Summary

This chapter discussed the application of object-oriented technology to the area of hypermedia. Hypermedia has been defined as the combination of hypertext and multimedia.

The concept of hypermedia

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slide: Section 12.1: The concept of hypermedia

Hypertext consists of document nodes and machine-supported links between these nodes. Multimedia, in the context of hypermedia, as been characterized as programmable media. We looked at the requirements for hypermedia user interfaces and discussed a number of applications of hypermedia technology. A hypermedia model has been presented, that combines the Dexter hypertext reference model and a multimedia model supporting channels and synchronization. We also reflected on the nature of links, and discussed the notion of active documents.

Multi-paradigm programming

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  • hush -- a C++ API for Tcl/Tk
  • handlers -- C++ binding to actions and events
  • events -- interactions with the user
  • widgets -- graphical interface development
  • hypertext -- embedded widget commands

slide: Section 12.2: Multi-paradigm programming

In section 2, we looked at the multi-paradigm hush toolkit for developing hypermedia interfaces. The hush toolkit provides a large number of widgets and graphics features, and supports the combination of the scripts written in Tcl/Tk with handler objects defined in C++.

Heterogeneous systems

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  • hybrid components -- symbiosis
  • object technology -- wrapping, embedding, distribution

slide: Section 12.3: Heterogeneous systems

Finally, in section 3, we discussed the contribution of object-oriented technology in relation to heterogeneous systems, consisting of multiple hybrid components. We reflected on the future of OOP, and concluded that standardization and consolidation is needed to realize the potential of OOP.

Questions

  1. How would you characterize hypermedia? What requirements can you think of for hypermedia interfaces?
  2. Discuss the problem of navigation in hypermedia systems. Think of some solutions.
  3. How would you classify hypermedia systems? Discuss some examples. \nop{
  4. Describe the Dexter hypertext reference model.
  5. How would you characterize the CMIF multimedia model? }
  6. Give an outline of an integrated hypermedia model. What problems do you expect in the realization of your model?
  7. Discuss the nature of links. How are links related to active objects?
  8. What is your opinion on combining C++ with scripts written in an interpreted language? Explain your point of view.
  9. Discuss the problems involved in realizing heterogeneous systems? How does object technology contribute to the solution of these problems?
  10. What do you consider the contribution of OOP to the practice of software development?

Further reading

As further reading, I recommend  [Conklin87] and  [Wood90]. For a study of hypermedia models, consult  [Halasz94] and  [Hardman94]. Another interesting paper in this respect is  [Nierstrasz]. As a source of information on multimedia, I recommend  [Burger93].