bundles/org.simantics.diagram/src/org/simantics/diagram/ui/WorkbenchSelectionProvider.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.diagram.ui;
  13
  14 import java.util.ArrayList;
  15 import java.util.Collections;
  16 import java.util.Optional;
  17 import java.util.concurrent.CopyOnWriteArrayList;
  18 import java.util.concurrent.TimeUnit;
  19
  20 import org.eclipse.jface.viewers.IPostSelectionProvider;
  21 import org.eclipse.jface.viewers.ISelection;
  22 import org.eclipse.jface.viewers.ISelectionChangedListener;
  23 import org.eclipse.jface.viewers.SelectionChangedEvent;
  24 import org.eclipse.jface.viewers.StructuredSelection;
  25 import org.eclipse.ui.IWorkbenchPartSite;
  26 import org.simantics.db.exception.DatabaseException;
  27 import org.simantics.diagram.elements.AdaptableImmutableProxyElement;
  28 import org.simantics.g2d.canvas.ICanvasContext;
  29 import org.simantics.g2d.canvas.impl.AbstractCanvasParticipant;
  30 import org.simantics.g2d.canvas.impl.DependencyReflection.Dependency;
  31 import org.simantics.g2d.canvas.impl.HintReflection.HintListener;
  32 import org.simantics.g2d.diagram.participant.ElementJSON;
  33 import org.simantics.g2d.diagram.participant.Selection;
  34 import org.simantics.g2d.element.ElementHints;
  35 import org.simantics.g2d.element.IElement;
  36 import org.simantics.ui.selection.WorkbenchSelectionUtils;
  37 import org.simantics.utils.datastructures.hints.IHintContext.Key;
  38 import org.simantics.utils.datastructures.hints.IHintObservable;
  39 import org.simantics.utils.threads.IThreadWorkQueue;
  40 import org.simantics.utils.threads.ThreadUtils;
  41 import org.slf4j.Logger;
  42 import org.slf4j.LoggerFactory;
  43
  44 /**
  45  * A canvas participant that listens to the #0 mouse selection and provides it
  46  * forward through the {@link IPostSelectionProvider} interface.
  47  *
  48  * @author Tuukka Lehtonen
  49  */
  50 public class WorkbenchSelectionProvider extends AbstractCanvasParticipant implements IPostSelectionProvider, ElementJSON {
  51
  52     private static final Logger LOGGER = LoggerFactory.getLogger(WorkbenchSelectionProvider.class);
  53
  54     private static final long                                 POST_SELECTION_DELAY = 300;
  55
  56     @Dependency protected Selection selection;
  57
  58     protected IThreadWorkQueue                                swt;
  59     protected IWorkbenchPartSite                              site;
  60     protected ISelection                                      currentSelection = StructuredSelection.EMPTY;
  61     protected CopyOnWriteArrayList<ISelectionChangedListener> listeners        = new CopyOnWriteArrayList<ISelectionChangedListener>();
  62     protected CopyOnWriteArrayList<ISelectionChangedListener> postListeners    = new CopyOnWriteArrayList<ISelectionChangedListener>();
  63
  64     public WorkbenchSelectionProvider(IThreadWorkQueue swt) {
  65         this(swt, null);
  66     }
  67
  68     public WorkbenchSelectionProvider(IThreadWorkQueue swt, IWorkbenchPartSite site) {
  69         this.swt = swt;
  70         this.site = site;
  71         if (site != null)
  72             site.setSelectionProvider(this);
  73     }
  74
  75     @Override
  76     public void addedToContext(ICanvasContext ctx) {
  77         super.addedToContext(ctx);
  78         if (site != null && site.getSelectionProvider() != this) {
  79             swt.asyncExec(new Runnable() {
  80                 @Override
  81                 public void run() {
  82                     if (site.getSelectionProvider() != WorkbenchSelectionProvider.this)
  83                         site.setSelectionProvider(WorkbenchSelectionProvider.this);
  84                 }
  85             });
  86         }
  87     }
  88
  89     @Override
  90     public void removedFromContext(ICanvasContext ctx) {
  91         if (site != null && site.getSelectionProvider() == this) {
  92             swt.asyncExec(new Runnable() {
  93                 @Override
  94                 public void run() {
  95                     if (site.getSelectionProvider() == WorkbenchSelectionProvider.this)
  96                         site.setSelectionProvider(null);
  97                 }
  98             });
  99         }
 100         super.removedFromContext(ctx);
 101     }
 102
 103     public void fireSelection(Iterable<?> selection) {
 104         final ISelection s = constructAdaptableSelection(selection);
 105         swt.asyncExec(new Runnable() {
 106             @Override
 107             public void run() {
 108                 currentSelection = s;
 109                 fireSelectionChanged(s);
 110                 schedulePostSelectionChanged(s);
 111             }
 112         });
 113     }
 114
 115     @HintListener(Class = Selection.class, Field = "SELECTION0")
 116     public void hintChanged(IHintObservable sender, Key key, Object oldValue, Object newValue) {
 117         Iterable<?> selection = (Iterable<?>) newValue;
 118         fireSelection(selection);
 119     }
 120
 121     @HintListener(Class = Selection.class, Field = "SELECTION0")
 122     public void hintRemoved(IHintObservable sender, Key key, Object oldValue) {
 123         //System.out.println("selection removed: " + oldValue);
 124         fireSelection(Collections.emptyList());
 125     }
 126
 127     // Post selection changed scheduling helper.
