XTEAM: Architecture-Based Modeling and Analysis Tools
with Metamodeling
Nenad [email protected]
George [email protected]
Computer Science DepartmentUniversity of Southern California
Blue Cell SoftwareLos Angeles, CA
XTEAM Project• Processes, notations, tools, and designs that enable
automated synthesis of domain-specific toolsets for architecture modeling, analysis, and code generation
• Example application areas:– Embedded and real-time systems– Safety- and mission-critical systems– Cloud and grid systems
XTEAM Capabilities• Metamodeling
Domain-specific language definition
• Architecture modelingSystem design and requirements definition
• System simulation and code generationDesign and requirements analysis
procedure Chunker.NextChunk(this: ref where $IsNotNull(this, Chunker)) returns ($result: ref where $IsNotNull($result, System.String));
// in-parameter: target object free requires $Heap[this, $allocated]; requires ($Heap[this, $ownerFrame] ==
$PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && (forall $pc: ref :: $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[this, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[this, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv]
// out-parameter: return value free ensures $Heap[$result, $allocated];
XTEAM Collaboration• Real-time
distribution of model updates
• Automatic checks for consistency
• Conflict notification and resolution
XTEAM Use Cases• Providing design rationale
and feasibility evidence
• Weighing architectural trade-offs
• Discovering emergent behavior of component assemblies
• Testing component implementation prototypes
5
Domain-Specific Languages (DSLs)• Customized for a particular
family of problems(the domain)
• Concise and intuitive– No missing or extra features– Capture patterns– Enforce constraints– Use native symbols and terms
• Can be modified, evolved, and composed
Model-Based Systems Engineering using DSLs
• DSLs for requirements and architecture modeling and analysis– Metamodels define DSL syntax– Model interpreters define DSL semantics
• COTS tools provide only partial support for DSLs– Metamodel editor with built-in metamodeling language– Metamodel interpreter that configures metaprogrammable model
editor
Metamodel Editor
Metaprogrammable Model Editor
Model Execution
Environment (Semantic Domain)
MetamodelInterpreter
ModelInterpreter
Off-the-shelf
Auto generated
Built by engineer
Domain-Specific Model
Domain-Specific Model
Domain-Specific ModelMetamodel
Metamodeling Language
Domain-Specific Language
Executable Model
Executable Model
Executable Model
“The difficulty of building and maintaining a DSM solutionstems essentially from the complexity of the mapping between the concept instances expressed in the DSML and the code that has to be generated.”
A. L. Santos et al. Automating the Construction of Domain-Specific Modeling Languages for Object-Oriented Frameworks. Journal of Software and Systems, 2010.
Problems with MBSE using DSLs• Building and maintaining
code generators for DSLs is inherently difficult– High design complexity– Disproportionate
maintenance and evolution costs
– Hard to verify correctness– Redundant development
effort– Opaque semantics
embedded in source code
“There is a fundamental problemin keeping the model interpreters up to date with metamodel changes ... Current practice requires each model interpreter to be modified manually after each metamodel schema change. This can be a very time-consuming and error prone task for complex model interpreters of considerable size.”
Jing Zhang. Metamodel-Driven Model Interpreter Evolution. Conference on Object Oriented Programming Systems Languages and Applications, 2005.
“Checking mathematicalproperties like correctness or completeness of transformations based on common programminglanguages is very difficult...”
I. Malavolta, H. Muccini, P. Pelliccione, and D. Tamburri. Providing Architectural Languages and Tools Interoperability through Model Transformation Technologies. IEEE Transactions on Software Engineering, 2009.
“The state-of-the-art of modelinterpreter writing needs to be advanced to enhance thereusability and maintainability of this software...”
G. Karsai. Structured Specification of Model Interpreters. Engineering of Computer-Based Systems, 1999.
“Writing translators by hand...in addition to being inefficient, has yet another serious drawback: the semantic mapping between the input and the output is vaguely specified...[Building model interpreters] is the most time consuming and error prone phase of the MIC approach...”
G. Karsai, A. Agrawal, F. Shi, J. Sprinkle. On the Use of Graph Transformation in the Formal Specification of Model Interpreters. Journal of Universal Computer Science, 2003.
