org.graphstream.stream.net.URLSource Maven / Gradle / Ivy

/*
 * 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.
 */

/**
 * @since 2009-04-17
 * 
 * @author Yoann Pigné 
 * @author Antoine Dutot 
 * @author Guilhelm Savin 
 * @author Hicham Brahimi 
 */
package org.graphstream.stream.net;

import java.io.IOException;
import java.net.URL;

import org.graphstream.stream.Source;

/**
 * Graph event input source from an URL.
 */
public interface URLSource extends Source {
	/**
	 * Read the whole URL in one big non-interruptible operation.
	 * 
	 * @param url
	 *            The URL to fetch.
	 * @throws IOException
	 *             If an I/O error occurs while fetching the URL.
	 */
	void fetchAll(URL url) throws IOException;

	/**
	 * Begin fetching the URL stopping as soon as possible. Next graph events from
	 * the URL will be send by calling {@link #nextEvents()}. Once begin() as been
	 * called, you must finish the reading process using {@link #end()}. You cannot
	 * call begin() twice without having called {@link #end()} in between.
	 * 
	 * @param url
	 *            The URL to fetch.
	 * @throws IOException
	 *             If an I/O error occurs while reading.
	 */
	void begin(URL url) throws IOException;

	/**
	 * Try to process one graph event, or as few as possible, if more must be read
	 * at once. For this method to work, you must have called {@link #begin(URL)}.
	 * This method return true while there are still events to read.
	 * 
	 * @return true if there are still events to read, false as soon as the file is
	 *         finished.
	 * @throws IOException
	 *             If an I/O error occurs while reading.
	 */
	boolean nextEvents() throws IOException;

	/**
	 * Finish the reading process (even if {@link #nextEvents()} did not returned
	 * false). You must call this method after reading.
	 * 
	 * @throws IOException
	 *             If an I/O error occurs while closing the file.
	 */
	void end() throws IOException;
}