File reading example doesn't work

[matwell-dev]

The example here: https://graphstream-project.org/doc/Tutorials/Reading-files-using-FileSource/ doesn't work. The construction of the file-source can throws an IOException.

Also, not a bug, but the example might as well display the constructed graph (I've defaulted it to Swing as a lowest-common denominator, as per some of the other examples), so I've added the code for that and tightened up the clean-up code in the case of an exception and the FileSource not being constructed.

At the risk of over-engineering an example, I might also have added only initialising the UI choice if not already defined, and also taking a list of (at least one) file-name parameters and processing them from the command-line, but it's your code! :o)

import org.graphstream.graph.Graph;
import org.graphstream.graph.implementations.DefaultGraph;
import org.graphstream.stream.file.FileSource;
import org.graphstream.stream.file.FileSourceFactory;

import java.io.IOException;

public class TutorialFileSource {

public static void main(String ... args) {
	String filePath = "<<<YOUR-FILENAME-HERE>>>";

	System.setProperty("org.graphstream.ui", "swing");

	Graph g = new DefaultGraph("g");
	FileSource fs = null;

	try {
		fs = FileSourceFactory.sourceFor(filePath);

		fs.addSink(g);

		fs.begin(filePath);

		while (fs.nextEvents()) {
			// Optionally some code here ...
		}

		g.display();

	} catch( IOException e) {
		e.printStackTrace();
	}

	try {
		if (fs != null) fs.end();
	} catch( IOException e) {
		e.printStackTrace();
	} finally {
		if (fs != null) fs.removeSink(g);
	}
}

}