public static TypedFunctionExecutor forClass()

in invoker/core/src/main/java/com/google/cloud/functions/invoker/TypedFunctionExecutor.java [37:80]

40 lines of code
5 McCabe index (conditional complexity)


  public static TypedFunctionExecutor forClass(Class<?> functionClass) {
    if (!TypedFunction.class.isAssignableFrom(functionClass)) {
      throw new RuntimeException(
          "Class "
              + functionClass.getName()
              + " does not implement "
              + TypedFunction.class.getName());
    }
    @SuppressWarnings("unchecked")
    Class<? extends TypedFunction<?, ?>> typedFunctionClass =
        (Class<? extends TypedFunction<?, ?>>) functionClass.asSubclass(TypedFunction.class);

    Optional<Type> argType = handlerTypeArgument(typedFunctionClass);
    if (argType.isEmpty()) {
      throw new RuntimeException(
          "Class "
              + typedFunctionClass.getName()
              + " does not implement "
              + TypedFunction.class.getName());
    }

    TypedFunction<?, ?> typedFunction;
    try {
      typedFunction = typedFunctionClass.getDeclaredConstructor().newInstance();
    } catch (Exception e) {
      throw new RuntimeException(
          "Class "
              + typedFunctionClass.getName()
              + " must declare a valid default constructor to be usable as a strongly typed"
              + " function. Could not use constructor: "
              + e.toString());
    }

    WireFormat format = typedFunction.getWireFormat();
    if (format == null) {
      format = LazyDefaultFormatHolder.defaultFormat;
    }

    @SuppressWarnings("unchecked")
    TypedFunctionExecutor executor =
        new TypedFunctionExecutor(
            argType.orElseThrow(), (TypedFunction<Object, Object>) typedFunction, format);
    return executor;
  }