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 /**
  28  * <p>SimpleSelectionProvider class.</p>
  29  *
  30  * @author p.ciardelli
  31  * @author n.hoffmann
  32  * @created 16.05.2008
  33  * @version 1.0
  34  */
  35 public class SimpleSelectionProvider implements ISelectionProvider {
  36
  37         private Set<ISelectionChangedListener> selectionChangedListeners = new HashSet<ISelectionChangedListener>();
  38         private ISelection selection;
  39         private Job job;
  40
  41         /*
  42          * (non-Javadoc)
  43          * @see org.eclipse.jface.viewers.ISelectionProvider#addSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  44          */
  45         /** {@inheritDoc} */
  46         public void addSelectionChangedListener(
  47                         ISelectionChangedListener listener) {
  48                 selectionChangedListeners.add(listener);
  49         }
  50
  51         /*
  52          * (non-Javadoc)
  53          * @see org.eclipse.jface.viewers.ISelectionProvider#getSelection()
  54          */
  55         /**
  56          * <p>Getter for the field <code>selection</code>.</p>
  57          *
  58          * @return a {@link org.eclipse.jface.viewers.ISelection} object.
  59          */
  60         public ISelection getSelection() {
  61                 if (selection != null){
  62                         return selection;
  63                 }
  64                 // TODO we have to return an empty selection to avoid NPE
  65                 // I don't really understand why this was not the case before
  66                 return new StructuredSelection();
  67         }
  68
  69         /*
  70          * (non-Javadoc)
  71          * @see org.eclipse.jface.viewers.ISelectionProvider#removeSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
  72          */
  73         /** {@inheritDoc} */
  74         public void removeSelectionChangedListener(
  75                         ISelectionChangedListener listener) {
  76                 selectionChangedListeners.remove(listener);
  77         }
  78
  79         /*
  80          * (non-Javadoc)
  81          * @see org.eclipse.jface.viewers.ISelectionProvider#setSelection(org.eclipse.jface.viewers.ISelection)
  82          */
  83         /** {@inheritDoc} */
  84         public void setSelection(ISelection selection) {
  85                 this.selection = selection;
  86
  87                 // cancel previous selection setting
  88                 if(job != null){
  89                         if(job.getState() != Job.NONE){
  90                                 job.cancel();
  91                         }
  92                         job = null;
  93                 }
  94
  95                 if(job == null){
  96                         final SelectionChangedEvent selectionChangedEvent = new SelectionChangedEvent(this, selection);
  97                         final Display display = Display.getCurrent();
  98                         job = new Job("Setting Selection"){
  99
 100                                 @Override
 101                                 protected IStatus run(IProgressMonitor monitor) {
 102                                         monitor.beginTask("Setting Selection", 10);
 103
 104                                         if(!monitor.isCanceled()){
 105                                                 display.asyncExec(new Runnable() {
 106
 107                                                         public void run() {
 108                                                                 SimpleSelectionProvider.this.fireSelectionChanged(selectionChangedEvent);
 109                                                         }
 110                                                 });
 111                                         }
 112
 113                                         return Status.OK_STATUS;
 114                                 }
 115
 116                         };
 117
 118                         job.setPriority(Job.DECORATE);
 119                         job.schedule();
 120                 }
 121
 122         }
 123
 124         private void fireSelectionChanged(final SelectionChangedEvent event) {
 125
 126                 for (final ISelectionChangedListener listener : selectionChangedListeners) {
 127                         SafeRunnable.run(new SafeRunnable() {
 128                                 public void run() {
 129                                         listener.selectionChanged(event);
 130                                 }
 131                         });
 132                 }
 133         }
 134 }