Runtime Model for Role-based Software Systems Tobias Jckel * , - - PowerPoint PPT Presentation

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

Position Paper:

Runtime Model for Role-based Software Systems

Tobias Jäckel*, Martin Weißbach†, Kai Herrmann*, Hannes Voigt*, Max Leuthäuser‡

* Database Systems Group † Computer Networks Group ‡ Software

Technology Group

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

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Modeling Languages Programming Languages

2

Motivation

Helena- Approach (2014) Onto-UML (2012) DCI (in Scala) (2009) INM (2009) Metamodel for Roles (2007) JavaStage (2012) NextEJ (2009) Rumer (2007) powerJava (2006) OT/J (2005)

• roles allows for an intuitive separation of static and

dynamic, context-dependent behavior

• investigation of roles throughout all steps of the

software development process and across all layers

• f developed software applications

ORM 2 (2005) Raw (2006)

Modeling & Programming Languages taken from: T . Kühn, et al., “ A Metamodel Family for Role-Based Modeling and Programming Languages, ” in Software Language Engineering, Cham: Springer International Publishing, 2014, pp. 141–160.

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

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Compartment Role Object Model (CROM) [3],[4]

3

Motivation

Programming Language / Framework Database

LyRT [1],[2] SCROLL [6] RSQL [4]

Runtime Environment

Java Virtual Machine (JVM)

Formal Foundation

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

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Our Assumed Role Model

4

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DFG · RoSI · Martin Weißbach

HighBandwidth BrightEnvironment LowBandwidth

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Our Assumed Role Model

LazyLoading

+fetchData()

EagerLoading

+fetchData()

Browser

+fetchData() +displayContent()

Downloadable

+download() +save(File)

BrightDisplay

+displayContent()

• bjects may play

different roles simultaneously

• bjects may

acquire and abandon roles dynamically features of an

• bject can be

role-specific

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• Roles have properties and behaviors
• objects may play different roles simultaneously
• objects may acquire and abandon roles dynamically
• roles can be transferred between objects
• the state of an object can be role-specific
• features of an object can be role-specific
• an object and its roles share identity
• an object and its roles have different identity
• roles depend on compartments
• compartments have their own identity

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Our Assumed Role Model

Browser

+fetchData() +displayContent()

Downloadable

+download() +save(File)

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

DFG · RoSI · Martin Weißbach

• applied role concept to different layers of the

application independently

• Are the states of roles the same on each layer?
• Are any transitions between layer-specific role states

possible?

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Role States

B1:Browser D1:Downloadable

Database Runtime

B1:Browser D1:Downloadable

Application

B1:Browser D1:Downloadable

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DFG · RoSI · Martin Weißbach

LowBandwidth HighBandwidth

8

Application Layer (AL)

Application Layer Not Existent Bound Active Passive

• Bound Active roles’ behavior

is ‘visible’ to the user

• Bound Passive roles’

behavior is not perceivable

• role-base application thats behavior can be modified

dynamically at run time (through roles)

• user-interaction, business logic etc.

B1:Browser LazyLoading EagerLoading

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Runtime Environment Layer (REL)

Runtime Environment Layer Not Existent Unbound Player Compartment Bound

• Bound roles are considered

for the method dispatch

• Unbound states are

transparent for the application and transient

• book-keeping of currently played roles (binding

information)

• dispatch of method invocations
• creation, deletion, binding etc. of roles

B1:Browser LazyLoading EagerLoading

fetchData()

HighBandwidth

fetchData()

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• mapping of the programming-language specific
• bject instances of roles and players to their

respective representation on the database layer

• autonomous storage to the database on changes

made to the objects

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Persistence Layer (PL)

Persistence Layer Not Existent Bound

• Bound roles are stored to the

database

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Database Layer (DBL)

Database Layer Not Existent Bound

• Only information about roles

being bound to players are required being persistent

• stores roles, players and bind information persistently

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• combinatorics allow invalid states → might also occur

if the system is left unattended

• motivation: roles instances might exist on a single

layer only, but the “entity” of the role cuts all layers in the layer stack

• limit space of possible transitions of a role, globally in

the system

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Global Role State

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Create and Store a Role

Runtime Environment Layer Database Layer Persistence Layer Application Layer

P1:Browser R1:BrightDisplay not existent not existent not existent not existent C1:BrightEnvironment Unbound Player Unbound Compartment bound bound Passive bound Active bound bound

