SEERE Workshop, Neum 2009 1

Tempura RetargetingDamyan Mitev, Vladimir ValkanovPlovdiv University “Paisii Hilendarski”

SEERE Workshop, Neum 2009 2

CAMeLS project

• flexible, adaptive, collaborative, context-aware service and agent-oriented eLearning environment

• uses InfoStation network architecture• delivers personalized, mobile, any-time and

any-where assess to educational content and services

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InfoStation middleware

• manages services and mobile users• scenario based– « No change » scenario– « Change IS » scenario– « Change MD » scenario– « Change both » scenario

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Scenarios

• depend on movement of user and used mobile device

• mandate different behavior of the middleware– different device profiles (capabilities)– cached information in the InfoStations– availability of services in different InfoStations

• time dependant

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Scenario detection and control

• we need– formal description of scenarios– mechanisms to interpret that description

• we gain– flexible mechanisms for creating new (sub)

scenarios – easily define corresponding middleware behavior

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Scenario formalism

• Interval Temporal Logic– propositional and first-order logical reasoning– finite sequences – time intervals – capable of handling sequential and parallel

composition

• Tempura - executable ITL framework.

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Tempura usage

• middleware– written in Java

• Tempura– written in C– open source

• possible usage of Tempura– wrapping existing Tempura executable with Java IO

redirection– development of entirely new project, based on execution

rules of ITL– reengineering of Tempura and rewriting it in Java

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Tempura retargeting

• homogenous environment• usage of quality code as a basis• no steep curve learning ITL nuts and bolts

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Tempura source code diagram

top-lev.c

init.c

system.c

r-assign.c

r-expr.c

r-int.c

r-io.c

r-linear.c

r-lists.c

r-symbol.c

r-system.c

mem.c

store.c

io.c

errors.c

version.c

parser.c

lexer.c

val.c

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Retargeting plan

• based on iterations• iteration phases– research phase– implementation phase– testing phase

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Plan for first iteration

• research– understand Interval Temporal Logic• In progress

– learn code structure, main program flow, structures and variables of Tempura interpreter• Mostly done

– check possible usages of existing C-to Java conversion tools• No suitable software found

– check possible usages of existing C analysis tools• No suitable software found

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Plan for first iteration (cont’d)

• implementation– create a Java class for every C source file and its associate header file– create a static method in the Java class for every function in the C file

with the same name (ignoring Java naming conventions)– create static variable in the Java class for every global variable in the

header file– create a static method in the Java class for every macro function in the

header file (where appropriate)– expand the contents of every macro, not covered by the previous step– implement all struct and union types as Java classes– convert integer boolean assignments and expressions into proper Java

boolean constructs– replace function pointers with instances of specially created Interface,

which will call the desired Java method (delegates)

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Plan for first iteration (cont’d)

• implementation status (estimated)– 40 % of the source code – 80 % of the structures – 30 % of function pointers

• problems– console oriented– scattered functions and variables– heavy use of c-specific syntax structures like macros, pointers, memory

addressing, null terminated strings, inline initializers

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Plan for first iteration (cont’d)

• testing– run the examples, which come with the original

sources, on the Java interpreter and compare results

• desired outcome– working JTempura interpreter by the end of the

year

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Plan for second iteration

• towards object-oriented structure– converting different Node types (denoted by their

type member) into hierarchy of base class TNode and a descendant for every node type, supported by JTempura

– converting various reducers from static members to Java classes and creating hierarchy of reducers with base class TReducer

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Plan for second iteration (cont’d)

• towards object-oriented structure– redirecting input and output of the interpreter into

streams– redesign memory management– redesign error handling and notification– group similar and relevant methods in one class– design complex objects for storing lexemes– implement syntax tree outcome of the parser,

representing the given ITL expression

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Plan for second iteration (cont’d)

• Object-oriented model for the second iteration

Tempura

TInterpreter

+ init () : int

TReducer

TLexer

TParser

TAssignmentReducer

TException

TInputOutput

TUtilsTNode

TInteger TStringTLink

TDouble TBoolean

TEnvironment

TBlock

TBinding

TList

TName

TSymbolTMemory

TLocation

TExpressionReducer

TListReducer

TLinearReducer

TIOReducer

TIntervalReducer

TStatement

TSymbolReducerTSystemRecurer

TStack

TState

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Plan for third iteration

• research– analyze different runtime verification (RV) tools and

frameworks – learn different RV strategies– choose suitable strategy for our needs (service

monitoring, scenario detection, Java)

• implementation– towards runtime verification framework– implement at least one of the strategies

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Tools

• Eclipse-CPP• Eclipse-Java• PowerDesigner

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Thank you