org.eclipse.jface.databinding.viewers.ObservableMapCellLabelProvider Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2006, 2015 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
* Brad Reynolds - bugs 164247, 164134
* Matthew Hall - bug 302860
*******************************************************************************/
package org.eclipse.jface.databinding.viewers;
import java.util.Set;
import org.eclipse.core.databinding.observable.map.IMapChangeListener;
import org.eclipse.core.databinding.observable.map.IObservableMap;
import org.eclipse.jface.viewers.CellLabelProvider;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.jface.viewers.ViewerCell;
/**
* A label provider based on one or more observable maps that track attributes
* that this label provider uses for display. The default behavior is to display
* the first attribute's value. Clients may customize by subclassing and
* overriding {@link #update(ViewerCell)}.
*
* @since 1.3
*
*/
public class ObservableMapCellLabelProvider extends CellLabelProvider {
/**
* Observable maps typically mapping from viewer elements to label values.
* Subclasses may use these maps to provide custom labels.
*
* @since 1.4
*/
protected IObservableMap[] attributeMaps;
private IMapChangeListener mapChangeListener = event -> {
Set affectedElements = event.diff.getChangedKeys();
LabelProviderChangedEvent newEvent = new LabelProviderChangedEvent(ObservableMapCellLabelProvider.this,
affectedElements.toArray());
fireLabelProviderChanged(newEvent);
};
/**
* Creates a new label provider that tracks changes to one attribute.
*
* @param attributeMap attribute map to track
*/
public ObservableMapCellLabelProvider(IObservableMap attributeMap) {
this(new IObservableMap[] { attributeMap });
}
/**
* Creates a new label provider that tracks changes to more than one
* attribute. This constructor should be used by subclasses that override
* {@link #update(ViewerCell)} and make use of more than one attribute.
*
* @param attributeMaps attribute maps to track
*/
@SuppressWarnings("unchecked")
protected ObservableMapCellLabelProvider(IObservableMap[] attributeMaps) {
System.arraycopy(attributeMaps, 0, this.attributeMaps = new IObservableMap[attributeMaps.length], 0,
attributeMaps.length);
for (IObservableMap attributeMap : attributeMaps) {
attributeMap.addMapChangeListener(mapChangeListener);
}
}
@Override
public void dispose() {
for (IObservableMap attributeMap : attributeMaps) {
attributeMap.removeMapChangeListener(mapChangeListener);
}
super.dispose();
this.attributeMaps = null;
this.mapChangeListener = null;
}
/**
* Updates the label of the cell with the value for the cell element. Note:
* The value for the first map is always used, for all columns.
*
* @param cell
* The cell to be updated.
*/
@Override
public void update(ViewerCell cell) {
Object element = cell.getElement();
// Always use the value from the first map
Object value = attributeMaps[0].get(element);
cell.setText(value == null ? "" : value.toString()); //$NON-NLS-1$
}
}