1 Introduction
close this book View the PDF document Extending Greenstone for Institutional Repositories : David Bainbridge, Wendy Osborn, Ian H. Witten, David M. Nichols
View the document 2 Background
View the document 3 Example of Operation
Open this folder and view contents 4 Implementation
View the document 5 Extended example: emulating DSpace
View the document 6 Discussion
View the document 7 Conclusion
View the document References

5   Extended example: emulating DSpace

To demonstrate the versatility of the design, a submission workflow in Greenstone was developed that closely emulates DSpace’s [1]. Since both are open source systems, much of the HTML was transferred directly. The functionality is very similar, the difference being in how a submission involving multiple files is handled—as when submitting a web page including external resources such as images. In DSpace each file must be individually specified from within the form-based submission process. Since Greenstone can already handle archive formats such as Zip and Tar, we decided to ask the user to submit multiple-file works in this form. All files that make up the work must still be identified, but this happens outside the form-based submission, and is usually easier since the files can be multiply selected in one go.

In DSpace, runtime functionality for the submission process is handled by the server. If Title metadata is compulsory this is checked when the user proceeds to the next step of the submission process. In Greenstone the analogous functionality was embedded into each web page using JavaScript. This offers more flexibility to customize the workflow and more immediate feedback to the user.

Figure 4 shows snapshots of a faculty member working their way through the Greenstone adaptation of the DSpace submission procedure. To submit an item of work the user starts by logging in, and then selects the DSpace repository clone collection. Using Greenstone’s collection macro override facility, this repository provides its own tailored workflow—eight steps in all, visible at the top of the snapshots. In the simple example of Figure 1 the progress bar was located at the bottom of the page, but it is easy to move the position of the macro _depositorbar_ within the structured HTML to move it to at the top. In DSpace the progress bar is implemented as a series of images, and although we could have emulated this we chose not to because there is an existing Greenstone facility with the same function—furthermore it makes it easier to change the color scheme, fonts and wording used. (We tend to avoid textual images in Greenstone to facilitate multilingual operation.)

The scenario here is a university that uses DSpace-style submission to manage its staff’s digital outputs. In Figure 4a the instructor for a Machine Learning course is at the first page of submitting a lecture on Bayesian networks. He has entered his and a colleague’s name, the title of the talk and its type (a presentation). Other fields such as series, report number, and ISBN are not relevant and so he leaves them blank.

In Figure 4b the instructor has moved to the second step, which prompts for descriptive metadata: keywords, abstract, sponsors, and description. Again not every field is relevant. For each part of the form contextual help is available that describes the purpose of the field. In Figure 4c he has moved to the point where the file (in this case PowerPoint) is requested. Next (Figure 4d) information is displayed about the file transfer from submitter’s computer to the server. The checksum is shown so he can check that no transmission errors occurred. This is accomplished using AJAX technology [7] to retrieve the information from the server in an extensible manner.

Text Box:  

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Figure 4: Emulating the submission workflow for DSpace (a) primary metadata (b) secondary metadata (c) select file (d) check file (e) review metadata (f) choose license.

The fifth step (Figure 4e) provides an opportunity to review and edit all information entered so far. It is also possible to return to any previous stage by clicking the progress bar. Making the system remember existing fields—even when they support an arbitrary number of values, as with authors—is tricky in JavaScript but possible. Figure 4f shows the final user input page, where the user decides whether to grant the distribution license. If he does, the PowerPoint presentation, along with its metadata, is time-stamped and deposited into the collection area. The collection’s editor will be notified by email, and/or the collection will be incrementally rebuilt, depending on the settings in the collection’s configuration file.