Скачать презентацию Not all of a large system will be
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Скачать презентацию Not all of a large system will be
Скачать презентацию Not all of a large system will be
Not all of a large system will be well designed.
Strategic Design Making Models Work in Large Projects Eric Evans Domain Language, Inc. Partnered in Scandinavia with
Not all of a large system will be well designed.
Ground Up Rebuild
Ground Up Rebuild
Ground Up Rebuild
Ground Up Rebuild Legacy Replaced Year 1 Exciting New Features Year 2 Year 3
Let’s Refactor
Let’s Refactor
Define Domain domain A sphere of knowledge, influence, or activity.
Define Domain domain A sphere of knowledge, influence, or activity. The subject area to which the user applies a program is the domain of the software.
Why bother with models?
Critical Complexity Is The critical complexity of most software projects is in understanding the domain itself.
What is a model?
Chinese Map
Mercator Map
Define Model model A system of abstractions that describes selected aspects of a domain and can be used to solve problems related to that domain.
Define Model model A system of abstractions that describes selected aspects of a domain and can be used to solve problems related to that domain.
Define Model model A system of abstractions that describes selected aspects of a domain and can be used to solve problems related to that domain.
A Model Serves a Particular Use.
A Model Serves a Particular Use. • Not “as realistic as possible”
A Model Serves a Particular Use. • Not “as realistic as possible” • Useful relative to specific set of domain scenarios
Define Ubiquitous Language ubiquitous language A language structured around the domain model and used by all team members to connect all the activities of the team with the software.
Define Context context The setting in which a word or statement appears that determines its meaning.
There always multiple models.
Rowing 8
“Context Map”
cooperative upstream/downstream
uncooperative upstream/ downstream
Custom House Currency Exchange System early 2006
Custom House Context Map
Custom House Context Map
Custom House Context Map
Custom House “SPOT” Model of Currency Exchange Deal
Object Interpretation of Implicit “TBS” Model
Explicit Translation
Custom House Currency Exchange System late 2006
Map What Is
Push Translation to the Borders
Single, Unified Model within Any One Context
Single, Unified Model within Any One Context (Where careful design is going on. )
Single, Unified Model within Any One Context No duplication. . .
Single, Unified Model within Any One Context No duplication. . . within a context! Duplication between. . .
Single, Unified Model within Any One Context No duplication. . . within a context! Duplication between. . . AOK!
Ground Up Rebuild
Let’s Refactor
The Enterprise Model One Ring to rule them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them
Not all of a large system will be well designed.
Distilling the Core Domain
Distilling the Core Domain Generic Subdomains
Distilling the Core Domain Generic Subdomains Supporting Subdomains
Distilling the Core Domain Generic Subdomains Supporting Subdomains Core Domain
Distilling the Core Domain – What makes your system worth writing?
Distilling the Core Domain – What makes your system worth writing? – Why not buy it off the shelf?
Distilling the Core Domain – What makes your system worth writing? – Why not buy it off the shelf? – Why not outsource it?
Distilling the Core Domain – What makes your system worth writing? – Why not buy it off the shelf? – Why not outsource it?
Effort Distribution
Effort Distribution
Effort Distribution
Effort Distribution
Ground Up Rebuild Legacy Replaced Year 1 Exciting New Features Year 2 Year 3
Which Part is Core?
Which Part is Core?
Responsibility Traps …Or, Why do irresponsible programmers become heroes?
Let’s Hack
Let’s Hack
Which Parts are Core?
Which Parts are Core?
Responsibility Traps • Building a platform to make other (lesser) programmers more productive. • Cleaning up other people’s mess.
What’s a responsible designer to do? !!
How could we just build the core part?
Build Platform Based on Model
Build Platform Based on Model
Strategy • Draw a Context Map. • Work with business leadership to define Core Domain. • Design a platform that supports work in the Core Domain. • Work with management to give freedom to the Core Domain Platform Context. • Develop and model in the Core Domain.
Strategy • Keep an eye on your Context Map. • Keep working with business leadership as Core Domain narrows and shifts. • Guard your platform that supports work in the Core Domain. • Keep working with management to maintain freedom of the Core Domain Platform Context. • Keep developing and evolving the model in the Core Domain.
Strategic DDD Resources www. domaindrivendesign. org Domain-Driven Design by Eric Evans PART 4! www. domainlanguage. com
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