FCS: A Real World Example• DSL with hundreds of types
– Modified on a daily basis
• Automated generation of:– Discrete event simulations– Middleware configuration files– Fault trees– Spreadsheets for documentation
Tool building and maintenance required approximately five full-time MDE experts
Synthesize domain-specific code generators
using the same mechanisms that have proven
successful for synthesizing domain-specific model
editors.
XTEAM Solution Approach
Metamodel Editor
Metamodel
Metamodel Interpreter
A
Model Editor Framework
Metamodel Interpreter
B
Code Generator Framework
Target Platform
Presentation Semantics
Platform Semantics
Application Model(Abstract
Representation) Executable
Code
Types and Views
Presentation Properties
Platform Properties
Presentation Logic
Presentation Rules
Code Generation Logic
Code Generation Rules
Target Display
Visualized Model
Selected Applications of XTEAM• MIDAS: wireless sensor network (WSN) applications for
building monitoring and control
• RoboPrism: analysis, implementation, deployment, and monitoring framework for mobile robotics systems
• SASSY: automated run-time generation of service-oriented architectures
• RESIST: dynamic reliability estimation and proactive adaptation in situated software systems
• FUSION: self-tuning self-adaptive software systems
• PATFrame: predictive tools for UAS T&E
Proposed Next Step: Model Checking• Used to verify requirements and design
– Safety, security, and other properties– Successfully used in real-time and embedded systems
Existing model checkers do not provide metamodeling
Answer
Yes (if model satisfies rqmts)
Counter-example (if model does not satisfy rqmts)
• Well-known tools: SPIN/dSPIN, SMV, Java Pathfinder/JPF
Model Checking
Application Model
System Requirement
s
Planned Research Approach• Refine the XTEAM
metamodeling language– Include sufficient semantic
information for mapping to model checking input
• Implement metaprogrammable model checker– Metamodel interpreter– Model interpreter framework
Define Metatypes
Develop Components
Define/refine core architectural
metatypes
Embed semantic assumptions in
metatypes
Attach semantic properties to
metatypes
Implement model interpreter framework
Implement metamodel interpreter
Semantic Definitions• Embedded semantic assumptions
– Independent of the metamodel– Capabilities
• Behaviors that metatypes exhibit by default– Responsibilities
• Information required to map metatypes to the semantic domain
• Semantic properties– Capture semantic
variability among metamodels
– Values map to a semantic configuration
Outcome and Benefits• End product: MBSE toolset with model
checking and metamodeling capabilities– DSLs: customizable, concise, intuitive modeling– Model checking: formal verification of requirements and
design– No model interpreter development
• Generally 4 person-months to 24 person-months of effort
– Predictable cost and timeline for tool development• Less risk than a conventional DSL tool chain
Conclusions• Ready-to-use tool exists today
– Metamodeling and DSL definition– Architecture modeling– Discrete event simulation
• Future plans– Model checking– Enhanced real-time collaboration– Automated composition of metamodels
Additional Information• XTEAM Website:
http://softarch.usc.edu/~gedwards/xteam.html• Papers:
– George Edwards and Nenad Medvidovic, Model Interpreter Frameworks, Technical Report USC-CSSE-2009-514, Center for Software and Systems Engineering, Univ. of Southern California, July 2009.
– George Edwards and Nenad Medvidovic, A Highly Extensible Simulation Framework for Domain-Specific Architectures, Technical Report USC-CSSE-2009-511, Center for Software and Systems Engineering, University of Southern California, May 2009.
– George Edwards and Nenad Medvidovic, A Methodology and Framework for Creating Domain-Specific Development Infrastructures, Proceedings of the 23rd IEEE ACM International Conference on Automated Software Engineering (ASE), September 2008.
– George Edwards, Chiyoung Seo, and Nenad Medvidovic, Model Interpreter Frameworks: A Foundation for the Analysis of Domain-Specific Software Architectures, Journal of Universal Computer Science (JUCS), Special Issue on Software Components, Architectures and Reuse, 2008.
– George Edwards, Chiyoung Seo, and Nenad Medvidovic, Construction of Analytic Frameworks for Component-Based Architectures, Proceedings of the Brazilian Symposium on Software Components, Architectures and Reuse (SBCARS), August 2007.
– George Edwards, Sam Malek, and Nenad Medvidovic, Scenario-Driven Dynamic Analysis of Distributed Architectures, Proceedings of the 10th International Conference on Fundamental Approaches to Software Engineering (FASE), March 2007.