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1   /**
2    * This file Copyright (c) 2020 Magnolia International
3    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
4    *
5    *
6    * This file is dual-licensed under both the Magnolia
7    * Network Agreement and the GNU General Public License.
8    * You may elect to use one or the other of these licenses.
9    *
10   * This file is distributed in the hope that it will be
11   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12   * implied warranty of MERCHANTABILITY or FITNESS FOR A
13   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14   * Redistribution, except as permitted by whichever of the GPL
15   * or MNA you select, is prohibited.
16   *
17   * 1. For the GPL license (GPL), you can redistribute and/or
18   * modify this file under the terms of the GNU General
19   * Public License, Version 3, as published by the Free Software
20   * Foundation.  You should have received a copy of the GNU
21   * General Public License, Version 3 along with this program;
22   * if not, write to the Free Software Foundation, Inc., 51
23   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24   *
25   * 2. For the Magnolia Network Agreement (MNA), this file
26   * and the accompanying materials are made available under the
27   * terms of the MNA which accompanies this distribution, and
28   * is available at http://www.magnolia-cms.com/mna.html
29   *
30   * Any modifications to this file must keep this entire header
31   * intact.
32   *
33   */
34  package info.magnolia.pages.app;
35  
36  import info.magnolia.ui.contentapp.browser.drop.DropConstraint;
37  
38  import javax.jcr.Item;
39  import javax.jcr.RepositoryException;
40  
41  import org.slf4j.Logger;
42  import org.slf4j.LoggerFactory;
43  
44  import com.vaadin.shared.ui.grid.DropLocation;
45  
46  /**
47   * This {@link DropConstraint} delegates back to a {@link PageContentClipboard} to
48   * decide whether a node can be moved to its intended target.
49   */
50  class PageContentClipboardConstraint implements DropConstraint<Item> {
51      private static final Logger LOG = LoggerFactory.getLogger(PageContentClipboardConstraint.class);
52  
53      private static final int WORKSPACE_DEPTH = 1;
54  
55      private final PageContentClipboard pageContentClipboard;
56  
57      PageContentClipboardConstraint(PageContentClipboard pageContentClipboard) {
58          this.pageContentClipboard = pageContentClipboard;
59      }
60  
61      @Override
62      public boolean isAllowedAt(Item source, Item target, DropLocation dropLocation) {
63          try {
64              switch (dropLocation) {
65              case ON_TOP:
66                  return pageContentClipboard.canPasteInto(source, target);
67              case BELOW:
68              case ABOVE:
69                  return (source.getDepth() == WORKSPACE_DEPTH && target.getDepth() == WORKSPACE_DEPTH)
70                          || pageContentClipboard.canPasteInto(source, target.getParent());
71              }
72          } catch (RepositoryException e) {
73              LOG.error("Failed to evaluate drop constrain", e);
74          }
75          return false;
76      }
77  }