www.modeliosoft.com

EU projects MODAClouds and JUNIPER –

Writing and testing transformations from abstract

object oriented domain modelsMarcos Almeida, SOFTEAM | ModelioSoftRCIS’13

1

What’s this presentation about?

•This is not a presentation about solutions but about problems.

•Future of Internet = Platform Fragmentation

•MDE Approach =

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BusinessObjects Transformation

HDFS

MySQL

MongoDB

Abstract ModelsSpecific Models / code

Transformation

Transformation

PROBLEM!!PROBLEM!!Given this fragmentationfragmentation:

How to writewrite and testtest these transformations?

Context: two FP7 projects that just started…

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http://www.modaclouds.eu/ - 318484 http://www.juniper-project.org/ - 318763

What’s the “Future of Internet” for MODAClouds?

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The Cloud

The Cloud

The Cloud

The Cloud

The cloud? No!

Multiple clouds,Multiple providers,Fragmentation!

Our mission: •Develop applications in a cloud independent way•Provide support for app monitoring, adaption and migration

What’s the “Future of Internet” for JUNIPER?

• The main keyword: Big Datao Multiple streamso Multiple typeso Real-time constraints

• Current state of the art: NoSQLo Pros

• Optimized for non-relational data• Optimize query engines for performance not for expressivity

o Cons• The code is “ the model” • How to deal with the different NoSQL databases?

• Our missiono Modeling support for non relational & real-time big data application

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The main problem is FRAGMENTATIONFRAGMENTATION!

•Many different database management systemso Ex:

• MySQL (www.mysql.com/), • Big Table (http://research.google.com/archive/bigtable.html)• SimpleDB (http://aws.amazon.com/simpledb/)• Memcached (http://memcached.org/)• …

•Many underlying data representation paradigmso Ex:

• Relational Databases• Key-value Stores• Object-oriented Databases• Big Tables• …

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The basis of our solution is MDE… Why?

•Separating the problem from the solution

•Fostering automationo Analysiso Code generation

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BusinessObjects Transformation

HDFS

MySQL

MongoDB

Abstract ModelsSpecific Models / code

Transformation

Transformation

What do we get from MDE?

Pros•D

esign data once, store everywhere!

•Write your transformation once, transform anything!

Cons•T

ransformations are hard to write…

•How to make sure they are CORRECT? i.e.– Is there any data/semantic

loss?

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Understanding the problem… Why is it so HARD? (1/3)

•Target Technologies based on different paradigms

•Example:

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A

B

JPA@Entitypublic class A { @Basic public B getB(){ … }…}

SQLcreate table A (…)create table B (…)create table A_B (…)

Understanding the problem… Why is it so HARD? (2/3)

•Target structure is variable

•Example:

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A

B

ER

NoSQL

A

BAB

Here A and B are

independent entities

Here, for performance reasons, B is

embedded in AA

B

Understanding the problem… Why is it so HARD? (3/3)

•Different implementations support different features

•Example:

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A

B

JPAIn JPA inheritance is usually implemented as

an extra column with a type

x:int y:string Disc(?):int(?)

Hibernate: ignores the

column

Hibernate: ignores the

column

Toplink: ignores its

type

Toplink: ignores its

type

Our experience

•Just in the beginning

•Some experimentso Persistence Model JPA x SQL

•Current approach:o Decomposing transformationso Dealing with variability by replacing sub-transformationso Unit testing sub-transformations

• Automated Tests– 90 JUnit Tests

• Manual Integration Test – ~100 Tests

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Decomposing transformations

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Persistence Model JPA

Entities Java Classes

Identifiers Attributes

…

Dealing with variability by replacing sub-transformations

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Persistence Model JPA (JSR 317)

Entities Java ClassesEntities Java Classes

Identifiers Attributes

…

Persistence Model JPA (Hibernate)

Entities Java ClassesEntities Java Classes

Identifiers Attributes

…

Unit testing sub-transformations

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+ at : Integer

TransformationInput Output

@Basic(fetch=FetchType.LAZY)private Integer at;

@Basicprivate Integer at;

Desired output

Obtained output

Limitations

•Actual tools do not behave exactly as expected…o Each tool interprets the outputs in a different wayo The range of acceptable outputs may vary from a tool to another

•Integration Test Involves interfacing with complex codeo Modelio, testing databases (MySQL…), Different JPA implementations (Hibernate Eclipse

Link, TopLink…)

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TransformationTransformationInputInput OutputOutput

Tool 1

Tool 2

Conclusion

•We focus on MDE for future of the internet applications

•But in practice… MDE needs to support to the platforms supporting these applications…

•Limitations, Limitations, Limitations…o Fragmentation x Integration Testing

•Problemso Too many different targets

• How to test such transformations?• How to interface with complex software?• How to reduce manual work?

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Thank you for your attention!

Marcos Almeida

SOFTEAM | ModelioSoft

marcos.almeida@softeam.fr

SOFTEAM R&D Web Site:

http://rd.softeam.com

ModelioSoft Web Site:

http://www.modeliosoft.com

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M o d e l i n g s o l u t i o n s.