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  * @version 1.0
  36  */
  37 public class SimpleSelectionProvider implements ISelectionProvider {
  38
  39     private static final String SETTING_SELECTION = Messages.SimpleSelectionProvider_SETTING_SELECTION;
  40     private Set<ISelectionChangedListener> selectionChangedListeners = new HashSet<ISelectionChangedListener>();
  41         private ISelection selection;
  42         private Job job;
  43
  44         /*
  45          * (non-Javadoc)
  46          * @see org.eclipse.jface.viewers.ISelectionProvider#addSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  47          */
  48         /** {@inheritDoc} */
  49         @Override
  50     public void addSelectionChangedListener(
  51                         ISelectionChangedListener listener) {
  52                 selectionChangedListeners.add(listener);
  53         }
  54
  55         /*
  56          * (non-Javadoc)
  57          * @see org.eclipse.jface.viewers.ISelectionProvider#getSelection()
  58          */
  59         /**
  60          * <p>Getter for the field <code>selection</code>.</p>
  61          *
  62          * @return a {@link org.eclipse.jface.viewers.ISelection} object.
  63          */
  64         @Override
  65     public ISelection getSelection() {
  66                 if (selection != null){
  67                         return selection;
  68                 }
  69                 // TODO we have to return an empty selection to avoid NPE
  70                 // I don't really understand why this was not the case before
  71                 return new StructuredSelection();
  72         }
  73
  74         /*
  75          * (non-Javadoc)
  76          * @see org.eclipse.jface.viewers.ISelectionProvider#removeSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  77          */
  78         /** {@inheritDoc} */
  79         @Override
  80     public void removeSelectionChangedListener(
  81                         ISelectionChangedListener listener) {
  82                 selectionChangedListeners.remove(listener);
  83         }
  84
  85         /*
  86          * (non-Javadoc)
  87          * @see org.eclipse.jface.viewers.ISelectionProvider#setSelection(org.eclipse.jface.viewers.ISelection)
  88          */
  89         /** {@inheritDoc} */
  90         @Override
  91     public void setSelection(ISelection selection) {
  92                 this.selection = selection;
  93
  94                 // cancel previous selection setting
  95                 if(job != null){
  96                         if(job.getState() != Job.NONE){
  97                                 job.cancel();
  98                         }
  99                         job = null;
 100                 }
 101
 102                 if(job == null){
 103                         final SelectionChangedEvent selectionChangedEvent = new SelectionChangedEvent(this, selection);
 104                         final Display display = Display.getCurrent();
 105                         job = new Job(SETTING_SELECTION){
 106
 107                                 @Override
 108                                 protected IStatus run(IProgressMonitor monitor) {
 109                                         monitor.beginTask(SETTING_SELECTION, 10);
 110
 111                                         if(!monitor.isCanceled()){
 112                                                 display.asyncExec(new Runnable() {
 113
 114                                                         @Override
 115                             public void run() {
 116                                                                 SimpleSelectionProvider.this.fireSelectionChanged(selectionChangedEvent);
 117                                                         }
 118                                                 });
 119                                         }
 120
 121                                         return Status.OK_STATUS;
 122                                 }
 123
 124                         };
 125
 126                         job.setPriority(Job.DECORATE);
 127                         job.schedule();
 128                 }
 129
 130         }
 131
 132         private void fireSelectionChanged(final SelectionChangedEvent event) {
 133
 134                 for (final ISelectionChangedListener listener : selectionChangedListeners) {
 135                         SafeRunnable.run(new SafeRunnable() {
 136                                 @Override
 137                 public void run() {
 138                                         listener.selectionChanged(event);
 139                                 }
 140                         });
 141                 }
 142         }
 143 }