private void addToStringMethod(ClassOutline co,
JClass delegateImpl,
JFieldRef toStringDelegateStyleParam) {
final JDefinedClass implementation = co.implClass;
final JMethod toStringMethod = implementation.method(JMod.PUBLIC, String.class, "toString");
final JInvocation invoke = delegateImpl.staticInvoke("valueOf");
invoke.arg(JExpr._this());
invoke.arg(toStringDelegateStyleParam);
toStringMethod.body()._return(invoke);