Dear Wiki user, You have subscribed to a wiki page or wiki category on "Xerces Wiki" for change notification.
The "gsoc_xs_override_proposal" page has been changed by uswick. http://wiki.apache.org/xerces/gsoc_xs_override_proposal?action=diff&rev1=13&rev2=14 -------------------------------------------------- }}} . Implementation of xs:override should take into account the aforementioned factors so that dependencies are correctly evaluated and necessary schema preprocessing is performed. + . Xerces2-j XMLSchema processing and supporting structures are mainly handled by classes located in org.apache.xerces.impl.xs package. Primarily XMLSchemaFactory and XMLScehmaLoader are responsible for loading(ie:- #loadGrammar() ) and handling schemas from a set of sources. Actually XMLSchemaLoader acts as an wrapper that provides necessary inputs for a XSDHandler (org.apache.xerces.impl.xs.traversers) instance which will inturn be coordinating the construction of a grammar object corresponding to a schema throughout several stages. XSDHandler instance is responsible for parsing each schema source (including the ones’s that are imported resulting in other grammers) , preprocessing/resoving /loading grammers etc. + + . XSDHandler#parseSchema() is responsible for coordinating these critical stages of schema composition which includes , + + . a) constructTrees – constructs XSschema objects .Attempts to resolve <include>,<redefine> schema components and builds a dependency map . + + . b) buildGlobalNameRegistries - builds registries for all globally-referenceable names. Keeps track of <redefine> component mapping. + + . c) traverseSchemas – traverse globally declared elements with appropriate traverser object (ie:-SimpleType/ComplexType/Attribute traversers) and handle them accordingly. + + . d) traverseLocalElements-Traverse all the deferred local elements + + . e) resolving ID/Key references + + . f) storing imported grammars and building the Grammer Pool + + . + xs:override implementation intends to extend this functionality to implement <override> structure semantics. Also several supporting structures will be needed so that <override> schema components will be identified during schema processing. For example extending of following class structures. + + . • org.apache.xerces.impl.xs.SchemaSymbols – keeps track of collection of symbols used in parsing Schema Grammer. Need to introduce new <override> grammer symbols to this. + + . • org.apache.xerces.impl.xs.XSDDescription - keeps track of all information specific to XML Schema grammars. This can be used to indicate the Schema processor that the current schema document is overridden by another scheama document. + + . Additionally Xs:override implementation may require many new components/data structures to be added to org.apache.xerces.impl.xs package inorder to handle different scenarios regarding <override> semantics as was described in the beginning. + + + == Things I have Done So far == . Since this project is about implementing a XMLSchema 1.1 specification construct , I had to go through this specification docs several times to understand the exact structure and semantics of the component I’m going to implement which I think is of vital importance when it comes to the design n implementation. Previous discussions (that has happened in Xerces-j-dev mail archives) about this xs:override support , online articles and tutorials also helped a lot in this cause. I also interacted with Xerces mailing list (especially with my mentor) to clarify critical points and implementation details. Since knowing Xerces and it’s internal framework(XNI) is obviously essential for the implementation I had to dig into various documentation, API information ,samples regarding Xerces Design,architecture and especially XML schema processing. I did download source code of Xerces2-j from trunk and build the code inorder to try and test out some samples to get a hang on the flow of things related to schema loading and processing. @@ -70, +97 @@ * Documentation (java docs + design details) on xs:override implementation/API == Community Interaction == - Initially i had trouble selecting a project since the project i was keeping in mind was already undertaken. Xerces-2j mailing list was really helpfull in this ,giving me lot of feedback on available projects that was not even initally declared as Summer projects for 2010 . I also was later able to get lot of insight on xs:override specification semantics and implementation details through the interaction on mails from xerces-j dev community . Through this I managed to digg into and clarify lot of details that would be very helpful through out my project and has definitely been a much needed guidance in writing this proposal as well. + Initially i had trouble selecting a