UML 2'0 Preview

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UML 2.0 Preview

• Cris Kobryn
• cris.kobryn_at_telelogic.com
• February 2003

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Overview

• Background
• Proposal status
• Featured proposal U2 Partners
• Customizing UML for Systems Engineering
• User benefits

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What is UML?

• Unified Modeling Language is a visual language
  for specifying, constructing, and documenting
  systems
• Derived from synthesis of Booch, OMT and
  Objectory modeling languages
• roots can be traced to ER data modeling,
  Specification and Description Language (SDL),
  Message Sequence Charts (MSCs), Statecharts, etc.
• Adopted by OMG in November 1997 as UML 1.1
• most recent minor revision is UML 1.4, adopted
  May 2001
• next planned major revision is UML 2.0, scheduled
  to be completed during Q1 2003

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Why is UML important?

• As software architectures grow in size and
  complexity so does the need for software models
• compare building blueprints and visual CAD
• UML is the software industrys dominant modeling
  language
• currently a de facto standard adopted by the
  Object Management Group, worlds largest software
  consortium
• difficult to find a software project with gt 10
  developers who do not use UML in some way to
  specify their architecture
• UML has enormous growth potential
• lingua franca across the software lifecycle
  (requirements through testing) and across
  platforms and domains
• refinement and customization can broaden support
  for systems engineering
• executable UML can automate software development,
  reducing chasm between analysis design and
  implementation

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Why UML 2.0?

• Although UML 1.x has enjoyed widespread
  acceptance, it shortcomings include
• excessive size and gratuitous complexity
• uneven precision
• inadequate support for components and executable
  models
• limited customizability
• non-standard implementations
• lack of support for diagram interchange
• lack of support for systems engineering
• Work on Requests for Proposals for a major
  revision to address these issues started in Q1
  2000

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UML 2.0 RFPs
Superstructure
Diagram Interchange
Defines user-level constructs to specify
structure and behavior of systems (e.g., class
diagrams, sequence diagrams)
OCL
Infrastructure
Defines basic constructs to specify UML and to
customize it for specific domains (e.g.,
real-time)
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Proposal Status

• 2nd revised Superstructure and 3rd revised
  Infrastructure proposals were presented to the
  OMG in January 2003
• The voting process to adopt UML 2.0 is scheduled
  to begin during the OMG meeting in March 2003

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Featured Proposal U2 Partners

• Insufficient time to review all proposals
• please download all submissions and judge for
  yourself
• U2 Partners proposal selected because
• work of the largest submission team (40
  submitters and supporters)
• balanced approach to integrating language
  Infrastructure with Superstructure
• architecturally aligned with other industry
  standards (e.g., ITU-T languages, EXPRESS, AP-233)

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Goals

• Restructure and refine the language to make it
  easier to apply, implement and customize
• Improve support for component-based development
• specify both platform-independent components
  (e.g., business components) and platform-specific
  components (e.g., EJB, COM)
• Refine architectural specification capabilities
• support hierarchical composition of parts with
  interfaces (compare SDL blocks and processes)
• Increase the scaleability, precision and
  integration of behavioral diagrams
• augment sequence diagrams with advanced contructs
  from MSCs that can be combined and integrated
  with other behavior
• update state machines diagrams to make
  generalizable and able to support a
  transition-centric view
• revise activity diagrams to support more flexible
  parallelism and furnish more I/O options
• support executable models
• Review all UML 1.x constructs and diagrams

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U2 Partners

• A consortium of UML vendors and users dedicated
  to making UML easier to apply, implement and
  customize
• Submitters
• Alcatel, CA, Ericsson, Fujitsu, HP, IBM, I-Logix,
  IONA, Kabira, Motorola, Oracle, Rational,
  SOFTEAM, Telelogic, Unisys
• Supporters
• Advanced Concepts Center LLC, Ceira Technologies,
  Commissariat à L'Energie Atomique, Compuware,
  DaimlerChrysler, Embarcadero Technologies, Enea
  Data, France Telecom, Fraunhofer FOKUS,
  Gentleware, Intellicorp, Jaczone, Kennedy Carter,
  Klasse Objecten, KLOCwork, Lockheed Martin,
  Mercury Computer, MSC.Software, Northeastern
  University, Popkin Software, Proforma, Sims
  Associates, Syntropy Ltd., Sun Microsystems,
  University of Kaiserslautern, University of Kent,
  VERIMAG, WebGain, and 88solutions
• Largest and most experienced submission team,
  includes many veterans of UML Partners team that
  proposed UML1
• Collaborating with other submission teams to
  integrate best ideas

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Top-Level Packages
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Specification Outline

• Part I Structure
• Classes
• Components
• Composite Structures
• Deployments
• Part II Behavior
• Actions
• Activities
• Common Behaviors
• Interactions
• State Machines
• Use Cases
• Supplement
• Auxiliary Constructs
• Profiles
• Appendices

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Examples

• Proposed notation for new UML 2.0 constructs and
  diagrams

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Use Cases

• Notationally, use cases are not changed much from
  UML 1.4

VendingMachine
BuyItem
include
User
ValidateCoin
Refill
ServiceMan
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Interactions (Sequences)

