CellGraphContentProvider.java

/*
 * Copyright (c) 2012 Data Harmonisation Panel
 * 
 * All rights reserved. This program and the accompanying materials are made
 * available under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     HUMBOLDT EU Integrated Project #030962
 *     Data Harmonisation Panel <http://www.dhpanel.eu>
 */

package eu.esdihumboldt.hale.ui.common.graph.content;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map.Entry;

import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.zest.core.viewers.IGraphContentProvider;

import eu.esdihumboldt.hale.common.align.model.Alignment;
import eu.esdihumboldt.hale.common.align.model.Cell;
import eu.esdihumboldt.hale.common.align.model.Entity;

/**
 * Graph content provider that models entities and cells as nodes. Supports an
 * {@link Alignment}, a {@link Cell} or an {@link Iterable} of {@link Cell}s as
 * input.
 * 
 * @author Simon Templer
 */
public class CellGraphContentProvider extends ArrayContentProvider implements IGraphContentProvider {

	/**
	 * @see IGraphContentProvider#getSource(Object)
	 */
	@Override
	public Object getSource(Object rel) {
		if (rel instanceof Edge) {
			Edge edge = (Edge) rel;
			return edge.getFirst();
		}

		return null;
	}

	/**
	 * @see IGraphContentProvider#getDestination(Object)
	 */
	@Override
	public Object getDestination(Object rel) {
		if (rel instanceof Edge) {
			Edge edge = (Edge) rel;
			return edge.getSecond();
		}

		return null;
	}

	/**
	 * @see IGraphContentProvider#getElements(Object)
	 */
	@Override
	public Object[] getElements(Object input) {
		if (input instanceof Alignment) {
			return getEdges(((Alignment) input).getCells());
		}

		if (input instanceof Cell) {
			return getEdges(Collections.singleton(input));
		}

		if (input instanceof Iterable<?>) {
			return getEdges((Iterable<?>) input);
		}

		return super.getElements(input);
	}

	/**
	 * Get all edges for the given cells.
	 * 
	 * @param cells an iterable of {@link Cell}s, other objects will be ignored
	 * @return the array of edges
	 */
	protected Object[] getEdges(Iterable<?> cells) {
		List<Edge> edges = new ArrayList<Edge>();

		for (Object object : cells) {
			if (object instanceof Cell) {
				Cell cell = (Cell) object;
				addEdges(cell, edges);
			}
		}

		return edges.toArray();
	}

	/**
	 * Adds the edges for the given cell to the given list.
	 * 
	 * @param cell the cell to add
	 * @param edges the list to add the edges to
	 */
	protected void addEdges(Cell cell, List<Edge> edges) {
		// add edges leading to the cell for each source entity
		if (cell.getSource() != null) {
			for (Entry<String, ? extends Entity> entry : cell.getSource().entries()) {
				edges.add(new Edge(entry.getValue(), cell, entry.getKey()));
			}
		}

		// add edges leading to the target entities from the cell
		for (Entry<String, ? extends Entity> entry : cell.getTarget().entries()) {
			edges.add(new Edge(cell, entry.getValue(), entry.getKey()));
		}
	}

}