将Clojure的map以vector为key转换成java HashMap

Question

我们正在将一些业务逻辑从 Clojure 迁移到 Java。 目前我正在研究 2 种方法，但我在第 2 种方法上遇到了问题。

第一个是 - 我相信 - 将映射转换为向量，但只包括我们为其提供键的值（并删除空值）。

(defn- spec-vec [tags-with-classification & tag-types]
  (into [] (remove nil? (map tags-with-classification tag-types))))

这就是我将它翻译成 Java 代码的方式：

    private List<String> specVec(Map<String, String> tagsWithClassification, List<String> tagTypes) {
        List<String> list = new ArrayList<>();
        for (String tagType : tagTypes) {
            String value = tagsWithClassification.get(tagType);
            if (value != null) {
                list.add(value);
            }
        }
        return list;
    }

我发布这个，因为它用于另一种方法，但我可能误解了它的作用。

另一个映射以字符串向量作为键，字符串作为值，但也有一些与过滤键相关的逻辑，但我已经猜对了那部分 - 我想。

这是到目前为止我得到的 java 代码，但我一直在思考如何以一种很好的方式将此映射转换为 HashMap（因为 ArrayList/LinkedList 不是很好的建议，用作 HashMap 中的键）。 或者我应该使用完全不同的方法/不同的结构？ 提前致谢 ：）

注意：只能返回 5 个（4 个不同的字符串和 null）可能的值。

第二种Java方法：

    private String bookingModelFor(Map<String, String> tagsWithClassification, List<String> tagTypes) {
        List<String> tagNames = new ArrayList<>(Arrays.asList("event", "product", "client-trade-direction", "r-factor-direction"));
        List<String> filteredTagValues = specVec(tagsWithClassification, tagNames);
        filteredTagValues.addAll(tagTypes);
        /*
        missing part
         */
        return null;
    }

第二个Clojure函数：

(defn booking-model-for [tags-with-classification & tag-types]
  (get {[:trade :goal :increase :vanilla]                              "Astrid"
        [:trade :goal :decrease :vanilla]                              "Maja"
        [:trade :bloc :increase :vanilla]                              "Isabelle"
        [:trade :bloc :decrease :vanilla]                              "Luna"
        [:trade :perles-plus :increase :call]                          "Astrid"
        [:trade :perles-plus :increase :put]                           "Luna"
        [:trade :perles-plus :increase :kickout]                       "Astrid"
        [:trade :perles-plus :decrease :call]                          "Maja"
        [:trade :perles-plus :decrease :put]                           "Isabelle"
        [:trade :perles-plus :decrease :kickout]                       "Maja"
        [:trade :reverse-perles-plus :increase :call]                  "Astrid"
        [:trade :reverse-perles-plus :increase :put]                   "Luna"
        [:trade :reverse-perles-plus :increase :kickout]               "Astrid"
        [:trade :reverse-perles-plus :decrease :call]                  "Maja"
        [:trade :reverse-perles-plus :decrease :put]                   "Isabelle"
        [:trade :reverse-perles-plus :decrease :kickout]               "Maja"
        [:trade :kig :increase :put]                                   "Astrid"
        [:trade :kig :increase :kickout]                               "Maja"
        [:trade :kig :decrease :put]                                   "Maja"
        [:trade :kig :decrease :kickout]                               "Astrid"
        [:expire :goal :decrease :vanilla]                             "Maja"
        [:expire :bloc :decrease :vanilla]                             "Luna"
        [:expire :kig :decrease :put]                                  "Maja"
        [:expire :kig :decrease :kickout]                              "Astrid"
        [:expire :perles-plus :increase :put]                          "Maja"
        [:expire :perles-plus :increase :call]                         "Isabelle"
        [:expire :perles-plus :increase :kickout]                      "Isabelle"
        [:expire :reverse-perles-plus :increase :put]                  "Maja"
        [:expire :reverse-perles-plus :increase :call]                 "Isabelle"
        [:expire :reverse-perles-plus :increase :kickout]              "Isabelle"
        [:barrier-breach :kig :kickout]                                "Astrid"
        [:barrier-breach :perles-plus :kickout]                        "Astrid"
        [:share-adjustment :goal :r-factor>=1 :vanilla]                "Maja"
        [:share-adjustment :goal :r-factor<1 :vanilla]                 "Astrid"
        [:share-adjustment :bloc :r-factor>=1 :vanilla]                "Luna"
        [:share-adjustment :bloc :r-factor<1 :vanilla]                 "Isabelle"
        [:share-adjustment :kig :r-factor>=1 :put]                     "Maja"
        [:share-adjustment :kig :r-factor>=1 :kickout]                 "Astrid"
        [:share-adjustment :kig :r-factor<1 :put]                      "Astrid"
        [:share-adjustment :kig :r-factor<1 :kickout]                  "Maja"
        [:share-adjustment :perles-plus :r-factor>=1 :call]            "Astrid"
        [:share-adjustment :perles-plus :r-factor>=1 :put]             "Luna"
        [:share-adjustment :perles-plus :r-factor>=1 :kickout]         "Astrid"
        [:share-adjustment :perles-plus :r-factor<1 :call]             "Maja"
        [:share-adjustment :perles-plus :r-factor<1 :put]              "Isabelle"
        [:share-adjustment :perles-plus :r-factor<1 :kickout]          "Maja"
        [:share-adjustment :reverse-perles-plus :r-factor>=1 :call]    "Astrid"
        [:share-adjustment :reverse-perles-plus :r-factor>=1 :put]     "Luna"
        [:share-adjustment :reverse-perles-plus :r-factor>=1 :kickout] "Astrid"
        [:share-adjustment :reverse-perles-plus :r-factor<1 :call]     "Maja"
        [:share-adjustment :reverse-perles-plus :r-factor<1 :put]      "Isabelle"
        [:share-adjustment :reverse-perles-plus :r-factor<1 :kickout]  "Maja"}
       (into (spec-vec tags-with-classification :event :product :client-trade-direction :r-factor-direction) tag-types)))

