Xcore meets IncQuery: How the New Generation of DSLs are Made


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  • Xcore meets IncQuery: How the New Generation of DSLs are Made

    1. 1. XCORE MEETS INCQUERY: HOW THE NEW GENERATION OF DSLS ARE MADE Tamás Szabó (itemis AG), István Ráth (BUTE) With contributions from: Ed Merks Gábor Bergmann, Ábel Hegedüs, Ákos Horváth, András Ökrös, Zoltán Ujhelyi, Benedek Izsó Budapest University of Technology and Economics Fault Tolerant Systems Research Group IncQueryLabs Ltd. Itemis AG
    2. 2. Overview     Introduction Live graph search for EMF Query-based language engineering Conclusion
    4. 4. Queries in modeling tools  Important! o Model management o Queries o Views o Transformations
    5. 5. Incremental queries  Key observation: model queries are expensive o Models are large (1-5-10+ M elements) o Queries are complex (attribute value checks + navigation/joins + iterations) o Industrial example: well-formedness validation of a 4M element AUTOSAR model takes 30+ minutes • Despite being hand-coded in Java (no OCL, …)  Usability issues  Productivity issues  How to address this? o Lazy evaluation o Incrementality: calculate once, update afterwards
    6. 6. Comparison  Normal queries  Live (incremental) queries o Java, OCL, … Quer y Model Evaluator Results Model change (Re-)traversal necessary if the model is changed Model change Quer y Model Evaluator Updated results Efficient change propagation Result deltas 1. Always up-to-date results without model traversal 2. Track changes of your model in terms of queries
    7. 7. EMF-INCQUERY  An EMF model query engine for live graph search • Expressive query language based on graph patterns and Xbase • Incremental evaluation based on the Rete algorithm • Instantaneous response for complex queries over large models • Incremental model processing (validation, synchronization, ...) Language Execution Tools http://eclipse.org/incquery
    8. 8. Important use-case: Live abstractions abstract Complex model Computed overlay aka. “View” Defined by a query Items = SELECT … Id Label Prop0 Prop1 0 N1 a B 1 N2 c D
    9. 9. Important use-case: Live abstractions UI update Model Modification abstract Complex model Computed overlay aka. “View” Change notification Defined by a query Items = SELECT … Id Prop0 Prop1 0 N1 a B 1 Query result update Label N2 c D 2 N3 e F
    10. 10. INCQUERY Viewers 1. Model Modification On-the-fly abstractions over the model EMF Model 2. Change Notifications Live Live Queries Queries Labeled, hierarchic property graph Derived Model 3. Continuous, efficient synchronization UI 4. UI updates  Visualize things that are not (directly) present in your model  Provides an easy-to-use API for integration into your presentation layer o Eclipse Data Binding o Simple callbacks
    11. 11. DEMO INCQUERY Viewers  Using pattern annotations for the specification of on-thy-fly abstractions  Using the INCQUERY Viewers Sandbox for development and testing  Visualizing large graphs with yFiles  Using INCQUERY Viewers Extensions APIs in your own apps
    12. 12. Live abstractions: simple example  Influence relationships in the Library W1 W1: Writer W2: Writer : writers B1: Book : writers : cites B2: Book : influencedBy Derived relationship W2 : citations : citations Bx: Book Transitive closure EMF instance model Visualization
    14. 14. Xcore  Xcore o Extended textual syntax for Ecore-based metamodeling, built on Xtext o Fully fledged programming language o To specify structure + behavior (operations, datatype conversion logic) o http://wiki.eclipse.org/Xcore Xbase • Xtext-based programming language • Compiles to Java • Java type system • Supports advanced constructs (closures, type inference, operator overloading, …) • http://wiki.eclipse.org/Xbase
    15. 15. Derived features in Ecore  Getters (and setters) implemented with Java  Frequently used to transparently integrate complex queries into the language o Can also be specified by means other than Java  Nice proposition o Transparent: integrate queries into the model – no utility classes needed o Extend the expressive power of metamodeling  Many language engineers are reluctant to use them – why?