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Reload a Role from the Database

Runtime Environment Layer Database Layer Persistence Layer Application Layer

P1:Browser R1:BrightDisplay C1:BrightEnvironment bound not existent not existent not existent bound Unbound Player Unbound Compartment bound bound Passive bound Active

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The Global State Manager

Runtime Environment Layer Database Layer Persistence Layer Application Layer

P1:Browser R1:Downloadable C1:BrightEnvironment bound bound bound bound Active Global State Manager

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Global State Manager

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The Global State Manager

R1 R6 R3 R4 R5 R2

…knows…

• the roles in the

system

• their current state on

each layer

R7

{ba,b,b,b} {AL,REL,PL,DBL} {nex,nex,nex,nex} {ba,b,nex,nex} {bp,b,nex,nex} {ba,b,nex,nex} {nex,nex,nex,b} {ba,b,nex,nex}

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• transitions of global role states can be checked at run

time

• model can be used to check the system in advance

for correctness

• possibly especially interesting in the case of

constraints or collaborations between roles

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Benefits

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DFG · RoSI · Martin Weißbach

Global State Manager

18

The Global State Manager

R1 R6 R3 R4 R5 R2

…knows…

• the roles in the

system

• their current state on

each layer

• roles and their

players

• the object net of

players

{ba,b,b,b} {AL,REL,PL,DBL} {ba,b,nex,nex} {bp,b,nex,nex} {ba,b,nex,nex} {nex,nex,nex,b} {ba,b,nex,nex}

P2

constraint to be always played together collaboration

P3 P1 P4 P5

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

DFG · RoSI · Martin Weißbach

• transitions of global role states can be checked at run

time

• transactional changes of multiple roles can both be

checked and guided

• model can be used to check the system in advance

for correctness

• possibly especially interesting in the case of

constraints or collaborations between roles

19

Benefits

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

DFG · RoSI · Martin Weißbach

• role-concept on the modeling and programming

language level

• exemplary investigation of the role-concept in an

entire software application

• argument to incorporate the concept in a run-time

model to allow for dynamic adaptation and validation

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Conclusion

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DFG · RoSI · Martin Weißbach

• refinement of layers
• superset of role models that fulfil the state machine
• different quality / isolation levels
• e.g. transactional storage of changes of role

bindings / creations vs. lazy storage that allows information loss

• distributed settings & decentralization aspects

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Future Work

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Thank you for your attention!

Questions?

Department of Computer Science Institute of Systems Architecture, Computer Networks Group

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[1] Nguonly Taing, Thomas Springer, Nicolás Cardozo, Alexander Schill: A Dynamic Instance Binding Mechanism Supporting Run-Time Variability of Role-Based Software Systems. Modularity Companion 2016, Màlaga, Spain [2] Nguonly Taing, Markus Wutzler, Thomas Springer, Nicolás Cardozo, Alexander Schill: Consistent Unanticipated Adaptation for Context- Dependent Applications. To appear at COP'16, 2016, Rome, Italy [3] Thomas Kühn, Max Leuthäuser, Sebastian Götz, Christoph Seidl, Uwe Aßmann: A Metamodel Family for Role-Based Modeling and Programming Languages, In Proc. of the 7th International Conference on Software Language Engineering (SLE 2014), 2014. [4] Tobias Jäkel, Thomas Kühn, Hannes Voigt, Wolfgang Lehner: RSQL - A Query Language for Dynamic Data Types. In Proc. of the 18th International Database Engineering & Applications Symposium (IDEAS '14), 2014. [5] Thomas Kühn, Stephan Böhme, Sebastian Götz: A Combined Formal Model for Relational Context-Dependent Roles. In Proc. of SLE'15, ACM, 2015. [6] Max Leuthäuser: SCROLL - A Scala-based library for Roles at Runtime. In Proc. of the 3rd Workshop on Domain-Specific Language Design and Implementation (DSLDI 2015)

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References