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/*
 * This file is part of GraphStream .
 *
 * GraphStream is a library whose purpose is to handle static or dynamic
 * graph, create them from scratch, file or any source and display them.
 *
 * This program is free software distributed under the terms of two licenses, the
 * CeCILL-C license that fits European law, and the GNU Lesser General Public
 * License. You can  use, modify and/ or redistribute the software under the terms
 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
 * URL  or under the terms of the GNU LGPL as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
 */

/**
 * @author Hicham Brahimi 
 * @author Yoann Pigné 
 * @since 2017-11-08
 */
package org.graphstream.util;

import org.graphstream.graph.Graph;
import org.graphstream.ui.view.Viewer;

public interface Display {
	/**
	 * Try to get the default display according to the "org.graphstream.ui" property.
	 * 
	 * It will look for three class candidates:
	 * 1. name defined in the property;
	 * 2. #1 one with a ".util.Display" suffix;
	 * 3. #2 one with a "org.graphstream.ui." prefix.
	 * 
	 * If the property is not set, or if no valid candidate can be found, a {@link MissingDisplayException} will be
	 * thrown.
	 *
	 * @return the Display object linked to the UI property
	 * @throws MissingDisplayException if no Display can be found
	 */
	static Display getDefault() throws MissingDisplayException {
		String uiModule = System.getProperty("org.graphstream.ui");

		if (uiModule == null) {
			throw new MissingDisplayException("No UI package detected! "
					+ "Please use System.setProperty(\"org.graphstream.ui\") for the selected package.");
		} else {
			Display display = null;
			String[] candidates = { uiModule, uiModule + ".util.Display",
					"org.graphstream.ui." + uiModule + ".util.Display" };

			for (String candidate : candidates) {
				try {
					Class clazz = Class.forName(candidate);
					Object object = clazz.newInstance();

					if (object instanceof Display) {
						display = (Display) object;
						break;
					}
				} catch (ClassNotFoundException e) {
					continue;
				} catch (Exception e) {
					throw new RuntimeException("Failed to create object", e);
				}
			}

			if (display == null) {
				throw new MissingDisplayException("No valid display found. "
						+ "Please check your System.setProperty(\"org.graphstream.ui\") statement.");
			} else {
				return display;
			}
		}
	}

	Viewer display(Graph graph, boolean autoLayout);
}