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

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2017 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  *     Semantum Oy - #7586
  12  *******************************************************************************/
  13 package org.simantics.diagram.ui;
  14
  15 import java.util.ArrayList;
  16 import java.util.Collections;
  17 import java.util.Optional;
  18 import java.util.concurrent.CopyOnWriteArrayList;
  19 import java.util.concurrent.TimeUnit;
  20
  21 import org.eclipse.jface.viewers.IPostSelectionProvider;
  22 import org.eclipse.jface.viewers.ISelection;
  23 import org.eclipse.jface.viewers.ISelectionChangedListener;
  24 import org.eclipse.jface.viewers.SelectionChangedEvent;
  25 import org.eclipse.jface.viewers.StructuredSelection;
  26 import org.eclipse.ui.IWorkbenchPartSite;
  27 import org.simantics.db.exception.DatabaseException;
  28 import org.simantics.diagram.elements.AdaptableImmutableProxyElement;
  29 import org.simantics.g2d.canvas.ICanvasContext;
  30 import org.simantics.g2d.canvas.impl.AbstractCanvasParticipant;
  31 import org.simantics.g2d.canvas.impl.DependencyReflection.Dependency;
  32 import org.simantics.g2d.canvas.impl.HintReflection.HintListener;
  33 import org.simantics.g2d.diagram.participant.ElementJSON;
  34 import org.simantics.g2d.diagram.participant.Selection;
  35 import org.simantics.g2d.element.ElementHints;
  36 import org.simantics.g2d.element.IElement;
  37 import org.simantics.ui.selection.WorkbenchSelectionUtils;
  38 import org.simantics.utils.datastructures.hints.IHintContext.Key;
  39 import org.simantics.utils.datastructures.hints.IHintObservable;
  40 import org.simantics.utils.threads.IThreadWorkQueue;
  41 import org.simantics.utils.threads.ThreadUtils;
  42 import org.slf4j.Logger;
  43 import org.slf4j.LoggerFactory;
  44
  45 /**
  46  * A canvas participant that listens to the #0 mouse selection and provides it
  47  * forward through the {@link IPostSelectionProvider} interface.
  48  *
  49  * @author Tuukka Lehtonen
  50  */
  51 public class WorkbenchSelectionProvider extends AbstractCanvasParticipant implements IPostSelectionProvider, ElementJSON {
  52
  53     private static final Logger LOGGER = LoggerFactory.getLogger(WorkbenchSelectionProvider.class);
  54
  55     private static final long                                 POST_SELECTION_DELAY = 300;
  56
  57     @Dependency protected Selection selection;
  58
  59     protected IThreadWorkQueue                                swt;
  60     protected IWorkbenchPartSite                              site;
  61     protected ISelection                                      currentSelection = StructuredSelection.EMPTY;
  62     protected CopyOnWriteArrayList<ISelectionChangedListener> listeners        = new CopyOnWriteArrayList<ISelectionChangedListener>();
  63     protected CopyOnWriteArrayList<ISelectionChangedListener> postListeners    = new CopyOnWriteArrayList<ISelectionChangedListener>();
  64
  65     public WorkbenchSelectionProvider(IThreadWorkQueue swt) {
  66         this(swt, null);
  67     }
  68
  69     public WorkbenchSelectionProvider(IThreadWorkQueue swt, IWorkbenchPartSite site) {
  70         this.swt = swt;
  71         this.site = site;
  72         if (site != null)
  73             site.setSelectionProvider(this);
  74     }
  75
  76     @Override
  77     public void addedToContext(ICanvasContext ctx) {
  78         super.addedToContext(ctx);
  79         swt.asyncExec(() -> {
  80             if (site != null && site.getSelectionProvider() != WorkbenchSelectionProvider.this)
  81                 site.setSelectionProvider(WorkbenchSelectionProvider.this);
  82         });
  83     }
  84
  85     @Override
  86     public void removedFromContext(ICanvasContext ctx) {
  87         swt.asyncExec(() -> {
  88             if (site != null && site.getSelectionProvider() == WorkbenchSelectionProvider.this)
  89                 site.setSelectionProvider(null);
  90         });
  91         super.removedFromContext(ctx);
  92     }
  93
  94     public void fireSelection(Iterable<?> selection) {
  95         final ISelection s = constructAdaptableSelection(selection);
  96         swt.asyncExec(() -> {
  97             currentSelection = s;
  98             fireSelectionChanged(s);
  99             schedulePostSelectionChanged(s);
 100         });
 101     }
 102
 103     @HintListener(Class = Selection.class, Field = "SELECTION0")
 104     public void hintChanged(IHintObservable sender, Key key, Object oldValue, Object newValue) {
 105         Iterable<?> selection = (Iterable<?>) newValue;
 106         fireSelection(selection);
 107     }
 108
 109     @HintListener(Class = Selection.class, Field = "SELECTION0")
 110     public void hintRemoved(IHintObservable sender, Key key, Object oldValue) {
 111         //System.out.println("selection removed: " + oldValue);
 112         fireSelection(Collections.emptyList());
 113     }
 114
 115     // Post selection changed scheduling helper.
