/*******************************************************************************
* Copyright (c) 2008, 2017 Matthew Hall and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Matthew Hall - initial API and implementation (bug 215531)
* Matthew Hall - bugs 226765, 222991, 238296, 263956, 226292, 265051,
* 266038
* Conrad Groth - Bug 371756
******************************************************************************/
package org.eclipse.jface.internal.databinding.viewers;
import org.eclipse.core.databinding.observable.IObservable;
import org.eclipse.core.databinding.observable.IObservableCollection;
import org.eclipse.core.databinding.observable.Observables;
import org.eclipse.core.databinding.observable.masterdetail.IObservableFactory;
import org.eclipse.core.databinding.observable.masterdetail.MasterDetailObservables;
import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.core.databinding.observable.value.WritableValue;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.databinding.swt.DisplayRealm;
import org.eclipse.jface.databinding.viewers.IViewerUpdater;
import org.eclipse.jface.viewers.AbstractListViewer;
import org.eclipse.jface.viewers.AbstractTableViewer;
import org.eclipse.jface.viewers.CheckboxTableViewer;
import org.eclipse.jface.viewers.IElementComparer;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.widgets.Display;
/**
* NON-API - Abstract base class for content providers where the viewer input is
* expected to be an {@link IObservableCollection}.
*
* @since 1.2
*/
public abstract class ObservableCollectionContentProvider implements
IStructuredContentProvider {
private Display display;
private IObservableValue viewerObservable;
/**
* Element comparer used by the viewer (may be null).
*/
protected IElementComparer comparer;
private IObservableFactory elementSetFactory;
private final IViewerUpdater explicitViewerUpdater;
/**
* Interface for sending updates to the viewer.
*/
protected IViewerUpdater viewerUpdater;
/**
* Observable set of all elements known to the content provider. Subclasses
* must add new elements to this set <b>before</b> adding them to the
* viewer, and must remove old elements from this set <b>after</b> removing
* them from the viewer.
*/
protected IObservableSet knownElements;
private IObservableSet unmodifiableKnownElements;
/**
* Observable set of known elements which have been realized in the viewer.
* Subclasses must add new elements to this set <b>after</b> adding them to
* the viewer, and must remove old elements from this set <b>before</b>
* removing them from the viewer.
*/
protected IObservableSet realizedElements;
private IObservableSet unmodifiableRealizedElements;
private IObservableCollection observableCollection;
/**
* Constructs an ObservableCollectionContentProvider
*
* @param explicitViewerUpdater
*/
protected ObservableCollectionContentProvider(
IViewerUpdater explicitViewerUpdater) {
this.explicitViewerUpdater = explicitViewerUpdater;
display = Display.getDefault();
viewerObservable = new WritableValue(DisplayRealm.getRealm(display));
viewerUpdater = null;
elementSetFactory = new IObservableFactory() {
@Override
public IObservable createObservable(Object target) {
IElementComparer comparer = null;
if (target instanceof StructuredViewer)
comparer = ((StructuredViewer) target).getComparer();
return ObservableViewerElementSet.withComparer(DisplayRealm
.getRealm(display), null, comparer);
}
};
knownElements = MasterDetailObservables.detailSet(viewerObservable,
elementSetFactory, null);
unmodifiableKnownElements = Observables
.unmodifiableObservableSet(knownElements);
observableCollection = null;
}
@Override
public Object[] getElements(Object inputElement) {
if (observableCollection == null)
return new Object[0];
if (realizedElements != null) {
if (!realizedElements.equals(knownElements)) {
asyncUpdateRealizedElements();
}
}
return observableCollection.toArray();
}
private void asyncUpdateRealizedElements() {
if (realizedElements == null)
return;
display.asyncExec(new Runnable() {
@Override
public void run() {
if (realizedElements != null) {
realizedElements.addAll(knownElements);
}
}
});
}
@Override
