java8 从命令式到函数式的转变

Question

以下是我的命令式代码风格

for (int i = 1; i <= sundayOpenAreas.size(); i++) {
    String area = sundayOpenAreas.get(i - 1);
    String postcode = "XX" + i + " 1AA";

    boolean sundayDeliveryAvailable = sundayDeliveryAvailable(area, postcode);
    Assert.assertTrue(sundayDeliveryAvailable, area + " should accept deliveries on Sunday to " + postcode + "!");
    System.out.println(area + ", " + postcode);
}

想转换为函数式风格的 java8 流，以下是到目前为止的尝试

 IntStream.range(0, sundayOpenAreas.size())
        .forEach(
                idx -> {
                    sundayOpenAreas.stream()
                            .map(x -> "XX" + idx + "".concat("1AA"))
                            //Struck here on how to proceed
                    //System.out.println(abc);
                });

哪里sundayOpenAreas is List<String>

Answer 1

首先，我认为您应该坚持命令式方法，因为管道中需要多个变量。

我会试一试:

IntStream.range(0, sundayOpenAreas.size())
    .mapToObj(i -> new String[] { sundayOpenAreas.get(i), "XX" + i + " 1AA" })
    .peek(s -> Assert.assertTrue(sundayDeliveryAvailable(s[0], s[1]),
        s[0] + " should accept deliveries on Sunday to " + s[1] + "!"))
    .forEachOrdered(s -> System.out.println(s[0] + ", " + s[1]));