TableRowTransferHandler.java

package org.openpnp.vision.pipeline.ui;

import java.awt.Cursor;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.dnd.DragSource;

import javax.activation.ActivationDataFlavor;
import javax.activation.DataHandler;
import javax.swing.JComponent;
import javax.swing.JTable;
import javax.swing.TransferHandler;

/**
 * Handles drag & drop row reordering
 * 
 * From: http://stackoverflow.com/questions/638807/how-do-i-drag-and-drop-a-row-in-a-jtable
 */
public class TableRowTransferHandler extends TransferHandler {
    private final DataFlavor localObjectFlavor = new ActivationDataFlavor(Integer.class,
            "application/x-java-Integer;class=java.lang.Integer", "Integer Row Index");
    private JTable table = null;

    public TableRowTransferHandler(JTable table) {
        this.table = table;
    }

    @Override
    protected Transferable createTransferable(JComponent c) {
        assert (c == table);
        return new DataHandler(new Integer(table.getSelectedRow()),
                localObjectFlavor.getMimeType());
    }

    @Override
    public boolean canImport(TransferHandler.TransferSupport info) {
        boolean b = info.getComponent() == table && info.isDrop()
                && info.isDataFlavorSupported(localObjectFlavor);
        table.setCursor(b ? DragSource.DefaultMoveDrop : DragSource.DefaultMoveNoDrop);
        return b;
    }

    @Override
    public int getSourceActions(JComponent c) {
        return TransferHandler.COPY_OR_MOVE;
    }

    @Override
    public boolean importData(TransferHandler.TransferSupport info) {
        JTable target = (JTable) info.getComponent();
        JTable.DropLocation dl = (JTable.DropLocation) info.getDropLocation();
        int index = dl.getRow();
        int max = table.getModel().getRowCount();
        if (index < 0 || index > max)
            index = max;
        target.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
        try {
            Integer rowFrom = (Integer) info.getTransferable().getTransferData(localObjectFlavor);
            if (rowFrom != -1 && rowFrom != index) {
                ((Reorderable) table.getModel()).reorder(rowFrom, index);
                if (index > rowFrom)
                    index--;
                target.getSelectionModel().addSelectionInterval(index, index);
                return true;
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    @Override
    protected void exportDone(JComponent c, Transferable t, int act) {
        if ((act == TransferHandler.MOVE) || (act == TransferHandler.NONE)) {
            table.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
        }
    }

}