getTransferdata() not working as expected in drag drop from jtable to jtree

[Shabana Patel]

Hi
I am trying to drag multiple rows (discontinuous ) from a jtable to a jtree. I am using a customized transferable object and a customized transferhandler. However,I lose my objects within the import data method, as it gets lost inside the java method getTransferData(DataFlavor df) within class DropTargetContext.java. The code is as follows:

public class cObjectList extends ArrayList<cObject> implements Transferable, Serializable {    
    public static DataFlavor OBJECT_LIST_FLAVOR = new DataFlavor(cObjectList.class, "Object List");
    private DataFlavor flavors[] = { OBJECT_LIST_FLAVOR };
    @Override
    public DataFlavor[] getTransferDataFlavors() {        
         return flavors;    
    }//end method  getTransferDataFlavors
    @Override
    public boolean isDataFlavorSupported(DataFlavor flavor) {
        return flavor.getRepresentationClass() == cObjectList .class;    
    }//end method isDataFlavorSupported
    @Override
    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
        if (isDataFlavorSupported(flavor)) {  
return this; } else { 
throw new UnsupportedFlavorException(flavor);        }//end else
    }//end method getTransferData    
}//end class  cObjectList

The class cObject is serializable. The customized transfer handler is declared as an inner class within the panel that contains both tree and table.

class ObjectTreeTransferHandler extends TransferHandler{
/*the createTransferable method successfully creates the transfer object */
@Override
    public boolean importData(TransferSupport support) {
        if (!canImport(support)) {
            return false;
        }
        if (support.isDataFlavorSupported(cObjectList.OBJECT_LIST_FLAVOR)) {            
            cObjectList obList = null;
            try {
                Transferable t = support.getTransferable();               
               [color=darkred] [b]obList = (cObjectList) t.getTransferData(cObjectList.OBJECT_LIST_FLAVOR);[[/b]/color]
            } catch (UnsupportedFlavorException ufe) {
                System.out.println("UnsupportedFlavor: " + ufe.getMessage());
                return false;
            } catch (java.io.IOException ioe) {
                new myException(ioe);
                return false;
            }
            
            if (obList != null && support.getComponent() instanceof myJTree) {
//do work 
            }//end if
}//end inner class ObjectTreeTransferHandler

The transferable object t has the objects in array list correctly but when I call t.getTransferData, the array list comes back the null objects. E.g. if three rows were chosen from the table, This calls getTransferData method in cObjectList which returns these objects in the arraylist correctly but when it reaches getTransferData in DropTargetContext.java the values nside the array list return as null even thought the list/ object itself still shows size =3.

The drop mode selected for the tree is:
treeObjectStructure.setTransferHandler(new ObjectTreeTransferHandler());
treeObjectStructure.setDropMode(DropMode.ON_OR_INSERT);
Can anyone help me figure out what I have done wrong? I posted this question on stack overflow as well but did not receive any good suggestions, so now I'm asking here.
link:
http://stackoverflow.com/questions/13730660/gettransferdata-in-transferhandler-not-working-as-expected-for-multiple-droppi

[Kemal Sokolovic]

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