Linking table providers and consumers

The table data registry allows table data providers and consumers to be linked, e.g. the data in the table editor to be plotted in the bar chart view. A workbench part registers to provide table data and later notifies its listeners when the table data or structure changes. Other parts may lookup table providers by their key and react to notifications.

Both the table editor and view provide the currently filtered and selected table data through this mechanism. Hence, a bar chart linked to an editor will update when the row selection changes or a filter is applied. The views that derive new table data also provide the resulting table. This allows e.g. a crosstab to be plotted.

The views that consume table data from the registry allow the user to select the table source by clicking the link button (double straight arrows):

The xaw editor supports executing xaw scripts inside the workbench and may take part in this action. The script may import tables from the registry or export to it, thus when a script has run, the tables exported during the execution may be picked up and shown in other views.

The snapshot below, shows the workbench with several (linked) parts:

• The currently available tables in the registry is shown in the Table Registry view (upper right).
• The file whiskey.csv has been opened in the Table editor (upper left). The current view of this table is automatically provided through the table registry, and since the Row Id column has been hidden (thus not shown) it is not available to consumers.
• The script in the xaw editor (upper middle) declares the Whiskey table type with only the taste-related columns. The whiskey.csv table is imported and populates a new instance of the Whiskey table type. Then a new table is created, based on selecting the rows with a smokeyColumn value greater than zero. This table is exported with the nonNullSmoky key.
• The Table # 13 view (lower left) uses the nonNullSmoky table as its source (selected using the Tables meny in the view drop-down, and shown in the view title tool tip). A filter has been added to the Medicinal column. The resulting table view is automatically provided through the table registry.
• The Bar Chart view (lower right) uses the Table # 13 table as its source and shows the Smoky and Honey values for each Distillery. If the filter in the Table # 13 view is changed or cleared, the bar chart will update accordingly.