eu.etaxonomy.taxeditor.editor/src/main/java/eu/etaxonomy/taxeditor/editor/SimpleSelectionProvider.java

   1 /**
   2 * Copyright (C) 2007 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9
  10 package eu.etaxonomy.taxeditor.editor;
  11
  12 import org.eclipse.core.runtime.IProgressMonitor;
  13 import org.eclipse.core.runtime.IStatus;
  14 import org.eclipse.core.runtime.ListenerList;
  15 import org.eclipse.core.runtime.Status;
  16 import org.eclipse.core.runtime.jobs.Job;
  17 import org.eclipse.jface.util.SafeRunnable;
  18 import org.eclipse.jface.viewers.ISelection;
  19 import org.eclipse.jface.viewers.ISelectionChangedListener;
  20 import org.eclipse.jface.viewers.ISelectionProvider;
  21 import org.eclipse.jface.viewers.SelectionChangedEvent;
  22 import org.eclipse.jface.viewers.StructuredSelection;
  23 import org.eclipse.swt.widgets.Display;
  24
  25 /**
  26  * <p>SimpleSelectionProvider class.</p>
  27  *
  28  * @author p.ciardelli
  29  * @author n.hoffmann
  30  * @created 16.05.2008
  31  * @version 1.0
  32  */
  33 public class SimpleSelectionProvider implements ISelectionProvider {
  34
  35         private ListenerList selectionChangedListeners = new ListenerList();
  36         private ISelection selection;
  37         private Job job;
  38
  39         /*
  40          * (non-Javadoc)
  41          * @see org.eclipse.jface.viewers.ISelectionProvider#addSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  42          */
  43         /** {@inheritDoc} */
  44         public void addSelectionChangedListener(
  45                         ISelectionChangedListener listener) {
  46                 selectionChangedListeners.add(listener);
  47         }
  48
  49         /*
  50          * (non-Javadoc)
  51          * @see org.eclipse.jface.viewers.ISelectionProvider#getSelection()
  52          */
  53         /**
  54          * <p>Getter for the field <code>selection</code>.</p>
  55          *
  56          * @return a {@link org.eclipse.jface.viewers.ISelection} object.
  57          */
  58         public ISelection getSelection() {
  59                 if (selection != null){
  60                         return selection;
  61                 }
  62                 // TODO we have to return an empty selection to avoid NPE
  63                 // I don't really understand why this was not the case before
  64                 return new StructuredSelection();
  65         }
  66
  67         /*
  68          * (non-Javadoc)
  69          * @see org.eclipse.jface.viewers.ISelectionProvider#removeSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  70          */
  71         /** {@inheritDoc} */
  72         public void removeSelectionChangedListener(
  73                         ISelectionChangedListener listener) {
  74                 selectionChangedListeners.remove(listener);
  75         }
  76
  77         /*
  78          * (non-Javadoc)
  79          * @see org.eclipse.jface.viewers.ISelectionProvider#setSelection(org.eclipse.jface.viewers.ISelection)
  80          */
  81         /** {@inheritDoc} */
  82         public void setSelection(ISelection selection) {
  83                 this.selection = selection;
  84
  85                 // cancel previous selection setting
  86                 if(job != null){
  87                         job.cancel();
  88                         job = null;
  89                 }
  90
  91                 if(job == null){
  92                         final SelectionChangedEvent selectionChangedEvent = new SelectionChangedEvent(this, selection);
  93                         final Display display = Display.getCurrent();
  94                         job = new Job("Setting Selection"){
  95
  96                                 @Override
  97                                 protected IStatus run(IProgressMonitor monitor) {
  98                                         monitor.beginTask("Setting Selection", 10);
  99
 100                                         if(!monitor.isCanceled()){
 101                                                 display.asyncExec(new Runnable() {
 102
 103                                                         public void run() {
 104                                                                 fireSelectionChanged(selectionChangedEvent);
 105                                                         }
 106                                                 });
 107                                         }
 108
 109                                         return Status.OK_STATUS;
 110                                 }
 111
 112                         };
 113
 114                         job.setPriority(Job.DECORATE);
 115                         job.schedule();
 116                 }
 117
 118         }
 119
 120         private void fireSelectionChanged(final SelectionChangedEvent event) {
 121
 122                 Object[] listeners = selectionChangedListeners.getListeners();
 123                 for (int i = 0; i < listeners.length; ++i) {
 124                         final ISelectionChangedListener l = (ISelectionChangedListener) listeners[i];
 125                         SafeRunnable.run(new SafeRunnable() {
 126                                 public void run() {
 127                                         l.selectionChanged(event);
 128                                 }
 129                         });
 130                 }
 131         }
 132 }