private static LambdaRequestHandler wrapRequestHandlerClass()

in aws-lambda-java-runtime-interface-client/src/main/java/com/amazonaws/services/lambda/runtime/api/client/EventHandlerLoader.java [266:311]

42 lines of code
11 McCabe index (conditional complexity)


    private static LambdaRequestHandler wrapRequestHandlerClass(final Class<? extends RequestHandler> clazz) {
        Type[] ptypes = findInterfaceParameters(clazz, RequestHandler.class);
        if (ptypes == null) {
            return new UserFaultHandler(makeUserFault("Class "
                    + clazz.getName()
                    + " does not implement RequestHandler with concrete type parameters"));
        }
        if (ptypes.length != 2) {
            return new UserFaultHandler(makeUserFault(
                    "Invalid class signature for RequestHandler. Expected two generic types, got " + ptypes.length));
        }

        for (Type t : ptypes) {
            if (t instanceof TypeVariable) {
                Type[] bounds = ((TypeVariable) t).getBounds();
                boolean foundBound = false;
                if (bounds != null) {
                    for (Type bound : bounds) {
                        if (!Object.class.equals(bound)) {
                            foundBound = true;
                            break;
                        }
                    }
                }

                if (!foundBound) {
                    return new UserFaultHandler(makeUserFault("Class " + clazz.getName()
                            + " does not implement RequestHandler with concrete type parameters: parameter "
                            + t + " has no upper bound."));
                }
            }
        }

        final Type pType = ptypes[0];
        final Type rType = ptypes[1];

        final Constructor<? extends RequestHandler> constructor;
        try {
            constructor = getConstructor(clazz);
            return wrapPojoHandler(newInstance(constructor), pType, rType);
        } catch (UserFault f) {
            return new UserFaultHandler(f);
        } catch (Throwable e) {
            return new UserFaultHandler(makeUserFault(e));
        }
    }