Research lines on MDE and SE (March 2015

What we’re working on –
Research lines on MDE and SE
(March 2015 Edition)
Inria Lillle
March 2015
Jordi Cabot (and colleagues)
jcabot@uoc.edu
http://modeling-languages.com

MDE = Model-Driven Everything
3
MDE
(engineering)
MDSD
(software
development)
MDE

5
© AtlanMod - atlanmod-contact@mines-
nantes.fr
The need for formal specifications

6
Employee
age: Integer
age > =18
Please no
underaged
employees!
alter = 21
e3:Employeee1:Employee
age = 17
e2:Employee
age = 37  

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Original
model
1st
refinement
nth
refinement
Model
Transformation
Model
Transformation
Source
Code
...
MDE-based software development process
Errors in models breed and generate
more errors in the code
Why model verification

Student
EnrolsIn20..*
Course
Likes
1
5 1
• Spot the error
It’s not that easy…

Person
name: string children
2
*
+ constraint : Nobody can be his own ancestor
parent

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…..
No finite (and non-empty) solution

Consistent?
Proven?
Formalism / Logics
• Dynamic Logic (KEY)
• High-Order Logics (HOL-OCL)
• Deductive database queries (CQC)
• SAT (Alloy + UML2Alloy), …
Translate
Prove
Deduce
UML model
1. Class diagram
2. OCL constraints
Typical solutions

MDE
1E+18 scenarios for small
models (classes=10)
More than cells in the
human body!!!

Verification
Automation Efficiency
Expressiveness Precision (e.g.
completeness)
Decide what to sacrifice

Our pragmatic approach
14 © AtlanMod - atlanmod-contact@mines-nantes.fr
Solution?
Constraint Satisfaction Problem
1. Variables – basic types + struct/list
2. Domains – finite
3. Constraints – Prolog (+our OCL Prolog lib)
4. Property  Additional Constraint
Translate
Solve
Deduce
Property?
+
Model Constraints

Define cardinality variables
Constraints on cardinalities
Assign cardinalities
Define attribute variables
Constraints on attributes
Assign attributes
Proof
Resolution of the CSP

Trade-offs in verification
• Decidability/termination: is
automation possible? Yes
• Completeness: proof for any input?
No, bounded verification
• Expressiveness: input language?
UML class diagram + full static
OCL
• Basic Property: Satisfiabililty

Exists? Post?
Find legal
final state
Find legal
initial state
Inconsistent Model Proving
Example
UML Model
OCL
invariants
OCL
precondition
OCL
postcondition
Pre?
NO
YES
NO
YES
YES
NO
Verification of the Weak Executability Property
Also applied to
machine
op1
NAC:
machine
LHS:
machine
op2
RHS:
c :Class t :Tablec2t :Cl2Tb
name
persistent
name{new}
{new} {new}
{new} {new}

ATLTest (testing of M2M)
18© AtlanMod - atlanmod-contact@mines-nantes.fr
White-box approach: Analyzing the ATL code to
derive test models that “exercise” it

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Model-based testing
OCL analysis to improve the partitioning –
EMFtoCSP to generate the test models

© AtlanMod - atlanmod-
contact@mines-nantes.fr
20
To read more
• Carlos A. González, Jordi Cabot: Formal verification of static
software models in MDE: A systematic review. Information &
Software Technology 56(8): 821-838 (2014)
• Jordi Cabot, Robert Clarisó, Daniel Riera: On the verification
of UML/OCL class diagrams using constraint
programming. Journal of Systems and Software 93: 1-23
(2014)

Existing tools
No support for DSLs
creation

Our proposal
Collaboro
Participation Collaboration

But… technically?
• Providing means to discuss about language elements
• Overcoming technical barriers
Participation
• Suitable environment fostering end-user discussion
• Facilitating voting and decision processes
• Keeping traceability
Collaboration

