How Can I Efficiently Retrieve Selected Rows from a JTable with Large Datasets?

Efficiently Obtaining Selected Rows from a JTable using AbstractTableModel

The process of retrieving selected rows from a JTable can become inefficient when dealing with large datasets, as it involves sequentially traversing all rows. This article presents a more efficient approach using an AbstractTableModel-based listener mechanism.

Problem Statement

In a JTable with a JCheckBox in the first column for row selection, retrieving selected rows necessitates iterating through all the rows to gather those that are checked. As the dataset grows, this becomes an undesirable approach.

Suggested Solution: Implement a TableModel Listener

The solution involves adding a TableModelListener to the JCheckBox column. Whenever a JCheckBox's state changes (SELECTED/DESELECTED) within the listener class, the selectedRows array is updated. Additionally, table.getSelectedRow(..) can be invoked within the listener class to capture the selected row's index.

Is There a Better Way?

The example provided showcases an alternative approach, where the TableModel updates a Set named checked upon changes in its setValueAt() method. An adjacent JList is bound to this TableModel and dynamically displays the selected row numbers. This method proves efficient when the number of selected rows is small compared to the total row count.

Implementation Details

The CheckModel class extends AbstractTableModel and handles the rowList and checked set, maintaining them based on checkbox state changes. The DisplayPanel class contains a JList that listens to the table model changes and updates its display accordingly.

Conclusion

While the sequential row traversal approach may suffice for small datasets, using a TableModel listener or the alternate method shown above provides significant efficiency gains when dealing with large datasets. These techniques enable efficient retrieval of selected rows, regardless of the table size.

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