From 91389ef09b2e7113c9bd65c1d85b9b0ef65c8bc3 Mon Sep 17 00:00:00 2001
From: Branislav Stojkovic <Branislav Stojkovic@Bancika-PC>
Date: Sun, 3 Feb 2019 00:54:53 +0100
Subject: [PATCH] cancel d&d when dropped back to the tree

---
 .../diylc/swing/plugins/tree/TreePanel.java   |  3 +
 .../plugins/tree/TreeTargetListener.java      | 62 +++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreeTargetListener.java

diff --git a/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreePanel.java b/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreePanel.java
index 02cacff2..08feeb64 100644
--- a/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreePanel.java
+++ b/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreePanel.java
@@ -27,6 +27,7 @@ import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.dnd.DnDConstants;
 import java.awt.dnd.DragSource;
+import java.awt.dnd.DropTarget;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.awt.event.FocusAdapter;
@@ -181,6 +182,8 @@ public class TreePanel extends JPanel {
     // Initialize drag source recognizer.
     DragSource.getDefaultDragSource().createDefaultDragGestureRecognizer(getTree(),
         DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK, new TreeGestureListener(plugInPort));
+    // Initialize drop target.
+    new DropTarget(getTree(), DnDConstants.ACTION_COPY_OR_MOVE, new TreeTargetListener(plugInPort), true);
   }
 
   public JScrollPane getTreeScroll() {
diff --git a/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreeTargetListener.java b/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreeTargetListener.java
new file mode 100644
index 00000000..f97e94a2
--- /dev/null
+++ b/diylc/diylc-swing/src/org/diylc/swing/plugins/tree/TreeTargetListener.java
@@ -0,0 +1,62 @@
+/*
+ * 
+ * DIY Layout Creator (DIYLC). Copyright (c) 2009-2018 held jointly by the individual authors.
+ * 
+ * This file is part of DIYLC.
+ * 
+ * DIYLC is free software: you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License as published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ * 
+ * DIYLC 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 for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along with DIYLC. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+package org.diylc.swing.plugins.tree;
+
+import java.awt.dnd.DnDConstants;
+import java.awt.dnd.DropTargetDragEvent;
+import java.awt.dnd.DropTargetDropEvent;
+import java.awt.dnd.DropTargetEvent;
+import java.awt.dnd.DropTargetListener;
+
+import org.diylc.common.IPlugInPort;
+
+
+/**
+ * {@link DropTargetListener} for {@link TreePanel}.
+ * 
+ * @author Branislav Stojkovic
+ */
+class TreeTargetListener implements DropTargetListener {
+
+  private IPlugInPort presenter;
+
+  public TreeTargetListener(IPlugInPort presenter) {
+    super();
+    this.presenter = presenter;
+  }
+
+  @Override
+  public void dragEnter(DropTargetDragEvent dtde) {}
+
+  @Override
+  public void dragExit(DropTargetEvent dte) {}
+
+  @Override
+  public void dragOver(DropTargetDragEvent dtde) {
+    dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
+  }
+
+  @Override
+  public void drop(DropTargetDropEvent dtde) {
+    presenter.setNewComponentTypeSlot(null, null, false);
+  }
+
+  @Override
+  public void dropActionChanged(DropTargetDragEvent dtde) {
+  }
+}