Abstract Syntax
Concrete Syntax

Example of DSL creation/improvement with
Collaboro

Participation CollaborationTraceability

Discussing the abstract syntax

Discussing the concrete syntax

41
To read more
• Javier Luis Cánovas Izquierdo, Jordi Cabot: Enabling the
Collaborative Definition of DSMLs. CAiSE 2013: 272-287

EMF-REST: A REST API for your
models
• Addressable resources
– Eclipse: platform:/resource/project/Simpsons.xmi
– Web API: https://example.com/rest/Family/Simpsons
 Uniform and Constrained Interface & Statelessness
‒ CRUD operations using HTTP verbs : POST, GET, PUT, DELETE
PUT https://example.com/rest/Family/Simpsons/parents/Homer
• Representation-oriented
– JSON:
{"family":{"address":"742 Evergreen Terrace",…}}
– XML:
<family><address>742 Evergreen Terrace</address></family>

Architecture of EMF-REST generated application
EMF
JAX-RS
EJB/CDI
JAXB OCL JPA
JavaScript
API
Browser
REST Client
Validation SecurityNavigation/
Operation
Content
format
Content management
Web ClientWeb Application

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Scalable persistence: NoSQL + Lazy loading

Sometimes you need to bypass the EMF API

47
To read more
• Amine Benelallam, Abel Gómez, Gerson Sunyé, Massimo
Tisi, David Launay: Neo4EMF, A Scalable Persistence Layer
for EMF Models.ECMFA 2014: 230-241
• Abel Gómez, Massimo Tisi, Gerson Sunyé and Jordi Cabot.
Map-based transparent persistence for very large models.
FASE 2015, to appear

MoDisco: Legacy to Cloud
Pre-Migration
(Feasibility
Assessment)
Migration
(Reverse Engineering +
Forward Engineering)
Post-Migration
(Validation,
Certification)
Migration Artifacts Reuse & Evolution
Target Environment Specification
Target
Requirements
Target
Selection
Cloudification
Optimization
Deployment
Business and Organizational aspects
MoDisco ATL Acceleo
CloudML
GoalML
UML
EPF GoalML fUML

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EMFViews
Model c
Model b
Metamodel C
Runtime
Design time1
2
Viewpoint
(Metamodel)
View
(Model)
Metamodel B
Metamodel A
Model a
Viewpoint
Builder
(Virtualization)
View
Builder
(Virtualization)
Conforms to Conforms to
Weaving model
Weaving model

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Similarly for metamodel extensions

Research by MDE
(MDE techniques to solve SE
challenges)

Reverse Eng. of firewall security policies

Unify firewall configuration languages (and
semantics) for a global analysis
• Similar approach for databases, CMSs and Java web
clients

57
To read more
• Salvador Martínez Perez, Joaquín García-Alfaro, Frédéric
Cuppens, Nora Cuppens-Boulahia, Jordi Cabot: Model-
Driven Extraction and Analysis of Network Security
Policies. MoDELS 2013: 52-68
• Salvador Martínez Perez, Valerio Cosentino, Jordi
Cabot, Frédéric Cuppens: Reverse Engineering of Database
Security Policies. DEXA (2) 2013: 442-449

OSS development

How communities make decisions?
 Majority? Unanimity?
 Minimal participation level?
 Depending on the phase? (proposals,
comments, solution)

Governance model is a challenge
 From a survey among OSS contributors :
– Understanding the governance model (e.g.
who/when/how decides to accept a patch or
include it in the next release) was very
difficult (implicit, scattered,…)
– A clear view of this model would attract
more contributors

Let’s help all OSS projects define their
governance rules! (with MDE tools)

Tool architecture

Governance metamodel

Example of our DSL syntax (a wizard-
based tool to create the rules && a DSL-to-
English translation also available)
Project myProject {
Roles: Committers
Deadlines:
myDeadline : 7 days
Rules:
myMajorityRule : Majority {
applied to Task
when TaskReview
people Committers
range Present
minVotes 3
deadline myDeadline
}
}

