8029979: Allow multiple calls to DropTargetDropEvent.acceptDrop()

Reviewed-by: pchelko, serb

jdk/src/share/classes/sun/awt/dnd/SunDropTargetContextPeer.java

@@ -627,14 +627,14 @@ public abstract class SunDropTargetContextPeer implements DropTargetContextPeer,
         if (dropOperation == DnDConstants.ACTION_NONE)
             throw new IllegalArgumentException("invalid acceptDrop() action");
 
-        if (dropStatus != STATUS_WAIT) {
+        if (dropStatus == STATUS_WAIT || dropStatus == STATUS_ACCEPT) {
+            currentDA = currentA = mapOperation(dropOperation & currentSA);
+
+            dropStatus   = STATUS_ACCEPT;
+            dropComplete = false;
+        } else {
             throw new InvalidDnDOperationException("invalid acceptDrop()");
         }
-
-        currentDA = currentA = mapOperation(dropOperation & currentSA);
-
-        dropStatus   = STATUS_ACCEPT;
-        dropComplete = false;
     }
 
     /**

jdk/test/java/awt/dnd/AcceptDropMultipleTimes/AcceptDropMultipleTimes.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8029979
+ * @summary Checks if acceptDrop() can be called several times
+ * @library ../../regtesthelpers
+ * @build Util
+ * @compile AcceptDropMultipleTimes.java
+ * @run main/othervm AcceptDropMultipleTimes
+ * @author anthony.petrov@oracle.com
+ */
+
+import test.java.awt.regtesthelpers.Util;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.datatransfer.*;
+import java.awt.dnd.*;
+import java.awt.event.InputEvent;
+
+public class AcceptDropMultipleTimes {
+
+    private static final int FRAME_SIZE = 100;
+    private static final int FRAME_LOCATION = 100;
+
+    private static volatile Frame f;
+
+    private static void initAndShowUI() {
+        f = new Frame("Test frame");
+        f.setBounds(FRAME_LOCATION, FRAME_LOCATION, FRAME_SIZE, FRAME_SIZE);
+
+        final DraggablePanel dragSource = new DraggablePanel();
+        dragSource.setBackground(Color.yellow);
+        DropTarget dt = new DropTarget(dragSource, new DropTargetAdapter() {
+            @Override public void drop(DropTargetDropEvent dtde) {
+                // The first call always succeeds
+                dtde.acceptDrop(DnDConstants.ACTION_COPY);
+
+                // The second call should succeed if the fix works
+                dtde.acceptDrop(DnDConstants.ACTION_MOVE);
+
+                dtde.dropComplete(true);
+            }
+        });
+        dragSource.setDropTarget(dt);
+        f.add(dragSource);
+
+        f.setVisible(true);
+    }
+
+    public static void main(String[] args) throws Throwable {
+        try {
+
+            SwingUtilities.invokeAndWait(() -> initAndShowUI());
+
+            Robot r = new Robot();
+            Util.waitForIdle(r);
+            Util.drag(r,
+                    new Point(FRAME_LOCATION + FRAME_SIZE / 3, FRAME_LOCATION + FRAME_SIZE / 3),
+                    new Point(FRAME_LOCATION + FRAME_SIZE / 3 * 2, FRAME_LOCATION + FRAME_SIZE / 3 * 2),
+                    InputEvent.BUTTON1_MASK);
+            Util.waitForIdle(r);
+        } finally {
+            if (f != null) {
+                f.dispose();
+            }
+        }
+    }
+
+    private static class DraggablePanel extends Panel implements DragGestureListener {
+
+        public DraggablePanel() {
+            (new DragSource()).createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY, this);
+        }
+
+        @Override
+        public void dragGestureRecognized(DragGestureEvent dge) {
+            dge.startDrag(Cursor.getDefaultCursor(), new StringSelection("test"));
+        }
+    }
+}