Java Swing, 2nd Edition

Handling Selections

The JList class in Swing depends on a second model, this one to monitor the elements that have been selected by the user. As with the list data model, the programmer is given many places in which standard behavior can be altered or replaced when dealing with selections. Swing uses a simple interface for models that handle list selections (ListSelectionModel) and provides a default implementation (DefaultList-SelectionModel).

The ListSelectionModel Interface

The ListSelectionModel interface outlines the methods necessary for managing list selections. Selections are represented by a series of ranges, where each range is defined by its endpoints. For example, if the elements One, Two, Three, Six, Seven, and Nine were selected in the opening example of the chapter, the list selection model would contain three entries that specified the ranges {1,3}, {6,7}, and {9,9}. All selection indices are zero-based, and the ranges are closed, meaning both endpoint indices are included within the selection. If only one element is present in a range, such as with Nine, both endpoints are identical.

Properties

Table 7-5 shows the properties of the ListSelectionModel interface. The first four properties of the list selection model can be used to retrieve various indices that are currently selected in the list. The anchorSelectionIndex and leadSelectionIndex properties represent the anchor and lead indices of the most recent range of selections, as illustrated in Figure 7-2. The ...