FLACOS08

1
Contract-Oriented
Software Development for Internet Services -
Where is the project now?
NorduNet3 Project 2006 - 2010

• FLACOS08
• Malta November 2008
• Olaf Owe, Cristian Prisacariu,, Gerardo
  Schneider, Oslo University
• Gordon Pace, University of Malta
• Seif Haridi, Pablo Giambiagi, Björn
  Bjurling,Swedish Institute of Computer Science
• Joseph C. Okika, and Anders P. Ravn, Aalborg
  University

www.ifi.uio.no/cosodis/
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Why Contracts ?
Collaboration across organizational domains
presumes trust, but

When trust is insufficient, use contracts
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SOA and contracts

• The consumer either trusts the provider
• or they sign a contract which
• Determines the rights and obligations of each
  signatory
• Usually states how the contract is to be
  monitored
• Specify functional but also extra-functional
  qualities of the service e.g. security,
  performance

4
How ?

• Developers need language support to program
  services that are
• Distributed
• Interoperable
• Discoverable
• Contract-aware

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COSoDIS Mission

• develop novel approaches to implement and reason
  about contracts in a service oriented
  architecture.
• design and give proof of usefulness of system
  modeling tools and programming language tools
• to empower SOA developers to deploy
  highly-dynamic, negotiable and monitorable
  Internet services.

• Pablo Giambiagi, Olaf Owe, Anders P. Ravn, and
  Gerardo Schneider, Language-Based Support for
  Service Oriented Architectures Future Directions
  
• Pablo Giambiagi , Olaf Owe, Anders P. Ravn and
  Gerardo Schneider, Contract-Oriented Software
  Development for Internet Services

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Key Issues for Contracts

• Definition
• Feasibility checking
• Compatibility checking
• Conformance checking
• Monitoring

C
C ?Ø
C1 C2
P C
P I(C)
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Is SOA really New? (Wolfgang Reisig)
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The Marketplace
P,C

• Joseph C. Okika and Anders P. Ravn,
  Classification of SOA Contract Specification
  Languages

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1. Formal modelling of contracts
C

• develop a model of contracts in a SOA
• A minimum requirement is to combine QoS
  specification and behavioral models (essential to
  constrain protocol implementation and to enforce
  confidentiality).
• develop practical and efficient methods to
  enforce information flow properties of realistic
  code, including cryptographic protocol
  implementations.

• Johs H. Hammer and Gerardo Schneider, On the
  definition and policies of confidentiality
• Cristian Prisacariu and Gerardo Schneider, A
  Formal Language for Electronic Contracts
• ...

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2. Programming language support for contracts
P I(C)
P C

• extend Creol with wrapper primitives for
  correct-by-construction wrapped code.
• contracts for QoS and confidentiality will be
  modeled as first-class entities
• develop techniques for constructing monitors from
  contracts.

• A. Torjusen, Olaf Owe, and Gerardo Schneider,
  Towards integration of XML in the Creol
  object-oriented language
• Olaf Owe, Gerardo Schneider, and Martin Steffen,
  Components, Objects, and Contracts

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3. Reasoning about contracts
C ?Ø
C1 C2

• extraction of models to facilitate reasoning
  about contracts.
• timing constraints will be mapped to timed
  automata
• using the Maude tools for model checking and
  exhaustive search.

• Emilia Cambronero, Joseph C. Okika, and Anders P.
  Ravn, Analyzing Web Service Contracts - An Aspect
  Oriented Approach
• Gordon Pace, Cristian Prisacariu, and Gerardo
  Schneider, Model Checking Contracts -a case study

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Contract Patterns and Case Studies

• establishing representative examples, equipping
  them with suitable contracts.
• distill some useful contract patterns
• provide corresponding verification patterns.

• Zhenbang Chen, Zhiming Liu, Volker Stolz,
  Lu Yang, and Anders P. Ravn, A refinement driven
  component-based design
• Sakyibea Darko-Ampem, Maria Katsoufi, and Pablo
  Giambiagi, Secure Negotiation in Virtual
  Organizations
• Bjørn Burling,

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Fitting it Together
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Expected Results - 2010
Applications
Logics.

• A modal logic for defining high level contracts
• Model checking tools for checking WS-style
  contracts
• Larger Case Study?
  CoCoME
• Monitoring?

C
C ?Ø
C1 C2
WS-CDL
Models
P C
Implement- ations.
Creol, Java, etc
WS-BPEL
Platform
P I(C)
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Is SOA really New? (Wolfgang Reisig)