66
To read more
• Enabling the Definition and Enforcement of Governance
Rules in Open Source Systems. Javier L. Canovas
Izquierdo; Jordi Cabot. ICSE SEIS 2015, to appear

Complex ecosystem: We are
human!!!
doc
code
support
request
question
bug
pull request

How Labels are used
Title
Author
Description
Asignee
Status
Labels

Label Issues in GitHub
bug
duplicate
enhancement
help wanted
invalid
question
wontfix
Default labels

GILA: What can labels teach you about your project?
Three simple yet powerful visualizations to better understand WHO is doing WHAT
Label Usage
User
involvement
Label
timeline
Visualize the labels used in your
GitHub project, their frequency and how
they relate to each other
Discover the most active users and
contributors per label: who opens
them? who closes them?
Understand the typical evolution of
issues under each label: when are they
discussed?, solved?, etc.

What can issue labels teach you about your project?
Three simple yet powerful visualizations to better understand WHO is doing WHAT
Label Usage
User
involvement
Label
timeline
Visualize the labels used in your
GitHub project, their frequency and how
they relate to each other
Discover the most active users and
contributors per label: who opens
them? who closes them?
Understand the typical evolution of
issues under each label: when are they
discussed?, solved?, etc.

GitHub Analysis
GHTorrent
RQ1. Label Usage
How many labels are used in Github? How many labels are
used per project? What are the most popular ones?
RQ2. Label Influence
For those projects using labels, does its usage influence the
evolution of the project?
GiLA
Early Research Achievement
Can we detect group of labels commonly used together? Are
there label families?

Label Usage in GitHub
Using Labels
122,012
3%
Not Using labels
3,635,026
97%
Lesson: Labels are scarcely used in GitHub

Label Influence
26.93
46.18
74.92
101.3
111.8
145.7
116.4
127.2
116.4
70.4
306.4
148.1
22.53
43.51
48.76
53.21
55.27 56.3
58.82 57.95 59.28
63.23
47.59
60.19
0
10
20
30
40
50
60
70
0
50
100
150
200
250
300
350
0 1 2 3 4 5 6 7 8 9 10 >10
# labels used in the project
Med. Time to solve % solved
On average, the percentage of solved labeled issues
tends to increase together with the number of labels
used in the project
It might come at the cost of taking more time to solve
those labeled issues
ρ = 0.80
ρ = 0.73

Detecting families
bug build
contribution
documentation
duplicate
0 - backlog
1 - ready
2 - working
3 - done
docs
enhancement
invalid
urgent
priority-high
high-priority
priority-low
question
priority-medium
usability
component-logic
component-notyi
component-ui
priority-low
component-mode-perl
component-ui-gtk
frontend-gtkfrontend-pango
milestone
imported
0.0.1
0.0.1
0.0.3
1.0.0.rc1
0.2.0
0.5.0
1.0.0 update
type-cleanup
p1 p2
p3
taken
fixeddiscuss milestone-release0.4
milestone-release0.7
performance
medium-priority
usability
wontfix
new
type-ask
low-priority

Calculating the bus factor?
“Number of key developers who would need to be
incapacitated (hit by a bus), to send the project into
such a disarray that it would not be able to proceed”

Why it is important?
Measuring the concentration of
information per developer
Assessing the employee
turnover risk

turnover risk
Identifying the key
developers in the project

turnover risk
Identifying the key
developers in the project
Identifying the developers
that can be lost

Our tool
Bus factor measurement Employee turnover simulation

87
To read more
• Jordi Cabot, Javier Luis Canovas Izquierdo, Valerio
Cosentino and Belen Rolandi. Exploring the Use of Labels to
Categorize Issues in Open-Source Software Projects.
SANER’15
• Valerio Cosentino, Javier Luis Canovas Izquierdo and Jordi
Cabot. Assessing the Bus Factor of Git Repositories.
SANER’15

Research lines on MDE and SE (March 2015

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