 116     private int modCount = 0;
 117
 118     protected void schedulePostSelectionChanged(final ISelection s) {
 119         final int count = ++modCount;
 120         ThreadUtils.getNonBlockingWorkExecutor().schedule(() -> {
 121             int newCount = modCount;
 122             if (count != newCount)
 123                 return;
 124             if (isRemoved())
 125                 return;
 126             swt.asyncExec(() -> {
 127                 if (!isRemoved())
 128                     firePostSelectionChanged(s);
 129             });
 130         }, POST_SELECTION_DELAY, TimeUnit.MILLISECONDS);
 131     }
 132
 133     protected ISelection constructAdaptableSelection(Iterable<?> selection) {
 134         ArrayList<Object> objects = new ArrayList<Object>();
 135         for (Object o : selection) {
 136             if (o instanceof IElement) {
 137                 IElement e = (IElement) o;
 138                 Object object = e.getHint(ElementHints.KEY_OBJECT);
 139                 if (object != null) {
 140                     objects.add(new AdaptableImmutableProxyElement(e));
 141                 } else {
 142                     System.out.println("  discarding element from selection, null object for " + e);
 143                 }
 144             } else {
 145                 System.out.println("  unrecognized selection: " + o.getClass() + ": " + o);
 146             }
 147         }
 148         return new StructuredSelection(objects);
 149     }
 150
 151     void fireSelectionChanged(ISelection selection) {
 152         SelectionChangedEvent e = new SelectionChangedEvent(this, selection);
 153         for (ISelectionChangedListener l : listeners)
 154             l.selectionChanged(e);
 155     }
 156
 157     void firePostSelectionChanged(ISelection selection) {
 158         SelectionChangedEvent e = new SelectionChangedEvent(this, selection);
 159         for (ISelectionChangedListener l : postListeners)
 160             l.selectionChanged(e);
 161     }
 162
 163     @Override
 164     public void addPostSelectionChangedListener(ISelectionChangedListener listener) {
 165         postListeners.add(listener);
 166     }
 167
 168     @Override
 169     public void removePostSelectionChangedListener(ISelectionChangedListener listener) {
 170         postListeners.remove(listener);
 171     }
 172
 173     @Override
 174     public void addSelectionChangedListener(ISelectionChangedListener listener) {
 175         listeners.add(listener);
 176     }
 177
 178     @Override
 179     public void removeSelectionChangedListener(ISelectionChangedListener listener) {
 180         listeners.remove(listener);
 181     }
 182
 183     @Override
 184     public ISelection getSelection() {
 185         return currentSelection;
 186     }
 187
 188     @Override
 189     public void setSelection(ISelection selection) {
 190         System.out.println("WorkbenchSelectionProvider: TODO: set selection: " + selection);
 191     }
 192
 193     @Override
 194     public Optional<String> getJSON(IElement element) {
 195         ISelection sel = constructAdaptableSelection(Collections.singleton(element));
 196         try {
 197             return Optional.ofNullable( WorkbenchSelectionUtils.getPossibleJSON(sel) );
 198         } catch (DatabaseException e) {
 199             LOGGER.error("Unexpected failure while constructing JSON from element " + element, e);
 200             return Optional.empty();
 201         }
 202     }
 203
 204 }