org.eclipse.jface.databinding.viewers.ObservableMapLabelProvider.java Source code

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Here is the source code for org.eclipse.jface.databinding.viewers.ObservableMapLabelProvider.java

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/*******************************************************************************
 * 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
 *     Alexander Kurtakov <akurtako@redhat.com> - Bug 459761
 *******************************************************************************/

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.core.databinding.observable.map.MapChangeEvent;
import org.eclipse.jface.viewers.ITableLabelProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.swt.graphics.Image;

/**
 * A label provider based on one or more observable maps that track attributes
 * that this label provider uses for display. Clients may customize by
 * subclassing and overriding {@link #getColumnText(Object, int)},
 * {@link #getColumnImage(Object, int)}, for tables or trees with columns, or by
 * implementing additional mixin interfaces for colors, fonts etc.
 *
 * @since 1.1
 *
 */
public class ObservableMapLabelProvider extends LabelProvider implements ITableLabelProvider {

    /**
     * Observable maps typically mapping from viewer elements to label values.
     * Subclasses may reference these maps to provide custom labels.
     *
     * @since 1.4
     */
    protected IObservableMap<Object, Object>[] attributeMaps;

    private IMapChangeListener<Object, Object> mapChangeListener = (MapChangeEvent<?, ?> event) -> {
        Set<?> affectedElements = event.diff.getChangedKeys();
        LabelProviderChangedEvent newEvent = new LabelProviderChangedEvent(ObservableMapLabelProvider.this,
                affectedElements.toArray());
        fireLabelProviderChanged(newEvent);
    };

    /**
     * @param attributeMap the tracked attribute map
     */
    public ObservableMapLabelProvider(IObservableMap<?, ?> attributeMap) {
        this(new IObservableMap[] { attributeMap });
    }

    /**
     * @param attributeMaps the tracked attribute maps
     */
    @SuppressWarnings("unchecked")
    public ObservableMapLabelProvider(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;
    }

    @Override
    public Image getImage(Object element) {
        return getColumnImage(element, 0);
    }

    @Override
    public String getText(Object element) {
        return getColumnText(element, 0);
    }

    @Override
    public Image getColumnImage(Object element, int columnIndex) {
        return null;
    }

    @Override
    public String getColumnText(Object element, int columnIndex) {
        if (columnIndex < attributeMaps.length) {
            Object result = attributeMaps[columnIndex].get(element);
            return result == null ? "" : result.toString(); //$NON-NLS-1$
        }
        return null;
    }

}