14.06.2013 Views

Databases and Systems

Databases and Systems

Databases and Systems

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

25 6<br />

(GUI) components for the display <strong>and</strong> visualization of genomic data, potentially over<br />

the World Wide Web.<br />

Background: bioTk<br />

A similar observation about the utility of component-based software led David Searls<br />

to create bioTk [2], a set of graphical user interface <strong>and</strong> data visualization tools. In<br />

bioTk, the direct progenitor of bioWidgets, Searls used the language Tcl/Tk to define<br />

visualization components (widgets, in Tk parlance) to display sequence, mapping <strong>and</strong><br />

chromosome data. He provided a simple specification for invoking the widgets, as<br />

well as such ancillary components as menus, a context-sensitive help system, <strong>and</strong><br />

utility dialog boxes. Searls also set a high st<strong>and</strong>ard with the documentation <strong>and</strong><br />

tutorials that accompanied his toolkit. Figure 1 depicts the bioTk chromosome<br />

widget used in a simulated karyotype display.<br />

New technologies: Java<br />

In the short time since Searls’ work in Tcl/Tk, a number of significant new<br />

technologies have been introduced, among them Java TM [ 3]. Typifying the growing<br />

popularity of the object-oriented paradigm in software engineering, Java is a<br />

language designed to provide a secure way to “program the web.” Java TM programs<br />

called “applets” can be sent across the network along with web pages <strong>and</strong> a web<br />

browser will interpret the applets by running them on the user’s local machine.<br />

In the past, web-based interfaces to the databases <strong>and</strong> tools used in bioinformatics<br />

were greatly restricted in the interactivity they provided. A user might be able to<br />

request information <strong>and</strong> pose queries through a “fill in the blanks” form-based<br />

interface (e.g. retrieve the sequence with accession number x, or perform a<br />

BLAST[4] search against database y with sequence z). The information would be<br />

returned either as another web page (perhaps containing some “clickable” but<br />

otherwise-static images) or as an e-mail message. “Interacting” with the resulting<br />

data consists of navigating through it in a web browser or scrolling through the tens<br />

or hundreds of pages of results in a text editor.<br />

Using JavaTM , however, it is possible to implement widgets like those found in<br />

bioTk <strong>and</strong> have them run —<br />

as applets—on any PC equipped with a web browser.<br />

Since Java support is an integral part of all major web browsers, it is possible to<br />

implement almost any imaginable user interface in this manner. For this reason,<br />

among others, the bioWidgets project has chosen an object-oriented approach to<br />

visualization component design <strong>and</strong> has st<strong>and</strong>ardized on the Java language for its<br />

specification <strong>and</strong> implementation efforts.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!