project since the project i was keeping in mind was already undertaken. Xerces-2j mailing list was really helpfull in this ,giving me lot of feedback on available projects that was not even initally declared as Summer projects for 2010 . I was later able to get lot of insight on xs:override specification semantics and implementation details through the interaction on mails from xerces-j dev community . Through this I managed to digg into and clarify lot of details that would be very helpful through out my project and has definitely been a much needed guidance in writing this proposal as well. == About me == . I'm a Computer Science Engineering undergraduate (final year),of the department of Computer Science and Engineering, University of Moratuwa, Sri Lanka . I'm very much passionate about Computer science and am especially interested in subject areas related to Compiler Theory ,Distributed Systems and Enterprise Middelware and also Artificial Intelligence.I do have experience in open source development and related aspects and always loved working in such a dynamic and encouraging environment . - . I have worked on projects related to Apache Axis2 where I developed a tool [5](incubating) to extract WS-Policy(ie:-Security Policy) from WS policy compliant SOAP messages. Tool is especially useful in scenarios such as for clients who wish to build compatible client side policy for repective Services which don’t expose their messaging policy explicitly. This gave me a great understanding on WS:Security specifications and on mechanisms used by security modules such as Apache Rampart as well. Furthermore i developed Axis2 Messaging and Service Level Infrastructure for Rubyscript [6], so that Ruby Scripts can be exposed and accessed via WebServices by clients . + . I have worked on projects related to Apache Axis2 where I developed a tool [7](incubating) to extract WS-Policy(ie:-Security Policy) from WS policy compliant SOAP messages. Tool is especially useful in scenarios such as for clients who wish to build compatible client side policy for repective Services which don’t expose their messaging policy explicitly. This gave me a great understanding on WS:Security specifications and on mechanisms used by security modules such as Apache Rampart as well. Furthermore i developed Axis2 Messaging and Service Level Infrastructure for Rubyscript [8], so that Ruby Scripts can be exposed and accessed via WebServices by clients . - . I also do have experience involved in projects related to Eclipse plugins, OSGi , XML parsers(this for our internal module DSD2.0[7] parser) and Data Mining (ie:-Collaborative Filtering), which got me working in a wide variety of frameworks ,programming/scripting languages such as Java ,C,C++, Javascript,Ruby,etc and under various platforms of Linux and Windows. I am currently involved in implementing a TupleSpace based Distributed System framework (which runs on top of a DHT[distributed hash table] named FreePastry [opensource implementation of Microsoft Pastry] ) for our final year project ,which facilitates time and space decoupling as well as content based addressing for messages in a distributed environment [8]. I consider my self a motivated computer science enthusiast who is willing to self learn and accept challenges and achieve them to the best of my ability. + . I also do have experience involved in projects related to Eclipse plugins, OSGi , XML parsers(this for our internal module DSD2.0[9] parser) and Data Mining (ie:-Collaborative Filtering), which got me working in a wide variety of frameworks ,programming/scripting languages such as Java ,C,C++, Javascript,Ruby,etc and under various platforms of Linux and Windows. I am currently involved in implementing a TupleSpace based Distributed System framework (which runs on top of a DHT[distributed hash table] named FreePastry [opensource implementation of Microsoft Pastry] ) for our final year project ,which facilitates time and space decoupling as well as content based addressing for messages in a distributed environment [10]. I consider my self a motivated computer science enthusiast who is willing to self learn and accept challenges and achieve them to the best of my ability. . . == REFERENCES == @@ -91, +118 @@ [6] http://www.w3.org/TR/xmlschema11-1/#chameleon-xslt - [5] https://wso2.org/repos/wso2/trunk/carbon/components/policy-builder + [7] https://wso2.org/repos/wso2/trunk/carbon/components/policy-builder - [6] https://wso2.org/repos/wso2/trunk/carbon/components/jruby/ + [8] https://wso2.org/repos/wso2/trunk/carbon/components/jruby/ - [7] http://www.brics.dk/DSD/dsd2.html + [9] http://www.brics.dk/DSD/dsd2.html - [8] http://sourceforge.net/projects/bissa/ + [10] http://sourceforge.net/projects/bissa/ --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