以下是一些帮助我进行迁移的测试用例：

第一个功能的测试：

(deftest spec-vec-test
  (is (= [] (#'ksm.build.transform.neds/spec-vec nil)))
  (is (= [:trade :goal 1] (#'ksm.build.transform.neds/spec-vec {:a :trade :b :goal :c :decrease :d :vanilla :e 1} :a :b :e))))

测试第二个功能：

       (deftest booking-model-for-test
  (is (nil? (#'ns/booking-model-for {})))
  (is (nil? (#'ns/booking-model-for {:a 1 :b 2 :c 3} :d :e)))
  (is (= "Maja"
         (#'ns/booking-model-for {:event :trade :product :goal :client-trade-direction :decrease :r-factor-direction :vanilla})))
  (is (= "Isabelle"
         (#'ns/booking-model-for {:event :expire :product :reverse-perles-plus :client-trade-direction :increase :r-factor-direction :kickout})))
  (is (= "Luna"
         (#'ns/booking-model-for {:event :share-adjustment :product :reverse-perles-plus :client-trade-direction :r-factor>=1 :r-factor-direction :put}))))

Answer 1

我认为这些标签的顺序并不重要。 在这种情况下，您不能比遗留代码做得更好。 看到这个

https://cs.stackexchange.com/questions/14208/set-combination-data-structure-and-storage-complexity

您可以将关键字替换为常规字符串，并且您可以使用 Set 而不是 List 作为键。 此外，由于这是常量数据，将查找表存储在static成员中以避免在每次调用时重新创建它。 例如。

class A {
    static Map<Set<String>, String> lut = new HashMap<Set<String>, String>() {{
        put(new HashSet<String>(Arrays.asList("x", "y")), "foo");
        put(new HashSet<String>(Arrays.asList("x", "y", "z")), "bar");
    }};
    public static void main(String[] args) {
        System.out.println(lut.get(new HashSet<String>(Arrays.asList("x", "y"))));
    }
}