private RequestContext getRequestContext(String reqTradeAppr, String reqCreditAppr, int buyPrice) throws Exception {
final RequestType request = new RequestType();
request.getSubject().add(createSubject(reqTradeAppr, reqCreditAppr, buyPrice));
request.getResource().add(createResource());
request.setAction(createAction());
request.setEnvironment(new EnvironmentType());
final RequestContext requestCtx = RequestResponseContextFactory.createRequestCtx();
requestCtx.setRequest(request);
return requestCtx;