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 java.util.HashSet;
  13 import java.util.Set;
  14
  15 import org.eclipse.core.runtime.IProgressMonitor;
  16 import org.eclipse.core.runtime.IStatus;
  17 import org.eclipse.core.runtime.Status;
  18 import org.eclipse.core.runtime.jobs.Job;
  19 import org.eclipse.jface.util.SafeRunnable;
  20 import org.eclipse.jface.viewers.ISelection;
  21 import org.eclipse.jface.viewers.ISelectionChangedListener;
  22 import org.eclipse.jface.viewers.ISelectionProvider;
  23 import org.eclipse.jface.viewers.SelectionChangedEvent;
  24 import org.eclipse.jface.viewers.StructuredSelection;
  25 import org.eclipse.swt.widgets.Display;
  26
  27 import eu.etaxonomy.taxeditor.editor.l10n.Messages;
  28
  29 /**
  30  * <p>SimpleSelectionProvider class.</p>
  31  *
  32  * @author p.ciardelli
  33  * @author n.hoffmann
  34  * @created 16.05.2008
  35  */
  36 public class SimpleSelectionProvider implements ISelectionProvider {
  37
  38     private static final String SETTING_SELECTION = Messages.SimpleSelectionProvider_SETTING_SELECTION;
  39     private Set<ISelectionChangedListener> selectionChangedListeners = new HashSet<ISelectionChangedListener>();
  40         private ISelection selection;
  41         private Job job;
  42
  43         @Override
  44     public void addSelectionChangedListener(
  45                         ISelectionChangedListener listener) {
  46                 selectionChangedListeners.add(listener);
  47         }
  48
  49         /**
  50          * <p>Getter for the field <code>selection</code>.</p>
  51          *
  52          * @return a {@link org.eclipse.jface.viewers.ISelection} object.
  53          */
  54         @Override
  55     public ISelection getSelection() {
  56                 if (selection != null){
  57                         return selection;
  58                 }
  59                 // TODO we have to return an empty selection to avoid NPE
  60                 // I don't really understand why this was not the case before
  61                 return new StructuredSelection();
  62         }
  63
  64         @Override
  65     public void removeSelectionChangedListener(
  66                         ISelectionChangedListener listener) {
  67                 selectionChangedListeners.remove(listener);
  68         }
  69
  70         @Override
  71     public void setSelection(ISelection selection) {
  72                 this.selection = selection;
  73
  74                 // cancel previous selection setting
  75                 if(job != null){
  76                         if(job.getState() != Job.NONE){
  77                                 job.cancel();
  78                         }
  79                         job = null;
  80                 }
  81
  82                 if(job == null){
  83                         final SelectionChangedEvent selectionChangedEvent = new SelectionChangedEvent(this, selection);
  84                         final Display display = Display.getCurrent();
  85                         job = new Job(SETTING_SELECTION){
  86
  87                                 @Override
  88                                 protected IStatus run(IProgressMonitor monitor) {
  89                                         monitor.beginTask(SETTING_SELECTION, 10);
  90
  91                                         if(!monitor.isCanceled()){
  92                                                 display.asyncExec(new Runnable() {
  93
  94                                                         @Override
  95                             public void run() {
  96                                                                 SimpleSelectionProvider.this.fireSelectionChanged(selectionChangedEvent);
  97                                                         }
  98                                                 });
  99                                         }
 100
 101                                         return Status.OK_STATUS;
 102                                 }
 103
 104                         };
 105
 106                         job.setPriority(Job.DECORATE);
 107                         job.schedule();
 108                 }
 109
 110         }
 111
 112         private void fireSelectionChanged(final SelectionChangedEvent event) {
 113
 114                 for (final ISelectionChangedListener listener : selectionChangedListeners) {
 115                         SafeRunnable.run(new SafeRunnable() {
 116                                 @Override
 117                 public void run() {
 118                                         listener.selectionChanged(event);
 119                                 }
 120                         });
 121                 }
 122         }
 123 }