private boolean hasNoCorsAccessControlAllowOrigin(ApiResponse response) {
        return !response.getHeaders().containsKey("Access-Control-Allow-Origin");
    }
Returns true if the Access-Control-Allow-Origin is not present.

@param response the ApiResponse
@return true if has no Access-Control-Allow-Origin header, else false
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/http/HttpPolicyAdapter.java