private void generateEdge(PrintStream out, Relationship relationship) {
        out.println("    edge [");
        out.println("               shape = \"edge\"");
        out.println("                 dir = \"both\"");
        out.println("               style = \"" + lineStyle2Dot(relationship.getLineStyle()) + "\"");
        out.println("           arrowtail = \"" + decoration2Dot(relationship.leftEndPoint().getDecoration()) + "\"");
        out.println("           arrowhead = \"" + decoration2Dot(relationship.rightEndPoint().getDecoration()) + "\"");
        out.println("           taillabel = \"" + formatEdgeLabel(relationship.leftEndPoint().getLabel()) + "\"");
        out.println("           headlabel = \"" + formatEdgeLabel(relationship.rightEndPoint().getLabel()) + "\"");
        out.println("       labeldistance = " + edgeLabelDistance);
        out.println("            fontsize = " + edgeFontSize);
        out.println("            fontname = \""+ fontName + "\"");
        if(relationship.hasStyle("minlen")) {
        out.println("              minlen = "+ relationship.getStyle("minlen"));
        }
        if(relationship.hasStyle("len")) {
        out.println("                 len = "+ relationship.getStyle("len"));
        }
        out.println("    ];");
        out.println("    N" + id2Int(relationship.leftEndPoint()) + " -> N" + id2Int(relationship.rightEndPoint()));
    }