 128     private int modCount = 0;
 129
 130     protected void schedulePostSelectionChanged(final ISelection s) {
 131         final int count = ++modCount;
 132         ThreadUtils.getNonBlockingWorkExecutor().schedule(new Runnable() {
 133             @Override
 134             public void run() {
 135                 int newCount = modCount;
 136                 if (count != newCount)
 137                     return;
 138                 if (isRemoved())
 139                     return;
 140                 swt.asyncExec(new Runnable() {
 141                     @Override
 142                     public void run() {
 143                         if (isRemoved())
 144                             return;
 145                         firePostSelectionChanged(s);
 146                     }
 147                 });
 148             }
 149         }, POST_SELECTION_DELAY, TimeUnit.MILLISECONDS);
 150     }
 151
 152     protected ISelection constructAdaptableSelection(Iterable<?> selection) {
 153         ArrayList<Object> objects = new ArrayList<Object>();
 154         for (Object o : selection) {
 155             if (o instanceof IElement) {
 156                 IElement e = (IElement) o;
 157                 Object object = e.getHint(ElementHints.KEY_OBJECT);
 158                 if (object != null) {
 159                     objects.add(new AdaptableImmutableProxyElement(e));
 160                 } else {
 161                     System.out.println("  discarding element from selection, null object for " + e);
 162                 }
 163             } else {
 164                 System.out.println("  unrecognized selection: " + o.getClass() + ": " + o);
 165             }
 166         }
 167         return new StructuredSelection(objects);
 168     }
 169
 170     void fireSelectionChanged(ISelection selection) {
 171         SelectionChangedEvent e = new SelectionChangedEvent(this, selection);
 172         for (ISelectionChangedListener l : listeners)
 173             l.selectionChanged(e);
 174     }
 175
 176     void firePostSelectionChanged(ISelection selection) {
 177         SelectionChangedEvent e = new SelectionChangedEvent(this, selection);
 178         for (ISelectionChangedListener l : postListeners)
 179             l.selectionChanged(e);
 180     }
 181
 182     @Override
 183     public void addPostSelectionChangedListener(ISelectionChangedListener listener) {
 184         postListeners.add(listener);
 185     }
 186
 187     @Override
 188     public void removePostSelectionChangedListener(ISelectionChangedListener listener) {
 189         postListeners.remove(listener);
 190     }
 191
 192     @Override
 193     public void addSelectionChangedListener(ISelectionChangedListener listener) {
 194         listeners.add(listener);
 195     }
 196
 197     @Override
 198     public void removeSelectionChangedListener(ISelectionChangedListener listener) {
 199         listeners.remove(listener);
 200     }
 201
 202     @Override
 203     public ISelection getSelection() {
 204         return currentSelection;
 205     }
 206
 207     @Override
 208     public void setSelection(ISelection selection) {
 209         System.out.println("WorkbenchSelectionProvider: TODO: set selection: " + selection);
 210     }
 211
 212     @Override
 213     public Optional<String> getJSON(IElement element) {
 214         ISelection sel = constructAdaptableSelection(Collections.singleton(element));
 215         try {
 216             return Optional.ofNullable( WorkbenchSelectionUtils.getPossibleJSON(sel) );
 217         } catch (DatabaseException e) {
 218             LOGGER.error("Unexpected failure while constructing JSON from element " + element, e);
 219             return Optional.empty();
 220         }
 221     }
 222
 223 }