A data item is a Java object that provides the InfoBus access to a packet of data. This access is structured for exchange of the data among members of the InfoBus using standardized method calls. A data item also has standard methods for describing the data and listening for changes in the data. By using InfoBus data items, Java components can call the same methods on every provider or consumer of data in order to transfer data, without dealing with data's internal representation.
An InfoBus object manages both the components that publish or listen for data and the requests for data access. InfoBus members identify a data item by its data item name. When one applet makes data available via the InfoBus, other applets can then process or display the data.
A data item object typically doesn't actually contain the data, particularly for large-size data. It provides methods for accessing data that can be stored elsewhere, for example with the component that produces it.
For example, to pass a set of data from the eSuite spreadsheet applet via the InfoBus to the eSuite chart applet, you name a range containing that data in the spreadsheet. The spreadsheet automatically creates an ArrayAccess data item with the range name as the data item name. You place the eSuite chart applet on an HTML page with a <PARAM> tag specifying the spreadsheet range name from which to receive its data. The chart automatically retrieves a chart data set from the data item and displays the data.
InfoBus overview
ScriptHelper applet
InfoBusVector class
FileReader applet
Data set files