Graph drawing using ZEST framework when button pressed, not working?

Question

I am trying to draw a graph using the ZEST framwework in JAVA. The intended work of code is as follows:

1) Shell is set to FormLayout.
2) Added a label, textbox, and a button using FormData customization.
3) Added a composite on the right of button (the one with the border).
4) Added a listener to the button
5) When the button is pressed, a graph with three nodes, "Rock", "Paper" and Scissors should be created on the composite to the right of the button. (confined to the composite only).

But the graph is not getting displayed.

Please assist me in finding out the bug. Thanks in advance.

    import java.io.FileNotFoundException;
    import java.io.IOException;

    import org.eclipse.swt.SWT;
    import org.eclipse.swt.events.DisposeEvent;
    import org.eclipse.swt.events.DisposeListener;
    import org.eclipse.swt.graphics.Font;
    import org.eclipse.swt.graphics.FontData;
    import org.eclipse.swt.layout.FormAttachment;
    import org.eclipse.swt.layout.FormData;
    import org.eclipse.swt.layout.FormLayout;
    import org.eclipse.swt.widgets.Button;
    import org.eclipse.swt.widgets.Composite;
    import org.eclipse.swt.widgets.Display;
    import org.eclipse.swt.widgets.Event;
    import org.eclipse.swt.widgets.Label;
    import org.eclipse.swt.widgets.Listener;
    import org.eclipse.swt.widgets.Shell;
    import org.eclipse.swt.widgets.Text;
    import org.eclipse.zest.core.widgets.Graph;
    import org.eclipse.zest.core.widgets.GraphConnection;
    import org.eclipse.zest.core.widgets.GraphNode;
    import org.eclipse.zest.layouts.LayoutStyles;
    import org.eclipse.zest.layouts.algorithms.SpringLayoutAlgorithm;

    public class Demo{
        public static void main(String[] args) throws FileNotFoundException, IOException {
            Display display = new Display();
            final Shell shell = new Shell(display);
            shell.setText("Demo Map");

            FormLayout formLayout= new FormLayout();
            shell.setLayout(formLayout);

            //Label
            Label label = new Label(shell, SWT.NONE);
            label.setText("TEXT:");
            FontData[] fontData = label.getFont().getFontData();
            for(int i = 0; i < fontData.length; ++i)
                fontData[i].setHeight(12);

            final Font newFont = new Font(display, fontData);
            label.setFont(newFont);
            FormData formData= new FormData();
            formData.top= new FormAttachment(0, 6);
            formData.left= new FormAttachment(0,5);
            label.setLayoutData(formData);

            //Listener for font object(we created it, so we dispose it)
            label.addDisposeListener(new DisposeListener() {
                public void widgetDisposed(DisposeEvent e) {
                    newFont.dispose();
                }
            });

            //Text BOX

            final Text textBox= new Text(shell, SWT.NONE);
            FormData textData = new FormData();
            textData.top= new FormAttachment(0, 8);
            textData.left= new FormAttachment(label, 10);
            textData.height= 20;
            textData.width= 200;
            textBox.setFont(newFont);
            textBox.setLayoutData(textData);

            //Button

            Button button = new Button(shell, SWT.PUSH);
            button.setText("Enter");
            FormData buttonData= new FormData();
            buttonData.top= new FormAttachment(0,5);
            buttonData.left= new FormAttachment(textBox, 10);
            buttonData.height= 25;
            buttonData.width=50;
            button.setLayoutData(buttonData);


            //Composite to hold the graph visual

            final Composite composite = new Composite(shell, SWT.BORDER);
            FormData compositeFormData= new FormData();
            compositeFormData.top = new FormAttachment(0,5);
            compositeFormData.left = new FormAttachment(button,15);
            compositeFormData.right= new FormAttachment(100,-10);
            compositeFormData.bottom= new FormAttachment(100,-10);
            composite.setLayoutData(compositeFormData);


            //drawNodes on button press
            button.addListener(SWT.Selection, new Listener() {
                public void handleEvent(Event e) {
                    switch (e.type) {
                    case SWT.Selection:
                    System.out.println("Button pressed");
                    Graph g = new Graph(composite, SWT.NONE);
                    GraphNode n = new GraphNode(g, SWT.NONE, "Paper");
                    GraphNode n2 = new GraphNode(g, SWT.NONE, "Rock");
                    GraphNode n3 = new GraphNode(g, SWT.NONE, "Scissors");
                    new GraphConnection(g, SWT.NONE, n, n2);
                    new GraphConnection(g, SWT.NONE, n2, n3);
                    new GraphConnection(g, SWT.NONE, n3, n);
                    g.setLayoutAlgorithm(new SpringLayoutAlgorithm(LayoutStyles.NO_LAYOUT_NODE_RESIZING), true);
                    break;
                    }
                }
                });



            shell.open();
            while(!display.isDisposed()){
                if(!display.readAndDispatch()){
                    display.sleep();
                }
            }
            display.dispose();
        }


    }

Answer 1

I think the problem is in the fact that Graphs can be drawn only on FillLayout. As you can see in example, they use FillLayout, not FormLayout.