• Purpose
• capturing requirements
• tracing communications
• test cases and test suites

sd Trace
VendingMachine
User
Display(1)
Insert(.10)
Display(.90)
Insert(.50)
Display(.40)
Insert(.50)
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Variations in Sequence Diagrams

• Express variations
• parallelism and alternatives
• iterations and optionality
• exceptions
• Dramatically reduces number of sequence diagrams
  required to express system functionality

sd ValidateCoin
VendingMachine
User
Insert(coin)
alt
Display(price)
else
RejectCoin()
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Decomposition

• To hide information, a lifeline can be subdivided
  into more detailed sequences

sd Decomposition
Detector
create
Controller
sd Overview
Insert(coin)
VendingMachine ref Decomposition
User
ValidateCoin()
RejectCoin()
Insert(coin)
RejectCoin()
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Referencing Sequences

• To avoid unnecessary duplication, it is possible
  to refer to already existing sequence diagrams
• a way to quickly create new scenarios (e.g.,
  tests and test suites)

sd BuyScenario
User
VendingMachine
ref
ChooseProduct
Display(price)
ref
ValidateCoin
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Organizing Sequences

• It is possible to organize sequence diagrams into
  flows to indicate how they fit together
• Interaction Overview diagram interaction
  diagram activity diagram
• combine interactions in different ways to create
  new scenarios

sd Overview
ref
Initiate
ref
ValidateCoin
else
price0
ref
DispenseProduct
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Component-Based Development

• Interface-based design
• required and provided interfaces allows each
  class to be defined as a stand-alone entity

• Encapsulation
• the class is viewed a black box
• also need to know how the interfaces may be used

Class
interface Display
VendingMachine
Display() NoChange() OutOfOrder()
InsertCoin
Display
Provided interface
Required interface
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Specifying Communicating Classes

• Only classes with matching interfaces are allowed
  to communicate with each other
• supports contracts

• A port serves several roles
• acts as a unique interaction point of the class
• gives a view of the class

Controller
composite port
CoinControl
port
Display
Detector
pCtrl
Maintenance
Counter
InsertCoin
CoinControl,Counter
Counter
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Assembling Classes

• A class can be used as a part of an internal
  structure of another class
• hierarchical decomposition

• Connectors are used as contextual associations
• represent communication paths

Class
Part
VendingMachine
Counter
Detector
pCtrl
Counter
InsertCoin
InsertCoin
Controller
CoinControl
Display
Display
Connector
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Internal Structure and Behavior

• Behavior can be mixed with the internal structure
• e.g., a state machine

• Allows the container to interact with the parts

Behavioral ports
Behavior (of Sensor)
Sensor
Maintenance
SensorInitiation
Input
pS
Monitor
pM
Regulator
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Activities Hierarchical Partitions
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Other Improvements

• Harmonization of Classes and Components
• Harmonization of Actions and Activities
• State Machine generalization, encapsulated
  Submachines and Protocol State Machines
• Information flows
• All other areas have been reviewed and updated to
  improve quality and readability

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UML2 for Systems Engineering

• Architectural specifications
• supports hierarchical decomposition of structure
  and behavior
• includes structured classifiers (classes,
  components, subsystems), sequence diagram
  references, and activity diagram partitions.
• allows modelers to specify large, complex
  architectures
• Crosscutting functionality
• increases the integration of structure with
  behavior
• allows modelers to define functions that apply
  across structural and behavioral boundaries.
• Unification of actions and activities
• reuses the same basic for defining actions and
  activities
• increases precision and efficiency for specifying
  process workflows and other types of behavior.
• Multiple views
• allows different system stakeholders to view the
  system from different, complementary perspectives

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UML2 for Systems Engineering (contd)

• Profiles
• include enhanced stereotype construct that allows
  the specification of meta associations
• allow systems engineers to customize UML
  constructs with names and notation consistent
  with domain usage
• allow systems engineers to extend UML with new
  constructs needed for the domain (e.g.,
  HardwareComponent)
• although UML2 is based on discrete time model,
  nothing precludes customizing it to specify
  continuous time varying attributes or continuous
  time behavior

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User Benefits

• UML 2.0 marks a major milestone in model-driven
  development
• significantly more mature than UML 1.x
• more precise, concise and consistent
• Major improvements include enhanced support for
• component-based development
• architectural specifications of large, complex
  systems
• more scaleable, precise and integrated behavioral
  models
• executable models
• language customization
• UML 2.0 Action Semantics driven development
  tools can realize potential of model-driven
  development and MDA
• automate generation of production quality code
• automate system validation verification
  throughout software lifecycle
• UML 2.0 Profiles can customize the language for
  domains, platforms and processes

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Wrap Up

• UML is used extensively inside and outside OMG
• common language for OMGs Model Driven
  Architecture
• de facto standard ? de jure standard
• UMLs evolution is following a well-planned
  roadmap
• UML 1.5 with Action Semantics marks end of
  significant changes for UML 1.x
• UML 2.0 is next planned major revision
• U2 Partners submission for UML 2.0 proposes many
  improvements
• will allow vendors and users to realize potential
  of model-driven development
• can be used as a baseline for customizing UML for
  SE

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Further Info

• www.u2-partners.org
• mailtou2p-info_at_yahoogroups.com
• mailtou2p-issues_at_yahoogroups.com