Name: sdC67446 Date: 03/24/98


The specification for ctor
java.awt.dnd.DragSourceContext(DragSource,DragSourceContextPeer,
Component,int actions,Cursor,Image,Point,Transferable,DragSourceListener)
does not specify behavior for argument actions when
it is invalid. The current behavior is to throw IllegalArgumentException for
DnDConstants.ACTION_NONE and ignore other invalid values.
More acceptable behavior for all invalid actions here is to throw
IllegalArgumentException unless otherwise specified.

Here is what doc says:
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public DragSourceContext(DragSource ds,
                         java.awt.dnd.peer.DragSourceContextPeer dscp,
                         Component c,
                         int a,
                         Cursor dragCursor,
                         Image dragImage,
                         Point offset,
                         Transferable t,
                         DragSourceListener dsl)

      construct a DragSourceContext (called from DragSource)
      Parameters:
            ds - The DragSource that originated this operation
            dscp - The DragSourceContextPeer for this operation
            a - The operation(s)
            dragCursor - The initial Cursor
            dragImage - The image to drag (or null)
            offset - The offset of the image origin from the hotspot
                     at the instant of the
            triggering event
            t - The Transferable
            dsl - The DragSourceListener
            
Here is the test demonstrating the bug
-----------------Test.java------------------------
import java.awt.*;
import java.awt.image.*;
import java.awt.dnd.*;
import java.awt.dnd.peer.*;
import java.awt.datatransfer.*;

public class Test {

    public static void main(String[] args) {

        // valid actions
        int actions[] = {
            DnDConstants.ACTION_NONE,
            DnDConstants.ACTION_COPY,
            DnDConstants.ACTION_MOVE,
            DnDConstants.ACTION_COPY_OR_MOVE,
            DnDConstants.ACTION_LINK,
            DnDConstants.ACTION_REFERENCE
        };

        DragSource ds = new DragSource();

        DragSourceContextPeer dscp = new DragSourceContextPeer() {
            public void startDrag(DragSourceContext ds, AWTEvent trigger,
                                  Cursor cursor, int actions) {}
            public Component getComponent() { return null; }
            public void cancelDrag() {}
            public Cursor getCursor() { return null; }
            public void setCursor(Cursor c) {}
            public AWTEvent getTrigger() {return null;}
        };

        Component component = new Button();

        Cursor cursor = DragSource.DefaultCopyDrop;

        Image image = new Image() {
            public int getWidth(ImageObserver observer) {return 0;}
            public int getHeight(ImageObserver observer){return 0;}
            public ImageProducer getSource() {return null;}
            public Graphics getGraphics() {return null;}
            public void flush() {}
            public Object getProperty(String name, ImageObserver observer) {
                return null;
            }
        };

        Point point = new Point(0,0);

        Transferable transferable = new Transferable() {
            public Object getTransferData(DataFlavor df) {
                return null;
            }
            public DataFlavor[] getTransferDataFlavors() {
                return null;
            }
            public boolean isDataFlavorSupported(DataFlavor df) {
                return false;
            }
        };

        DragSourceListener dsl = new DragSourceListener() {
            public void dragEnter(DragSourceDragEvent dsde) {}
            public void dragOver(DragSourceDragEvent dsde) {}
            public void dropActionChanged(DragSourceDragEvent dsde) {}
            public void dragExit(DragSourceEvent dsde) {}
            public void dragDropEnd(DragSourceDropEvent dsde) {}
        };

        int act = 666;

        // make sure act is unsupported
        for (int i=0;i<actions.length;i++) {
            if (act == actions[i]) {
                System.out.println("oops!");
                return;
            }
        }

        DragSourceContext dsc = null;
        try {
            dsc = new DragSourceContext(ds,
                                        dscp,
                                        component,
                                        act, // !!!
                                        cursor,
                                        image,
                                        point,
                                        transferable,
                                        dsl
                                       );
        } catch (Exception e) {
            System.out.println(e);
            return;
        }
        System.out.println("No reaction.");

        try {
            dsc = new DragSourceContext(ds,
                                        dscp,
                                        component,
                                        DnDConstants.ACTION_NONE, // !!!
                                        cursor,
                                        image,
                                        point,
                                        transferable,
                                        dsl
                                       );
        } catch (Exception e) {
            System.out.println("but here is "+e);
            return;
        }
        System.out.println("No reaction too.");
    }
}
---------Output from the test---------------------
No reaction.
but here is java.lang.IllegalArgumentException: actions == DnDConstants.ACTION_NONE
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