design Ideas

What we have learned

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Majid Hajian

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Slides and link to source code

bit.ly/ddd-flutter

majid[at]softiware[dot]com

Strategic Domain-Driven Design for Improving Flutter architecture

By Majid Hajian

Strategic Domain-Driven Design for Improving Flutter architecture

Architecting software, especially on a large-scale where it needs to meet the business requirements is always a challenge and Flutter apps are not an exception. Strategic Domain-Driven Design techniques ensure your application is optimized to support business goals while identifying cohesive modules, known as bounded context which creates a maintainable, comprehensible codebase by isolating dependencies and describe business value. In this talk, I explorer the idea of the ubiquitous language, the bounded context, sub-domains while they are being implemented in a real application. All in all, You'll learn how I attempted to architect a (large-scale) Flutter application by technical solution and appropriate methodology in order to have a sustainable app.

9,665

Majid Hajian

Majid Hajian is a passionate software developer with years of developing and architecting complex web and mobile applications. He is passionate about web platform especially flutter, IoT, PWAs, and performance.

Strategic

Domain-Driven-Design

for

Improving

Flutter

Architecture

Share Experiences

Well?

Best Practices

Patterns

Methodology

+

When DDD can help?

Flutter APP

Amount of data

Performance

Business Logic complexity

Technical complexity

YAGNI

KISS

DDD

What we will learn today

ME.dart

mhadaily

Domain

Driven

Design

When we develop a Software

Primarily focus is

Technology

When we develop a Software

Primarily focus is

Technology

Business

D

DOMAIN

Strategic design tools

Tactical

design tools

Strategic design tools

Tactical

design tools

Strategic

DDD

Decomposing

Strategic

DDD

Decomposing

Core Domain

Sub Domains

A Manufacturer App

Bounded Context

Ubiquitous Language

Context Map

Flutter

Architecture

Enterprise

Simpler

Demo

NOT HARD RULES

Summary

Strategic Domain-Driven Design for Improving Flutter architecture

More from Majid Hajian