Presented by: Thabet Kacem Spring 2010

Outline Contributions Introduction Proposed Approach Related Work Reconception of ADLs XTEAM Tool Chain Discussion Conclusion Future Work

Contributions Address the shortcoming of ADLs Propose a new conception of ADL within MDE paradigm Approach combines extensible modeling language within a framework enabling implementation of customized dynamic analysis at architectural level Approach was implemented in XTEAM which helped to accommodate both new modeling features and new architectural styles

Introduction Emergence of highly distributed, resource constrained and mobile computing environments Consequence: Complexity of software development increased difficulties to cope with network latency, security & unpredictable network topology Efforts went toward raising the level of abstraction for describing large scale software systems beyond OO concept ADL emerged to provide the architect with a higher level of architectural constructs

Introduction ADL has many problems: Focus on structural elements Rely on rigid formalisms Many crucial aspects of a system cannot be expressed MDE emerged as an approach to distributed software systems combining DSMLs with model transformers, analyzers and generators

Proposed Approach The approach combines extensible modeling languages with a model interpreter framework for rapid implementation of dynamic analysis at arch level Analysis provides information about the behavior & cross-cutting properties that help an architect to compare architectural alternatives and weigh tradeoffs XTEAM: Provides ADL extension for mobile systems Implements a set of dynamic analysis on top of the model interpreter framework

Proposed Approach Two requirements to success: Extensibility of the language to accommodate new domain-specific concepts Flexibility of tools to allow rapid implementation of new architectural analysis techniques

Related work GME: GME: tool implementing MDE paradigm that enables the creation of DSML and other related models

Related work MILAN: MILAN: compromises DSML for embedded systems based on a dataflow representation & a set of models to generate executable specs for simulation engines Automates the synthesis of software implementation for system models It provides highly accurate simulations Drawback: Drawback: suitable for signal processing systems but not efficient for large scale distributed architectures

Related work WML &CUTS: WML &CUTS: it’s a DSML that enables dynamic analysis of component-based architectures WML creates models that are transformed into XML- based inputs for CUTS Drawbacks: Drawbacks: WML performs syntactic translation not semantic The analysis is implemented in the emulator engine not the model interpreter It does not capture component behavior

Related work xADL: xADL: can accommodate new domain specific concepts. It is defined by XML schemas. Core Schema: standard constructs to all ADLs Extension Schema: new modeling elements that are written by domain experts Drawback: Drawback: xADL toolset is semantically agnostic then it cannot be extended to enforce semantic consistency

Related Work FSP: FSP: a modeling notation for capturing the behavior of software architectural constructs Allows construction of composite behavior Drawback: Drawback: It lacks research concerning the execution in heterogeneous environment, deployment and extensibility

Reconception of ADLs Key shortcomings for arch. Based approaches to software modeling: Inflexible notation with a narrow vocabulary Supporting tools that enable only a limited set of analysis Assumption: Assumption: Shortcomings can be addressed by representing ADL via domain specific language DSML and performing arch. Analysis via model interpreter

Reconception of ADLs Avoid the creation of ADL from scratch and use ADL composition and enhancement These concepts are present in XTEAM Model Interpreter framework allows the architect to implement custom analysis techniques without knowing details of semantic mapping Use the ‘hook’ methods implemented by architect where objects are arch. constructs defined in ADL extensions

Reconception of ADLs Two types of analysis techniques: Static: Static: relies on the formalism underlying models to provide info about system properties or possible errors Problem: Difficulty that system implementation must match the model so that the analysis can be relevant Dynamic: Dynamic: explores the behavior of the model-based arch. representations at runtime by executing them It is more useful in comparing high level design possibilities early in the development cycle and don’t rely on the experience of the architect

XTEAM Tool Chain XTEAM ADL: compose a structural ADL (xADL) with a behavioral ADL (FSP) Creates execution architecture representation Adds language extension to capture system change in order to help Model Interpreter to implement architectural analysis Semantic mapping is done by the Model Interpreter

XTEAM Tool Chain

Domain Specific ADL extension: Domain Specific ADL extension: Example: Energy consumption

XTEAM Tool Chain Mobile Application testbed used to illustrate the energy consumption:

XTEAM Tool Chain The energy consumption simulation generator allows to do some measurements that can be plotted in function of time

XTEAM Tool Chain Many factors affect energy consumption: Assignment of components to host or deployment architecture Determining a dynamic redeployment strategy when consumption values differ from expected values Many other ADL extensions exist in XTEAM: End to end latency Memory utilization Component reliability

Discussion Three cases where the approach is relevant Providing design rationale Weighing tradeoffs Understanding compositions of Off-the-shelf components Are these three cases enough to judge that the approach is reliable ? Is implementing the approach in XTEAM sufficient to say the approach is correct ?

Conclusion The paper presented a software arch-based approach to modeling & analysis of distributed architecture that leverage the domain specific extensibility provided by model-driven engineering Approach addressed shortcomings of ADL Deployed & evaluated on XTEAM Considered as an improvement over traditional ADL and other MDE tools

Future Work Use XTEAM in the context of real world security application in embedded & mobile devices Integrate XTEAM with Desi and Prism-MW Determine the exact class of analysis technologies