Model Driven Development and Code Generation

1. Model Driven Development and Code Generation Make the Model Do the Work Chip Temm

2. Target Audience • Small Teams in Medium-sized Workgroups • Established processes • Discussion • Light process and tooling to produce rapid results and reduce overhead of new projects & system maintenance. • Model driven as differentiated from database-driven. • Linking modeling to code generation. • Not describing MDA. • Forward looking – not all of what is discussed exists

3. Where I’m Coming From • Managing matrixed development teams • Quality is key • Process matters • Trying to find balance between quality and accuracy • Understanding team drivers

4. MDD can help teams improve Maintenance Documentation Development Design

5. Documentation • Challenge: Getting code documented • Challenge: Keeping docs in sync • “Painful, boring, tedious” • Who is it for? • De-prioritized • Important • Memory Reallocation • Staff Turnover • HBAB

6. Document the Design • Makes less sense to document after the code is done • Model Metadata: • Communicates the original intention of the concepts modeled • Drives / can be derived from component metadata

7. Design • Design docs as communication • Reduce code-as-you-go • Enable better re-use

8. Development • Forward generate the repetitive • Enable easier distribution of work • Outlined development

9. Maintenance • Forward-generating new components is easier when you can see the rest of the model. • Know the ramifications of what you change • Refactoring can be easier: metaprogramming • … or at least no harder: round-tripping is a challenge. • Help get unit tests framed up

10. Using modelling tools. • Tools overview • Approaches to generation • Exporting to XMI • Tool-based generation

11. Tools Overview • Most UML modeling tools now support code generation • Java is a key target • ColdFusion not supported out of the box • Most tools export to XMI • Some have extended XMI • Different flavors

12. Sampling of tools • Tigris.org • ArgoUML -opensource • SparxSystems • Enterprise Architect- $200 • Gentlesoft • Poseidon- $900 (cfcxmi plugin)

13. Approaches to generation • Write your own generator • Modify a tool’s generation templates

14. Exporting to XMI • Pros: If you want to • write your own generators • pick your language • Modeling independence (ish) • Cons: • XMI is not the most readable • You do the heavy lifting

15. XML Transformation

16. ModelGlue Transformation <?xml version="1.0" encoding="UTF-8" ?> - <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="text" indent="no" /> - <xsl:template match="/"> <cfset listEvent = viewstate.getValue("myself") & viewstate.getValue("xe.list") /> <cfset commitEvent = viewstate.getValue("myself") & viewstate.getValue("xe.commit") & "& <xsl:value-of select="object/name" /> Id=" & urlEncodedFormat(viewstate.getValue(" <xsl:value-of select="object/name" /> Id")) /> <cfset <xsl:value-of select="object/name" /> = viewstate.getValue("

17. Example CF Char Sub Transform … «cfstoredproc procedure=“#currentTable#_Insert" datasource="$application.datasource$" » <cfloop collection="#currentcfc.properties#" item="thisProp" > «cfprocparam value="$variables.instance.#thisProp#$" type="In" /» </cfloop> «cfprocparam variable="objectID" type="Out" /» «/cfstoredproc» «cfset variables.instance.objectID = objectID /» «cfreturn variables.instance.objectID/»

18. CF Parsing of XMI     <cfscript>      xmlDoc = xmlparse('OpenModel.xmi');      classes = xmlsearch(xmlDoc,"//UML:Class[@xmi.id]");      classesLen = arrayLen(classes);      for(i=1;i lte classesLen;i=i+1){        thisClass = classes[i];        //now loop down into properties, methods and arguments      }    </cfscript>

19. Using tool-based generation • Pros: • Tool does heavy lifting • Results are rapid • Toolset easily sharable • Cons • May have to learn a new language to write your templating logic • Create your own datatypes… • Vendor lock-in

20. Poseidon template macro • See Eclipse…

21. Sparx Template Editor

22. Generating to frameworks • Frameworks are geared toward driving code into patterns • Repetition is a good target for automation • Some existing frameworks have generation capabilities but are not model-first • Generate those ORM files from models

23. Converting Code to Models • Why? • Code needs to have reliable metadata • Reflection can be used to extract information • Layout of diagrams is no fun

24. Challenges to MDD • Technology • Round-tripping • Mindset • Management

25. Challenge: Technology • Commercial pkgs geared toward • Larger shops • Mainstream languages • Can be expensive • Learning curve • Getting lost in the feature set

26. Challenge: Round-tripping • ColdFusion not XML compliant, hard to parse • Flex is probably a good target • Version control

27. Challenge: Developer Mindset • Fear of ‘wizards’ • Fear of change • Fear of oppression

28. Challenge: Management • Requires investment • How many people do I have to train? • What processes do I have to change? • What will toolchain changes cost? • Where to allocate the risk of change?

29. Good Luck! Presentation will be available later today at: http://anthrologik.net/presentations/ dc_frameworks_2007_02_01.ppt Email: chip@temm.net http://del.icio.us/chiptemm/ http://cfdj.sys-con.com/author/temm.rss

30. Article COMPONENTNAME e.g."XMI_Parser"[   name [string]   displayname [string]   hint [string]    PROPERTIES[      PROPERTYNAME[        name [string]        type [string]        required [BOOLEAN]        displayname [string]        hint [string]        default [string]      ]    ]    FUNCTIONS[      FUNCTIONNAME[        string name [string]        access [string]        returntype [string]        roles [string]        hint [string]        output [BOOLEAN]        ARGUMENTS[          ARGUMENTNAME[            name [string]            type [string]            required [BOOLEAN            default [string]            hint [string]          ]        ]      ]    ]]