core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/ui/viewsupport/ProblemTableViewer.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *******************************************************************************/
package org.eclipse.dltk.ui.viewsupport;

import java.util.ArrayList;

import org.eclipse.core.resources.IResource;
import org.eclipse.dltk.internal.ui.IWorkingCopyProvider;
import org.eclipse.dltk.ui.ProblemsLabelDecorator.ProblemsLabelChangedEvent;
import org.eclipse.jface.viewers.IBaseLabelProvider;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.Widget;


/**
 * Extends a  TableViewer to allow more performance when showing error ticks.
 * A <code>ProblemItemMapper</code> is contained that maps all items in
 * the tree to underlying resource
 */
public class ProblemTableViewer extends TableViewer implements ResourceToItemsMapper.IContentViewerAccessor {

	protected ResourceToItemsMapper fResourceToItemsMapper;

	/**
	 * Constructor for ProblemTableViewer.
	 * @param parent
	 */
	public ProblemTableViewer(Composite parent) {
		super(parent);
		initMapper();
	}

	/**
	 * Constructor for ProblemTableViewer.
	 * @param parent
	 * @param style
	 */
	public ProblemTableViewer(Composite parent, int style) {
		super(parent, style);
		initMapper();
	}

	/**
	 * Constructor for ProblemTableViewer.
	 * @param table
	 */
	public ProblemTableViewer(Table table) {
		super(table);
		initMapper();
	}

	private void initMapper() {
		fResourceToItemsMapper= new ResourceToItemsMapper(this);
	}

	@Override
	public void doUpdateItem(Widget item) {
		doUpdateItem(item, item.getData(), true);
	}

	@Override
	protected void mapElement(Object element, Widget item) {
		super.mapElement(element, item);
		if (item instanceof Item) {
			fResourceToItemsMapper.addToMap(element, (Item) item);
		}
	}

	@Override
	protected void unmapElement(Object element, Widget item) {
		if (item instanceof Item) {
			fResourceToItemsMapper.removeFromMap(element, (Item) item);
		}
		super.unmapElement(element, item);
	}

	@Override
	protected void unmapAllElements() {
		fResourceToItemsMapper.clearMap();
		super.unmapAllElements();
	}

	@Override
	protected void handleLabelProviderChanged(LabelProviderChangedEvent event) {
		if (event instanceof ProblemsLabelChangedEvent) {
			ProblemsLabelChangedEvent e= (ProblemsLabelChangedEvent) event;
			if (!e.isMarkerChange() && canIgnoreChangesFromAnnotionModel()) {
				return;
			}
		}

		Object[] changed= event.getElements();
		if (changed != null && !fResourceToItemsMapper.isEmpty()) {
			ArrayList others= new ArrayList(changed.length);
			for (int i= 0; i < changed.length; i++) {
				Object curr= changed[i];
				if (curr instanceof IResource) {
					fResourceToItemsMapper.resourceChanged((IResource) curr);
				} else {
					others.add(curr);
				}
			}
			if (others.isEmpty()) {
				return;
			}
			event= new LabelProviderChangedEvent((IBaseLabelProvider) event.getSource(), others.toArray());
		}
		super.handleLabelProviderChanged(event);
	}

	/**
	 * Answers whether this viewer can ignore label provider changes resulting from
	 * marker changes in annotation models
	 */
	private boolean canIgnoreChangesFromAnnotionModel() {
		Object contentProvider= getContentProvider();
		return contentProvider instanceof IWorkingCopyProvider && !((IWorkingCopyProvider)contentProvider).providesWorkingCopies();
	}
}