public class DiagSeqEditPartProvider extends AbstractEditPartProvider {
    @Override
    protected Class getNodeEditPartClass(View view) {
        if (view.getElement() instanceof CustomStyle) {
            CustomStyle customStyle = (CustomStyle) view.getElement();
            if (customStyle.getId().equals(DiagSeqConstants.INSTANCE_ROLE_STYLE_ID)) {
                return InstanceRoleStyleEditPart.class;
            }
        }
        return super.getNodeEditPartClass(view);
    }
}

package org.eclipse.gmf.runtime.diagram.ui.editparts;

import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.ImageFigure;
import org.eclipse.draw2d.XYLayout;
import org.eclipse.gef.DragTracker;
import org.eclipse.gef.Request;
import org.eclipse.gmf.runtime.gef.ui.figures.DefaultSizeNodeFigure;
import org.eclipse.gmf.runtime.gef.ui.figures.NodeFigure;
import org.eclipse.gmf.runtime.notation.View;
import org.eclipse.sirius.diagram.CustomStyle;
import org.eclipse.sirius.diagram.DNode;
import org.eclipse.sirius.diagram.ui.edit.api.part.AbstractNotSelectableShapeNodeEditPart;
import org.eclipse.sirius.diagram.ui.edit.api.part.IStyleEditPart;
import org.eclipse.sirius.diagram.ui.tools.api.figure.AirStyleDefaultSizeNodeFigure;
import org.eclipse.sirius.viewpoint.SiriusPlugin;

public class InstanceRoleStyleEditPart extends AbstractNotSelectableShapeNodeEditPart
implements IStyleEditPart
{

    /**
     * the content pane.
     */
    protected IFigure contentPane;

    /**
     * the primary shape.
     */
    protected ImageFigure primaryShape;

    /**
     * Create a new {@link ChangingImageEditPart}.
     *
     * @param view
     *            the view.
     */
    public InstanceRoleStyleEditPart(View view) {
        super(view);
    }

    public DragTracker getDragTracker(Request request) {
        return getParent().getDragTracker(request);
    }

    protected NodeFigure createNodeFigure() {
        NodeFigure figure = createNodePlate();
        figure.setLayoutManager(new XYLayout());
        IFigure shape = createNodeShape();
        figure.add(shape);
        contentPane = setupContentPane(shape);
        return figure;
    }

    private NodeFigure createNodePlate() {
        DefaultSizeNodeFigure result = new AirStyleDefaultSizeNodeFigure(getMapMode().DPtoLP(40), getMapMode().DPtoLP(40));
        return result;
    }

    /**
     * Create the instance role figure.
     *
     * @return the created figure.
     */
    protected ImageFigure createNodeShape() {
        if (primaryShape == null) {
            primaryShape = new ImageFigure();
        }
        return primaryShape;
    }

    /**
     * Return the instance role figure.
     *
     * @return the instance role figure.
     */
    public ImageFigure getPrimaryShape() {
        return primaryShape;
    }

    /**
     * Default implementation treats passed figure as content pane. Respects
     * layout one may have set for generated figure.
     *
     * @param nodeShape
     *            instance of generated figure class
     * @return the figure
     */
    protected IFigure setupContentPane(IFigure nodeShape) {
        return nodeShape; // use nodeShape itself as contentPane
    }

    public IFigure getContentPane() {
        if (contentPane != null) {
            return contentPane;
        }
        return super.getContentPane();
    }

    protected void refreshVisuals() {
        CustomStyle customStyle = (CustomStyle) this.resolveSemanticElement();
        if (customStyle.eContainer() instanceof DNode) {
            this.getPrimaryShape().setImage(SiriusPlugin.getDefault().getBundleImage((DNode) customStyle.eContainer()).getName());
        }
    }

    protected void createDefaultEditPolicies() {
        // empty.
    }
}

@Override
    protected void refreshVisuals() {
        CustomStyle customStyle = (CustomStyle) this.resolveSemanticElement();
        if (customStyle.eContainer() instanceof DNode) {
            ImageDescriptor imageDescriptorFromPlugin = AbstractUIPlugin.imageDescriptorFromPlugin(Activator.PLUGIN_ID, "/icons/myIcon.png");
            this.getPrimaryShape().setImage(imageDescriptorFromPlugin.createImage());
        }
    }

String EMPLOYEE_ID="EMPLOYEE_ID"