Auto Resize Columns in a JTable (Java Swing)

Here's some code to automatically resize columns in a Java Swing JTable, based on the data in that table...


Usage:

        templatesTable.setModel(tableModel);
        UserInterfaceUtility.resizeColumns(templatesTable);

Source:

package ui;

import java.util.ArrayList;
import java.util.List;
import javax.swing.JTable;
import javax.swing.table.TableColumnModel;
import javax.swing.table.TableModel;

/**
 * http://javajon.blogspot.com/
 * @author Jonathan
 */
public class UserInterfaceUtility {

    /**
     * resizes the columns in a JTable based on the data in that table. data
     * scanned is limited to the first 25 rows.
     *
     * @param table the table with the columns to resize
     */
    public static void resizeColumns(JTable table) {

        final TableModel model = table.getModel();
        final int columnCount = model.getColumnCount();
        final int rowCount = model.getRowCount();
        final List charactersPerColumn = new ArrayList();

        // initiazlize character counts
        final Integer integerZero = Integer.valueOf(0);
        for (int col = 0; col < columnCount; col++) {
            charactersPerColumn.add(integerZero);
        }

        // scan first 25 rows
        final int rowsToScan = (rowCount < 25) ? rowCount : 25;
        for (int row = 0; row < rowsToScan; row++) {
            for (int col = 0; col < columnCount; col++) {

                // character counts for comparison
                final int existingCharacterCount = charactersPerColumn.get(col).intValue();
                final Object cellValue = model.getValueAt(row, col);
                if (cellValue != null) {
                    final Integer newCharacterCount = Integer.valueOf(cellValue.toString().length());

                    // do we need to increase the character count?
                    if (newCharacterCount.intValue() > existingCharacterCount) {
                        charactersPerColumn.set(col, newCharacterCount);
                    }
                }

            }
        }

        // prepare the table for column resizing
        final TableColumnModel columnModel = table.getColumnModel();
        table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
        
        // set maximum character counts
        final Integer maximumCharacterCount = Integer.valueOf(24);
        for (int col = 0; col < columnCount; col++) {
            final int existingCharacterCount = charactersPerColumn.get(col).intValue();
            if (existingCharacterCount > maximumCharacterCount.intValue()) {
                charactersPerColumn.set(col, maximumCharacterCount);
            }
        }

        // set column widths
        for (int col = 0; col < columnCount; col++) {
            final int existingCharacterCount = charactersPerColumn.get(col).intValue();
            final int columnWidth = 18 + (existingCharacterCount * 7);
            columnModel.getColumn(col).setPreferredWidth(columnWidth);
        }        
        
    }
}