public void dispose() {
if (observableCollection != null)
removeCollectionChangeListener(observableCollection);
if (viewerObservable != null) {
viewerObservable.dispose();
viewerObservable = null;
}
viewerUpdater = null;
knownElements = null;
unmodifiableKnownElements = null;
realizedElements = null;
unmodifiableRealizedElements = null;
display = null;
}
@Override
public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
setViewer(viewer);
setInput(newInput);
}
private void setViewer(Viewer viewer) {
viewerUpdater = createViewerUpdater(viewer);
comparer = getElementComparer(viewer);
viewerObservable.setValue(viewer); // (clears knownElements)
}
private static IElementComparer getElementComparer(Viewer viewer) {
if (viewer instanceof StructuredViewer)
return ((StructuredViewer) viewer).getComparer();
return null;
}
IViewerUpdater createViewerUpdater(Viewer viewer) {
if (explicitViewerUpdater != null)
return explicitViewerUpdater;
if (viewer instanceof AbstractListViewer)
return new ListViewerUpdater((AbstractListViewer) viewer);
if (viewer instanceof CheckboxTableViewer)
return new CheckboxTableViewerUpdater((CheckboxTableViewer) viewer);
if (viewer instanceof AbstractTableViewer)
return new TableViewerUpdater((AbstractTableViewer) viewer);
throw new IllegalArgumentException(
"This content provider only works with AbstractTableViewer or AbstractListViewer"); //$NON-NLS-1$
}
void setInput(Object input) {
if (observableCollection != null) {
removeCollectionChangeListener(observableCollection);
observableCollection = null;
}
knownElements.clear();
if (realizedElements != null)
realizedElements.clear();
if (input != null) {
checkInput(input);
Assert.isTrue(input instanceof IObservableCollection,
"Input must be an IObservableCollection"); //$NON-NLS-1$
observableCollection = (IObservableCollection) input;
addCollectionChangeListener(observableCollection);
knownElements.addAll(observableCollection);
}
}
/**
* Throws an exception if the input is not the correct type.
*
* @param input
* the input to check
*/
protected abstract void checkInput(Object input);
/**
* Register for change event notification from the given collection.
*
* @param collection
* observable collection to listen to
*/
protected abstract void addCollectionChangeListener(
IObservableCollection collection);
/**
* Deregisters from change events notification on the given collection.
*
* @param collection
* observable collection to stop listening to
*/
protected abstract void removeCollectionChangeListener(
IObservableCollection collection);
/**
* Returns whether the viewer is disposed. Collection change listeners in
* subclasses should verify that the viewer is not disposed before sending
* any updates to the {@link ViewerUpdater viewer updater}.
*
* @return whether the viewer is disposed.
*/
protected final boolean isViewerDisposed() {
Viewer viewer = (Viewer) viewerObservable.getValue();
return viewer == null || viewer.getControl() == null
|| viewer.getControl().isDisposed();
}
/**
* Returns the set of elements known to this content provider. Label
* providers may track this set if they need to be notified about additions
* before the viewer sees the added element, and notified about removals
* after the element was removed from the viewer. This is intended for use
* by label providers, as it will always return the items that need labels.
*
* @return unmodifiable observable set of items that will need labels
*/
public IObservableSet getKnownElements() {
return unmodifiableKnownElements;
}
/**
* Returns the set of known elements which have been realized in the viewer.
* Clients may track this set in order to perform custom actions on elements
* while they are known to be present in the viewer.
*
* @return the set of known elements which have been realized in the viewer.
* @since 1.3
*/
public IObservableSet getRealizedElements() {
if (realizedElements == null) {
realizedElements = MasterDetailObservables.detailSet(
viewerObservable, elementSetFactory, null);
unmodifiableRealizedElements = Observables
.unmodifiableObservableSet(realizedElements);
asyncUpdateRealizedElements();
}
return unmodifiableRealizedElements;
}
}