public class MyDslXtextSourceViewer extends XtextSourceViewer {

	public MyDslXtextSourceViewer(Composite parent, IVerticalRuler ruler,
			IOverviewRuler overviewRuler, boolean showsAnnotationOverview,
			int styles) {
		super(parent, ruler, overviewRuler, showsAnnotationOverview, styles);
	}
	
	@Override
	protected IDocumentAdapter createDocumentAdapter() {
		// TODO return your adapter instance
		return super.createDocumentAdapter();
	}

}

public class MyDslXtextSourceViewerFactory implements XtextSourceViewer.Factory {
	
	public XtextSourceViewer createSourceViewer(Composite parent,
			IVerticalRuler ruler, IOverviewRuler overviewRuler,
			boolean showsAnnotationOverview, int styles) {
		return new MyDslXtextSourceViewer(parent, ruler, overviewRuler, showsAnnotationOverview, styles);
	}

}

public Class<? extends XtextSourceViewer.Factory> bindXtextSourceViewer$Factory() {
		return MyDslXtextSourceViewerFactory.class;
	}