User interface software development for the WIYN One Degree Imager (ODI)

User interfaces (UIs) are a necessity for almost any data acquisition system. The development team for the WIYN One Degree Imager (ODI) chose to develop a user interface that allows access to most of the instrument control for both scientists and engineers through the World Wide Web, because of the web's ease of use and accessibility around the world. Having a web based UI allows ODI to grow from a visitor-mode instrument to a queue-managed instrument and also facilitate remote servicing and troubleshooting. The challenges of developing such a system involve the difficulties of browser inter-operability, speed, presentation, and the choices involved with integrating browser and server technologies. To this end, the team has chosen a combination of Java, JBOSS, AJAX technologies, XML data descriptions, Oracle XML databases, and an emerging technology called the Google Web Toolkit (GWT) that compiles Java into Javascript for presentation in a browser. Advantages of using GWT include developing the front end browser code in Java, GWT's native support for AJAX, the use of XML to describe the user interface, the ability to profile code speed and discover bottlenecks, the ability to efficiently communicate with application servers such as JBOSS, and the ability to optimize and test code for multiple browsers. We discuss the inter-operation of all of these technologies to create fast, flexible, and robust user interfaces that are scalable, manageable, separable, and as much as possible allow maintenance of all code in Java.