    16. 16. The functionality challenge  Typical modeling tool architecture View o Model: EMF o Controller: ~ EMF.Edit o View: e.g. JFace Viewers  Change notifications are essential for this to work  EMF has nice notifications o Notifier - Adapter o … except for derived features Controller Change notifications Model
    17. 17. The performance challenge  What happens when a getter is called? class Book { String title = "" // set a default value refers Writer[] writers derived String longName get { return title + " (" + writers.size + ")" } derived String shortName get { return longName.subString(0,5) } } dependencies Tougher problem than you  Dependencies might think: o The value of “longName” depends on “title” and “writers” - DFs are used explicit o The value of “shortName” depends on “longName” –a lot in dependency complex • … and thus on “title” and “writers” – implicit dependency DSLs - Query complexity times  Performance challenge: getters may be called manycan explode easily o Make sure they execute quickly – but how? o Cache whenever you can – but how?
    18. 18. Solution: well-behaving derived features  Key idea o Changes in the value of “name” depend on changes in the values of “title” and “writers” o Change notifications can be used to implement an efficient caching strategy o As long as every feature is behaving well • i.e. sends notifications when necessary  But… o How do I discover implicit dependencies? graph Live search! o How do I get/send notifications for derived features?
    19. 19. DEMO Query integration options for INCQUERY  INCQUERY Java API  Add-on APIs o INCQUERY Validation o INCQUERY Viewers
    20. 20. DEMO Query integration options for INCQUERY  INCQUERY Java API  Add-on APIs o INCQUERY Validation o INCQUERY Viewers  Query-based derived features o Automatically computes and maintains references and attribute values o Transparent integration with Xcore and (pure) Xbase • Works with traditional genmodeled Ecore too o Unique feature: well-behaving derived features with efficient and automated notification support
    21. 21. Scalability? Yes! Eclipse OCL, SPARQL engines, Neo4j, … Characteristic difference, note the log scales • IncQuery can provide near zero response times for complex queries over models up to 14M elements • Check http://incquery.net/publications/trainbenchmark for more details
    22. 22. CONCLUSION
    23. 23. What can I do with all this? – query-based live abstractions Eclipse technology Pros Trees, tables, Properties (JFace viewers) EMF.Edit The real deal: doesn’t hide abstract syntax Diagrams GEF, GMF, Graphiti Easy to read and write for non-programmers Textual DSLs Xtext Easy to read and write for programmers INCQUERY Viewers Makes understanding and working with complex models a lot easier Syntax JFace, Zest, yFiles Your tool!
    24. 24. What can I do with all this? – query-based derived features  Boost the power and scalability of Ecore: live graph search tightly integrated into your DSL o Self validating models • 30+ min batch  <1s on-the-fly o Query-based traceability links / language integration o INCQUERY Viewers  “derived EObjects” o << your idea here >>  Get rid of lots of legacy stuff o Legacy model elements o Legacy helper/utility classes o Legacy UI boilerplate
    25. 25. Top 3 cool applications of INCQUERY Model-driven development toolchain for avionics systems, Based on a combination of Eclipse tech and MATLAB/Simulink Well-formedness validation in a modeling tool for an automotive OEM Development tools for live dependency analysis of a large software infrastructure model
    26. 26. Three points to take home 1. Live abstractions are very powerful. 2. Use well-behaving derived features to boost your DSL’s expressive power. 3. Xcore+INCQUERY is how the new generation of DSLs are made 
    27. 27. Final points  Find all details, examples, demos at o http://eclipse.org/incquery o http://incquery.net  Check out the blog post o http://incquery.net/blog/2013/10/xcore-meets-incqueryhow-new-generation-dsls-are-made-talk-eclipseconeurope-2013 o Demo projects o Further reading (docs + the theory behind)  Release 0.8 (including all these new features) is scheduled shortly after the Xtext 2.5 release  Your contributions (feedback, forum posts, ideas, bugzillas, patches) are very welcome!