mdd with executable uml models

Model-driven Development with Executable UML Models

Rafael Chavesrafael@alphasimple.com

Small scale vs. large scale

Small

single developer

small feature set

short lived

Largeteam

large feature set

long lived

Small scale vs. large scale

Small

work properly (once)

Large

understandable by others

throughout time

extensible

resilient to change

work properly (continuously)

Enterprise software is very hard

Problem domains are typically not very complex (information management + business rules)

How come?

Secondary concerns abound

persistence, concurrency, (a)synchronism, distribution, transactions, security, caching, replication, logging, ...

Two dominant dimensions

business domain concerns vs. technological or implementation concerns Completely different beasts(why treat them the same way?)

change rateabstraction level toolsskillsreuse

Current approaches won't cut it

Model Driven Development to the rescue

model: a simplified representation of something from a particular point of view and with a particular purpose

Models in software

brainstormingcommunicatingdocumentingunderstanding (rev. eng.)

That is not what MDD is about

Models in MDD

are the central artifacts in software (re: source vs. object code) are well-formedare precise*are complete*are executable (directly/code gen.)*are technology-independent*

MDA pattern

source: MDA Guide (OMG)

Technology-agnostic models

source: eclipse.org

source: openarchitectureware.org

Code generation

Model interpretation

MDD with UML

Relevant UML features

UML has always had support for modeling:

structure: classes, attributes, operations and relationships (class diagrams)dynamics: state machines (state diagrams)

Added in 1.5 (2003)/2.0 (2005):

behavior: action semantics (no standard notation, typically textual)

UML finally enabled for MDD

source: UML 1.5 spec (OMG)

Action Semantics: basic concepts

actions

input/output pins

data flows

activity nodes

activities

Action Semantics: basic actions

read/write variable

create/destroy object

read self ("this")

read/write attribute

create/destroy link

call operation

activity node (block)call function

conditional (if/switch)

loop

raise exception

send signal

newCustomer = new Customer();

source: UML 1.5 spec (OMG)

current_account.balance = new_balance;

source: same

if (factor == 2) { ... }

source: same

Diagrams vs. Text

graphical representation not suitable for AS

models != diagrams (no loss of abstraction)

textual notations preferred (action languages)but... isn't UML required to be graphical?

but... aren't we back to coding?

Model-driven Development with Executable UML Models

Rafael Chavesrafael@alphasimple.com