A COM implementation of the KSpace

A ‘Knowledge Space prototype’ by

Santhosh (vpanchap@hotmail.com) CST UMKC

Presentation Layout

The DAL system and the KSpace KSpace: COM and XML KSpace: Implementation details

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The DAL System

Introduction to the DAL system Distributed Adaptive Learning system

DAL System components Learner Space, Knowledge Space, Presentation

Space (E-Game, E-Book)

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The Knowledge Space

KSpace – A part of the DAL system KSpace – A ‘Data storage and retrieval'

component Features expected of the KSpace

Distributed environment (Concurrency, Synchronization, Fault tolerance …)

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KSpace: COM and XML (1/2)

COM features implemented by the KSpace prototype Component developed as a DLL Provides support for

‘Self-Registration’ ‘Type-libraries’ ‘Multithreading’ clients ‘Automation’, Dual interface ‘Exception handling’

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KSpace: COM and XML (2/2)

XML and the KSpace MSXML parser DOM API

Provides support for Creating, reading, writing XML documents

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Implementation details (1/3)

Concept Map

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KSpace Client

1. Create XML file2. Write to XML file3. Read from XML file

KSpace Component

1. Set up environment (Type libraries and Automation)2. Serve client XML requests

Exceptions / Client service results

KSpace query

Implementation details (2/3)

Sample scenario (Connection establishment) Scan registry for server component GUID Load DLL into memory if component exists in the form

of a DLL, else instantiate executable component (use DLL surrogate if needed)

Get address of class object factory Instantiate class factory

Create instantiate of KSpace server component

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Implementation details (3/3)

KSpace Component interfaces IUnknown (AddRef, Release, QueryInterface) IXMLInterface (Create, Read, Write) ISupportErrorInfo (InterfaceSupportsErrorInfo) ICreateErrorInfo (SetGUID, SetSource,

SetDescription, SetHelpFile, SetHelpContext) IClassFactory (CreateInstance, LockServer)

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Conclusion: The KSpace prototype

Experience gained COM and XML Windows programming (Registries, DLLs, HRESULTS, GUIDs, Threading

Apartments …)

References “Inside COM” by “Dale Rogerson” published “1997 by the Microsoft press” “Inside Distributed COM” by “Guy Eddon” and “Henry Eddon” published “1998

by the Microsoft press”. “Inside COM+” by “Guy Eddon” and “Henry Eddon” published “1999 by the

Microsoft press”

Programming language, Environment VC++, Win 2000 XML SDK

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